Shed heating ornament

[Gerbilsquasher]

After a loooooonnnnngggg time I have finally found motivation to finish my shed pot belly.... or did I finally realise that moving to a higher altitude it gets a bit colder in the shed at night?

Here is a mock up of the parts which have been compulsorily acquired thus far:

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The basis is a couple of brake drums off a prime mover. The other basic parts are a ring which sits in between the two drums and a plate to cover the holes top and bottom, and some way to get rid of the smoke. Mine is somewhat more elaborate because I have access to CNC lasers and as with everything I make, it has to have extra '#### factor' :D

269898
I am attaching the top and bottom plates with 'rivets' made from some laser cut washers and short lengths of 20.0mm merchant bar. These are pushed through from inside and are plug welded to the plate on the outside. Plate has the same PCD as the brake drum.
269900
The 20.0mm merchant bar has to machined down to about 19.0mm to fit through the holes in the brake drums.

I will post further updates as I progress.

I realise that this is nothing new to some of you guys... but these things are so easy to build I thought I might throw it up here for those who haven't seen it done before.

The simplest design I have seen has only one bolt on the 'lid' which acts like a pivot. The lid is moved sideways to open the top of the stove to throw in the wood.

As stated in the title of the thread, this is a 'shed heating ornament'. No doubt you will suffer the wrath of OHS pedants and tree huggers if you actually start a fire inside the thing. What you do after it is constructed in the privacy of your own home is entirely your business..... :wink:

[Oldneweng]

I will keep watching to see how you get on. I have a couple of tractor rims that are slightly bigger than the brake drums which are to be used for the same purpose one day. Mine will be a bit too big for the shed I think. Never get in to the shed with it going anyway.

Dean

[.RC.]

Very nice, I need to make something like that, why just the other day it got under 20C in the shed and was freezing..

[eskimo]

Very nice, I need to make something like that, why just the other day it got under 20C in the shed and was freezing..

keep your eyes off it...its mine.

where does one look to get the brake drums at a cheap price?

[bollie7]

G.S
I noticed you use the term "merchant bar" which is one I haven't come across before. Can you explain please? I'm assuming its what we, in the backward northern states,:) call "black bar" but I might be wrong. (apparently I am, quite frequently.:rolleyes:)

bollie7

[argeng]

Made a similar unit with the intention of it going into the workshop, but it ended up outside as I had to remove 100 cubic mtrs of dirt/rock from under the house to fit the work shop in. Never did get around to getting permission from the wife to relocate it.

Cheers Bruce

[Stustoys]

Looking good so far.

Can't imagine the hoops I'd have to jump through to get that in my shed.

I have a little gas "jet" heater for my shed, works great but has little "Charm", the noise it makes doesnt do a lot for the serenity, costs about $3.50 an hour to run and you cant heat anything up on/in it.

Still I guess the up side is you wont leave your finger prints on it either ;)

Stuart

[Ueee]

Very nice, I need to make something like that, why just the other day it got under 20C in the shed and was freezing..

How did you cope?

I put an old pot belly in. We had a -4 here on Monday morning, there was ice already formed on the cars at 7 on Sunday evening. You would think all the hot air coming from parliament would keep it warmer than that.....

Cheers
Ew

[anglesmith]

bollie7, I've used the term merchant bar for last 20 years or so, to describe the lowest grade common (black) steel bar or rod, what we use to call "mild steel." The modern "merchant' bar isn't mild any more as I think it is higher in carbon and other alloys from being made from scrap in Mini mills? but what I do know is it that will harden if quenched from a red heat after forging, something that the old mild steel wouldn't do! t Graeme

[bollie7]

bollie7, I've used the term merchant bar for last 20 years or so, to describe the lowest grade common (black) steel bar or rod, what we use to call "mild steel." The modern "merchant' bar isn't mild any more as I think it is higher in carbon and other alloys from being made from scrap in Mini mills? but what I do know is it that will harden if quenched from a red heat after forging, something that the old mild steel wouldn't do! t Graeme
GraemeT
There you go, Thats my "learnt something new for day" moment. Thanks for enlightening me.
regards
bollie7

[rascal]

Eskimo and anyone else,
I have plenty of truck brake drums available for pickup in Melbourne or Adelaide.
PM me with your needs.Free.
John

[cava]

Eskimo and anyone else,
I have plenty of truck brake drums available for pickup in Melbourne or Adelaide.
PM me with your needs.Free.
John

What part of Melbourne? ie North, south, east or west.

[rascal]

Derrimut or Regency Park

[cava]

Derrimut or Regency Park

Thank you. Too far for me.

[DJ’s Timber]

Thank you. Too far for me.

I should be able to get some for you and possibly drop them off somewhere near to you, was actually down your way the other day.

[argeng]

Geez DJ you are a nice bloke.
Cheers Bruce

[DJ’s Timber]

Geez DJ you are a nice bloke.
Cheers Bruce

Dunno about that Bruce, quite few people I know wouldn't agree with that, have been called an ugly fella a few times :q

[argeng]

As Gerbilsquasher has done, a good size flue is required to get the setup to draw well, I only cut in a 3" pipe which was not out the top, but just out the rear, not quite big enough. I also put a baffle in the flue, theory being to dampen down the fire.It does really get going but at times you need to open the front door. Really should have a plate inside the combustion chamber to stop the heat going straight up the flue.

Welding the cast iron drums with the Mig was interesting, I known this is not how it should be done but time and do what you can works. Basically due to the difference in the properties of cast iron and the filler from the Mig they were never going to cool at the same rate. For a non structural weld it works. The first run between the drums will split down the middle, you now have 2 bonded substrates on the cast drums. Run another bead to join the 2, no probs. Have had the unit glowing red and the welds are fine.
It looked so good sprayed black, nice turned wooden handle for the front door opener. Now the elements have taken hold. I see a new project.

That is if the thumb allows me.
Went back to the Surgeon on Monday, took the Xrays that I had done the week before, as he mentioned, we will remove the wires next week. Didn't feel right, Monday I rock up and say well I am no expert but it looks like there is a big black line through my thumb, he looks at them and says, Wow there is a big black line through the fracture, maybe we shouldn't pull the wire out yet. Come back in 4 weeks, that makes 10 since I introduced it to the saw. Bugger is we fly out to Thailand on the next Saturday, looks like I will have the wires in on the trip. That will make 10 weeks the prospect of getting movement back in my thumb is slim. They are still talking about a bone graft , but as they said you will go on a list. So, do I have wires sticking out of my thumb for 6 months?? Time to look up a private plastic surgeon. I must say Red wine does wonders for smoothing out the worries. 3 hours at out patients!!!! When I got home my wife had a glass of wine on the table next to her, I said I thought we we no wine during the week, well you sounded a bit down on the phone, Luckly I had stopped at Dan's for a RED.

Sorry for the Blerb, many have more pressing issue., For me it is hard as I have gone from being very active, big Reno on the go plus ongoing house maintenance, to don't re fracture the thumb.

Well we do have this site/group.

PS Did pick up a nice Rega oil can at Wantirna Trash and Treasure, don't tell you know who.
Cheers Bruce

[Oldneweng]

Derrimut or Regency Park

Regency park sounds good for me. I might grab a couple if I can. I will be in Adelaide on 24th june and will be staying at prospect so just down the road. I might be able to make one that will fit in my shed.

Dean

[Ueee]

As Gerbilsquasher has done, a good size flue is required to get the setup to draw well, I only cut in a 3" pipe which was not out the top, but just out the rear, not quite big enough. I also put a baffle in the flue, theory being to dampen down the fire.It does really get going but at times you need to open the front door. Really should have a plate inside the combustion chamber to stop the heat going straight up the flue.


I have a 6" flue on the pot belly, it has a butterfly flap to close it mostly off. When full open the flue glows red in minutes from lighting......
The other thing that adds to the draw is the length of the flue, the longer the more draw.
And make sure birds can't get down the chimney....Squab is not so good feathers and all.....

Cheers
Ew

[TKO]

The cold weather came in quick so did my drum fire for the shed, light truck drums,and will have to keep a low fire going if I want to work in the shed,Should have made a smaller one,gets very hot very quick,

http://i1232.photobucket.com/albums/ff365/aussieddie/A30%20Car/ASE%20car/006-2.jpg.

Eddie

[fxst]

building one was on the books until a friend offered me a Metters No5 in near new condition for $100 inc the flue so guess what...yep 1 less job on the list. :U
Pete

[Gerbilsquasher]

Looks like these things aren't as 'ornamental' as I was thinking. Maybe if you try to sell these on a commercial basis you might get into trouble because they don't meet Australian Standards or have a 6-star energy rating. :oo:

Made a bit more progress on mine tonight. Machined up the fabricated 'rivets'....
270112
Merchant or black bar it is, cheap and nasty stuff, takes a lot of effort to get a decent surface finish on it and I wouldn't try to cut a decent thread in it. Even though it has been made from melted down Hyundais it should have enough tensile strength to hold the end plates on.

The 'rivets' are inserted from the inside. These particular drums seem to be a universal type which share both five and six holes on the same radius... so I made a total of ten 'rivets' for each of the top and bottom.

270113

Here I have poked the 'rivets' through from the inside of the drum and through the hole in the bottom plate and have started to tack the ends of the 'rivets' . It does help having an inside plate to support the other end of the 'rivet' to stop it from falling out... seem to have avoided a Tourette's relapse with a little bit of thinking...:D As shown in the photo, the length of the rivet has been 'sorta' calculated to be about 4-5 mm below the surface of the plate when clamped together.
270114

I kept the clamps on as I worked around the bottom plate with plug welds.
270115

All plug welds finished. I did it this way to try and avoid welding the mild steel plates to the cast iron brake drums... I wasn't sure how well they would mix!
270116

Unfortunately that is as far as I can get for a few days (work, kids, missus etc) but I should be able to start up again Monday night, and the goal is to get the stove working within two weeks... more to come...

[CMB]

I took care of the heat issue last winter. Considered brake drums to start with but went more elaborate.

6" flue, 1 1/2" fire sprinkler pipes with 2" outside intake for primary and secondary air sources (for secondary burn of fumes/smoke), fire brick lined, heavy duty grate for fire to sit on and hinged framed glass door. I have a 6mm steel plate baffle inside with additional stainless plates in flame path to minimise direct contact with the cut down 44 gallon drum (chopped 1/3 off). Front is completely removable for thorough cleaning and maintenance if required.

Managed to get the air supply/draw ratio balanced for maximum efficiency and so it is smokeless out the flue when up and running. Keeps my large unlined/uninsulated shed up to 10 degrees warmer than outside. Had a ball.

270135

Craig.

[rascal]

Heater builders,
There are 2 sizes of drum available,dimensions are on the drawing.
John.

[Oldneweng]

I have a 6" flue on the pot belly, it has a butterfly flap to close it mostly off. When full open the flue glows red in minutes from lighting......
The other thing that adds to the draw is the length of the flue, the longer the more draw.
And make sure birds can't get down the chimney....Squab is not so good feathers and all.....

Cheers
Ew

For those members that haven't been dealing with slow combustion heaters for most of their lives you should also know that too much flue causes too much draw and makes it hard to control the burn. You wont be able to reduce the heat. Try to keep to a max of 4 to 5 meters. Probably more than you were thinking anyway, but just in case someone decided to go all out.

Happy Heating

Dean

[Ueee]

Yeah, thanks for adding that Dean. My Uncle had some ridiculous length of flue on his pot belly on his old property. He use to delight in getting the whole thing glowing.....:no:
I think i have about 3.5m, its plenty actually i have been thinking i may shorten it. The rules here say if the flue is within 3m of the ridge it has to be at least 600mm above the ridge line, otherwise at least 1000mm above the roof. Not that our fires are used or approved......:rolleyes: They are just ornaments right? Mine was somewhat ornamentally warm today!

[Oldneweng]

Yeah, thanks for adding that Dean. My Uncle had some ridiculous length of flue on his pot belly on his old property. He use to delight in getting the whole thing glowing.....:no:
I think i have about 3.5m, its plenty actually i have been thinking i may shorten it. The rules here say if the flue is within 3m of the ridge it has to be at least 600mm above the ridge line, otherwise at least 1000mm above the roof. Not that our fires are used or approved......:rolleyes: They are just ornaments right? Mine was somewhat ornamentally warm today!

Glowing is good, if you want to impress your mates. Control is better. I think 3m or so should be fine. The reason for the warning about excess height is we had a setup that required 6m of flue and we were told to watch the result due to the length. Worked out ok but not really needed generally. If a long flue is needed sometimes a restriction may be required.

The top of the flue should be covered with a conical cap that is raised about 50mm or so above the top edge of the flue pipe with straps riveted/screwed on. The cone wider than the flue so it runs the water off. This can also keep the juvenile pidgeons out.

If you were serious you could make a water jacket to produce hot water so you could wash your hands before going inside to the family. Probably impress them no end.

I kept the door/surround off an old slow combustion stove from the lounge for inclusion in a future project. Glass door. Lovely view of a nice fire. Who wants to work anyway LOL.

Dean

[shedhappens]

If you were serious you could make a water jacket to produce hot water so you could wash your hands before going inside to the family. Probably impress them no end.
Dean

G/day Dean, at my last place the first section of flu was a water jacket type heater and it worked really well, the thing that ornamental heater builders have to remember is that ornamental water jacketed heaters work by thermosiphon and when the fire is out the water in the storage tank will be cooled by the heater unless you fit ornamental non return valves :D

[Oldneweng]

G/day Dean, at my last place the first section of flu was a water jacket type heater and it worked really well, the thing that ornamental heater builders have to remember is that ornamental water jacketed heaters work by thermosiphon and when the fire is out the water in the storage tank will be cooled by the heater unless you fit ornamental non return valves :D

Actually that is not totally correct. If the hot water storage is higher than the heating jacket there will be no movement of water after the fire goes out. Our hot water is supplied from a heating jacket in a slow combustion kitchen range. This is the only hot water heating we have. When the fire goes out the water stays hot. Design and layout is everything.

I have thought about making a flue jacket for our lounge heater to provide more water heating but it is not really needed. We have enough already.

Dean

[shedhappens]

Actually that is not totally correct. If the hot water storage is higher than the heating jacket there will be no movement of water after the fire goes out. Our hot water is supplied from a heating jacket in a slow combustion kitchen range. This is the only hot water heating we have. When the fire goes out the water stays hot. Design and layout is everything.

I have thought about making a flue jacket for our lounge heater to provide more water heating but it is not really needed. We have enough already.

Dean

That does surprise me Dean, in the last house I built I put the tank as high as I could get it in the roof and put the solar hot water panels as low as possible, ie near the gutter, these also had to be lower at one end that the other, the lowest point being the inlet and the highest point being the outlet to the hot water tank, these panels were supplied with non return valves to stop the water cooling at night and during ###### weather.
Then when I fitted the water jacketed flu heater I also fitted non return valves but I had problems with the hot water in the tank cooling somewhat through the day during inclement weather when the heater had gone out, when I noticed this I put I put my hand on the flu heater and it was quite warm ? So why was the water circulating through ?
Because I was a tight #### and fitted el cheepo non return valves, so I replaced them with good quality vavles ($180) and added much more insulation to the pipes between the water heater and the tank, problem fixed.

Cold water falls, hot water rises, that is how a thermosiphon hot water system works.

I would be interested to know why your system doesn't require non return valves ?
I'm thinking that your slow combustion stove is always burning so this problem might not be evident ?

shed

[Oldneweng]

That does surprise me Dean, in the last house I built I put the tank as high as I could get it in the roof and put the solar hot water panels as low as possible, ie near the gutter, these also had to be lower at one end that the other, the lowest point being the inlet and the highest point being the outlet to the hot water tank, these panels were supplied with non return valves to stop the water cooling at night and during ###### weather.
Then when I fitted the water jacketed flu heater I also fitted non return valves but I had problems with the hot water in the tank cooling somewhat through the day during inclement weather when the heater had gone out, when I noticed this I put I put my hand on the flu heater and it was quite warm ? So why was the water circulating through ?
Because I was a tight #### and fitted el cheepo non return valves, so I replaced them with good quality vavles ($180) and added much more insulation to the pipes between the water heater and the tank, problem fixed.

Cold water falls, hot water rises, that is how a thermosiphon hot water system works.

I would be interested to know why your system doesn't require non return valves ?
I'm thinking that your slow combustion stove is always burning so this problem might not be evident ?

shed

The thermosyphon system works by, as you say, hot water rising and cold water falling. When the fire is burning the hot water in the jacket gets hot and the water rises up to the tank thru the upper pipe (inlet). This lift pushes the slightly heavier cold water down the lower (outlet) pipe and back to the jacket. The system needs to be hotter at the bottom for a thermosyphon flow to occur. If it is hotter at the top the hot water wants to stay there.

When the fire is not burning the hot water is all at the top so to speak so there is no lift to move water. The water settles according to density. Cold at bottom and hot at top.

Our stove goes out all the time. We get lazy, surprisingly enough. Early this week it went out overnight (we slept in). It was lit again that night and the water was hot very quickly, as in the hot water was cycling around.

I know that if the heat source is higher than the storage tank then non return valves and a pump is required. I have seen every mm of our pipes except for the 6mm in the ceiling (asbestos sheet) and I can tell you that there are no non return valves there. Also I installed the piping to this stove when it was installed. The pipe was already there but needed a bit of adjustment to fit the new stove.

I have started making some solar hot water panels (some years ago) based on plans from an Earth Garden book (self sufficiency magazine). There is no mention of non return valves. The only time I have seen mention of non return valves is when the storage tank is lower than the collector panels.

I do not know why your flue jacket was cooling the water.

Dean

[Oldneweng]

Another point I just thought of is that the hot water storage tank is a thermosyphon system in itself. If the tank is full of "hot" water and the fire goes out and then some hot water is used:-

The remaining hot water will stay at the top of the tank
The new cold water fed in to replace the hot, will stay at the bottom.

Over time the temperature will even out but after 24 hrs we can have a shower and the water is still quite hot.

Dean

[Ueee]

Its got me stuffed to, were i grew up we had a rayburn that supplied all our hot water, plus heat, cooking etc. In summer we generally had to light it every 3 days to get hot water, in other words the water definitely didn't cool by syphoning back into the jacket. The tank was on a stand directly behind the stove (In a sort of cupboard, great place to grow mushrooms), that way any heat loss from the tank went into house heating.....
My current solar hot water system is the opposite, pump driven with check valves and a fancy "soft" valve, it stops the thermosyphon but will open when the pump comes on.
Dean, way OT but have you seen this site? Solar Water Heating Projects and Plans (http://builditsolar.com/Projects/WaterHeating/water_heating.htm#1KSolarWater)

Of course the other thing to do with hot water from the shed stove is pump it to a radiator on the other side of the shed......

Cheers,
Ew

[Oldneweng]

Its got me stuffed to, were i grew up we had a rayburn that supplied all our hot water, plus heat, cooking etc. In summer we generally had to light it every 3 days to get hot water, in other words the water definitely didn't cool by syphoning back into the jacket. The tank was on a stand directly behind the stove (In a sort of cupboard, great place to grow mushrooms), that way any heat loss from the tank went into house heating.....
My current solar hot water system is the opposite, pump driven with check valves and a fancy "soft" valve, it stops the thermosyphon but will open when the pump comes on.
Dean, way OT but have you seen this site? Solar Water Heating Projects and Plans (http://builditsolar.com/Projects/WaterHeating/water_heating.htm#1KSolarWater)

Of course the other thing to do with hot water from the shed stove is pump it to a radiator on the other side of the shed......

Cheers,
Ew

Thanks Ewan but I have seen that one and been through most of the designs. IIRC my design is represented in there. I have to get back to making those panels. It should save us having to light the stove in summer.

My grandparents had a Rayburn and our neigbours also have one. Both supplying hot water.

Some years ago SWMBO bought one cheapish. The top plate was stuffed. The rope grooves were rusted off. We did have some fun getting a Tiger Snake out from underneath it, on the back verandah while we had about 3 big pots of plum jam cooking up on various gas BBQ's etc. The jam did get slightly burnt.

Dean

[shedhappens]

I do not know why your flue jacket was cooling the water.

Dean

Dean there are a lot of variables when installing a thermosiphon hot water system, the position of heat source and the position of the storage tank are not always going to be perfect so you have to adapt and design your system around those problems.
Here is a document that can help explain "Reverse Thermosiphon" to you, http://solar1.mech.unsw.edu.au/glm/papers/reverse_flow_SE86.pdf
If you do go ahead with your solar hot water panels and want them to be efficient and reliable you will need non return valves, and no doubt frost valves if you have the problem of pipes and pumps freezing at certain times of the year.

shed

[Oldneweng]

Dean there are a lot of variables when installing a thermosiphon hot water system, the position of heat source and the position of the storage tank are not always going to be perfect so you have to adapt and design your system around those problems.
Here is a document that can help explain "Reverse Thermosiphon" to you, http://solar1.mech.unsw.edu.au/glm/papers/reverse_flow_SE86.pdf
If you do go ahead with your solar hot water panels and want them to be efficient and reliable you will need non return valves, and no doubt frost valves if you have the problem of pipes and pumps freezing at certain times of the year.

shed

I am going to have a considerable distance between the hot water tank and the collectors so I don't consider reverse flow to be an issue. It will probably be 3 to 4ft. I am lifting the storage tank above the roof, along with the cold water supply tank stand so we get better water pressure and because there will not be sufficient height between the top of the collectors and the storage tank. I have already got this one worked out. The storage tank will be fully enclosed and surrounded with lots of insulation. This all makes the solar design simple.

The article still does not explain why you were getting reverse flow as the temperature at the jacket would not be all that cold. At most ambient I would have thought.

Dean

[Ueee]

Dean, how will you frost protect it? Well I pressume you get below zero there? Mine has a line of code in the controller (home made) that turns the pump on if the temp gets too low, feeding the collector's with water from the bottom of the storage tank, usually about 14 or 15deg in winter.

[Oldneweng]

Dean, how will you frost protect it? Well I pressume you get below zero there? Mine has a line of code in the controller (home made) that turns the pump on if the temp gets too low, feeding the collector's with water from the bottom of the storage tank, usually about 14 or 15deg in winter.

Below zero is actually rare around here. It does happen a couple of times a year I suppose. I was going to look into the frost valves but I have't decided yet. Winter would not be much of an issue with solar hot water as we generally get all our water heating from the range. I could even drain the collectors. I will be fitting isolation valves at the connection points of the pipes near to the storage tank. The solar is only to provide hot water during the hot months.

Dean

[shedhappens]

I am going to have a considerable distance between the hot water tank and the collectors so I don't consider reverse flow to be an issue. It will probably be 3 to 4ft. I am lifting the storage tank above the roof, along with the cold water supply tank stand so we get better water pressure and because there will not be sufficient height between the top of the collectors and the storage tank. I have already got this one worked out. The storage tank will be fully enclosed and surrounded with lots of insulation. This all makes the solar design simple.

The article still does not explain why you were getting reverse flow as the temperature at the jacket would not be all that cold. At most ambient I would have thought.

Dean

G/day Dean, I think that the problem with my flue heater demonstrates that rules can be broken when it comes to thermosyphon, the pipes from my hot water tank had to travel about 7 mtrs before descending another 2 mtrs down the wall to the flue heater, that is roughly an 18 mtr round trip for the water.
When I noticed the warmth in the flue heater (when the fire was out) I got up in the roof and felt the pipes at the hot water tank that went to and from the flue heater, the top one was quite warm for a considerable distance and the bottom one was less warm, that is how I determined that I was getting reverse flow when the fire was out.
So why ? You tell me, I think that there only needs to be a temperature difference at the upper and lower pipes for the flow to commence, but why it would wanna flow backwards ? I don't know.
I am assuming/guessing that any heat in the flue heater from the water would cause a draft in the flue that might perpetuate the problem and "possibly" further cool the water in the heater to make it sink and thus drawing the hot water out the upper pipe, if, how and at what speed this could or would happen I don't know ? If at all. I would be interested on all theories of this phenomenon.
When I did all this there was no internet, the research that I did at that time suggested that I would need non return valves.
Maybe I didn't need to replace them with better valves, maybe I didn't need them at all because it could have been the extra insulation that I put on the pipes that did the trick ?
Why does yours work without valves ? Or are they in the stove or the hot water tank ? If not, then it shows that two systems that work on the same principles can act quite differently. Why I don't know ?

Here bellow is a cut n' paste from a gov dept about the requirements for a wet back or flue heater, I think that (b) iii relates to not using shut off valves, so you don't make a bomb, they don't mention non return valves, I broke a couple or more of their stooopid rules but ended up with an excellent water heater once the bugs were ironed out.
From what I have just read on the internet there seems to be a few different opinions out there.

7.4.1
Installation considerations
When installing a boiler as a booster, the following issues should be considered:
(a)
The heat source should be located below the storage tank to allow thermosiphon flow.
(b)
The flow and return lines from the storage tank to the boiler should:
i be copper
ii rise or fall in a continuous gradient
iii have no valves fitted to them
iv have no dissimilar metals in them
v have no elbows fitted to them
vi have a diameter relative to the length specified in Table 7.2;
vii connect separately from those lines to the collectors to prevent interference between
the two systems
viii be insulated to the required R-value so as not to be a hazard.
(c) The storage tank must be copper or stainless steel. Vitreous enamel tanks should not be
used as the enamel can dissolve at high temperatures.
(d) The system must be open vented to the atmosphere to prevent any pressure build up in
the boiler.
(e) Pressure/temperature relief valves must not be used.
(f) Boilers must not be connected directly to mains pressure storage tanks.
(g) A tempering valve must be fitted to the hot-water line to the house

That came from here and might be worth a look :2tsup:
http://ee.ret.gov.au/sites/climatechange/files/documents/03_2013/plumber-reference-guide.pdf

[shedhappens]

Dean, how will you frost protect it? Well I pressume you get below zero there? Mine has a line of code in the controller (home made) that turns the pump on if the temp gets too low, feeding the collector's with water from the bottom of the storage tank, usually about 14 or 15deg in winter.

G/ay Ueee, the frost valves I had often started to dribble at 9.30 to 10.00 pm on a clear night, the water just run down into the gutter and back to the storage tank so it didn't matter. I had a tank up the hill that gravity fed the house so when the frost valves opened they not only stopped the solar hot water panels from freezing but also the exposed pipework from there to the house.

It got pretty cold there one night and the water jacket on the pilot motor of my D4 dozer was frozen up and split open :oo: That taught me not to be a tight #### and put the green stuff in :doh:

[Gerbilsquasher]

Made some more progress over the last few days...

The 'throttle' is welded in... the plate rotates via a pin which is plug welded to the plate on the top (as pictured) to a lever underneath.... a lesson learnt a while ago... attach earth clamp to the bits you want to rotate rather than the biggest chunk of metal, or it might not ever move again....

271076


I've attached a few legs made from 50 x 50 x 3 SHS. Here you can see the lever that rotates the plate inside. There is a bit of stuffing about here.... if you weld it in the wrong spot you might never really know what the plate inside is doing as you move the lever. When upright, this stove will be full open with the lever to the left and fully closed to the right... I think....:D

271077

I fished a couple of big slugs from one of the scrap bins and turned them into feet... I drilled the holes to bolt the stove down with a couple of dynabolts. If you look carefully you can see the 'pierce' and 'lead in' from the laser which I have filled with weld..... working for a laser cutting company is pretty good, but the dangerous part is there is an endless supply of stuff that 'might come in handy one day'.....
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271078

Attached the shelf for the cinder box and guides made from a bit of angle. The round plate is once again a big slug from the centre of a 5.0mm mild steel flange we cut for a customer.
271079


The base is now finished, just needs a bit of a cleanup with the grinder mounted wire brush and a chiseling of the stubborn weld spatter. Will probably paint the legs with VHT Engine Enamel and the hot bits with pot belly black.

[Oldneweng]

Shedhappens, my stove pipes go straight up the chimney for about 2m and then about 5m across the attic on a slight rise, the top one a bit more due to different heights of connections. When me bought the house there was a different stove/wetback and no insulation on the pipes at all. I have added some and will cover all of it in the attic.

I am pretty sure there are no valves in the wetback or the hotwater tank. I have had the connections off both and if there were any valves they would have to be non-removable/repairable. Our hot water tank is about 60yrs old. I have poked stuff into the connections to check for silt etc.

The insulation would have some effect for sure but it is too complex for me.


So why ? You tell me, I think that there only needs to be a temperature difference at the upper and lower pipes for the flow to commence, but why it would wanna flow backwards ? I don't know.

I was hoping you could explain it to me. It is always good to learn about stuff like this in case it comes in handy. You are correct that a temp difference at the top and bottom pipes can cause flow. Hot water is less dense than cold due to expansion. This causes it to want to rise. It is a combination of hot water trying to rise and cold water trying to fall.


the top one was quite warm for a considerable distance and the bottom one was less warm, that is how I determined that I was getting reverse flow when the fire was out.

The top pipe on the storage tank is the inlet for the hot water. It goes in here. There is of course heat transfer to the water in the pipes and the top of the tank is always hotter than the bottom, unless the water is all boiling and rolling over. We have had that happen a few times.

I would suggest that there are some factors involved here that we are not aware of. My father built a hot water unit many years ago using a stove with a wetback, 1/2in copper pipe and a 44gall drum on a stand about 3ft high just outside. No insulation at all. As far as I remember it worked although it was for the seasonal workers hut so I did not use it myself.

Re the cut n' paste material, having valves and elbows tends to break up the flow. Not a good thing. Most is just common sense. Having a continuous gradient would be ideal but I doubt there are many around that have. I was planning on valves between collector panels for convenience in connecting, them as I was going to build them one at a time and just add them on as they are ready. I will probably put a valve on the ends of the top and bottom pipes to shut them off then remove the valves and connect the next panel with a compression fitting. The valves would also be attached with compression fittings.

Dean

[eskimo]

to try and avoid welding the mild steel plates to the cast iron brake drums... I wasn't sure how well they would mix!



so what holds and seals the middle section ( i guess its steel) to the top and bottom drum?

[Oldneweng]

Great to see see your progress Gerbilsquasher. We had to keep ourselves entertained while we waited lol.:rolleyes:


working for a laser cutting company is pretty good, but the dangerous part is there is an endless supply of stuff that 'might come in handy one day'.....

I am sure we can think of some ways to alleviate the Danger. We wouldn't want anything bad to happen to you.:D

Nice forge.:U

Dean

[Oldneweng]

so what holds and seals the middle section ( i guess its steel) to the top and bottom drum?

What I would do is just sit the middle section on the outer lower section of the ring so the inner section holds it in place. Same with the top drum. That way it can be moved easily. Depends on whether anything else id done with the middle section. When we replaced the slow combustion stove in the lounge some years ago I pulled the old one apart and kept the door and frame section so I could fit it to something like this stove. The door is probably wider than the drums tho. Maybe keep it for the tractor rim stove. This is planned for outdoor heating. These tractor rims are just like the brake drums in shape so perfect for this job. They are getting towards 3ft diam and about 15 to 18inches wide. They came off a tractor that was burnt out. I have seen a stove built similar operating in a huge shed. The type of shed that the header sitting off to one side looks normal. At 30 odd feet away the heat was .... hot.

Dean

[Gerbilsquasher]

Great to see see your progress Gerbilsquasher. We had to keep ourselves entertained while we waited lol.:rolleyes:



I am sure we can think of some ways to alleviate the Danger. We wouldn't want anything bad to happen to you.:D

Nice forge.:U

Dean

271215

It did cross my mind that at this stage the contraption could be used as a patio heater or even a BBQ if you threw a steel plate on top... but not a forge. I guess I don't think like a blacksmith..... yet!

Made some more progress over the last day or two, mainly the cone for the flue and the supports thereof.

Marking out bend lines:

271216

Bending on the Sorta Dodgy Micro Brake Press:

271218

Folding up the supports:

271219

Tacked together it looks like it means business before I weld it proper:
271220

Ironically I seem to have come down with the flu while working on the flue..... about time for some heat in the shed methinks....

[Gerbilsquasher]

so what holds and seals the middle section ( i guess its steel) to the top and bottom drum?

Gravity, mainly. The centre ring is slightly larger than the lip on the open side of the brake drum and the lip sits inside. If the edges of the ring are flat then it seals quite well... and if the stove is 'driven' properly there should be a partial vacuum inside while it is burning, so any small gaps will draw air into the flames rather than emitting smoke.

Even a commercial pot belly will produce smoke if not driven properly. Shut the flue flap with wet kindling and you will quickly see how many gaps there are in a store-bought stove...

[eskimo]

Eskimo and anyone else,
I have plenty of truck brake drums available for pickup in Melbourne or Adelaide.
PM me with your needs.Free.
John

thanks John
My son picked them yesterday....now to get some warmth into the shed

[eskimo]

Gravity, mainly. The centre ring is slightly larger than the lip on the open side of the brake drum and the lip sits inside. If the edges of the ring are flat then it seals quite well... and if the stove is 'driven' properly there should be a partial vacuum inside while it is burning, so any small gaps will draw air into the flames rather than emitting smoke.

Even a commercial pot belly will produce smoke if not driven properly. Shut the flue flap with wet kindling and you will quickly see how many gaps there are in a store-bought stove...

that makes sense

[shedhappens]

G/day Gerbs, the heater is coming along well:2tsup:

I can't see any empty bottles of inspirational fluid scattered around ? :D

[CMB]

G/day Gerbs, the heater is coming along well:2tsup:

I can't see any empty bottles of inspirational fluid scattered around ? :D

Excellent point. Might have fended that flu off too...lesson learnt I hope?!?:q

[Oldneweng]

G/day Gerbs, the heater is coming along well:2tsup:

I can't see any empty bottles of inspirational fluid scattered around ? :D

Nah. Its too cold in the shed for that. Wait til the heater is going!:D

Dean

[Gerbilsquasher]

G/day Gerbs, the heater is coming along well:2tsup:

I can't see any empty bottles of inspirational fluid scattered around ? :D

There were some out of view of the camera. I have lost a favorite beer glass when I left it on the welding bench and knocked it off. My peripheral vision was impaired when I was wearing the welding helmet. That's my story and I'm sticking
to it.


Excellent point. Might have fended that flu off too...lesson learnt I hope?!?:q

Learnt a along time ago... a couple of bevvies and then a straight whiskey and two aspirin before bed kicks viral butt!!!

Was feeling much better the next day.


Nah. Its too cold in the shed for that. Wait til the heater is going!:D

Dean

Too cold for beer? :?

[Oldneweng]

There were some out of view of the camera. I have lost a favorite beer glass when I left it on the welding bench and knocked it off. My peripheral vision was impaired when I was wearing the welding helmet. That's my story and I'm sticking
to it.



Learnt a along time ago... a couple of bevvies and then a straight whiskey and two aspirin before bed kicks viral butt!!!

Was feeling much better the next day.



Too cold for beer? :?

It is always too cold for beer as far as I am concerned. I have never liked it and don't drink it. Whisky is much better and cider if I have to and it is not too cold.

Dean

[Gerbilsquasher]

I have pulled my finger out and finished it... except for giving her a coat of pot belly black (local hardware only had aerosol cans... where's the fun in that?). Anyway, I will show a few more pics of the process and the completed 'ornament' with fake cellophane 'fire' burning inside.

Next I made the flap housing (which also connects to the flue) from some 140 mm diameter pipe I had lying around. The smaller piece was made from the same original pipe but was slit down the length (several times as there was some experimentation involved.... but the final amount of material removed was pretty close to the amount calculated from the difference of the two diameters (pi * d then subtract one circumference from the other) The smaller piece didn't end up very round at all, and had to be forced into a better shape with pressings and large hammers. Finally the smaller piece was located sorta concentric to the larger by sheet metal spacers of the appropriate thickness and cooked inside and out with the MIG.

273010

A flap was made by turning a 10mm thick round 'slug' into an elliptical shape.

273011

Once ground into a shape that wouldn't jam in the pipe, holes were cut in the side of the tube with a hole saw, for the pivots for the flap. I got these pretty close to being exactly opposite each other by using an indexing head and a vertical height gauge. The pivots are merchant bar and I have increase the bearing surface by welding some of the thick washers (left over from making the rivets) to the outside of the tube concentric with the holes.

273019

Completed pipe with flap. The handle gives a visual indication of flap position

273020

[Gerbilsquasher]

The top plate was made from two separate pieces of 8.0mm mild steel, and plug welded together. I did it this way to give a 'ledge' for the top cover to sit on.

273023

While welding the two plates together I was careful to make sure the holes lined up (I put the rivets in the holes to make sure of this) and I clamped everything tightly.

273026

The top cover is also made from two obround shapes of different sizes and plug welded together. These were actually the slugs from the holes in the top plates. This allowed me to machine the lifting hole as found in many commercial equivalents. A square hole was machined all the way through and a recess was machined on the underside with the trusty Cincinnati.

273024

I will need to make the appropriate tool for this slot but for now a screwdriver will do.

273025

The flap housing was welded to the top of the plates once they were welded together, and the whole assembly was attached to the top brake drum with the rivets as per the bottom plate

[Gerbilsquasher]

The plug welds on the top of the plate were ground and linished flat. This assembly is now finished.

273027

I didn't take too many snaps of the ring. A lot of the parts were laser cut, as was the door in the ring after it was rolled. I made the hinges from some stuff lying around. The handle and the hinges pivot on shoulder bolts.

273029

273028

The cinder box was folded up from some gal sheet and the corners TIG welded.

273030

[Gerbilsquasher]

After much grinding, the unit was finished. There were not many photos in these final stages because I trying to get the thing finished....

Here I have cleaned most of it up and painted the legs with VHT engine enamel

273037

The flue was installed in the roof and of course I had to try it out, along with a coldy or three....

273038

It really throws out some heat.This is the new shed which is at about 750m above sea level and regularly drops below zero.... and the shed is missing a large amount of the flashing between the roof and the walls, so a lot of the heated air escaped into the cold night. Still, if you were within 10 metres you could feel the radiant heat from the brake drums, which are around an inch thick in most places.

Of course should you decide to build one it doesn't have to be as elaborate as mine to do the same job... I started this one ten years ago, and a lot of things got in the way... but I am very happy with the result. :D

[shedhappens]

The length some blokes go to stop their beer freezing :D

[CMB]

The length some blokes go to stop their beer freezing :D

Drink it quicker and problem solved.

[Oldneweng]

The length some blokes go to stop their beer freezing :D

Not to mention their ar$%.

Dean

[Gerbilsquasher]

The length some blokes go to stop their beer freezing :D

True... I fired it up the next day too, for a bit of warmth while I bottled the latest batch of home brew:D

I'll throw up one final pic with a coat of pot belly black... when I get around to it....

[eskimo]

why a draft/damper in the bottom and one in the flue? Is there a reason other than to ...well why not

[Gerbilsquasher]

why a draft/damper in the bottom and one in the flue? Is there a reason other than to ...well why not

I have looked at a few factory built pot bellies and slow combustion heaters and they seem to have both. I'm no expert but I assume that the top one retains the heat in the stove and the bottom one controls the flow rate of air.

'Why not?' is a valid reason in itself. Another one is if there are more levers and other controls to play with, it looks better featured, and one scores highly with wankfactor based on the appearance and the apparent level of skill required to operate, especially to mesmerised and unknowing onlookers. :wink:

[th62]

If you close off both dampers it starves the fire of air and the fire goes out quicker.

[Oldneweng]

I have looked at a few factory built pot bellies and slow combustion heaters and they seem to have both. I'm no expert but I assume that the top one retains the heat in the stove and the bottom one controls the flow rate of air.

'Why not?' is a valid reason in itself. Another one is if there are more levers and other controls to play with, it looks better featured, and one scores highly with wankfactor based on the appearance and the apparent level of skill required to operate, especially to mesmerised and unknowing onlookers. :wink:

You are pretty much on the money on both counts. I am sure there are many more controls that can be built in. Our kitchen stove has a vent that is sited after the oven and flue damper which lets air into the heated air flow going to the flue. This reduces the air flow from the firebox and allows the oven to cool down a bit. It also has a vent on both the ash door and the firebox door.

Dean

[Gerbilsquasher]

I did also toy with the idea of forced air induction (I am a petrolhead... does it show?) by running compressed air directly into the combustion chamber... um I meant stove... I do have a 3/8" BSP tap...

Perhaps a ring of 'air injectors', 8 in total, at 45 degrees apart. Maybe next time.

[j.ashburn]

I did also toy with the idea of forced air induction (I am a petrolhead... does it show?) by running compressed air directly into the combustion chamber... um I meant stove... I do have a 3/8" BSP tap...

Perhaps a ring of 'air injectors', 8 in total, at 45 degrees apart. Maybe next time.May give you problems burning out later on would get the cast and the spacer ring to the semi oxidised state. can burn the a....se out of seamless steam pipe made into a crucible using 1/2 plate at bottom dont last long with a good shot of air through the glowing charcoal.I admire your idea though.,but all that hard work and quality workmanship would be a shame.seen the drums and flue red hot in the one the old garage in town here had.and how the soot used to rattle in the flue when it got baked and broke loose. John. a couple of ceiling fans if you got the height on low slow get you down to the ''wife beater'' [bluey singlet] in no time flat on a cold night.

[Oldneweng]

I am no expert on forced air induction into slow combustion stoves and pot belly stoves but I would have to agree with j.ashburn with the faulty shift key lol. I have a faulty one myself but mine just does not type the letter at all unless I press it hard.

If you want to go that way you should line with fire bricks but they will also burn out faster.

I think the next step would be to feed the inlet air in via a ring which would give a more even burn. You also need a convoluted flow path for the smoke to exit, which would slow the flow. Some heat transfer fins on the lower part of the flue section with a fan to blow the heat out into the shed. You will also want some turbulance here to move the heat around inside the flue so it can be transferred to the fins.

One of the best looking stoves I have seen was a horizontal electric motor casing about the size of a 44 gallon, sorry 200 litre drum. Fins and all.

Dean

[Steamwhisperer]

Nah, induced draught is the way to go. Negative firebox pressure means no smoke in the shed. That's a great thing.

Phil

[CMB]

No need for forced air. Leave the flue damper wide open. The flue, when heated, controls the draw. A secondary supply of air will naturally enter if catered for.I posted a pic of my heater earlier in the thread. Here is another from during the build which shows my primary and secondary inlets.

273579 273580

The pipes that enter from the back of the fire box super heat and introduce the secondary air. A 6mm plate (heat shield/baffle) sits directly on top of the perforated sections of pipe. This forces the flame path forward before it detours around the 6mm plate and back again to the flue (below the stainless separator visible at the top portion of the barrel.The two pipes seen across the top outer barrel are the primary air source. This supply is separated from the flame path by another stainless separator that directs the air flow over the glass of the door. This is what keeps the glass clean. It then passes under the grate visible in the second pic to feed the fire from underneath.Both sources initiate from an outside intake. This ensures that I'm not have the air from the shed sucked through the heater and up the flue.

273573

The outside supply pipe tail was not yet fitted when I took the pic.On top of the barrel I have what I call a manifold, bent out of stainless, to which I have a run of 5" gal duct mounted.

The duct then bends and terminates approx. 4m away from the heater. This gives excellent convectional draw and pumps out heated air 60 degrees or more (my shed thermometer maxes at 50).

273586 273574 273575 273576

The thermal mass of the 30 plus fire bricks inside the barrel ensures the heater retains a lot of heat long after the fire has died, and also offers excellent heat refraction during the burn for max efficiency.

Craig.