Thread: Oil Burners for Casting Furnace.

I've ordered another bag of refactory. The company I bought the first bag from some 2-3 years ago, (yes this furnace and casting idea has been going arround for that long.....and longer) Thermal Ceramics in Adelaide don't handle the Moral Cast brand anymore. But they gave me the 1300 contact number.

It's made by Shinagawa in NSW I beleive, pick it up tomorrow. It's rated to 1600 C.. I reckon it's cheaper this time than last @ $66.00 plus per bag. This will give me plenty to finish off plus extra for a couple of plinth blocks and other bits and pieces I'm not aware of right now. Sounds like I stumbled onto the right gear first off. That makes a change !.

What about crucibles ?. I intended making a couple out of steel tube for melting ally to start with. Weld in a bottom and some lugs and fashion a spout. I've got some 4" diameter pipe, approx. 2mm wall, would that suffice ?.

Sounds like a good idea on the lid. I'll have to put on the thinking cap soon and do something similar. Also a trolley to move it all arround is on the cards as I don't have a designated area as yet for it to permanently live.

As far as the burner is concerned I haven't made any progress there other than finding a couple of designs on the net.

Cheers............Barry.

2mm should be fine. I know a lot of folks use soup cans, and I think they are nuts, well, were nuts...

One of the castings I plan to do needs a big bit of ally, plus a lot of the things I need to break down are pretty wide.

I have lots of baby formula tins about, so one of them might have to see melting duty for a run or two. No more than that because it will die pretty quckly, plus I doubt it will hold enough metal at that temp before it dumps it's guts.

Thicker stuff buys more time till it needs replacing is all. My main pot is a piece of 100mm ID, 120mm OD, 250mm tall iron pipe with a 6mm base jammed in and welded. That thing will outlast me easily but it isn't quite big enough for the 7kg casting I want to make.

I can also get some stainless cooking pots that are wider but much shorter that will just hold the ally, but it's going to be close. Still holding out for some bigger pipe with about 2mm wall.

You will find that with a large furnace ID (mine is 250mm) and a much smaller pot OD (120mm for me) you use a lot of heat that doesn't get to do very much.

I want to get a 150-180mm OD pot, 3mm wall, and about the same high, maybe a little taller. The efficiency should go up a bit and make it less tedious to melt stuff. As it is, mine takes about 25-35 minutes from stone cold to @1500cc of molten ally. That's too long for the burner I have and in an insulated furnace. Problem is that thick crucible and it's small diameter.

(And stupid me was worried about burning it through too quickly, when after several heats it shows nothing from the effort...)

G'day All.

I hope everybody has had a good Anzac Day.

Schtoo, I have the official specs for the Shiracast 165 castable refactory that has replaced the Moral Cast. It is non-insulating as you thought and rated at 1650 C recommended operating temp. up to a maximum of 1850 C. The agent indicated you could go higher but don't expect much life out of the furnace.

The refactory contains high purity chamotte and low iron calcium aluminate cement. 12 month shelf life.

Thanks for the input on the fabricated crucibles.

Update on furnace construction.

I have now cast the last 3" to top up to the top of the drum. Tomorrow or Friday I will cast the lid as well as remove the former (friday) in the furnace and inspect. I'll take some more pics and post them here then.

It'll be getting close to fire-up time in a week or so, so I better "get a wriggle on" and make an oil burner !.

Thanks for your help............Barry.

G'day all,

Well time flys when you're having fun ?. After getting some RL issues sorted I managed to get the first "modified" babington burner running......in a fashion.

I say the "first" burner because number 2 WILL have some design changes.

Got some tuning issues to sort out, but it produces a good blue flame. Don't have any pic's yet but I'll post a couple when I fire it up next in a couple of days.

Then I'll wack it into the furnace for its first firing.

Cheers..........Barry.

Well done Barry.....would love to see the pics.

G'day All,
Here a couple of pics from a "burn" performed earlier tonight. Unfortunately the flame doesn't show up with the flash, but you'll get the idea. I'll take a couple more pics on the weekend without the flash when I get some oil feed issues sorted.

So this is what I've done so far. The burner tube is a piece of 45mm dia. x 150mm long exhaust tube I had in the scrap bin. Nice slide fit in the 2" tube I have in the furnace. I blanked off one end with a large flat washer. The Babington type oil feed is a 1/8" BSP brass 'T' fitting with a brass cap that I drilled .046" thou.. It became this size as it was the smallest I had and I couldn't buy the recommended #80 drill down south of Adelaide.

The cap screws onto the 'T' from inside the burner tube and locates the assembly. A groove was cut with a fine round file from the edge of this endcap to the centre to provide a "guide" for the oil to run down and over the Air outlet orifice. The hole was drilled in the lathe and on the inside of the cap I used a no.2 centre drill to put a small taper on the hole for the purposes of a needle valve seat.

Then to reduce the size of the Air outlet orifice I made a needle valve from a piece of 6mm MS rod machined to 5.3 mm OD and bored and threaded to suit a 4mm cap screws I had on hand. I "guesstimated" the taper require for the needvalve tip. The cap screw fits into a threaded cap which in turn fits to a bush and screws onto the other end of the brass 'T'. Now all I do is adjust the capscrew for air flow out the orifice. Works a treat.

Finally a 1/8" BSP to Ryco Air fitting was added to the setup. Delivery Air pressure seems to be quite low but I haven't checked it for a definative answer, but seems to be about 14-20psi. when it's burning nice.

The oil delivery has proven to be an issue. I have read and now beleive that the delivery rate is critical for consistant performance as "flame-out" is easy to achieve. Tonight I could only achieve maybe a minute of operation at "blue flame" before it became unstable and blow itself out.

Other problems are that the Quick connect Airline fitting gets way too hot. I'll have to fit a fixed pipe and fitting further away from the burner. The needle control also needs an extended operation handle simply to keep your fingers away from the burner.

With all that aside, I'm quite happy with the outcome so far.

Pic 1. Shows basic experimental setup. 3/16" copper pipe coupled to rubber vacuum line. T fitting with valve for some oil delivery control. Oil reservoir on top.

Pic 2.Ignition with paper dipped in 15w40 oil. Slowly turn the needle valve and increase flame.

Pic 3.Burning nicely now. If you look close you can see a very sligh yellow/red flame against the black bench.

Pic 4. Burning hotter now, blue flame, roaring nicely........seconds later, flame out with LOTS of smoke.

That's it for now. I'll have more after the weekend I hope.

Cheers.............Barry.

Just had a thought. Our gas cooktop has jets with varying sized holes. They're simply a brass nipple that screws into the top of the burner base. I wonder if it would be feasible to use one of them with the correct sized hole if people have a problem drilling holes that small?

Hi,

I dont really know whats inside your burner unit, but with the one i have built, it needed a hole size for your "jet" thats pretty close to what your useing! Another fellow told me at the time that it was supposed to be about the #80 size some .018", but i couldnt get enough oil through it for it to work, and after looking at his setup, it turned out to be lots closer to the .040" size, and this is keeping in mind that i have about 25psi of air on top of my oil... My thinking is the viscosity of the oil you are useing will probably be the most determining factor to jet size, anhd perhaps pressure depending on your setup. Hope that helps and made sence

G'day Mick C and Silent C,

Yeah, I had similar thoughts with the viscosity of oil etc.. I plan on using "old" oil from cars and trucks after running it through a filter. The ability to adjust the flow as well as pressure will be critical. I was using the 15w40 diesel oil 'cause I had it on hand. We use it in our Tool Truck and I have about 20L of old diesel oil on hand. I will persevere with the modified Babington Burner for the time being.

My next experiment will be with a modified "Kero" cleaning gun. I reckon a syphon feed like on a spraygun maybe more reliable than the current gravity feed setup. The tip will be the problem as they are not designed to cope with heat. Maybe a spraygun could be used also ?........I'll have to investigate that one too !......we have a "number" in stock.

As far as using gas burner jets, I'll have a look at one. The reason why I used the needle valve idea was to restrict the outlet size if it needed, as I only had .046" thou. drill on hand, and being a larger hole, would make cleaning easier. Personally I reckon a #80 hole will clog up over time with caked on carbon deposits etc..

Thanks for your suggestions. . I will report back here when I have more results.

Cheers............Barry.

Fuel Injectionshun for your furnace...


Your burners.. the spraying / atomisation bits should not be getting hot.

SUMP oils are FULL of nasties.... if they can be used, look up a way to commecially clean them up for burner use... see how they do it and if it's easy enough, use it other wise don't use raw sump oil.

A kero cleaning gun would be ideal for the right sized furnace.. (define huge) but they tend to flow far to much air for the given volume of fuel, also the atomisation is rather coarse.

BUT it's the PRINCIPLE of using a small amount of compressed air, coming through a small hole, into a bigger hole, and expanding at an included angle of 20* that leaves a partial vacuum behind it, that is where you hook your suction feed point into.


Set a simple needle jet into the feed line and then control your air pressure and fuel delivery and you will eventually get the mixture and flame size right.

Start with small holes and work your way up.

A simple gravity fed feed tank to the fuel suction reserviour is the easy way to feed the unit, a pump fed one, from the LOWER level is better.

It may pay to start your furnace on petrol (low air pressure and fuel rate = small flame and be fast to light it) and then switch over to the heavier oils when the furnace becomes hot enough for the heavier fuels to autoignite from the radiant heat in the furnace.

Spray guns.. they generally flow at a fuel delivery rate that is TOO low for a stable combustion process.

Start with small holes and work your way up.

That's why I thought the gas jets might be good because they come in graduated sizes.

I thought part of the beauty of the babington design was that you didn't need to filter out impurities because they just drop off the atomiser and into the sump below. As long as the return doesn't get clogged, all should be fine.

"I thought part of the beauty of the babington design was that you didn't need to filter out impurities because they just drop off the atomiser and into the sump below. As long as the return doesn't get clogged, all should be fine."

Yes, you're right. The oil flow is external over the jet in the babington design. The babington uses a ball shape burner with the jet at one end and the oil flows over the top in a thin film. Most of the oil flows off the burner, "unburnt" and is collect underneath. Then pumped back up to the reservoir.

The "modified" babington design I'm using, uses a "U" shaped groove cut into the burner face so that oil is guided over the jet. Excess oil drips off. My theory was to supply only a small amount and burn it all, no excess or only a small amount while warming up.

In my case where my theory has fallen over is I don't have enough oil flow. Increasing the flow almost eliminates the flame out problems I'm having. Now it's just a matter (I hope) of modifing the burner so as to collect the unused oil out the bottom.

I tried the kero gun and oil will not "pick up", so I'm guessing that the vacuum applied is too low for heavy viscousity fluids.

Cheers..........Barry.