Thread: Bandsawing a Spotted Gum

Originally Posted by Sawdust Maker

just rolled over in my hammock and noticed this happening

interesting

and now back to zzzzzzzz

Nick

Sorry! Didn't mean to intrude .

Regards
Paul

Originally Posted by Sawdust Maker

Tell you what - just to save you the trip I'll wander up and get it and store it at my place

Nick

Wow! That is so thoughtful and unselfish. If I hadn't put in for a little annual leave to fit in the trip and an 80th birthday party (no not mine!!) I'd have to consider such an offer .



Regards
Paul

Today I dug the Forest Red Gum out of the shipping container where I have had it stored since buying it from Mapleman. The FRG is only for the work bench. It was an assortment of shapes and sizes: A real hotchpotch.

I was lucky as there were four short lengths of nominally 150 x 100 so they were snapped up for the legs. I wanted some 125 x 40 to edge the top and some material for stretchers at the bottom and rails around the top of the legs. Some of the timber still had it's natural edge and that wasn't going to fit in the stack at all well so that was resawn for the 125 boards. There was some 100 x 100 so I threw that in for the bottom stretchers plus a few extra pieces to pad out that level in the stack.

I had a few extra 125 boards to make up the top layer. When I got to building the 100 deep layer it became apparent that I was going to have to thickness these as they just were not even enough.

boards 25 thick are relatively easy to lay up and season. Boards 50 thick are a little more challenging and by the time they are 100 deep you have a battle on your hands. The first problem is that while in a 25 board a little bit of curvature can be squashed down, you have Buckley's chance with a hardwood 100 thick. There is just no give at all.

So I took them all back off and ran them through the thicknesser. More time wasted . Not really as to my mind it was just unavoidable. The stack looks like this now with the extra layers:

air drying spotty 002.jpgair drying spotty 001.jpg

I inserted another sample board, this time for the FRG. It is not in an ideal spot at the moment as sample boards should be in the middle of the stack, but when I retrieve the remaining Spotty, always assuming Sawdust Maker has not discovered the location down in NSW) It will be better positioned.

air drying spotty 003.jpg

I measured the moisture content of the sample boards and weighed them too on SWMBO's kitchen scales.

The FRG was 16.5% (approx 18% when corrected for species) while the Spotty, not surprisingly, was a whopping 55% Corrections tables do not go up to this level as it is not in their most accurate band anyway. The difference in weight was very evident between the two boards just by picking them up. FRG was 2072g and the Spotty 2750g.

The Tallow Wood I has also in the shipping container I also measured (just for you Brett ) and it was in the range 11% to 16%. My correction tables did not include Tallow Wood and I haven't had time to surf the net to see if there is any information. bear in mind that although these timbers have not been stacked out for drying purposes they have been in a shipping container. It is painted blue and it gets uncomfortably hot during the summer months.

The range takes into account 25 thick boards through to 75 thick boards. Boards down the bottom of the pile were more moist as you would expect.

You could compare this to the FRG which was in the range 11% through to 18% for the different thicknesses.

Any how on the drying pile this is how they stacked up. I gave all the freshly cut ends a coat of paint as well as another coat for those previously painted. I probably wouldn't have to do that if I used a proprietary sealer.

air drying spotty 005.jpgair drying spotty 004.jpg

Regards
Paul

Another exellent example of how to go about stacking green timber for air drying, anybody new who is thinking about drying there own wood would be well advised to have a read of Paul's thread maybe make it a sticky



Pete

Originally Posted by Bushmiller

The Tallow Wood I has also in the shipping container I also measured (just for you Brett ) and it was in the range 11% to 16%. My correction tables did not include Tallow Wood and I haven't had time to surf the net to see if there is any information.

Pretty sure I have Tallow Wood in my list but it'll be Tuesday before I can check as it is in the shed and on on the road early in the morning and probably be late when I get home. So if you still need it, I'll check it on Tuesday for you.

Thanks Pete for the kind words. I hungrily snap up all compliments as they are not so plentiful .

There is one glaring pitfall in this stack and it is that there is a variety of different sizes and worse still different thicknesses. From the very start it means that the drying will not be as good as it could be.

Also the sample boards will hardly be a representative sample being only 25 thick. Clearly they only represent the 25 boards. I will have to get in and measure the thicker sections too.

The different widths inhibit vertical drainage through the stack. Ideal stack would just be 125 x 25 boards, but life isn't easy .

Regards
Paul

I struck lucky with searching for some species correction tables for Tallow Wood. Amazingly there is no correction needed all the way through from 6% to 23% which is the normal range quoted.

I should also have mentioned that there is some correction needed for temperature, except that it is for the temperature of the timber. However the differences are small and as at this time of year the temperature is about 20 deg, which is the reference point, I have not troubled with it.

You do also have to bear in mind that moisture content measured with a resistance style detector is at best a guide and not an exact science. We have to be wary of developing a level of inaccuracy that is based on slightly flawed measurements in the first place. The oven dry method is the only reliable method, but a little time consuming and I am not flushed with time at the moment. I might give it a go at a later date.

Regards
Paul

Originally Posted by DJ's Timber

Pretty sure I have Tallow Wood in my list but it'll be Tuesday before I can check as it is in the shed and on on the road early in the morning and probably be late when I get home. So if you still need it, I'll check it on Tuesday for you.

Thanks DJ

Your post must have come in while I was composing mine and I didn't see it straight away. As you may have seen, I did find some tables for Tallow Wood.

Regards
Paul

One of the aspects I should have emphasised, and didn't, is that for the stack to be successful it relies on weight pressing down on the layers. Towards the bottom the weight is supplied by the upper layers, but the upper layers in this case only had some old tyres to hold them down. This was a temporary measure.

A little while ago I had to pull up two concrete slabs from a footpath. They were monsters and the process was accomplished with much grunting and cursing. However, as is my way, I didn't throw them out and last night I cut them into smaller sections to place on the top of the stack. The pieces average about 30Kg with the heaviest at 40Kg. That's quite enough for this bloke to hoist up onto the tin.

spotty 2 004.jpgspotty 2 001.jpgspotty 2 002.jpgspotty 2 003.jpg

As you can see there was some very large aggregate used! It seems they put rocks on the ground and then poured concrete over the top. It must be a Millmerran trick as the previous house we lived in had the same thing for the garage. Only problem there was they appeared to have run out of concrete and there were boulders protruding out of the floor all over the place .

A diamond disc on a 9" angle grinder was used for cutting. It ate the concrete but wasn't so keen on the igneous rocks. I dribbled water onto the blade and used an inline circuit breaker to protect against accidental electrocution (ahem.. who does it deliberately). I also had ear muffs, safety glasses and I should have had a dust mask as the small bore hose didn't suppress the dust sufficiently.

A few tyres completed the weight.

Regards
Paul

Perhaps I should mention an alternative method of supplying weight to the stack. I appreciate that not everybody has a pathway they want to dig up and sacrifice.

I have to point out that I have never used this method and I am more than happy for somebody to correct me if I have details incorrect. The principle is to use the stickers which must be exactly the same length. Once the stack is in place, banding material (plastic, steel or fabric) are carefully looped crosswise around the whole pile including the stickers and tightened up. This is repeated on each line of stickers.

It is important to go around the stickers or the timber would all be drawn together removing the vertical ventilation spaces. Drying of the innermost boards would suffer as a consequence if this were to happen.

Moisture and direct sunlight need to be kept off the top of the stack, which is the reason for the tin roof and you still need to do this even if you have banded the stack. Then the roof has to be held down (weight?) Our lawn locker was demolished by a tree blown down in a storm and I kept the undamaged sheets. That was something else I didn't throw away .

Regards
Paul

Excellent detail Paul

Thanks Brett

There is still a bit to come including:

Frame for the solar kiln (a rather glorified description of something so basic you will probably fall about laughing)

How to measure moisture content of boards in the centre of the stack.

Oven Drying

Core sampling (Differential drying from outer layer of a board to the inner core)

I have to say these last two will be a first time for me so that in itself will be interesting .

Regards
Paul

Paul, this is a great topic your've created here!!, me being a bit of a newbie to bandsaw milling & drying my own timber there's so much to learn.
It requires a bit of effort to take & upload photos, type up detailed descriptions, answer questions etc etc. I appreciate the time your putting into this.

cheers,
Dean.

Is it possible to get longer prongs for your moisture testing thingy?

long enough to reach the centre of the stack?