[chriss]

I've started to build the stand for my new tank, but I have a dilema, I think know I've chosen the wrong wood!

Now, this isn't the first stand I've built and I'm pretty good at diy, building, designing and fabricating things from wood, stone, metal or whatever so it's not a 'skill' issue.

I decided to use SAWN 2x4 timbers, attempting to get maximum wood volume whilst accepting that they wouldn't be perfect due to the way they deform when drying. For those who don't know, if you look at the grain on a cross section, the timber 'bows' ever so slightly across the grain, not along the grain, thats something different.



I've exaggerated the problem in the image, it varies between each peice and the edges aren't always perfectly parrallel with each other either!

The problem I'm now find is that it's a real biach to get it assembled to the perfection my mind desires, I'm sure I would have lived with it when I was younger!

This is the sort of design I'm working too that will be clad inside and out...



Thankfully with my new mitre saw, that I spent an hour truing up, all my cuts are spot on and square, but due to the slight bow in the wood nothing really 'fits' right.

When you sit an upright on the bottom rail, looking down from the top it looks like this...



Things like the 'uprights' don't sit perfectly upright on the base rails, now I can jig them sqaure but then the load is only be transferred over the areas in contact.

When you butt two pieces uptogether you get this sort of problem...



... which means nothing will sit flat/sqaure across the two pieces, it's exaggerated in the photo but amounts to over a mm in places.

I can build it so that it is square across all the diagonals, but I can't convince myself that that will be good enough and that when I come to clad it, since the 'faces' of the frame are all over the place, the cladding ain't going to be true/square/right.

You get the picture?

Options...

1) bin it, buy some "planed" wood and start again

2) persevere and just live with it or choose option (1) at a later date if it's not acceptable.

Chris

[TrevC]

If it's going to annoy the hell out of you ...........go for option 1)

[tillysreef]

easy fix
before you clad it put a thin layer of foam/polystyrene on timber then clad over it will take up the minor imperfections and protect the cladding from any damp inside

[norman]

hello all, use planed wood for top surfaces or buy a plane, sides& ends dont matter that much as they will be covered. or use wood so top faces are concave then cover top with claddlig then polystirene, will help spread load over surface area & also help insulate bottom of tank. cheers, norman.

[bobba fett]

Metal and a tig welder!

Joking apart I used to work in a ship yard, for the reasons you said, everything was built from planed wood, I would suggest thats the best bet if you want perfection, however, once clad you will not notice

[SLAPPY]

Chris, I had exactly the same problem, in the end I dumped the lot and bought 3x2 planed timber to redo the same job a few months down the line.

[satsuma]

I would try 4x2 (38mm x 88mm) CLS timber from a builders merchant, it is used for stud walls etc its dried and cut to be a standard size.

"CLS is produced from kiln dried spruce (whitewood), planed and finished with eased edges to precise tolerances and in accordance with British Standards to either C16 or C24 grade."

CLS is also cheapest planed timber.

Ben.S

[Crabbit]

Can't you run it through a thickness plainer so it square and straight? Of do some work with a chisel so its straight on the joints? Could you get away with just doing the over laps?

[Cass1]

Sorry Chris i was a bit slow in responding yesterday. I got the same saw as you bought, you could have borrowed mine Also got an electric planer if you want to borrow it. I'm no Joseph but wouldnt the stand change in shape very slightly anyway once you got the weight on it. What size tank are you having. Only the last 2 i did was built on blocks and girders. Alot easier than poncing around with bendy wood and you can still clad it after
Martin

[chriss]

Thanks for all the suggestions guys, after spending another evening with it and getting quite close to completing the basic framework you can see where the issues are coming out because nothing sits squarely, I can jig it to fix it, but it's not going to be right, the wood is just too inconsistent, so looks like I'll be having a bonfire tomorrow and starting over.

Yes, I've got a plane, electric and manual, but thats a lot of wood to try truing up bearing in mind I wood need to do four sides of each piece, too much scope for error. Alas I don't have a table thicknesser, I'll put it on my christmas list!

Mig it, seriously thought about it, would probably have been cheaper time you include two lots of wood and by nice new mitre saw!

This wood was s'posed to be 47x100, but varied from 50x100 up to 53x103 allowing for the cross-grain-warp, even in the same 2.4m piece!

I've used CLS before, but don't think it's quite meaty enough for this tank (72x27) which is a shame since it is cheap and consistently true. I think something 44x96 planed would be required, tho it's twice the price

Blocks and girders? How easy is that to get them level? Tell me more, might be worth considering.

I'll sleep on it and see what I can come up with, perhaps take a trip to the saw mills tomorrow.

Cheers!

Chris

[norman]

hello all, bieng serious, good seasoned wood is a rare thing today & will cost an arm & leg. most wood will move slightly as it is kiln dried, not stacked[ old fashioned method]. best of luck with your build. cheers, norman.

[Cass1]

Hi Chris

The last 3 goes I've had it worked fine. The main tank I have at present (7 x 2 x 2.5) is sat on 3 peirs of 6 inch blocks. I put the angle iron across the blocks and bedded them in with 3:1 cement mix. As long as the floor is solid.
Cheap and very effective.
As for cladding... with your talents and a shiney saw you should be able to make a "skirt" around it and fix a frame and doors.
The only drawback in my experience is make sure the blocks sit on a solid floor. Dont be stupid and sit it on a 2" polysterene floor and stirling board
It can mean having Jas around with several tubes of silicon and a new base

What size is the new tank Chris?

[chriss]

Cass1, on Feb 13 2009, 06:33 PM, said:

Hi Chris

The last 3 goes I've had it worked fine. The main tank I have at present (7 x 2 x 2.5) is sat on 3 peirs of 6 inch blocks. I put the angle iron across the blocks and bedded them in with 3:1 cement mix. As long as the floor is solid.
Cheap and very effective.
As for cladding... with your talents and a shiney saw you should be able to make a "skirt" around it and fix a frame and doors.
The only drawback in my experience is make sure the blocks sit on a solid floor. Dont be stupid and sit it on a 2" polysterene floor and stirling board
It can mean having Jas around with several tubes of silicon and a new base

What size is the new tank Chris?

Thanks for that, food for thought.

The new tank will be 72x27x24, same length/height as the existing one but 50% wider front-to-back. As for the current half built stand, I'm going to turn it into a workbench, so not a total loss.

As for the existing-soon-to-be-replaced tank/stand, anybody want a 72x18x24 tank, stand and hood?

Cheers

Chris