Un-warping warped wood

Post by **Andrew** » Fri Jan 30, 2015 2:52 pm

Hello,

I've been working (awfully slowly!) on a model of one of the Welsh Highland Ashbury summer cars and am almost at a stage where I've made all the bits and can start putting them together.

Unfortunately the two ends (1.5 mm ply, with 0.5mm matchboarding on the outer side) have warped a little since I made them and developed a distinct bow. I've had them under a heavy box of books for a while which seemed to help, but they've bowed back since being removed.

Does anyone have any ideas for curing the problem, or should I just make new ones? I'd rather not - it's taken me months to get this far and I don't want to go backwards if I can avoid it!

Thanks,

Andrew.

tom_tom_go · Post by **tom_tom_go** » Fri Jan 30, 2015 2:56 pm

Clamp it in a vice and move up and down the wood bending gently at each interval to reform it?

Post by **philipy** » Fri Jan 30, 2015 4:42 pm

I'd hazard a guess that it is the layer of glue between the two different thicknesses of different woods, that is the cause of the problem.

I suspect that the only way to cure it is to repeat the matchboarding on the inside and allow that to all cure under a heavy weight for a week or so.

Anything else will just slowly warp again. Its the same principle as gluing a balancing sheet on the 'wrong' side of laminate boards, for exactly the same reason.

steamie1 · Post by **steamie1** » Fri Jan 30, 2015 7:01 pm

Cabinet makers stack wood end on (thinside down) and face the bow face away from the light.

Post by **Andrew** » Fri Jan 30, 2015 7:36 pm

Thanks chaps, much appreciated!

I'll probably try adding a matching layer on the inside for starters, should work quite nicely I think, sorting out another minor problem (grain the wrong way for the interior detail) in the process...

I'll let you know how it goes...

Cheers,

Andrew.

Big Jim · Post by **Big Jim** » Fri Jan 30, 2015 8:36 pm

As other have suggested, try bracing with metal or hardwood.
You could try and steam the wood to soften it and then either clamp it or weight it.
I have a vague recollection of my Father using a steam iron to flatten thin bits of strip wood but I can't remember if it worked or not. (best to do it when the domestic authorities are not looking).
Please follow this advice with care as my dad had some bloody funny ideas over the years and many were a bit like Baldrick's 'cunning plans' in the outcome!

MDLR · Post by **MDLR** » Fri Jan 30, 2015 8:57 pm

I have heard Microwaves can soften glue and allow things to un-warp: place under a heavy weight whilst the glue sets again. Take the advice above in this case, also.

Post by **Andrew** » Fri Jan 30, 2015 10:17 pm

Hmmm, some more interesting ideas, thanks... I've used a microwave for the opposite purpose, to introduce a bend into a roof. Overdid it a bit and the wood actually started to burn - no flames, just mildly blackened wood, a little smoke and a very bad smell that filled the kitchen. So yes, probably good advice about picking the right moment...

sstjc · Post by **sstjc** » Sat Jan 31, 2015 3:01 pm

A safer option may be an air gun or hair drier to soften it then place under a weight.

Barry

MDLR · Post by **MDLR** » Sat Jan 31, 2015 4:05 pm

sstjc:107847 wrote:A safer option may be an air gun or hair drier to soften it then place under a weight.

A hot air paint stripper is hotter...........................

sstjc · Post by **sstjc** » Sat Jan 31, 2015 4:25 pm

Thats the thing I meant...

MDLR · Post by **MDLR** » Sat Jan 31, 2015 4:27 pm

For Gawd's sake don't confuse the two - you could get frizzled hair!

METHSSNIFFER · Post by **METHSSNIFFER** » Thu Feb 05, 2015 9:03 am

Steam iron, but from experience once wqrped always warped.

Post by **Andrew** » Sat Feb 07, 2015 8:14 pm

Full marks all round chaps!

I tried a little of everything - and so far, so good.

I put the ends in the microwave and cooked them until the machine filled with yellow flashes (which seemed a good point to stop), then put them between some flat pieces of wood underneath a plant pot filled with slate chippings - that had held the Christmas tree upright until Jan 6th but hasn't quite made it back outside yet.

A couple of hours later it all seemed nicely flat, so I added an inner veneer to match the outer matchboarding, and have now placed it back under the plant pot until Monday, when I'll take it back to the "work workshop" for assembly during my lunchtimes next week...

Thanks for your help folks - fingers crossed it won't go all wonky again...

Andrew.

kandnwlr · Post by **kandnwlr** » Sun Feb 08, 2015 9:46 am

The prize for Best Use of Microwave Oven Over Christmas is certain.

Mrs F Controller · Post by **Mrs F Controller** » Wed Feb 11, 2015 4:52 pm

I know it's a bit late but for future reference steaming it. My sons a violin maker and its best to steam it over a kettle(as you are talking thin bits of wood) and then clamping it flat while it is still hot. Make sure it's well and truly dry before unclamping. It works to put a bend in it and works to flatten.

Post by **Andrew** » Wed Feb 11, 2015 9:53 pm

Good advice, thanks. I'll give it a shot sometime - I've got some more Ffestiniog 4-wheelers planned at some point, and they have curved ends. I did try steaming those for the last pair I made, using the asparagus pot as I recall (it gets precious little use out of asparagus season!), but it sounds like I didn't clamp them for long enough...

Violins eh? I think I'd be a VERY poor musical instrument maker...

Cheers,

Andrew.

Garden Railway Forum

Un-warping warped wood

Un-warping warped wood

Who is online