# Hardboard Stabilization



## cjwood.33 (Apr 25, 2019)

Hi All,
My current project is to glue a finished painting on canvas to 1/4" luan, which I will seal first. I want to prevent the board from warping, and have come up with 3 ways to glue strips to the back.

Which would be the most stable? : i would prefer avoiding miter cuts!

Thanks 👍


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## GeorgeC (Jul 30, 2008)

I would not expect 1/4" Laun to warp. Why do you think it will?


George


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## cjwood.33 (Apr 25, 2019)

Just my inexperience, I suppose. I've never done this before. Are you saying luan doesn't warp with time? That's good to know!


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## Steve Neul (Sep 2, 2011)

The only 1/4" sheet good I can think of that wouldn't warp would be melamine. 

I'm not sure it's a good idea to do this though. I paint and have always been told the canvas needs to breathe.


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## cjwood.33 (Apr 25, 2019)

Actually, I just googled luan warping, and it DOES warp! So.....what would be the best way to lay out the strips on the back side?


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## Steve Neul (Sep 2, 2011)

cjwood.33 said:


> Actually, I just googled luan warping, and it DOES warp! So.....what would be the best way to lay out the strips on the back side?


Any wood product is going to warp. What happens is when you glue something to one side of it, it seals that side from moisture in the air. The other side then is left unsealed so moisture in the air can get to it causing it to swell. It's sort of like wetting one side of a kitchen sponge. The side getting the water will swell up. It would help to put a varnish on the back side of the plywood however it wouldn't be sealing both sides the same. If one side or the other was sealed less then it would warp. This is why I suggested the melamine. It's already completely sealed on both sides. I should have noted two sided melamine. There is one made for drawer bottoms and cabinet backs that only has the melamine on one side.

If you haven't painted the picture yet why not just prime both sides of a sheet of lauan and paint the picture directly on the plywood?


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## gj13us (Apr 19, 2016)

Or maybe put canvas on both sides and paint gesso or something on the back canvas.


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## CharleyL (Jan 13, 2019)

The most stable sheet wood product that I know of is "Tempered Hardboard". It is also called "Tempered Masonite". It comes in 4 X 8' sheets and is moisture resistant and very stable, but it's only about 1/8" thick. It's also quite reasonably priced. Your frame idea, either #1 or #2 would be the best approach for strength, but consider half lapping the corners instead of the butt joint. For a half lap joint you overlap the two pieces, but remove 1/2 of the thickness of each piece at the point where they overlap, so the result is a joint that is the same thickness as just one of the boards. This makes for a very strong joint if glued together, but does require some accurate woodworking. Another way would be to use either of your #1 or #2 methods and use dowels, biscuits or pocket hole joints plus glue to get a good strong joint. The panel could then get glued, nailed, or screwed to your frame. I have no idea what your planned use is for this, but some triangle pieces of 1/4" plywood attached to the back side of each corner with glue and nails or screws would further strengthen the joint, if their use wouldn't be visually objectionable.

Pleas look at this material in a local lumber source and decide if it will do the job for you. If not, please tell us more about your intended final purpose of this.

Charley


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## woodnthings (Jan 24, 2009)

*hardboard is not luan plywood*



cjwood.33 said:


> Actually, I just googled luan warping, and it DOES warp! So.....what would be the best way to lay out the strips on the back side?



Your title is not consistent with your chosen material. Check out this list of various substrates to get a better idea of which one may suit your needs:
https://www.woodmagazine.com/materials-guide/lumber/sheet-goods-selector


This link describes Baltic Birch, one of the best plywoods available:


https://www.woodworkerssource.com/b...-birch-plywood-why-its-better-when-to-use-it/


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