The Framers Forum

Hi, a customer has bought in a acrylic painting on canvas board which has got very damp and curled along the long edge (600 x 450mm) by some 35mm from flat. . Customer has given me a free hand to try different methods to try to flatten and accepts the risk of further damage. Any suggestions as to how to flatten it. Could a gentle steam and then put under weights be the way forward?
Nick

Don't steam it. You'll make it worse.

Is it curling inwards or outwards?

My guess is inwards.

Yes Inwards, any suggestions ?

Do you have a picture of the canvas board?

I dont think you will flatten it like that, even putting it in a press hot press o dont think would help. These boards quite often warp when painted and are also often warped before thry arr painted on. I would try it in s frame with a 4 or 6mm mdf back that won't bend under the pressure. That would be non invasive and will probably work.

What's happened is the exposed card back has swelled due to moisture absorption. The painted on front remains the same size hence the bend.

Try placing in a warm, dry spot and see if it pulls flat. It probably will a bit but not completely.

If it's going in a frame, do what AG says and put a hefty back on it. If not, you will maybe have to glue it to a similar board.
With enough weight on top this should do it, but once done seal the back of the board it's stuck to with a solvented varnish.


I've seen acrylics bend a board into a cylinder. This is due more to a heavy paint layer shrinking than the back swelling.
One cute trick is to apply a thick layer of the same paint to the back to counteract this. Again it probably won't pull dead flat
and once you do this it will make gluing down tricky.

Thanks for all your help and suggestions