Stop fighting bowed plywood, a shop guy in Grand Rapids showed me the wet rag trick

Wesley Adams · 2026-10-20T00:30:08.1521+00:00

I had 14 sheets of 3/4 birch ply sitting in my garage for about a month and every last one of them was bowed enough that my boxes came out out of square on the diagonal by almost 3/8 inch. I was shimming and clamping and cussing and it kept springing back once I pulled the clamps. Then a guy I buy offcuts from in Grand Rapids told me to lay the sheet cup side down on the floor, soak a rag and wring it out so it's damp not dripping, wipe down the concave face, and let it sit flat with weights overnight. I tried it on two sheets as a test and by morning they were flat enough that I could cut parts and they stayed put after assembly. The trick is only working the concave side, because the damp face swells and pushes the bow out, and if you do the wrong side you just make it worse. Don't soak it either, I got impatient on the third sheet and it raised the grain bad and I had to sand it back down. It won't fix a sheet that's been twisted sitting on end for a year, but for normal cupping it saved me from buying new stock. Has anyone tried this with MDF or does it just swell and stay swollen?

Babble Community

Loading…

Stop fighting bowed plywood, a shop guy in Grand Rapids showed me the wet rag trick | Cabinetmakers - Babble Community