bikermom

I've never had a warping problem, but I did find this technique today that you may want to try. Their mat (brand unknown) had gotten warped in the heat, so they decided to try and use heat to reverse it. Good luck QuilterGary!

Here is how they did it:


Take a heavy piece of 1/2" to 3/4" plywood. (Make sure it is not warped and has at least one VERY CLEAN, SMOOTH side.) Lay the plywood on concrete pavement (not grass or asphalt, it's too soft), smooth side up in an area that gets sun ALL DAY. Lay the mat on the smooth side of the plywood. Place a large piece of PLATE GLASS on top of the mat (i.e. coffee table top, shelf glass or top of dresser). Our glass plate from the dresser did not quite make it, so I used a couple of a glass shelves in addition. Make sure the whole mat is covered with the glass, nor just the affected area. Leave this "contraption" in the sun all day, do not move or touch it. Early the next morning (preferably) we removed the glass and my mat was fixed!