Advice on MRMDF please

[tsb]

Have just picked up a 8x4 sheet of 22mm mrmdf, which had to be cut in two in order to get it in my van. When I got home, I realised that its slightly bowed. Any ideas how to get it flat. I intend using it for a router table top and some sample shaker doors for my kitchen but if its not flat it will be useless.

 

[newt]

You can lean it against a wall until it is flat but it is does not always work. If it is damp that has caused it to bow I afraid you have had it but if it is just the way that the muppets have stored it you may just get lucky.

 

[tsb]

If I try the leaning against the wall method, do you leave it over night or keep checking it every hour or so.

 

[Scrit]

I'd recommend that you don't lean sheet products against a wall as they will always bow unpredictably unless supported on angled uprights, thus:

Attempting to unbend them bay unsupported stacking doesn't always work that controllably in my experience. I've found in the past that inserting a bowed sheet into the middle of an existing pack on the floor (on a pallet) will flatten it out over a few days, or that cutting components to approximate size and stacking on a known flat surface such as a level concrete floor (with appropriate damp-proof membrane) and some heavy weights on top, such as a few breeze blocks, works quite well.

Scrit

 

[Shultzy]

Scrit, does that method apply to plywood as well. I have a length of 3/4" ply about 12" wide and 8' long and it has a bow of about 3" in the middle.

 

[Scrit]

Yes, any sheet stock. The prooblem I've found witjh trying to un bend it by supporting the other way is that it's difficult to get it just right

Scrit

 

[OPJ]

Great idea! Thanks for sharing, Scrit.

 

[tsb]

Thanks Scrit, I've cut some of the board into strips,( for the frame part of the shaker door) and laid them on a flat surface with a weight on them, so I see what happens in a few days