Warped MDF Sheets

[Nigel Gilbert]

Hiya all,

I have a bunch of 2mm MDF sheets (600mm x 400mm), that are warped enough to stop me being able to laser them. I can sometimes put weights around the edge but some of my designs use all the sheet and I can't weigh them down. Is there a way to flatten them? I'm assuming the warping is due to moisture. I have taken most of the sheets home in the hope that they flatten but I'm not having much luck!

Thank you,

Nige.

[Yuriy Karpov]

spray some water on them and put them on the flat surface with some good weight on top. Let it dry completely. I do this all the time with bamboo ply.

[Joe Pelonio]

If there's a spot near the center that won't be used, place it on the vector grid with the high center up, drill a small hole in the center, bend a stiff wire a bit and put the non-bent end into the hold. Pull tight to the bottom of the vector grid and bend at the bottom to hold it tight and flat to the grid. You can also do this using a thicker sacrificial piece of thicker plywood like 5/8", and just screw it down in the center.

[Kev Williams]

If your laser head will clear the weights you use (me, I have several 1x2x12" steel bars for weights), then work around them- Put them where they help, and laser everything around them. When done, move the weights around the places they were and finish up. You can always cut up vector lines, if your laser's working right it'll pick up where it left off just fine.

[Nigel Gilbert]

Hiya

Thanks all. Weights are tricky as I cut most of the sheet and there isn't much space. If I wight one are, the sheets pops up in another area. I'll give the wet sheet idea a go thought!

Thanks,

Nige.

[Rich Harman]

Switching to a longer focal length lens will help.