Not sure where this problem is coming from... I have two 1/2" layers of MDF (1200x1200mm) that I have screwed together and leveled. I shellac the leveled area so that my spray adhesive has better grip than raw MDF. Within 24 hours, different locations within a 24x24" area can vary by a whole millimeter. I'm cutting .025 aluminum sheet. So, that much variation is a problem. Is MDF easily effected by humidity change? Suggestions sincerely appreciated.
It most certainly is affected by humidity and barometric pressure. To say this is the cause of warpage is tough. I think the best way to approach this problem is to surface a spoilboard prior to your work. This will ensure that your work is parallel to your machines x and y. Joe
MDF is terrible in humid areas, at least here in Florida..... I surface my spoilboards every few weeks due to expansion... When I do aluminum or plastics I have a spoilboard for my spoilboard, usually a piece of scrap MDF or ply slightly larger than the pieces i'm cutting, I surface it just prior to cutting. Much faster to surface a small piece than the entire spoilboard...
The shellac may be the problem. Sealing just one side causes non-uniform moisture absorption which induces cupping.
