Weight Versus Vacuum for Veneering Pressure
If your door is 32" wide, 80" X 32" = 2560 sq in which at normal air pressure of 15 lb/sq. in. receives 38,400 lb of pressure on its area.
At 21" of vacuum, it would get 2560 X 21 = 53,760 lb total pressure.
If a 3/4 sheet of MDF weighs 70 lb, you'd need 15,360 / 70 = 219.4 sheets
From contributor T:
We're gonna need a few more sheets. 21" hg will net maybe 10.3 lbs/inch at sea level. There's more, but we'll let others play.
From contributor J:
I can't follow contributor G's math, but I agree it would take an impractically large amount of MDF, not to mention one heck of a forklift to place it where you need it.
21" HG is about 10.3 PSI, so a 32" x 80" door in a vac press is receiving more than 26,000 pounds of pressure, or the weight of around 375 sheets of MDF (at 70# each). Does your friend stack a 40' tower of MDF on his projects?
From contributor D:
I just love it when science meets myth. It always wins. And this from a guy that told his high school math teacher he would never need math since he would never be so stupid as to have a career that requires it. Duh'oh!
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