3/4" enough?

[Shawn]

Hi
i'm getting ready to buy the wood for my pitot style bench. I have 12 two stage motors that should allow me to pull very high depression (50+"'s) and high cfm (500cfm+). The problem i'm running across is simply finding 1" MDF in full sheets.With this type of depression i'm a bit worried about using 3/4" material,but i don't have any experience with this either.So i thought i would see what you guys think.
shawn

[Unkl Ian]

You can laminate thinner materials to get
whatever thickness you want.

Regular wood glue can be applied with a roller,
stack the pieces,and add some weights to hold the parts.
Or use some screws to hold them while the glue sets.

[larrycavan]

Also try to cross grain the pieces you laminate. Well..... as best as you can determine the grain pattern that may exist with that type of material.

I saw some photos somewhere of a bench that imploded on the corner. I couldn't believe my eyes but the photos were real.

[Shawn]

I actually thought about doing that. Just using 2 pieces of 1/2" and glueing them together, but if all i really need is 3/4" then i don't want to spend twice as much on materials. I know that 3/4" Medite has a 4,300 lbs./in2 rating and if my pressures don't exceed that, then i don't really need the 1" stuff. I guess what i really need to know is how much pressure in in.2 that i will generate.
shawn

[Rick360]

I used 5/8" plywood (measures just less than 5/8") and I test up to 40"wc without problems. I think 3/4" would be fine for 50" if it is constructed well. I added 2x2 braces around the edges of the plywood between the chambers for extra support. Also used angle iron brackets to bolt the front panel with. I don't notice any flexing or bowing of the sides when testing @ 40".

Rick

[2seater]

[Shawn]

thanks for all the input. I think i'll go with the 3/4" and make sure that i put good some supports in.
thanks again,
shawn