Glueing Phenolic Plastic To Plywood

[PNast]

I am finally setting up my PRSalpha 96x48 for a vacuum pump (cant wait to throw out all those Rockler clamps. Getting Popeye forearms from tightening them all day!) The pump should be on it's way soon from Shopbot, I ordered a 4x8x.75 sheet of Phenolic X and want to glue it to the plywood top. I will be using some screws but I have heard if the wood is cupped a little it can actually pull up the plastic if it's not secured good. Can anyone suggest a good glue or epoxy? I will be using the plastic tubing and gaskets like Shopbot uses to make the Handibot parts. I am looking to make 8 - zones for 23"x11" signs, any thoughts on setting up the zones, tubing size, connectors and valves would be greatly appreciated.

Thanks
Paul

[coryatjohn]

Just a guess but I would think regular contact cement would work quite well. Gorilla glue would work well too as that stuff will stick to anything. Using Gorilla glue would give you a chance to move it around a bit before it sets.

[PNast]

Thanks, I think I am going to use Gorilla Glue with some screws, Ryan at SB suggested a 2 part epoxy but I cant find anything larger then the little tubes. Most of the 2 part epoxy has a 5 min work time and I need more time to align the sheet. The 4x8 sheet of phenolic weighs about 180 lbs. I will post pictures when I get the vacuum table all setup.

[coryatjohn]

When using Gorilla glue, don't forget to add a bit of moisture to the wood to speed the reaction. If it's humid, no need though. The stuff works great. You might want to do a test on a small piece to be sure you have adequate adhesion.

[bleeth]

If there is a marine supply store near you they will have containers of liquid epoxy.

[Ger21]

US Composites has good quality epoxy at very good prices.
http://www.uscomposites.com/epoxy.html

Be aware that if you use Gorilla glue, the foaming as it cures can actually push the phenolic away from the plywood.

[coryatjohn]

I've used Gorilla glue many times to affix plywood to steel or other materials and as long as it's clamped well, it's not a problem.

[PNast]

The foaming with gorilla Glue was what I was worried about, it is hard to clamp a 4 x 8 sheet down. There is a West Marine in Knoxville and I think I will use the West System #105 epoxy resin with the #209 extra slow hardener, it gives about 45 minutes of working time and has nothing but excellent reviews. The Phenolic that I bought is very shiny and smooth like a countertop, I will be roughing it up with some 80 grit on my dual action air sander. Thanks for all the help!

[coryatjohn]

I'm sure that slow cure epoxy will work great.

[bleeth]

Good plan. Be ready with a bunch of sandbags, full 5 gal buckets, or something to plop on it and keep it weighed down while curing. Epoxy ooze can be cleaned up with acetone or lacquer thinner but also with vinegar
Stacking a few other sheets of melamine or mdf first will help distribute the load. Before you permanently position your plywood, determine your x and y zero and put the board slightly minus in both axes to be trimmed later so you have a perfect 0 axis registration permanently built in.This will be very useful down the road. If you haven't already verified that your y is dead square to x best to do that early as you can, even if it means postponing the permanent bed set-up. Although SB says the design is such that when powered down you lose perfect square if you are really patient and careful and somewhat anal about it you can get it tweaked so it will stay squared. The more accurate you set it up to begin with the happier you will be down the road.

[gc3]

http://fiberglasssupply.com/Product_Catalog/Epoxy/epoxy.html#West-Epoxy

105 with 205 would still give you plenty of open time, we use that combo for door/door panel glue up...and clamp for 24 hrs...with epoxy extreme clamp pressure will starve the bond...West System can bridge gaps up to .0625" and retain structural strength