Gluing plastic laminate - need help

[jim gossage]

i am building a pop up extension table for my table saw, and need to glue plastic laminate onto the table substrate which is made from two 1/2" x 52" x 30" pieces of baltic birch plywood glued together. i plan to use DAP weldwood contact cement. i glued up a 12 x 12" test piece by brushing on a thin coat of cement on both surfaces, waited the recommended 20 min, and then pressed together and rolled with a laminate roller. they bonded quickly but 24 later the pieces can still be separated slightly at the edges with a little force.
1) did i do something wrong, or does it just take a few days to fully cure?
2) do i need to laminate both sides of the table when using plywood for the substrate?

thanks

[Bartee Lamar]

I think 20 mins is way too long... I know what it says, but I wait more like 10 mins til the cement is dry to the touch.

Did you use J roller to roll out the surface?

[Ray Moser]

I don't think you need to laminate both sides but I would seal the underside with paint or several coats of varnish. This would, I think, prevent moisture from being absorbed on the underside which could cause the piece to warp. I have had plywood warp when subjected to moisture on one side only.

[John Lucas]

Ray,
To add to the others, the only thing I suggest is to double coat the BB ply. It is pourous and will soak up the first coat. No need to on the laminate. ANd no need for lam on the underside...a good paint will poly will seal it.

[Phil Phelps]

...if you roll or brush. The back of the laminate will soak up quite a bit of the first coat. If your doing the edge of MDF, you sould seal it first because the edge is nothing short of a sponge. Wait long enough for the cement to flash off and feel slightly tacky before laminating. Use a lamination roller to press the laminate to the surface. I've done this for forty years, but the last ten I've been using Sta-Put, a professional pressurized spray. But if I were to roll, I'd use an oil enamel roller cover.

[Howard Acheson]

I suspect you put too little adhesive on the substrate and the back of the laminate. Also, you should be sure you have a little extra film thickness around the perimeter to ensure a good bonding.

BTW, solvent based contact cement is more reliable than the water based contact cement.

[jim gossage]

... But if I were to roll, I'd use an oil enamel roller cover.

Phil, what is an "oil enamel roller cover".

BTW, i used a J-roller and the cement is solvent based. i suspect that i do need to put 2 coats onto the BB because some seemed to get soaked up. i waited 20 min by the clock after the first piece was coated, but maybe that was too long since it was no longer tacky when i pressed them together. Thanks for your suggestions.

[Tony Haukap]

I have never been real happy with the bond of contact cement around edges. So what I started doing is to masked off about 2-3" around the perimeter of both the substrate and laminate, apply contact cement as usual and once the contact cement sets up remove the tape and spread yellow carpenters glue to that area. This give you the benefit of the instant bond to the large surface and is usually enough to hold the edges down until the glue sets, but if the laminate has any curl to it you may need a few spring clamps around the perimeter. Since using this method I have not had any edges lift or edges deaminate like I experienced with contact cement alone.

[Justin McCurdy]

The last lamination job I did, I remember asking my dad the same questions, and for one of the first times in my life, I took his advice.

Supplies:

1: Titebond Coldpress for Veneers. It is non toxic and does not give off any more of a smell than yellow glue.

2: Small tight nap paint rollers from the borg

3: J-roller

4: Towel

5: Cement blocks


Procedure:

1: Spread the coldpress on both the laminate and the base material (mine was mdf). Give it a chance to dry completely. If it looks like there are dry/bare spots that have absorbed the glue without creating a totally non-porous surface, apply another coat.

2: After you are completely sure that both contact surfaces are non-porous, spread one more coat on both surfaces.

3. Put 3 dowels on the base surface, then put the laminate on top of the dowels.

4. Start from the inside dowel and start removing them.

5. Use the j-roller to push any air bubbles out that may have formed.

6. Put a towel down on top of the finished side of the laminate and then proceed to cover the surface with cement blocks.

7: Wait a day, take the blocks and towel off, trim up with a router, call it a day.


I had 0 lift on the laminate. It truly looks like part of the surface.

By the way, that was my first time laminating, but the technique was exactly the same as the one my father used for 15 years when building furniture and professional bars.