What glue can I use to glue phenolic plywood to phenolic plywood, and laminate to phenolic plywood?

Question

Basically:

I want to build some cabinets. Locally (Indonesia) there is 'cheap and nasty' 15mm plywood available, plus 15 & 18mm phenolic plywood. I tried ordering some 'slightly nicer' 18mm plywood, but it's apparently not going to come.

So I am looking at using (black coloured) phenolic, which for some purposes I will leave as is, but for others I will want to stick high pressure laminate (HPL) on it so it's not all black.

Question is: normally here we would use neoprene glue for HPL to plywood and basic white PVA glue for plywood to plywood, but will they work for phenolic? (Obviously in some cases the phenolic will probably get sanded off or rabbeted or whatever, so in that instance it's not an issue, but in other cases it will be.)

Edit: there appears to be some confusion about what plywood I'm referring to. Here nobody actually knows what it is called as it is called 'Garuda form', where Garuda is the brand (or was?), and 'form' refers to concrete formwork (it's often spelled/pronounced 'foam' here, because people here don't speak English so such homonyms aren't surprising)

Here's a fairly representative photo of a (12mm) version which looks kinda scratched, which is pretty much the state of the stuff I saw on sale as well:

Although nobody actually knows its formal name here, it is my understanding it that it is indeed generally referred to as 'phenolic plywood', and I'd guess that the quality of the wood itself isn't all that high although the phenolic that's on the outer faces means that it's much more durable for formwork.

Answer 1

Contact adhesive is generally what you'd use in a home workshop environment to glue high-pressure laminate to any substrate, and it will work here too. The bond may not be super durable, but this is the adhesive of choice for many people today laminating over old Formica and melamine surfaces which are similarly resistant to conventional glues.

Surface prep
I'm unclear on whether sanding/scuffing the surface of the phenolic will actually help improve bond strength with this type of glue. This is a desirable, even necessary, step to maximise adhesion with many glues but contact adhesive works in such a different way to other glues that 'rule' may not apply.

It would probably be advisable to do a few tests to see if the cleaned, but otherwise untouched, phenolic surface bonds better as-is or after giving it a thorough scratch pattern via sanding or use of an abrasive similar to Scotch-Brite. Abrade with more than one grit to check if coarse scratches or finer scratches provide the best bond, or if there's no difference.

IF you find sanding strengthens adhesion (and I wouldn't be surprised if it doesn't) my guess is there'll be no difference between about 80 and 150 grit, but beyond 220 you may begin to see a decline.

Answer 2

After a brief internet search to determine what "phenolic plywood" actually is, I turned up this:

Phenolic plywood is somewhat of a misnomer as it should more realistically be called “phenolic faced plywood” or “phenolic covered plywood.” The veneer core plywood itself isn’t made of phenolic; it’s generally made of birch. What makes it “phenolic” is that both surface veneers are soaked in phenolic resin before attaching them to the plywood. This creates an extremely stable, smooth, durable, highly water resistant and attractive surface
^{Source: http://theplywood.com/phenolic}

That same site also says:

Building things out of phenolic plywood is much like working with other types of plywood.

Then goes on to describe cutting, sanding (don't sand the face, just ease the edges as the plastic coating can leave a very sharp edge) and screwing (it's very good at holding screws).

Since the core of the plywood is standard, cabinet grade plywood, it would only stand to reason that standard plywood construction techniques apply. Regular PVC glue on the wood/wood joints, regular screws, etc.

The one difference I can see is if you're slipping the phenolic plywood into a dado. In this case, I can definitely see a benefit to sanding the coated outer layer off where it will go into the dado, then cutting the dado a fraction narrower to account for the loss of the surfaces. This would give you a wood-wood bond for the glue inside the dado. Even if you don't do this, you'd still have a wood-wood bond at the edge of the panel against the base of the dado and would probably still be good to go, especially so if you screwed through the dado into the shelf piece.

Additionally, since the phenolic resin impregnated outer layers are already laminated with plastic, I'm not sure why you'd want to put an additional layer of laminate on top. However, I believe that a very light scuff sand of the surface to be laminated to give it some tooth, then standard contact cement would probably hold just fine, just as it would if you were laminating standard plywood.

I would suggest, though, that if you're going to be laminating surfaces, you might consider making those surfaces out of a less expensive, lower grade plywood since you'll be covering any ugliness in the surface layer with the laminate.

If you're laminating to change color, the site above noted that phenolic plywood is available in many colors beyond brown and black, but that these other colors may have to be special ordered. You may have no choice but to apply a laminate if you want some sort of a patterned surface.

Answer 3

Based on the description of the "black-colored surface" I'd guess that the OP is not referring to the "furniture grade" stuff, but rather the "industrial" stuff that's commonly used for cement/concrete molds, the lining of agricultural enclosures, marine structures, and shipping containers, etc. Where durability and high water resistance is desired.

Not sure of exactly how the formulation of the coating is any different between the two, but the "furniture grade" stuff is built with essentially Baltic birch plywood and the phenolic (essentially plastic fused to the wood fibers) coating that comes in a variety of pretty colors. (Undoubtedly one of them is black.)

The factory impregnates the fiber surface of the "industrial" stuff with a thermosetting resin and then bonds the resin fiber surface to both sides of the board with heat and pressure with inter-ply construction of C or C-plugged veneer. Face veneers are B-grade.

As far as gluing to the phenolic surface, TiteBond makes a glue for Melamine that might work on Phenolic surfaces as well. You may want to scuff the surface before trying to glue it.

I also understand that abrading the mating surface with sand paper and using moisture-activated polyurethane adhesive (e.g. "Gorilla Glue") will work but PVA and epoxy will not.