Plywood beam adhesive 3

I've used the following without issues

Advantage EP-950A

EP-950A claims to be compliant:

TTFN (ta ta for now)
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I've use Lepage PL Premium for ages... I don't know what specs it conforms to... but you can securely glue a rock to a stick. Have often used it for gluing steel strap to wood for reinforcing.


added: not for glulam, apparently

Dik

Thanks guys. I have also contacted the APA and they sent me a technical paper about Structural adhesives. I have attached it here if you are interested. I think I have enough info for now.

Awesome shacked, glad you got it and thanks for the paper.

If I may sidetrack for a sec...

dik said:

Have often used it for gluing steel strap to wood for reinforcing

Click to expand...

Would you expand on that briefly? Are you not concerned about creep? Do you share load between glue and mechanical fasteners?

For reinforcing composite action and yes, I supplement it with screws. Not normally concerned about creep, but caution the client.

Dik

That is a useful document, but many of those adhesives are intended for the factory. Achieving the typical pressure spec is problematic in the field. I assume this is a field built element. Dik's suggestion of PL Premium is a good one. Epoxy is another, but the cost is considerable.

Brad, yes the majority of the information in the paper is intended for manufacturing environment. I was able to find an adhesive that can be used at lower temperatures with clamps spaced approximately 6 to 12" apart.

I gave epoxy some thought but I couldn't find any information on whether or not it has been tested for structural building components.
Attached is the

That glue has an open time of 10min, and total working time of 20min. Given they are aiming for a 11-12mil glue thickness I expect it is very runny. Unless this is a small assembly built on the ground laying flat, this could be a problem. It seems to be more applicable to use in a hot press or cold press application where they have automated equipment to spread the glue before it is put into the press. I have done a ton of veneer work with a vacuum bag, and that glue would only work for manual applications for very small projects.

West Epoxy has been tested for wood to wood, but I do not recall seeing a plywood test. That said, I would expect the wood fibers to fail long before the epoxy bond would fail. We have used West Epoxy to retrofit glulams with carbon fiber strips and it worked very well. The primary advantage to an epoxy is the thickness, gap ability, and the low clamp force needed (10psi typically). West Systems has an excellent tech support, so you can give them a call.

That glue spec is suggesting between 100-250psi depending on the species. As for your clamps, I am not sure you will generate much more than 25psi clamp force. The typical clamps you find at a hardware store clamp that would be convenient to work with is rated for up to about 600lb clamp force. You can find bar clamps to yield a greater clamp force, but the depth of the jaws is small and they would be difficult to use unless I am mistaken about the project. You will need to spec that they be careful re-tighten the clamps after the glue oozes around in the joint, or the clamp force could be far less. This is also assuming they use a stiff spreader. Without a spreader element you will get very localized clamping as the individual plywood lamination will simply bend. I use a vacuum press for veneer work, and at maximum vacuum I achieve about 15psi pressure.

I am assuming this is a structural application of some significance safety wise. If not, then I would not be too concerned. I still think Dik's suggestion of PL Premium is the best. Easy to get, and cost effective.