I am looking for input on what adhesive to use for structural laminated arches . Doug – fir 1×6 built into a 6×10 beam. based on some advice I am leaning to a UF based glue but I am always looking for new ideas. thanks
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For this type of application you need a glue that won't creep. That leaves out PVA and many other glues. If I remember correctly, UF is the correct glue because it won't creep. But for such an important application you should verify the glue's suitability with its manufacturer.
believe it or not, the best ( and used by mills) is RF curing glue. It cure with Radio Frequency...kinda like a microwave.
Being as you don't have one ( neither do I)
I would go with a polyurethane caulk...PL premium...notch trowel it on..very small, 1/16'' teeth. A thin film is remarkably strong.
The open time is long enough to work with, and it won't get brittle, like a lot of the urea glues.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
I second the PL Premium suggestion. Use a V-groove trowel. Don't use to much. You want some squeeze-out but not much. Too much clean-up. The stuff is super strong. Don't forget to wear rubber or latex gloves. The stuff doesn't wash off your hands - or anything else. I buy the gloves 50 prs at a time.
F
I only use resourcinol for bent laminations. Structural, submersion capable, simple cleanup. Long clamping time and won't work in cold temps are the drawbacks.
PAHS Designer/Builder- Bury it!
we're glueing wood here, right?
yellow wood glue .... I like Titebond.
Jeff
Buck Construction, llc Pittsburgh,PA
Artistry in Carpentry
I got a bottle of TB III today . It said not for structural use . But then it is sortof a light grey .
I do like the PL Premium easy to work with ,less mess than the gerrilla glue and no foaming . All the strength of the gerrilla and then some.
If it's available, Weldwood plastic resin glue. Mix powder with water, apply, clamp. 8hrs later, it's not moving. Very effective stuff.
"If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man." - Mark Twain
Resorcinol glues have been the industry standard for over fifty years. It has long been used for boats. It won't creep and is absolutely waterproof once set. A two component glue it has a limited pot life once mixed. Typically it has a reddish brown or maroon color. It isn't cheap.
Yeah, the cost and pot life would be the big limitations of resorcinol.
One question that should be asked here is how much moisture might be present. In a perfectly dry environment plain carpenter's glue would probably suffice (and would be easiest to work with), but something else is needed if there's any chance of significant moisture (or even high humidity).
But this is a structural element under load.
PVA will creep.