Polyurethane Glue Spreaders

12/15/2012


From original questioner:

I've been using UF resin/catalyst glues in laminated glue-ups for years with good results. Laminations are often 8 ply 3" x 36" long and go into male/female gently radiused cauls.

THe finished laminations go through many secondary operations, involving table saw trimming, bandsawing, and stationary sanding. Recently the Formaldehyde really did a number on me in these processes, and also contaminated the whole shop for my now hypersitized to formaldehyde body. I am comtemplating switching to polyurethane glue, which I've used sucessfully in the past. The only problem with the polyurethane is that it is so slow to spread the glue in a multi laminate glueup.

Are there any small shop spreaders for polyurethane glues.

From contributor B.


Jim,

We often avoid using polyurethane glue on laminations for the same reason. Our fall back adhesive has always been West System epoxy. Is there a reason you could not do the same?

Also polyurethane glue actually performed the worst of tested glues in a Fine Woodworking test a number of years ago.

BH Davis

From contributor Ji


I'm not sure how epoxy would be appropriate in a bent lamination.

By definition, you have to apply large amounts of pressure to form the bent lamination. As epoxy needs a thick glue line, epoxy doesn't want a pressed joint.

I called the Uni-bond 800 folks, the UF glue supplier about this. They have reformulated the glue and removed 90% of the Formaldehyde. THey say this qualifies it as a "green" glue. I was thinking of giving the new formaulation a try.

From contributor B.


Jim,

We usually do our laminations on a strap press or in vacuum sleeves as vs. between cauls. We typically use 1/8" strips up to around 8" wide. I've never had a problem with the straps applying enough pressure to reduce the epoxy glue line. We of course get some dripping out the bottom edge but it is always minimal.

In your shoes I'd certainly try the new formulation of the resin glue though, and would be interested to know the results.

BH Davis