Cold Versus Hot-Melt PUR Glues

Are the benefits of a hot-melt polyurethane resin glue system worth the cost? February 27, 2013

What would the best PUR setup be for doing mortise and tenon screen doors? I was sold on the glue machinery gun, but then I saw that the 3M gun is a lot cheaper, although they do not offer the fancy tips Glue Machinery has. I priced out a Glue Machinery gun at 1200 and a 3M gun at 500. So what's the extra 700 get you? Is it mostly durability? Are Glue Machinery's adhesives any better? Are there any other options for an industrial gun? At this time I am only gluing wood to wood.

Forum Responses
(Adhesive Forum)
From contributor R:
Why are you looking at the guns? You can get a very good PUR in caulk form without the cost of hot melt guns. We like Weiss out of NC. They make PUR for the window and door industry.

From the original questioner:
Thanks. I looked briefly at the adhesives available at Weiss and it seems these don't have the properties that attracted me to the hot melt PUR in the first place. The reason I am considering switching from PVA to PUR is the 2 minute set time you can get with a hot melt. The other main difference between cold and hot PUR that I see as problematic is that the adhesives I saw at Weiss say they foam, which is the reason I generally stay away from using Gorilla Glue. Are there any cold PURs that don't foam and have a 2 minute set time? I'm definitely open to suggestions. If you can tell me a little about your operation and why it is you like using the cold PUR it would be much appreciated.

From contributor B:
We [Spectrum Adhesives] offer a product CP-0712, which is a very fast set (3.5-5 minutes) liquid PUR. It does foam. In general, the more aggressive the cure, the more aggressive the foam. The foam does remove and clean up easily.

From the original questioner:
It seems you offer both hot and cold PUR. Does squeeze-out from the hot melt clean up better and/or easier than the foam from the cold? To tell the truth I'm still a little more drawn to the hot melt but I guess if I can avoid another equipment purchase that would be best.

From contributor B:
PUR hot melt squeeze out does clean up easily, though part of the intention of the hot melt is to minimize any squeeze out. It's easier to control the amount of hot melt and where it goes. I'd consider the liquid first and see if it does the job for you - a lot smaller investment!