XJet

I recently spilled a little polyurethe glue (Gorilla brand) on my bench and today, several days after I spilled it, I went to clean it up.

Boy, this stuff just crumbled and turned to powder with only a small amount of pressure being applied!

Epoxy, cyano, aliphatic and even good old PVA all seem to be very hard/strong when cured/dried but this polyurethene glue appears to have no strength at all.

What gives -- is my bottle bad or is this stuff simply not as strong as the other glues we tend tu use?

I sure wouldn't want to use it for any critical joins (which fortunately I haven't) in one of my planes after seeing how easily it crumbles.

Is it best just used for large-area, low-stress joins such as sheeting foam cores?

Stick Jammer

Don't know about Gorilla but the Probond polyurethane is mighty tough stuff when cured. Definitely doesn't crumble. Sounds like maybe the glue has gone bad or something.

aimmaintenance

Your glue may be bad but I doubt it. The situation in which your comparison is based is bad. Without diving into a chemistry seminar I'll just state that the poly glue left to cure in an unrestrained state. (on a benchtop) will expand TOO large and the air bubbles will be so big that surface thickness will be thin, therefore weak. Left to cure in a restrained sate (between 2 pieces of wood) keeps the density high therefore creating a strong bond.

phread59

Aim seems right to me. I have used Gorrilla glue on my current plane. Anyplace air gets to it, like when you join 2 sheets it foams up. The joints are very strong. The foaming is normal for this type of glue. I personally would not worry about it.

Mark Shuman