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Expanding Adhesives? 1

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tffy

Aerospace
Jun 5, 2006
25
Hi everyone. I'm trying to fill in a post-casting gap between two materials of differing CTEs, in a closed environment.

I'm looking for some sort of a slow cure (about 4 hours at appoximately 200 degrees F) adhesive that expands upon cure. Do any such materials exist out there?

Thanks a bunch!

Just to make sure, the adhesive does not need to be heat-activated, it's just it will have to cure in a high-temperature environment. Ideally it'd be a two-part mix adhesive.
 
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I have heard that some of anaerobic adhesives expand ever so slightly on curing, no details.

I would give the following company a call and discuss your requirements. They have been pretty good either with their products or referred me to another product.

 
Yes it is possible.

Some cylcic monomers expand when cured. There are some epoxies that do, I know as I once worked with a man who was developing them for dental adhesives.

Probably the easiest way to get expansion during cure is through expandable microbeads that expand when heated. You can add these to a normal adhesive formulation. The best known in Expancel from Akzo Nobel, contact for more information.
 
Thanks all... Will research this further, and see if I come up with anything on your leads.
 
Micro beads are also available in McMaster Carr and most boat dealers from West Systems Epoxies.

Absolutely the right thing, as the adhesiveexotherms, the airin the beads expands a little...It is generally the ingredient in an expanding non-foaming type material.
 
Sounds interesting panel guy. I haven't seen that type of bead. The beads I mentioned are an alkane (like gasoline) microencapsulated in a thin polymer shell. When heated the liquid boils and the beads expand to 40x their original volume. You can get different beads depending what expansion temperature you want.
 
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