CA vs Epoxy

[Subculture]

Yes it smells exactly like perspex/acrylic when it's being worked. The powder acts as the kicker and thickening agent.

I believe Tensol 70 is very close, although I haven't used that.

[Kazzer]

Bingo!

This material is also used in screeding floors. Up to 1/4" thick layers can be poured onto the floor and it flows out and rapidly sets, usually within an hour, at which time a fork-lift truck can be driven over it. Stinks like crazy and don't smoke or you'll blow the roof off the building. I tinkered with this stuff many years ago. Nice product! As for your Fusion, it is very expensive for what it is, packaging is everything.

The interesting thing about methyl methacrylate (MMA) is that although it needs a hardener (kicker) to set it up, it isn't like an epoxy. Once an epoxy sets, the only way you can get another layer of epoxy to stick is to mechanically abrade the surface to provide a 'key' for the subsequent layer to adhere. The rough surface and the jagged edges prevent the top layer from delaminating.

With MMA the top layer is very different, it actually melts the underlying area, like water poured on ice, and then sets, providing a monolithic material. No wonder they call it Fusion.

I'm not familiar with ASTM tests on adhesion of MMA to different substrates, but my gut feeling is that it won't surpass an epoxy. None of this is really relevant in our application because of the very small surface areas etc. involved. I suspect the bond is similar to CA, somewhat brittle.

In summary, MMA is not as good as using a solvent weld if bonding two thermoplastics together. It may set more rapidly than an epoxy, which may be an advantage. Personally, I feel the material is way overpriced in this form, considering what it does. I guess at the end of the day, its what you are happier with.

[Subculture]

One snag I've found with solvent welding, is that it can sometimes make the surrounding plastic brittle. I've found this is especially so when welding polycarbonate/lexan.

Don't know why it does that, but it always makes me wary of using a solvent in any application where stress may be a factor.

[Kazzer]

That could be cured by placing a fillet of material along the edge, just as if you were welding. It can also take quite a while (days) for the solvent to evaporate out of the joint, and this would make it weaker until it dried thoroughly.

One GREAT thing about your Fusion product - it welds and melts into Plexiglass (Perspex- Lexan) so is the perfect material for repairing spider cracks and splits in our Sub-driver cylinders. I've been using some Permatex MMA product, but it had no kicker in it, so took a while to cure out.

[Kazzer]

I found this really good article on MMA adhesives which explains the 'mechanics' of these types of adhesives.

MMA ADHESIVES