1960s-1970s Telephone Repair

Do you recall if the goo you used took 5 min or 20 min to set?

The Home Despot ad above shows "Epoxy Plastic" with a 5 minute time to set. However, I couldn't find that on the Loctite web pile, but found this instead: which is a "Plastic Epoxy Bonder" with a 20 minute time to set. I prefer the longer setting times and overnight hardening, so I'll start with the 20 min flavor.

The Plastic Epoxy Bonder stuff is NOT an epoxy. Epoxy is a thermosetting plastic. The Plastic Epoxy Bonder is an acrylic, which is thermoplastic. See first question at: That's fine because an acrylic based glue is what you want for ABS anyway.

I suspect it also has some sort of solvent to soften the base plastic. Looks like the formulation has changed slightly: (older) Yep, 1% carbon tetrachloride solvent, which should do nicely for softening plastics. Three different forms of methyl methacrylate (MMA). Incidentally, MMA was once used for fake finger nails, but was banned for some reason: I'm not sure what the other stuff does and am too lazy to dig it out.

So, what you have here is an acrylic plastic glue, with some rubber compound added to make it a little flexible, no epoxy resin anywhere in sight, and a bit of solvent to soften the base plastic. Also see the data sheet at:

The 5 min "Epoxy Plastic" MSDS is rather cryptic: and only shows "epoxy resin, proprietary". The hardener is listed as "tertiary amine" which is an epoxy resin curing agent.

I would go for the 20 minute flavor.

I don't remember if the stuff was 5 or 20 minutes but I suspect it was the 5 minute variety. I wondered about that epoxy name. Looking at the ingredients made me think it wasn't an epoxy but I don't know enough about epoxies to tell. I do know that there are some pretty damn good acrylic based adhesives though. I suspect that the adhesive backed aluminum tape made for ductwork (not duct tape!) uses an acrylic based adhesive. That stuff sticks remarkably well and does so for years. Eric

While it admits to not addressing the fine points of gluing all the different sorts of plastics, this web site is often really handy:

I?ve had great success mending most plastics of all kinds (varying degrees with poly-types) using Devcon Plastic Welder:

It?s my go-to solution when fixing anything plastic.

Cool phone. Brings back memories. Ours was (at different times, replacements installed after family of 6 abused it) red, yellow, black, white. With extra-long handset cord, of course.

Good luck.

History of the development of the Model 500 phone:

Fascinating...

Well, at least Devcon doesn't claim that it's an epoxy. From the MSDS sheet at: it appears to be similar to the MMA based Loctite Plastic Epoxy Bonder but without the carbon tetrachloride solvent to soften the base plastic.

Data sheet: "Not recommended for use on copper or brass"

Same here, but with fewer phones and colors. In college, I helped build a private exchange, complete with direct dialing and rotary steppers, in the dorms. Everything was "donated", which translated from student slang meant stolen. This was approximately when we first walked on the moon, so the administration was tolerant of anything that might be considered science and resisted the temptation to throw all us phone phreaks out of skool. Yep, fond memories.

Hello again, everyone and many thanks to all the timely responses from Jeff L. and others. Just one additional comment: When that plastic hook switch part breaks the phone will be permanently off-hook even with the handset parked in the cradle. Also, while many usenet groups have become silent, s.e.r is most certainly a notable exception! VTY,