Req: glue advice

November 8, 2005 10:53 AM

A sticky situation: what can be used to glue together smooth, glass-filled epoxy widgets?

The pressure sensor for my hottub, which cuts off heater power if there's no water flowing (otherwise it'd end up boiling in the heater tube!) broke off at its threaded insert. The material is smooth, hard, and appears to be some sort of glass-filled resin, possibly quite a bit like the fiberglass used for boat- and tub-building.

Superweld, Techsteel, and Shoe-goo won't form a strong, permanent bond. What would?

posted by five fresh fish to home & garden (14 comments total)

This To That will tell you what to use to glue X to Y.
posted by chuma at 11:04 AM on November 8, 2005

For using that site it would be helpfull for you to know that fiberglass is technically called Fiber Reinforced Plastic. They recommend PVC glue.
posted by Mr T at 12:18 PM on November 8, 2005

Plastic? But it's an epoxy, I think.

Maybe I need a resource that will help me identify what this thing is made of.

It's this thing. A Tecmark 3029P.
posted by five fresh fish at 12:21 PM on November 8, 2005

PVC glue won't work; it's anaerobic, and there's no way to make this attachment anaerobically.

And, dammit, SuperWeld is a two-part epoxy. Didn't stick to the plastic at all permanently.

Maybe JB Weld? It's a two-part epoxy, too.

Gah! Hate my clumsy fingers: the hot tub would be operational by now if I hadn't broken this C$40 part!
posted by five fresh fish at 12:30 PM on November 8, 2005

If it's like plexiglass, there's a special solvent you can use to "glue" the pieces together. You get it at any store that sells bulk plexiglass. It comes in a little bottle - looks and acts just like water - and is applied to the pieces with a syringe. The solvent dissolves the plexiglass enough so that when you put two pieces together, they're chemically bonded.

I don't know what the name of this liquid is, unfortunately.
posted by odinsdream at 12:34 PM on November 8, 2005

If you can identify the material(s), log on to the Loctite website and go to their tech support. They have amazing (but pricy) adhesives.
posted by Raybun at 12:34 PM on November 8, 2005

If you can get a stainless steel version for US$19.95, I wouldn't screw around with repairing it. It'll break again or cause you problems in some way in the future, and whatever fancy adhesive you buy to try to fix it is going to cost $10 anyway.
posted by jellicle at 12:43 PM on November 8, 2005

If it's that threaded stem that broke off, I think you're going to have trouble making a solid repair. It looks like you're supposed to screw the sensor into a threaded port, which means you can't gum up the thread, and you obviously don't want to plug the central hole.
If the whole thing is big enough, you might have some luck drilling little holes parallel to the central channel, then filling them with glue (epoxy) and maybe even bits of piano wire, to help hold the pieces together. But that's a lot of work, and not guaranteed to hold.
If the break is right where the threaded stem joins the base of the sensor, maybe you can scuff up the base and the last 2-3 threads of the stem and get a plastic epoxy or JBWeld to stick. Some plastic epoxies have a solvent that seems to dissolve the underlying material slightly to get a better bond. You'll know it when you smell the epoxy -- you can tell that the stuff is bad for you as soon as you open the tube.
posted by spacewrench at 12:45 PM on November 8, 2005

Truth is, the threaded part is already in the hole. It sticks out about 6mm. It's not at all like plexiglass, either: it is much more like, say, bakelite (but it is not bakelite).

Methinks I'll be coughing up another forty bucks for a new replacement. Gah.
posted by five fresh fish at 1:07 PM on November 8, 2005

Gorilla glue?
posted by Mr T at 1:51 PM on November 8, 2005

Well, I bought a new one.

There are times I miss living in a condo. There was so little that could go wrong there. Very low maintenance.
posted by five fresh fish at 6:30 PM on November 8, 2005

I see you bought a new part. Probably the best way to go.

For future reference, a good workable filler/bonder for wet environments is Marine-Tex.

It's an epoxy that's good in harsh environments, kind of like JB-Weld without the metal filler. I think of it as 3-D duct tape. There are some kinds of plastics it won't bond (e.g., polyethelyne) but other than that it pretty much rocks.
posted by Opposite George at 8:19 PM on November 8, 2005

I would have tried some locktite404(superglue) it is the absolute bomb ,but will not fill gaps, the parts have to fit closely.
posted by hortense at 11:38 PM on November 8, 2005

I have never found a good use for superglue. It tends to be very brittle, which makes it suitable for gluing the handle of a ceramic mug back in place, but pretty much useless for anything else...
posted by five fresh fish at 9:58 AM on November 9, 2005