What is the best glue for plastic?

[Axtman]

I am repairing a Fluke 8060A multimeter. It has a crack where a screw mounts into the case. A piece on the standoff broke off and I need to reglue it. What is the best glue to use? Thanks.

[dmeek]

I use 2-part epoxy like JB Weld or a new one I'm trying JB Plastic Bonder https://www.jbweld.com/products/j-b-...bonder-syringe I would not use any 5 minute epoxy.
Sometimes I will use Krazy Glue to hold the broken piece in position and then gob epoxy around the outside

[J M Fahey]

Agree with "overnight" epoxy.

Warm up the parts to join with a heat gun, apply tomating surfaces and let a little extrude as proof you filled voids , wipe excess with a Q Tip and then give the whole area a wjhiff or two of hot air.
Let cure overnight.

[Mick Bailey]

If the case is ABS then epoxy will not give you a strong bond. I've done some trials with Araldite Rapid, Araldite Standard (24hr) and JB weld. None of the bonds equal the strength of the parent material. JB weld held up best, but still breaks away leaving an undamaged surface and showed that the adhesive does not properly bond to the surface. Adhesives for ABS always have a solvent component. There are some adhesives that work by solvent action alone - solvent/weld adhesives which are essentially a solution of ABS in Methyl Ethyl Ketone (MEK). I always have a can of this in the workshop. The downside is that the repair takes quite a while to achieve full strength, but the repair line is as strong as the parent material.

I've also tested some of the epoxy plastic repair products that specifically mention ABS. One thing I noticed is that if you apply the mixed adhesive to the plastic, it softens the surface, which is a good sign that a good bond will take place and it's a test that I use prior to repairing something where I really need confidence in the repair, such as motorcycle plastics.

I would use an adhesive that is intended for plastics, and if you can't determine the material assume that it's ABS and pick one that mentions ABS suitability, as well as polycarbonate (another common enclosure material that's solvent-bonded in the same way)

[dmeek]

There is an ABS glue found in the plumbing section of any hardware store. I've never used it for anything other than gluing ABS drain pipes together. Maybe worth a try.
There is also a PVC glue for plastic eavestroughing.

[Bloomfield]

ABS plumbing cement is very thick and goopy. I once tried some to repair an ABS part and it was very messy and softened much of the surrounding area. That being said, it might well be worth another try using a very small amount and good clamping pressure. Don't use the brush that comes in the can as it is far too big.

[rjb]

Just to mention some specific products:
Loctite Plastics Bonder (2-part acrylic) is recommended for ABS and polycarbonate, but not for polypropylene or polyethylene.
https://dm.henkel-dam.com/is/content...-2018-08-16pdf
Loctite Plastics Bonding System (primer & super glue) works for polypropylene (eg. fake window shutters) and polyethylene.
https://dm.henkel-dam.com/is/content...-2016-08-26pdf

-rb

[g1]

Also some very good but expensive industrial products out there, for example scotch-weld DP8010 or 4693.

[nevetslab]

Also some very good but expensive industrial products out there, for example scotch-weld DP8010 or 4693.

Every time I'm forced to open up either of my Fluke 8060A, I shudder, as those molded screw bosses have one by one split apart, beyond trying to attempt gluing back together, since they turn into a pile of shrapnel. I've yet to make an official project out of creating new mounting standoffs to solve that on-going self-destruction, though I know the day is coming. I've used JB-Weld in the past, but am anxious to try some of the suggestions listed in this thread. When I get back to this project, I'll keep notes/photos and post the solutions, if it turns out successful.

I looked thru the 8060A Owners/Service Manual, and didn't find anywhere the mention of the type of molded plastic used for the case parts.

[dmeek]

As mentioned in post #4, sometimes JB Weld doesn't bond with the plastic. I've been using JB Plastic Bonder for a while now. It seems to be better but the jury is still out.
Maybe giving the plastic a wipe with a solvent like acetone first would help? I often melt in staples cut to size and hooked on both ends to add strength. Most often I am
repairing broken synth keyboard keys. I don't fully trust JB Weld on whatever that plastic is. Looking for something better, I haven't tried first cleaning with solvent yet.

[The Dude]

Along with various glue types and if there's enough material to work with, I'll often use my solder iron to melt a plastic crack back together. It smells, but has been effective.

[g1]

on the melted in staples. Great way to add strength when bonding plastic.

[1ampman]

Lately I've been using Gorilla Super Glue. The only down side is it takes over nite to dry. Other wise I had great luck with it....