Cycling UK Forum

Can you epoxy ABS plastics without much damage to the ABS

you are going to have to explain what you are asking a bit more I reckon

cheers

Hi,
ABS I think you will need solvent or like welding with plumbing, or super glue?
Plastics are horrible to fuse unless heat or solvent.
With heat you need pressure to bond.

Epoxy is good with metal not so good with plastic.

It's a small crack in a bike box.
I thought it could be bridged with mesh, so glass fibre plus epoxy or polyester resin. The two component type, resin plus hardener.

ABS is quite brittle and doesn't repair easily IME. If it's a flat surface, I'd be looking to rivet a piece of alu over it as a patch..

ABS is such terrible brittle stuff that they make motorcycle helmets out of it.

If you know what you are doing (or do a bit of research on the interweb), you will discover that you can weld ABS using hot gas or even something as simple as a soldering iron.

cheers

I have "soldered" an ABS case that had a piece knocked out of it. Basically using a soldering iron I replaced the piece back in and melted the join between the 2 parts. Initially spot welding and then slightly melting the ABS and moving the iron about to seal the crack. The outside of the case was a rough finish so it was easy to disguise the crack again using the soldering iron.
I'm not sure there is a glue/adhesive that would stick properly to ABS although this website gives advice:-
https://www.permabond.com/materials_bon ... -bond-abs/

Brucey wrote:ABS is such terrible brittle stuff that they make motorcycle helmets out of it.

Yes, and the helmets with ABS shells are generally the cheaper/nastier variety, because the high rigidity of ABS makes it brittle. Higher quality helmet shells are typically made out of polycarbonate. The rest have shells made out of GRP, CF, etc, but that's not in debate here. And neither is the fact that ABS is brittle, because it is.

believe it or not, not all ABS is the same. There are formulations that have considerably higher toughness than others.

Brucey wrote:believe it or not, not all ABS is the same. There are formulations that have considerably higher toughness than others.

The OP just said 'ABS', that's all - maybe he should have specified what particular formulation he was referring to. Meanwhile, if you want to start a new thread on the science of thermo-forming plastics, then fill yer boots...

I just wanted to correct the misinformed statement 'all ABS is brittle'.

It isn't.

Brucey wrote:I just wanted to correct the misinformed statement 'all ABS is brittle'.

It isn't.

That's not what I said though, Brucey, is it? My actual words (you can read them for yourself upthread) were "ABS is quite brittle.." which it is. Like I said earlier, if you want to get into a debate about the relative rigidity of certain formulations of ABS, then you'd probably need to talk to a polymer chemist. Meanwhile, I'll stick to ABS 'being brittle', because it generally is.

KM2 wrote:Can you epoxy ABS plastics without much damage to the ABS

3M makes glues used by auto body shops for ABS.

https://www.3m.com/3M/en_US/company-us/ ... 344&rt=rud

You dissolve pieces of ABS in acetone and use the solution as a glue. The process is actually very forgiving. The product is relatively seamless and corrections are possible.

The ABS would have to be butt jointed, this would not be strong enough, allowing for imperfect glueing. Can't press them together, no movement. It would need a bridging system both in and out for a reasonable mend. But I don't have any ABS to do this.