Polycarbonate glue?

[Martin Brown]

Food processor plastic bowl seems to be polycarbonate and took a sufficiently hard thump on the hard kitchen floor to put a vertical 4cm crack in the outer case near to the handle. It will doubtless get worse if not repaired. Any suggestions for a suitable thin glue for polycarbonate that will wick into the crack and prevent it from running.

Would it make sense to drill into the end of the crack for stress relief or be more likely to make it worse?

Ideal glue would be food safe (so epoxy which might work isn't ideal).

ISTR that petrol or ether might be good solvents for polycarbonate but I have a feeling they make it go brittle too which would be no use in a food processor where the mechanical strength is important.

Any suggestions for the best glue to use here?

[MrCheerful]

Methylene chloride fuses polycarbonate. You might find that the glue for solvent weld waste pipe would do.

[Capitol]

For fine cracks I always use superglue which has very good wixking properties. I find it will also fill slightly wider cracks with a few more coats. Easy to clean up with a scalpel.

[Thomas Prufer]

UHU allplast -- a solvent weld glue.

Thomas Prufer

[MrCheerful]

and contains cyanide.

[Bob Eager]

And is not toxic, excelt perhaps when inhaled while applying it.

[MrCheerful]

What is really unpleasant is the fumes if it is heated, I did that accidentally while using a belt sander.

[Syd Rumpo]

Whatever glue you use, duct tape of some variety on the outside is good if there's enough 'flat' space around the crack.

Cheers

[Andy Burns]

I've not tried it, but ... friction welding?

[Frank]

Looking through thread, that is a good suggestion as area of crack will probably remain the weakest of the part. I've repaired cracks in plastic areas where most stress occurs by gluing nylon screen over the crack.

I'd use the solvent based glues for polycarbonate and not worry about toxicity of any glue used as area is small and toxic materials are part of the polymer.

If the crack can be slightly widened it will allow better contact with glue or solvent, then resealed to complete gluing.

[unk]

Polycarbonate does not crack.

It's likely acrylic or styrene. MEK for acrylic, some other solvent- based glue for styrene.

[The Natural Philosopher]

NO, contains cyanoacrylate.

[The Natural Philosopher]

Oh yes, fumes are instant asthma for me, whether in use, or when sanding.

not QUITE as bad as aluminium flux though. That is REALLY nasty

[Poutnik]

Bound cyanogroup is not cyanide. Its pure form is used even in surgery.

[newshound]

I was quite impressed by that idea. There's impressive video out there of TWI's friction stir welding process which, IIRC, was used to make very neat looking butt joints for space shuttle fuel tanks (and loads of other stuff).

[Harry Bloomfield]

Me too, I have not come across that method before..

[Andy Burns]

I think a colleague mentioned getting a plastic welder a few weeks ago, but he hasn't mentioned any success or failure with it since ... I'll ask.

I should think a suitable plastic rod in a dremel would be all you'd need.

[Martin Brown]

Tell that to my rear light cluster.

It does when provoked sufficiently. It is a short hairline crack along a weak line near where the handle joins the body of the mixer bowl.

It will doubtless get worse if not repaired.

I'll test it but I want to avoid the mess that I got by using acrylic solvent glue on my definitely polycarbonate rear light cluster.

Acrylic would probably just about stand up to the duty but I doubt if polystyrene would (and the latter tends to yellow a lot with age).

[Martin Brown]

Cyanoacrylate. (Different functional group CNO vs CN). More significantly it doesn't get on that well with hot water.

It was originally intended for battlefield wound repairs on flesh and it is used as an alternative to sutures in hospitals for smaller wounds and in places where they would prefer to avoid scarring from stitches.

[Martin Brown]

That sounds a possibility. What I want to avoid is causing any stress corrosion cracking in a polycarbonate vessel that is basically exposed to high shear conditions and has plenty of surface microscratches.

Petrol for instance is very bad for polycarbonate.