Strongest glue for plastic?

r2015

I need to fix a plastic part on my wife's knitting machine which has to support quite a lot of weight.


I used epoxy resin but it keeps coming apart.


Also I only need a very little amount.


Any ideas?

casper_g

Do you know what material the parts are made from?

The strongest glues for plastic model kits are solvent-type products like "polystyrene cement" used for Airfix kits, which work by melting the plastic surfaces so they "weld" together.

As the name suggests most are meant for use with polystyrene* but there are also similar glues for other plastics. For example, "Plastic Magic" claims it can be used to bond polyester, acrylic, styrene, ABS, PVC, butyrate, and polycarbonate.

*Airfix model kits tend to be made from solid polystyrene, which doesn't look like the expanded or blown polystyrene familiar from its use as packaging material.

r2015

Do you know what material the parts are made from?

No, but here is a picture of the part inside the red box.

http://tinypic.com/view.php?pic=2uqenfc&s=9#.V7ND9Ir6uUl

the metal part slides into the white part.

firefox1956

I would have used a 'superglue' suitable for plastic myself.
HTH

JohnB47

r2015 wrote: »

No, but here is a picture of the part inside the red box.

http://tinypic.com/view.php?pic=2uqenfc&s=9#.V7ND9Ir6uUl

the metal part slides into the white part.

It's not actually clear what materials you are trying to glue together. Do you mean the white plastic part has broken and you need to glue it together again, or do you mean it has come away from one of the two metal parts it is connected to and you need to glue plastic to metal?

The answer might be academic anyway. Some thing simply are not as strong as needed when glued together. You might end up needing to buy a spare.

casper_g

casper_g wrote: »

Do you know what material the parts are made from?

The strongest glues for plastic model kits are solvent-type products like "polystyrene cement" used for Airfix kits, which work by melting the plastic surfaces so they "weld" together.

As the name suggests most are meant for use with polystyrene* but there are also similar glues for other plastics. For example, "Plastic Magic" claims it can be used to bond polyester, acrylic, styrene, ABS, PVC, butyrate, and polycarbonate.

*Airfix model kits tend to be made from solid polystyrene, which doesn't look like the expanded or blown polystyrene familiar from its use as packaging material.

Just re-read the OP and saw you've already tried glueing it with epoxy resin, so the plastic cements probably won't work - even assuming you want to glue plastic to plastic, you're no longer trying to bond two close-fitting pieces of similar material together as there'll be a big gob of epoxy in the way!

I'd try and get hold of a replacement part if you can, to be sure of a good result.

paddyrg

Quyite a lot left to guesswork here, but I'm assuming one of the 'jaws' of the white plastic thingy has sheared off, and so no longer holds the metal part securely?

If that's the case, what other constraints are there? Does the metal part need regular removal, does the external diameter have to remain constant? The small surface exposed by a shear would probably be unsuiitable for glueing with any strength, especially as it's already been shown to be a weak point in the design (and from the pic, any horizontal load or twist would strain it).

My approach - get some milliput, remove the broken bit, rough up the remaining side a little and pack the metal part in with milliput and then extend the milliput around the functioning/roughened side too. You'll never remove the metal part again, but it's a 5-minute 50p fix that'll last a decade.