Mastodawn

Another day, another of the little one's things repaired with a hot air tool and a bit of poking.

So many people assume broken plastic is unrepairable garbage because it's hard to glue.

But if it's a thermoplastic, as almost all mass market plastic goods are, all you need to do is gently heat up the pieces until they soften and push them back together to form a solid weld. Filler rod can help in some cases but isn't always necessary or useful depending on the nature of the repair, for flat surfaces I've had decent results just using a screwdriver to lightly press the heat affected zones into each other until they merge.

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robryk 20h ago

@azonenberg How can you tell if it's a thermoplastic? By trying?

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Andrew Zonenberg

@robryk you can look at the recycling symbol. Polyethylene (HDPE and LDPE), PVC, and polypropylene, among many other common plastics, are.

Anything injection molded is made from a thermoplastic by necessity since the molding process requires heating and softening the raw material to squish it into the mold.

Epoxy resin, as used in fiberglass parts, is one of the few common plastics that is *not* a thermoplastic.

Or yes, gentle heating. If it softens it's a thermoplastic, if it shows no change in hardness until reaching the point of discoloring (beginning to char/decompose) it's a thermoset and can't be heat welded.