I have successfully used the Hakko hot air tool to do a bit of
plastic welding. Not a large area, but for small stuff it gets plenty
Here's a photo of a scissor handle I fixed. Not an important job, but
It's not pretty -- I haven't yet used the Dremel sander to smooth it
out. But it's plenty strong, as strong as new, I'd guess. The new
plastic added to the weld is completely bonded to the original,
unlike adhesives, epoxies, J-B Weld, etc.
If I were to give any advice I'd say start with low temperature. Less
is better than more. You can always increase the heat as you need it,
but with too high a temperature the plastic can quickly get very soft
and out of control.
And if the parts are small, be sure to clamp them in place as they
will loose stability as the plastic softens and may take a warp when