I just made an order for a plastic welding heat gun to use with plastic welding rods. I guess it is a smaller version of a standard blower heat gun. I bought this because until now there is no such reliable plastic glue. I will be using it to stick or reinforce plastic parts together.
Does anyone of you or or have these on your workshops? Is it useful?

I used to have this as a kid, it welded plastic very well but the smell was awful
https://youtu.be/PnWpcwnR2YA

When I was an engineering apprentice a long, long, time ago we were taught welding as part of our training and this included plastic welding. The actual mechanics are very similar to oxy-acetylene welding in that you have a torch in one hand and a filler rod in the other. You heat up the joint with a narrow flow of superheated air and apply the plastic filler rod; everything starts to melt together and this causes fusion. The trick is to move and feed the rod at the correct speed and hold the torch at the right distance and that is down to good old fashioned practice.

This might add ideas: https://www.youtube.com/watch?v=r0zpqhhcmp4

For repairs, this is an interesting idea.
https://www.youtube.com/watch?v=ziPutFi1BlI

At the factory I use to work at, they used a Sonic Welder to attach plastic parts together. High pitched sound waves.

There is a pen being sold on Amazon that melts plastic in the pen to repair plastic parts. You might do a search for it. No mess, all in one pen. Then the light hardens the repair. Might be a solution.