School me on plastic welding?

[Brads70]

So I'm trying to get my dash back into the javelin ( 1971) and I have 2 dashes here but between both I still have a few broken parts I'd like to have a go at repairing myself?
I also have to shorten/modify it for the bigger trans tunnel after fitting in the T-56
Anyone have any experience, words of wisdom? I don't mind buying the needed equipment.

[Chryco Psycho]

Soldering gun with a flat tip can fuse it together .

[Brads70]

Soldering gun with a flat tip can fuse it together .

Yes I've watched a few u-tube video's and seen that. I bought this to see how it works? Cheap enough ....https://www.amazon.ca/dp/B0B4RDHKDR?smid=A1AY3A36ZICWRN&ref_=chk_typ_imgToDp&th=1

[RUNCHARGER]

I've repaired a few motorcycle panels. On one of my old bikes I used the flat soldering iron and introduced extra filler material into the mix. It worked well but I did bodywork on the panels afterwards. When the deer ran into my Bandit a year ago I carefully welded the back surfaces with the soldering iron but tried not to overheat the panels (a total of 5 Effin panels in total!) so the paint didn't bubble. I wasn't really confident it was as strong as original and it worked okay but I am not sure if the repairs lasted or not because I wanted an immaculate bike and sold it this spring.
My neighbor got a kit off Amazon that has zig-zag pieces of wire that you heat up and press into the plastic. That's what I'll do if I have to do it over again. My feeling is I would melt those in then do the smoothing afterwards and it should be a sturdy repair. Of course you would have to refinish afterwards.

[YellowThumper]

I've melted staples in to the back side to stitch seams together.
Let us know how the welder works out.