I ordered an aluminum canister for the vapor recovery system on the gas tank, so I'll take a break on that til it gets here. In the meantime, I need to get the air cleaner box to fit in here somewhere. It's unnessecarily huge and bulky but I want to keep as much of the OEM parts as possible. The MAF sensor is in this box also. I need to trim it down to size so here's one last lesson in automotive plastics.
There are about a dozen types of plastic used on cars and they all have their qualities and shortcomings. Most of what you'll find under the hood or in utility service will be either PP, ABS, PE, or PC.
PP is polyproylene. That's what the air cleaner box is made of. It's common to see it in components that need to be rigid and temperature resistant. It has similar properties to PE Polyethylene. They can very easily be cut and cleanly welded with heat. No cement required.
I set the finished pieces back together so you can see the original size. It was about 13" tall.
Also, any plastic part will have an ID stamp telling you what the material is. In this case you can see the "PP" circled.
The finished part below is a little less than 7" tall now. I welded inside and out and used some filler. You can buy this filler rod but I just use a box knife to shave a thin strip from the edge of some scrap material and use that to fill.
You can see in the close up that the weld is built up. At this point, if the part would be seen in the engine bay, you could file and sand this smooth, then go over the welds with a heat gun to smooth and gloss the surface.
I used this Weller wood burner/Hobby iron to do the welding. It comes will an assortment of tips. The one that is still in the iron is the one I used to weld. The only advantage to the wood burner over the soldering iron is that the wood burner has a shorter stem which makes it easier to control.
