Few months ago I bought a car for the air cleaner assy and its in rough shape but it is what it is looking for info on repairing these things.
plastic welding new plastic to existing? possibly making bigger and better aluminum to better repair like PO did although the pop rivets have the plastic cracking near the rivets, Please, your thoughts or if you have any experience with plastics I'm guessing these were made out of PVC plastic? the rest of the housings appear to be OK IMO
thanks

 

That repair with the aluminum sheet doesn't look too bad. I've seen much worse fixes. Go to YouTube for videos on plastic welding; helped me immensely. I have a '97 K2500 EC with a 7.4L that I'm still working on. The parts like the radiator shroud are N/A so I had to fix it and plastic welding was the answer. The main thing is that the plastic that you use for repairs has to be the same exact type of plastic since you're essentially melting the two pieces together in a controlled fashion. I had a spare SBC shroud that I could sacrifice for welding material for the shroud that I wanted to repair. The plastic has to be cleaned as well; just like welding metal. Brake cleaner works pretty well after a good scrubbing with a Simple Green or Purple Power cleaner.

 

It could be #5 or PP plastic, and not PVC. That PVC wouldn't work as fill material.

 

Personally, I'd just use roof "flashing" from Lowes. Get it all cut to shape and then use some Harbor Freight bed coating in a spray can for a few coats.
Gotta remember the age of these parts, and what you weld to could very well crack again, and in a different spot since the two plastics that you're joining won't be the same molecular structure per-se..
That spray ends up like 80-100 grit paper, not like 30 grit like the Line-X spray. Kinda satin'y.
I have a late 70's Jeep Cherokee and the heater core is in the engine compartment right beside the R-exhast manifold/valve cover. And over the decades it kinda turns the fiberglass ones into powder if you even rub on it let alone hit it with a wrench or the like..
I'm going to re-construct it with flashing or some other thin sheeting that I can just shoot over with the bed spray (inside and out with proper drainage) and call it done for the next couple decades.
Just did my front grill with it and it turned out soo nice that I'm going to spray the whole front cap/cab.
(it's a '95 2500 long bed frame with a wooden flat bed on it. It's a work truck, and NOT worried about dents and dings..)
Just thought I'd toss that in.
E

 

Get a smooth backing material with some rigidity, clamp it over the flat area as a backer. Wax your backer with a release agent, and lay up fiberglass cloth and resin to replace the missing material. When you've got it relatively solid, go in with a strong slow curing epoxy filler, and blend it all in. Sand excessively until it's smooth, clean well and spray with semi-gloss black Krylon Fusion.

It wouldn't be quick or easy, but with a little care it'd look the part, and you'd have a more structurally sound part. The center duct seems to be a heavier composite, it's just unfortunate SLP didn't bother to use a glass fiber reinforced plastic.

Alternatively, use the original parts to fab plugs. Use the plugs to create molds. Use the molds to lay up composite copies. ???. Profit.

 

I'd just throw that garbage away. Infact my zip is 36277, let me know what shipping is and I will get rid of that stuff for you��