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73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: BlackTomC on August 31, 2015, 08:27:08 am

Title: Rear AC Box Plastic Repair
Post by: BlackTomC on August 31, 2015, 08:27:08 am

So I recently scored all the rear AC components for my 78 suburban, and as expected, the plastic has started to dry rot. Yesterday I went through and scraped all the dry rot off, my question here is, how would you guys go about repairing the plastic after this happens? Would 3M Fiberglass Resin work? Thanks in advance.

Title: Re: Rear AC Box Plastic Repair
Post by: roger97338 on September 01, 2015, 05:51:06 am

There are plastic welders out there. I don't know if you'd want to buy, or maybe rent a plastic welder; Or look in the phone book and see if someone in your area offers that service.

I'm sure your way would work, though. Probably be a lot cheaper, too.

Title: Re: Rear AC Box Plastic Repair
Post by: Captkaos on September 04, 2015, 03:30:38 pm

I have fixed them with Fiberglass and Fiberglass resin...

Title: Re: Rear AC Box Plastic Repair
Post by: Dr_Snooz on September 04, 2015, 09:06:15 pm

I'm not sure what dry rotting plastic looks like, but I've used epoxy to repair plastic with some success. Sometimes it doesn't adhere though, so caveat emptor.

Title: Re: Rear AC Box Plastic Repair
Post by: BlackTomC on September 10, 2015, 09:46:08 am

Hey Dr. Snooz, it looks like crap, flaky, chunks falls off it, ugly messy stuff. I'm going to give it a go this weekend, I'll let you all know how it goes.

Title: Re: Rear AC Box Plastic Repair
Post by: BlackTomC on September 16, 2015, 09:29:09 am

Quick status update, the fiberglass adhered extremely well in the plastic, I've allowed the parts to sit out in the sun now for a few days (pretty darn hot here in AZ), it appears the difference in thermal expansion rates has no effect on the fiberglass/plastic bond.



Now I'm going to sand it all down and start over, this was my first time, the coat looks absolutely horrendous.