POR-15 putty too thin

Last week I cleaned a few spots to try filling rust holes without welding. The plan for today was to fill the holes with POR-15 putty. It comes in a metal tube, and I expected it to have the consistency of old fashioned spot filler. It turned out to be more liquid than plastic, sort of like really thick paint. I had a hard time filling even these small holes, which were at most about 1/16 in. wide. I ended up leaving some on my working cardboard until it hardened a bit, but that was sticky and difficult to smooth. The photos show the result. I doubt that these were effective repairs, because the material is so thin.



My idea is to buy some fiberglass filler and mix up my own putty. I think Redline has it. I also need to buy some solvent to clean my hands.

Another big disappointment: my latex gloves leaked again. I need to check the POR-15 web site to see if latex is the wrong stuff. Maybe I just keep poking holes in them. Another week with black fingertips!

While I was waiting for the filler to thicken I worked on removing the remaining sound dampening material from the other side of the car. First I tried GooGone, the stuff that smells like lemons. That softened the glue, but there was lots of adhesive and scraping it off was hard because it just wanted to stick to everything. Whatever BMW used was sure good, because after thirty years it still has plenty of stick. Later I switched to paint thinner, because I had a lot more of that. It worked about as well. I finished up wiping with a rag soaked in paint thinner, trying not to breath in too much.

As I suspected, removing the think, felt-like pad and all that glue exposed the beginnings of rust. That will all get the POR-15 treatment.



In the bay next to mine was a 'Vett about the same age, being worked on by a young guy. This brought out the old and experienced Chevy engine builders. During lunch I listened to a fascinating discussion about the differences between ZZ this and that. These guys really know their stuff.

It's Not Full Of Holes

Yesterday I made an encouraging discovery. Some spots I thought were rusted through from the inside out were surface rust with at most tiny rust throughs.

I used this opportunity to practice doing a complete POR-15 repair cycle in one day. What I mean by complete is starting with a rusty spot and ending with the damaged area treated with POR-15.

After grinding off the paint, filler, and loose rust the area is washed with Marine-Clean, thoroughly rinsed, and dried. I used a heat gun to speed up the drying. Next the area is treated with Metal Prep, which converts rust to something more stable. Treated areas must be wet for at least ten minutes. I brushed a coat here, then there, cycling through them all many times. I ended up with a frothy mess of air bubbles trapped in the thickening goo. After drying with the heat gun I brushed on a coat of POR-15. Next Sunday I will try out the putty.