After four rounds of sandblasting, I got the frame cleaned enough for my liking. All the rust was gone, and the only thing left was some stubborn black paint in various corners. I did a lot of research online to try and figure out what primer and paint to use. It was very confusing. Self etching primer, epoxy primer, enamel, two-step paint, etc. I felt like I was getting nowhere. It seemed like every one had a benefit and drawback. I stopped by the local O’Reilly’s and asked the guy behind the paint counter. He was of no help.
My ultimate goal was to get the frame sealed enough that rust would not be a future problem should I decide to drive the car in the elements, which is not in my plan. I ended up landing on a product called POR-15. It claims to seal metal, even rusted metal, so long as you prep the surface and apply the product according to their instructions. You basically use their degreaser to get rid of any leftover gunk, use their etching phosphoric acid product, let the frame dry completely, and then brush or spray on the product. It claimed to be self-leveling so you won’t see any brush strokes if you go that way.
A local paint supply store, Car Color, carried the product so I got all three products. It was not cheap: a quart of each came to $85.
I wheeled the frame out that evening and got started. I noticed there was still some sand in the holes of the frame. I ended up spending an hour spinning the frame on the rotisserie to pour out all the sand and using the shop vac to suck out the rest. I had no idea there was so much sand left in the frame. Once that was done, I moved to the degrease and etch, with a thorough water rinse after each step. That took less than two hours. Then I dried off the frame as much as I could and spun the frame over and over to drain out as much water as I could. I left it over night to dry with a fan blowing on it.
The next day the frame was good and dry. The manufacturer says to wear long sleeves and gloves and have lots of ventilation. That is good advice. The sealer sticks to anything it touches, skin included, and throws off lots of fumes. I decided to brush paint the frame, since you need to have separate breathing air if you decide to spray it. It recommended two coats.
The first coat went on very well. It’s black in color so it was really easy to see where you were getting coverage and where you were missing. It seemed like the metal was soaking up the product when I brushed it on. The first coat took about 1.5 hours and used half the quart.
The manufacturer says to put in the second coat within 2-6 hours. Since I was doing this after work, I didn’t get the first coat done until about 7:00. I waited until 9:00 and started the second coat. It went on with much less product, although it was dark and even with a big halogen drop light I couldn’t tell where I was getting coverage and where I was missing. It all just looked shiny and black, both coats. I did the best I could and stopped for the evening.
The next day, in daylight, I could see I had missed some areas on the second coat but had gotten full coverage on the first coat. You could tell the difference because the first coat was matte black and the second coat looked very glossy. But the self-leveling claim was true: it looked like it has been sprayed on, not brushed.
No matter. I am going to paint the frame so I’m not worried about the difference in sheen. The product has no UV protection, so if you leave it in the sun it will fade to gray in a few weeks. This will be under the car so that’s not a concern, but there will be other areas that I plan to paint black that will see the sun, and want it to look uniform. If I was going to leave it without paint, I definitely would go back in bright daylight and make sure I got two coats so it didn’t look matte in some areas and glossy in others. I expect the gloss will go away some as the product fully cures, but that won’t matter for me.
The frame is now stable and ready for winter. Next spring I will paint it with the same paint I will use for the other chassis and suspension bits. Until then, I won’t need to worry about rust. Over the winter I will do the same thing to the suspension and other chassis bits so I can prime and paint them knowing they are well-protected from future rust.