Primer Prep Help

M

mag67

I have prepped for primer to bare metal and can't get the underside of the roof structure as clean as the rest of the stripped areas. I need to figure out how to proceed. The roof structure and inner rear quarter sections cleaned up well with a final wire brush and 80 grit DA. No matter how much I wire wheel the underside of the roof, it's not good. The question is, if I want to treat with OSPHO, can I tape off and paint everything that is ready at this point and not do the underside of the roof. After the epoxy has cured then treat the underside roof with OSPHO, rinse, and then epoxy. Close up is roof underside. I glass bead blasted the firewall and toe kick and would hate to do that at this point to the roof structure since it would get into everywhere. Also, any suggestions on dealing with the inaccessible areas such as the top side of the structure and along the outside edges?
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Ideally, you want access to to every metal surface, but short of drilling out every spot weld on the car, it is not going to happen. Being that it is on the inside and will never see moisture, I would do the best I could and epoxy. Blasting would have been ideal, Ospho will work, also. The factory had not much of anything in there, and it has lasted 50+ years. My feeling is the amount of work you are putting into it should last another 50. Brushes and undercoating wands will get into places that a gun won't spray, but don't lose sleep over getting to every square inch because you can't.
 
Too late about the losing sleep part! My thoughts were to cavity wax the area not accessible in the roof area and elsewhere. Can the epoxy be used in those areas with the wand? I know there's surface rust there.
 
it looks like a delorean.

you did all that work, but like he said, follow the spot welds up at that roof rail and everything in between is rusted. That is the one thing that epoxy does that POR 15 says it does is keep any moisture from getting in and making it worse in there. Being inside, you went far beyond the call of duty, unless you are not going to install a headliner lol.
 
67 Camaro? I usually sandblast the inner quarters, floor, dash and around the glass openings. You can't blast the roof skin and outer panels-protect them with cardboard, rubber floor matts or anything similar. Sand what you can't blast and clean it really well. 2-3 coats of epoxy primer. If it's on a rotisserie you can use gravity to your advantage to pour epoxy into seams, use tape to trap it and dam as needed. The padding on the roof skin will need to be replaced with something-I've used Evercoat Q pads, some people use the foil backed auto insulation. http://www.evercoat.com/product-detail/base-part/100116/us/
 
Cavity wax is great after all the paint work is complete. As far as using a wand, I had the same thoughts on my current project. Wands are cheep, so it’s worth a try on something off the car to try first, which was my plan as well.
 
Big Dave said:
Cavity wax is great after all the paint work is complete. As far as using a wand, I had the same thoughts on my current project. Wands are cheep, so it’s worth a try on something off the car to try first, which was my plan as well.
Click to expand...

Good idea. A piece of tubing would work well for a test.
 
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