Protecting frame rails

[Casgar 21]

I have started to cut up the old floor on my 69 fastback since it was rusted through. Now that the floor is gone I can inspect the frame rails more thoroughly and beside surface rust, some minor dent from a jack and a wasp nest they seem to be in very good condition.

The rails under the floor is easy to get to now that the floor is removed, but the engine bay, over the axle and in the trunk seems harder to reach and clean without cutting up good metal. It's a couple of years down the road, but I'm not planning on leaving the car in the garage just because it's raining a little.

The big question now is what would be the best way to treat the rails on the inside? Should I also open up the rear torque box and treat it while the floor is out? The front torque box will probably be opened up anyway since I'm planning on installing vert inner rockers.

 

A second smaller problem is in the left rail under the floor/firewall. The inner overlap from the engine bay rail have rusted, cracked and expanded upwards. Anything that should be adressed too?

[Kris 90]

I opened the rear of my rocker panels as it was easy since it was a small cut to open it up. After that I started at the front of it and blew all the dirt and trash out with compressed air. I ran an inspection camera all the way down it to make sure it was completely cleaned out then welded the end closed. Once that was done I used Eastwood’s internal frame coating and completely coated the inner frame rails. Once it dried I ran my camera back through it from the holes in the top to make sure it was thoroughly coated. I think I used 5-6 cans to do the rockers, frame rails, lower radiator support, and inside my trunk lid frame.  The can comes with a hose with a metal tip that blast the coating in every direction. An inspection camera is great for this if you have one. 

[Casgar 21]

So no other treatment other than removing loose debris? Have you put it to the test? From what I'm reading it does sound promising.

[Kris 90]

Like I said I’ve done all my frame rails, rocker panels, core support, and trunk lid. As for testing it. Most of my body work is complete. My doors are done and under coated. My car hasn’t been driven as I’m still putting it back together. It worked pretty well and I’m pleased with it. I read a lot of reviews from other people online and they had good things to say about it. Obviously cutting it all open and removing the rust is always the best. This to me is a good compromise and time saver if your rockers and rails aren’t completely rusted out and only have surface rust inside like mine had. For me it would have been months more work to disassemble it all to remove the minimal rust. My car won’t be driven in bad weather so I don’t see any reason this shouldn’t last as long as I’m around.