Floor Pans- Rust prevention and Tunnel treatement, advice needed Options

[highways]

Hi all,

I'm working on my floor pans... I have them wire brushed down to bare metal. They are in overall decent shape though there is some rust around the perimeter where they meet the longitudinals. These corners seem innaccesable to all but a small wire brush (toothbrush size). Question is:

1. Should I apply POR 15 Surface Prep, then POR 15 to get in cracks, then Seam Sealer, then maybe another coat of POR 15 over Seam Sealer?

2. Or, should i just do Seam Sealer first over bare metal, partial rust areas around the perimeter? Then follow with POR 15?

Second question... the smaller 'cross tunnel'.. the one where the front seat adjustment bracket mounts, is in poor shape. Rust inside it looks bad... some of the lower edges are gone but it's still largely inaccesable to any tools or painting. I think my options are:

A. Drill some holes in top, blow it out, and spray as much paint in there as I can and call it a day.

B. Cut it out and weld in replacement. But is this part even available? And still how do you paint the bare metal inside after you've welded a new piece in?

Any advice would be appreciated.

[IronHillRestorations]

My post from '05

What we do in my restoration shop is clean, treat/arrest the corrosion, repair any corrosion that involves very heavy pitting or perforation, treat with phosphoric acid wash, rinse, dry, and paint. We use a undercoating kit that can be purchased at JC Whitney, Eastwood, and other auto supply houses. We treat the entire car, that is all the dead air spaces, boxed support members, etc.

First remove the control cables, and shift mechanism, as well as the pedal cluster, and most of the interior. Mask off the wiring harness with plastic and masking tape. Clean out the tunnel with compressed air and a shop vac. Manually scrape whatever you can reach with wire brushes, stainless toothbrushes, etc. Next you need very hot water and cheap automatic dishwashing detergent (like cascade). You don't want to get this on finished surfaces, as the trisoduim phosphate can dull painted surfaces. Mix up hot water with the detergent, and spray in into the tunnel. With the undercoating kit you get spray wands and different nozzles to blast in the corners, etc. Again, use the shop vac to remove the water. Next rinse with clean warm water, and clean this up. Blow dry with compressed air and the undercoating wands and nozzles. Check out the cleaning job with a light and a inspection mirror, make sure everything is nice and clean. Let it dry for a few days. At this point a little flash rust isn't going to hurt anything. Now it gets more fun! You can use Ospho, Oxysolve, any corrosion treatment with phosphoric acid that leaves a phosphate coating. You mix up the acid as directed, and after you've donned your safety goggles, respirator, and rubber gloves, you spray the area with the acid mixture. Most of them require liberal dousing, and you want to keep it wet for several minutes, longer if you've got more serious corrosion. Next you rinse the acid off with water, and clean it up. Blow it dry. Let it sit for a few days. Last you can use the same undercoating kit to blast your favorite corrosion paint over the treated areas.

This is alot of work, and makes a big mess, but it's the best thing you can do to mitigate corrosion. It's also a good thing to do if you've welded on structural supports like the GT stiffening kit, Mayeur kit, etc. If you don't treat the backside of a panel that you've welded, it will rust.

A thread: http://www.914world.com/bbs2/index.php?sho...=87664&st=0

Update: in many places you can't get cheap automatic diswashing powder with TSP anymore, so a product like "Marine Clean" may be an option. There are some paint supply stores that do sell TSP.