I used 3M Fast N Firm 08505 on the inside and outside of every seam after the epoxy. You never know if someone is going to kick over a bottle of water.  You've gone this far.......

I used Eastwood's seam sealer on the interior seams and am pleased with it.  I didn't finish the interior for several years after application of the seam sealer and it didn't peel off in any location.  I did also install Dynamat but I don't believe it is considered a replacement for sealing these joints.
I agree w/TimC, you've gone this far ...

I used Lord Fusor 803EZ, which is a urethane based seam sealer.  Mine came in a caulk tube.  It went on just like caulk but can be brushed to look like the factory typical swabbed-on appearance if you want.  I dries firm but flexible and can be painted over (whcih I did).  Very happy with it.

Last edited by jkordzi (8/23/2014 9:25 AM)

Chelby-Ann wrote:

This is the perfect time to take care of all the work underneath while its on the rotissary.
After I had mine media blasted, it was primed and I used Eastwoods brushable seam sealer on ALL of the seams! I had disposable plastic hyperdermic needles that I filled with the seam sealer and just forced it into all the seams following that with an acid brush to level it out. Had to work in small sections cuz the the seam sealer skinned over and was hard to spread. Then I coated with Bed Armor from Advance Auto.

Chelby-Ann, thats the same exact product I used to undecoat the underside of my car, it it great stuff from what I can tell. However I did not seam seal the underside like you did, now that I see this I wish I would have. I guess I could go back and re-seal it down the road and re-apply more under coating for good measure! For I now I am going to focus on finishing the inside, using Master Series AG111 Chasis kit with the silver undercoating that is a rust inhibitor, then seam seal over the silver as it seems to be the consensus here, then finish with the Epoxy black top coat. Not sure if I will roll on anything ovet the top of this as it is supposed to be a great stand alone unit! Thakns for all the input from everyone here, much appreciated!
 

MustangSteve wrote:

Seam sealers today are probably light years ahead of what the factory used 50 years ago.  You need to seam seal every gap, inside and out.  Condensation will occur at some point letting moisture into the seams and and water you drive through will keep the overlapped spot-welded areas wet for a long time.

I used rubber undercoater after painting the bottom with rustoleum, over the seamsealer.   I regret doing the undercoating. It is impossible to wipe down the bottom of the car to remove any grease slung off by the ujoints or cleanup of normal road grime. If doing over (and I'm NOT) I would paint it with a gloss light grey paint in the areas between the frame rails. The dark undercoat makes it very difficult to see under there when working on the car.  Even the factory red primer is better than black, if wanting to be able to see what you are working on is at all on your list.

I had not thought about the darkness complicating visibility under the car, nor had I thought about clean up, like they say "hindsight is 20/20". I dont forsee re-doing the underside at this point, but I will most likely go back and seal the seams underneath, then re-coat with undercoating. As for the inside, I will definetly seam seal everything, as most everywhere I have pried up the old seam sealer there has been flash rust. So I am treating all rust with OSPHO, grinding it off, then plan to use Master Series Silver primer/sealer, seam seal, then top coat with the Chasis black like I mentioned before.
Thanks Ya'll!