Sealing up your tub

Fiberglass or 'seam sealer' putty like they use at the factory.

RTV is 'room temperature vulcanization' silicone.

It is not good for sealing body parts. It will hold humidity under it and cause the metal to rot fast.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

snipped-for-privacy@columbus.rr.com wrote:

What does room temp have to do with the stuff? Works well under great heat.

Also, where can you pick up that seam sealer...any hardware store?? Thanks! Allen

Vulcanizing is a hardening process for the silicone rubber.

The old style stuff had to be heated big time to vulcanize. Like the old tire patches, they came with a metal cup filled with a flammable charcoal type stuff and you clamped it onto the tire with a big C-clamp, then lit it on fire. Come back 10 minutes later and the patch was done.

Most auto stores that sell bodywork materials will have seam sealer.

Mike

snipped-for-privacy@columbus.rr.com wrote:

On or about Fri, 28 Nov 2003, snipped-for-privacy@columbus.rr.com of snipped-for-privacy@columbus.r...:

RTV stands for "room temperature vulcanizing". It doesn't need to be silicone, it just means that it is a rubber-like substance that sets up without heat.

It is rumored that RTV silicone off-gasses during curing, and that the gas will eat automotive finishes and bare metal. I couldn't easily find anything on a Google search to support this, but there's a lot of anecdotal evidence in the form of big rusty holes in Jeeps with a bead of RTV silicone stretched across the opening. Chicken or egg, you decide.

What I've been using to seal various openings and seams on my re-pop `79 tub is a coil of butyl rubber I bought from a glass shop for $5. It is sort of like Silly Putty and it stays sticky and flexable and so far has stayed in place. YMMV.

Approximately 11/29/03 10:29, Lee Ayrton uttered for posterity:

It sets up without requiring heat. Most use moisture from the air and surroundings to drive the reaction, which generates a small amount of heat...not enough to be much of a worry.

There appear to be two main formulations of RTV silicone. The one that smells like stale vinegar has acetic acid in it, which stinks to high heaven and is mildly corrosive but somewhat self buffering. The other is ammonia based and may give off ammonia during cure. The label on the tubes will note which type. There may be others, these are the only two I just happen to have run across.

Whatever works. The caulk type silicones come in enough colors that you can do an extremely attractive job with the minimal trick of using a wet finger to smooth them into place, just like doing bathroom refurb. Not a particularly good idea to stick your finger in your mouth to wet it, I use that weak soap solution like is used for decals and window tint.

When you say silicone outgasses you're understating things - it outgasses and outgasses and outgasses some more. Worse than a Scout troop after pinto beans. The gas is acidic and it definitely will attack metal, especially if moisture is present.

I had the pleasure of building some equipment for space deployment where we had to seal the cases to insure that no foreign material entered or left. One of my techs was just SURE that silicone (RTV) would work until we put it under a 1 TOR vacuum and found that it was still outgassing 30 days later. Even under vacuum it ate solder and copper (even gold plated) off the circuit board. If you take a sniff of most of the silicone and RTV products after you apply them, that vinegar smell is just that. Add water and get acetic acid.

In my experience you will be much better off with a specialized body work supply store than with a generic auto supply store. These tend to have a greater variety of materials and also people who know what they are really intended for. Otherwise try talking to someone who works at a body shop or restoration business, and ask where they get their stuff.

Earle

Showin' your age here Mike. They haven't used this process since Bill was a kid. :-) I remember when the old timers couldn't get away from the heat vulcanizing process and used to light the rubber cement on fire to heat it before applying the patch.

-- Old Crow 24 hours in a day... '82 Shovelhead FLT 92" 'Pearl' 24 beers in a case... '95 Jeep YJ Rio Grande Co-incidence? I think not. ASE Certified Master Auto Tech + L1 TOMKAT, BS#133, SENS, MAMBM, DOF#51

Approximately 11/30/03 03:38, Old Crow uttered for posterity:

Eggshually if you put the rubber cement on both pieces after cleaning properly, lighting a match to burn off the excess ether was a good way to speed up the patch process. Rather than setting there sniffing fumes while the ether dried out, you just burned it off, then *carefully* put the patch in place as it will stick instantly. As for old timers, this glue/patch process predated the vulcanized style patch by decades. The advent of superstretchy radial tire tubes pretty much killed both processes.