What is best waterproofing material for top?

[Texas Tom]

I'm about to install the top on the 1930 Town Sedan that I'm restoring. I've read that it's wise to apply some waterproofing material along the surface of the channel to which the vinyl top material is tacked. I've also read that silicone caulk is to be avoided to prevent future rust issues.

So what precise brand of caulk is best? Almost every tube of caulk at Loews and Home Depot contains silicone. Those that don't contain silicone are priced so low that I question their quality.

Is a thin bead of silicone likely to cause problems in a year or two? Or perhaps 10-20 years later?

Any advice will be appreciated.

 

[Wick]

What comes to mind is roofing tar.

 

[Bubsyouruncle]

The biggest problem with any substance that contains silicone is that it is almost impossible to remove and the reason you use silicone in the first place is because nothing sticks to it. So when the silicone breaks, and it will, you can never, ever, get a good seal on that surface again.

Check with GE. They do not provide a substance to remove silicone. Isn't that interesting?

 

[Spokes]

I got a kick out of the reply roofing tar. Back in the 60's my Dad hAd a Model A with a leaking roof. He drove his A to a house being built and they were tarring the house. He asked if they would tar the roof of his A. They did and it lasted for over 30 years. True story

 

[Mitch//pa]

i would use a seam sealer or urethane

 

[eagle]

Lexan sealer works great although I would only use it where its not exposed to sunlight as it does degrade in UV.

 

[Doug in NJ]

I was very happy with butyl rubber caulking.
Search older postings for "butyl".

Doug

 

[lajones]

There are a few products sold by metal building suppliers that does not contain silicone

 

[MikeK]

3M Window-Weld Super Fast Urethane. It's black, you can wipe up excess for about 15 minutes with a rag and mineral spirits. The short mineral spirits exposure will not harm catalyzed paint or the top material. Get it at most any auto parts store. Also good for after-the-fact leaks and sewn seams so long as you don't mind getting the seam stitching black.

 

[Rocketsled]

You could use a Neutral Cure type RTV silicone adhesive/sealant. Dow Corning also has OS Fluid which is used to thin and clean-up uncured RTVs. It evaporates completely and will not harm paint, or plastic. Its great for getting the goo off your hands! Comes in spray cans and jugs.
R

 

[BILL WILLIAMSON]

I got a kick out of the reply roofing tar. Back in the 60's my Dad hAd a Model A with a leaking roof. He drove his A to a house being built and they were tarring the house. He asked if they would tar the roof of his A. They did and it lasted for over 30 years. True story

Spokes,
We were POOR, I helped Chief, my Dad, cover a '30 Coupe roof with chicken wire, then quilting cotton, (that Mamma donated) then covered it with canvas from an almost NEW cotton sack. After the Hide-Em Welt was nailed on, it looked quite Good!
We poured roof patching tar, the old kind in the silver, NO LABEL cans, all over it. As it gradually "SET-UP", we'd drag a wide hard old paint brush through it & it looked quite nice! (Looked almost like LONG GRAINED COPRA!) After a clean up with a rag & COAL-OIL, it almost looked like "A FACTORY JOB!!
Bill W.

 

[Bob V]

I've used a sealant named Big Stretch on several tops that I've installed. It's made by Sashco and can be purchased through Amazon or at some building supply or hardware stores for about $6.00. It's black acrylic latex that comes in a 10.5 oz. caulking gun tube. It's not like other latex calks in that in that it stretches 500% after it cures and acts like rubber. The best part is that it cleans up with soap and water. It helps makes a super neat top installation. Also, it does not cause the painting problems like silicone caulk does.

 

[Dale G.]

Texas Tom,

I have used something called 3M adhesive/sealant on several tops in the past. The number is #5300 or 3600 or close to it as I am out of it at the moment and can't remember the number. For your application you would probably use about 4 tubes. It come only in black or white. The only place I can find it in my area is West Marine and don't be shocked at the price as it is that good. It is used exclusively in the Marine business. For your application I use it in the moulding trough then nail or staple your top material down on the adhesive. Once that is done, then run a bead on top of the top material in the trough, then nail down your moulding. Also put it under the material in the front, then on top of the material and bring the front moulding down on that. Clean up with mineral spirits. You will not have a water leak in your lifetime.