Seam Sealer???

[paulrowe]

Does anybody happen to know what sealer GM used in the trough under the front window where it joins to the fire wall. I had a rotten spot in my fire wall and has to cut it out and repair it. The stuff that was there was a hard black sealer. I used some Proform seam sealer from a caulk gun but it doesn't seem to get as hard as the original stuff. Also after putting it on I noticed the package says not to fill a gap bigger than 1/8th. The gap is much bigger than 1/8th. What I'm noticing is after 3 days it still seems wet underneath. Here are some pictures of the repair and the trough area.

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Any help would be appreciated.

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[Cuba]

Hard black sealer? I'd imagine window sealer. It hardens somewhat over time, but never completely. Permatex makes one which can be found in most part stores. I don't know what exactly was used for certainty. Just an educated guess...

 

[RoryH19]

I'm replacing the seam sealer in my k5 before it's repainted. I'll use SEM.
They have white, black and gray.

 

[Cuba]

I'm replacing the seam sealer in my k5 before it's repainted. I'll use SEM.
They have white, black and gray.

I had no idea there was such a thing. A quick search, and all sorts of brands.

I know using caulk or any household sealer would never work and will break down prematurely. Doesn't seem to hold up well even for the house.

I appreciate your input, even if not my thread.

 

[bucket]

Yes, there are LOTS of brands and types of seam sealer. Different colors, different amounts of flexibility, some stay put after applied, some flow out and some are downright runny. Some fill large gaps without shrinking, some don't. There's a sealer designed for literally every type of application.

For inside a trough, you generally would want something that flows out, dries firm and does not tend to shrink.

 

[80BrownK10]

I used AC Delco to seal mine back up. It's white. I just painted it to match good enough for a driver hidden in a cowl. Mine stays flexible as well.

 

[paulrowe]

Thanks for the information all. I'm just going to leave the stuff I put on there then because it has all the characteristics that bucket listed. I'll just paint to match when I think it has dried enough underneith.

 

[T-crafter]

3M makes a great product. I have used it in aviation on floats and windshield. You can get it in black or white I have seen it at most marinas and home depot. put it on and smooth out with a latex glove on as it is difficult to get off. It is a great adhesive also.
3M 5200

 

[crpntr78]

Welcome back CubaI

 

[Rusty Nail]

SEM seam sealer would be my first choice.

 

[80BrownK10]

3M makes a great product. I have used it in aviation on floats and windshield. You can get it in black or white I have seen it at most marinas and home depot. put it on and smooth out with a latex glove on as it is difficult to get off. It is a great adhesive also.
3M 5200

We use that one and I think it's 3500 (semi permanent) in the Marine hobby. Sealing holes in the hull and for waterproofing, like where deck meets sides or windows through hull fittings etc.

 

[MikeB]

I don't know what GM used back then, but I'd bet the current sealers are a lot better.

I like this SEM product: https://www.amazon.com/SEM-29372-Gr...eywords=sem+seam+sealer&qid=1590703614&sr=8-3

It's available in several colors, and you can buy a package of 15 nozzles for around $7.

 

[Cuba]

Welcome back CubaI

Thanks. I peek I'm from time to time, but schedule doesn't permit too much online time. :/

 

[Rusty Nail]

I don't know what GM used back then

SEM?

 

[orskier]

I've got the SEM sealer ready to go. Has anyone found a good way to get it into the seams at each end of the cowl above the kick panels, the ones that run front to back? My side to side seam along the top of the firewall is still in good shape, but water is getting in at the passenger side kick panel and I'll be darned if I can figure out how to get the sealer into that seam!