Paintable Seam Sealer for Metal

[desertPOS]

Have some voids or spots where it doesn't make sense to lay more weld and fill in, but don't want to leave it to collect mud/debris or be tough to paint. Spots like where a sheetmetal panel is welded to tube on one side, and other side is just a semi porous backside of a weld. Or like pic below, panel spot welded to tube in big flat sheet, but bottom side has a big 'gap' that would easily fill with mud or debris. Needs to be able to stick to bare metal really well, and be paintable. Bonus points if it can handle some heat in spots around exhaust. Extra bonus points if comes in a tube that can be chucked up in a caulking gun. Triple extra bonus points if it's a bit flexible, so any potential sheetmetal flex in the future won't make it just crack

Who's used what and how did it work long term? I've done zero searching, other than on here, but would rather hear from people here that have used something before going down the google rabbit hole.

Spots like this where nothing really needs to be 'sealed,' but would be cool to fill in the gap there so it's easier to paint etc. Mostly talking about tube to sheetmetal, although overlapping sheetmetal like in the right side of pic below - I will push the overlap flush to the sheetmetal under it and just lay some tack welds along it, and would be nice to just smear some seam sealer on the edge to seal it up instead of welding the whole thing

 

[AgitatedPancake]

IIRC the 3m Dynatron is what I've used with good success. Dries pretty stiff, but not full hard so it can handle some wiggle over its lifetime. The title says "fast skinning", that can be good or a bit of a nuisance if you're still trying to finish forming/smearing it once it starts to skin up. But manageable once ya get a feel for it. And you can sand the rough stuff off once it dries without clogging up sandpaper too much.

Amazon.com

Sloppy, but ya get the point:

 

[desertPOS]

IIRC the 3m Dynatron is what I've used with good success. Dries pretty stiff, but not full hard so it can handle some wiggle over its lifetime.

Nice - and comes in a caulking gun tube


Btw, I don't think it needs to be super flexible or anything, but if someone forgets to strap the cooler down before hitting a whoop section at speed, let's say - and the floor bends or dents a bit. Would be cool to have a little flex to it instead of cracking. Picturing most factory seams sealers/adhesives there I guess

 

[arse_sidewards]

In my world stuff like bolt down trans covers, brake boosters, etc get butyl tape or sealant and stuff like spring hangers, bumpers and 5th wheel rails get roofing tar.

Something that needs to be printable I'd use a "real" seam sealer. Just about anything can fill a gap and displace water/oxygen. Not reacting poorly with paint is what you pay the money for.

 

[KT2]

IIRC the 3m Dynatron is what I've used with good success. Dries pretty stiff, but not full hard so it can handle some wiggle over its lifetime. The title says "fast skinning", that can be good or a bit of a nuisance if you're still trying to finish forming/smearing it once it starts to skin up. But manageable once ya get a feel for it. And you can sand the rough stuff off once it dries without clogging up sandpaper too much.

Amazon.com

Sloppy, but ya get the point:

You can wet it with wax and grease remover or thinner smooth it out when it sets up too fast.

 

[SHARPMACHINE]

I have needed this many times without knowing it.. lol

 

[rattle_snake]

paint/seal and use any regular seam sealer. All are paintable. Autozone has it.

 

[AKnate]

I've just used caulking.

 

[tac1]

I use the same 3m Dynatron mentioned above some of mine are 10 years old no issues and look good. It doesn't sand the greatest if that is important to you.

 

[akguy09]

https://www.amazon.com/s?k=seam+sealer+automotive&crid=9V4BHH1MCGX&sprefix=Seam+se%2Caps%2C216&ref=nb_sb_ss_ts-doa-p_1_7

 

[desertPOS]

Awesome - looks like 2 votes for the 3M Dynatron, so probably go that direction. Probably will be a few weeks before I'm actually using this stuff, but wanted to get it figured out and ordered at some point soon so it's there when I'm ready for it


And I know that I can search Amazon or google, or even walk into Autozone and see what they recommend - but the results of any of those are meaningless to me. What I care about are what people on here or people that I know have used and can critique, so thanks for the replies. Hopefully this thread is helpful to others in the future I'll try to remember to post up after I've used the stuff...

In my world stuff like bolt down trans covers, brake boosters, etc get butyl tape or sealant and stuff like spring hangers, bumpers and 5th wheel rails get roofing tar.

Link to butyl tape you recommend? What need is there for roofing tar on spring hangers or bumpers

 

[arse_sidewards]

Link to butyl tape you recommend?

I just buy the cheap shit no fucks given. Anything sold for sealing RV windows should be the correct stuff.

What need is there for roofing tar on spring hangers or bumpers

Fills up a place that otherwise fills up with dirt/salt trapping moisture and promoting rust.

Learned it from a boat guy. They do that shit where you have something that flange mounts to a deck or wall.

 

[Slander]

I have used that 3m stuff as well, works as advertised

 

[4Eyedturd]

I’ve had good luck wearing a plastic glove, dipping my finger in lacquer thinner and smoothing out the seam sealer.

 

[akguy09]

I like the ac delco personally

 

[Gunhand1]

I'll throw in on Dynatron as well, it works great