Automotive Body Seam Sealers

[Ulu]

What’s the best stuff to use on the bottom?

 

I’m going to have seams to seal in my modified floor pan, which will be mostly pre-painted in black acrylic enamel.

 

Also, some will be applied to bare steel. I’ll want to paint everything after sealing anyhow.

 

It should be easy, durable, and inexpensive. I’m not going for a show car look.

 

But I’m willing to spend what I should.

[Plymouthy Adams]

I use 3M brushable seam sealer.....there are other brands also...have use other names with as good a result.  Got a car here I painted in 1984 over the 3M seam sealer and it is as nice today as it was back then.  

[Dave72dt]

The last I used was 3m's Dynatron in a caulk tube. It's been in several of my projects for a number of years without issues.

[Eneto-55]

I have wondered about this as well, because when I was doing the body work on my 46 Plymouth, I removed the seam sealer in the rain gutter.  (The car had been repainted twice before I got it, once by brush (and not a good job, which some brush coats actually were), then sprayed heavily on top of that.  So I will need a seam sealer that can be used on the outside of the vehicle, can be painted, and will still look nice. The original stuff that was over the seams in the floor boards was very thick, and not for appearance sake.  It was a long time ago when I did the body work, so I do not remember what the stuff in the rain gutter seam looked like.  I just know I took it all out, and didn't think about needing to redo that at the time I was prepping for paint.

[Dave72dt]

43 minutes ago, Eneto-55 said:

I have wondered about this as well, because when I was doing the body work on my 46 Plymouth, I removed the seam sealer in the rain gutter.  (The car had been repainted twice before I got it, once by brush (and not a good job, which some brush coats actually were), then sprayed heavily on top of that.  So I will need a seam sealer that can be used on the outside of the vehicle, can be painted, and will still look nice. 

You might want to look at a 2 part self leveling sealer used on modern cars in the roof channel where they fasten the roof to the sides of the car.  Fusor is a name that comes to mind.

[Los_Control]

No idea about best, I have been using this brand.

I picked up a tube at the local parts store and was not pleased with it ..... It worked fine, once I opened the tube I should have finished it off ... All dried up and no 2nd use from it.

 

I bought a 3 pack from Amazon of this stuff, seems to work fine. The tip saves it .... all that is inside gets dried up and have to cut the tip a little larger and dig it out, am able to finish off the tube though and not throw it away.

 

 

[Ulu]

I won’t have any sealer aimed at the sky on this roadster. It will strictly be on the inside and outside of the floor.

 

It will have to fill gaps around the flutes.

 

[Dave72dt]

Different sealers for different applications.  Since you have gaps to fill, a caulking type sealer  be may preferable to a brush on.  The Dynatron I mentioned is about half the cost of 3m's urethane sealer.  Is it as good as? Don't know.  Other companies make good product also.  Use what's available locally.  That makes it easy to get more if you need it.  If it has date codes, get the freshest. Some of them have expiration dates.

[Ulu]

I was considering polyurethane, but I didn’t think it would hold paint.

[Plymouthy Adams]

be sure the primer you are using will not react with the seam sealer....yes...it can cause you major issue....not all systems are compatible.  

[Ulu]

I am just priming with dilute phosphoric acid wash. The paint is self etching too, so this makes it stick well without filler or sealer primers.