Automotive Body Seam Sealers

[CaddmannQ]

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.

[mccutter]

When I lived up north, I used to have to deal with body rot and vehicle safety inspections. The sheet metal would sometimes be very thin and not really "weldable" without replacing vast sections. For a cheap car with rotted footwells/floors, this would not be economical, so I would pop-rivet patches in for cars to "pass" inspection--ie: no holes in the floor that could let exhaust into the cabin.

To seal the gaps and cover the rivets I would use Lexonite which is pretty much just asphalt/pitch/roof tar. Applied from a can with a putty knife. After a week? it would eventually set up and harden. Petroleum products WILL dissolve it. There may be better products out there but this was my low-cost inspection-passing routine.

[arizonian]

Sikaflex. Home Depot has it.

Before I retired, we built frames to hold the bulletproof components of certain military vehicles, Humvees, dozers, graders etc. One of the requirements was NO RUST! The frames were blasted, seams were treated, then paint applied before sending the frames to the armorer.


The story behind this picture is here.

[GWIZ]

I cant say now but years ago Permatex Weatherstripping worked well.
Permatex Black was for sticking the plastic sheeting in the door panels at the time the black was like tar that did not dry and stayed tacky.

then there is the Yellow.
Back in the day when motorcycles leaked oil people would use the Yellow for assembling the engine cases
BUT it would require a hammer and chisel to get the engines apart.

I suggest you buy both and test them out for your application.

Edit.
Cant say how well it will work for automotive applications
at DH Loctite PL pro Line 3X Premium construction adhesive is some good stuff

back in the day I would use Liquid nails for construction but whatever they did it is now crap. took a while to find something the was just as good and it is the Loctite 3X comes in the long tubes and the price would be better than the Permatex Yellow.

[randydupree]

i use the white caulk like house painters use,i get it at any hardware store,home depot etc.
White Lighning was a brand i used,not sure if that name is still used.
I just bought 6 tubes the other day,$3 per tube,it used to be a buck a tube.
A local well driller machine builder used it on all fabricated parts,caulk the cracks/joints and paint.

[randydupree]

i use the white cheap caulk from home depot,same stuff the house painters use,cheap and works just fine.
$3 per tube.

[slip knot]

Check out Eastwood. They carry a variety of seam sealants. I've used their products in the past and have had good luck with them.

[Ironman]

I once patched a hole in my son's pickup where the rust had eat through the wheel well. I put roofing tar on a patch of blue jean cloth and slapped it down on the hole and then tarred over the cloth on the box inside.
The road gravel embedded in the tar on the well side and with a bit of sand on the tar inside it was not sticky.
This patch lasted 4 years til he sold it.

[Whitetrash]

Originally Posted by Ironman

I once patched a hole in my son's pickup where the rust had eat through the wheel well. I put roofing tar on a patch of blue jean cloth and slapped it down on the hole and then tarred over the cloth on the box inside.
The road gravel embedded in the tar on the well side and with a bit of sand on the tar inside it was not sticky.
This patch lasted 4 years til he sold it.

Basically "Ghetto Hardfacing"

[midmosandblasting]

I would lean toward using true seam seal from a supply house .