Seam sealer on underside?

-

GSS

Well-Known Member
Joined
Jul 20, 2010
Messages
115
Reaction score
90
Location
MN
None of my Mopars appear to have had any seam sealer on the underside of the car but there are a few places on my Demon that could really benefit from some. Do any of you guys do this?
 
I'm doing it to mine. Replacing seam sealer everywhere.
 
You’ll notice that all the seam sealing is done on the inside of the car and the seams are open on the underside. When you try and seal both side if water does find it’s way in the seam it won’t dry out and will stay wet in there and continuously corrode the seam. I haven’t done this yet to mine but I am going to get around to it is to spray a wax oil product used for corrosion rust proofing in between the seams on the bottom of my car. This product creeps in between the seams and then solidifies like wax. This is the gun that has a couple different tips that sprays the stuff, almost like a mist,
8021D3DC-FA68-4BE4-BEC2-270146D6FE16.jpeg


0E88D02C-3A76-4317-9B7C-2D722F40E6A8.jpeg


This method keeps the seams open so they can dry out but protected from the water. It does wipe off easily when first sprayed from the surfaces you don’t want it on.
 
So are you spraying the wax/oil product on the seams from underside?
What product did you use?
Thanks for the info.
You’ll notice that all the seam sealing is done on the inside of the car and the seams are open on the underside. When you try and seal both side if water does find it’s way in the seam it won’t dry out and will stay wet in there and continuously corrode the seam. I haven’t done this yet to mine but I am going to get around to it is to spray a wax oil product used for corrosion rust proofing in between the seams on the bottom of my car. This product creeps in between the seams and then solidifies like wax. This is the gun that has a couple different tips that sprays the stuff, almost like a mist,
View attachment 1715362240

View attachment 1715362241

This method keeps the seams open so they can dry out but protected from the water. It does wipe off easily when first sprayed from the surfaces you don’t want it on.
 
I use a homemade waxoyl on my old jeeps. They are notorious for frame rot. Just make sure all your welding is done before you do it. (IE frame is completely finished). The home brew recipe I’ve used on multiple vehicles is:
Large old pot
Jug of used motor oil
Toilet bowl wax rings

I use the side burner on my barbecue
Heat oil
Break up wax rings
Mix until melted
Get the consistency you are looking for. If you want thicker, use more wax
Use whatever tool to get wax where you need it (turkey baster, garden sprayer)
It will turn into a frosting type coating depending on the wax ratio

Just putting this out there as good for thought. On hot southern days my frame will weep a little bit of waxy oil
 
So are you spraying the wax/oil product on the seams from underside?
What product did you use?
Thanks for the info.

Yes Steve from the bottom, and your not trying to fill the seam just mist in a decent film and it will creep into the gaps it can for a time until it finally sets up. If you remember on my thread after I removed all the seam sealer on the inside of my car and blew as much of the loose rust and debris out of my seams I brushed a wet coat of Por15 on them, enough until they dripped out the bottom, and then after that dried I applied a modern seam sealer. Now that went a long way to protect the tight seams but the larger open seams on the bottom can use this wax oil spray to help protect them.
I used a product by Pro Form but if you do a web search you’ll find quite a few options and many have an aerosol can version so you don’t need the gun.
 
You’ll notice that all the seam sealing is done on the inside of the car and the seams are open on the underside. When you try and seal both side if water does find it’s way in the seam it won’t dry out and will stay wet in there and continuously corrode the seam. I haven’t done this yet to mine but I am going to get around to it is to spray a wax oil product used for corrosion rust proofing in between the seams on the bottom of my car. This product creeps in between the seams and then solidifies like wax. This is the gun that has a couple different tips that sprays the stuff, almost like a mist,
View attachment 1715362240

View attachment 1715362241

This method keeps the seams open so they can dry out but protected from the water. It does wipe off easily when first sprayed from the surfaces you don’t want it on.
That is what I do after all body/paint work is done. I use Transtar Amber in a rattle can. It is really thin so it gets into the door and rocker seams really well, then dries to a thick coat of wax that does't seem to let dirt and crap stick to it.
 
I used seam sealer around the flanges,any patches i found and where rockers meet the floor.
Made sure to blow out all the loose dirt and soaked the inner frame rails with rust convertor wherever i could spray it in. That stuff is like a primer for paint.
Then paint with chassis black wherever i could hit it.
 
Well, I guess my crap's gonna rust all to hell. I am seam sealing every nook and cranny top and bottom where I replaced the floor pans. Ain't havin it. I'm sealin everything I can find. A coat of Rustoleum before and after.
 
i hadn't thought about "sealing" the underside of the seams,thanks. i'll also be doing the inside of my frame too
Eastwood Internal Frame Anti-Rust Coating, 14 oz. Spray

Well, I guess my crap's gonna rust all to hell. I am seam sealing every nook and cranny top and bottom where I replaced the floor pans. Ain't havin it. I'm sealin everything I can find. A coat of Rustoleum before and after.
i don't know how old you are, but my cars not going to rust before i'm dead :D
 
Well, I guess my crap's gonna rust all to hell. I am seam sealing every nook and cranny top and bottom where I replaced the floor pans. Ain't havin it. I'm sealin everything I can find. A coat of Rustoleum before and after.

I'm just going through this process now too. Floor plans are in and I was thinking to use 3M's seam sealer both inside and underneath. Primer first, then seam sealer, then truck bed liner.

If you seal the seams completely, would there be concerns, or does condensation still allow water to be present under all of that?
 
I'm just going through this process now too. Floor plans are in and I was thinking to use 3M's seam sealer both inside and underneath. Primer first, then seam sealer, then truck bed liner.

If you seal the seams completely, would there be concerns, or does condensation still allow water to be present under all of that?

I don't think there would be concerns in your lifetime. I am using Dominion brushable seam sealer on mine and I really like how easily it brushes on. It dries quickly and cleans up with mineral spirits. I am sure the 3M is the same. I have a can of it too but I haven't gotten to it yet. I will before it's all done.
 
Is that a "paint" so to speak?
No sir. It a lot like others are talking about like the cavity wax but it dries harder and has excellent creeping characteristics. I've done tests with it and it will climb 4 inches up an aluminium can. I don't think it will hold up to an abrasive type salt test but for between seams that get sealed it is an excellent product or for interior work. And it wont keep leaking when it get hot. I use it along with this.
https://www.amazon.com/dp/B00KNCD32M/?tag=joeychgo-20 and then paint.
 
Heres an old can of 3M. I keep it in my shop display cabinet...looks about 30 years old.
Cleanup " with unleaded gasoline " lol

20190728_133423.jpg


20190728_133434.jpg
 
I'm just going through this process now too. Floor plans are in and I was thinking to use 3M's seam sealer both inside and underneath. Primer first, then seam sealer, then truck bed liner.

If you seal the seams completely, would there be concerns, or does condensation still allow water to be present under all of that?

I would avoid the bed liner and underneath seam sealer unless you are building a daily driver. If you use seam sealer on both sides of the seam, make sure there is no air trapped in there.
Just noticed you are in Duluth too, :thumbsup:
 
-
Back
Top