[dataway]

Anyone know of any good weld through paints or coatings? I'm doing a floor pan and I've got an area where the metal needs to be clean to be welded, but once welded I would not be able to get to the area to paint it. Only reason for the paint would be to prevent rust. I could, if necessary, flood the area with a rust inhibitor if no such weld through coating exists .... but seems like I've heard of them.

[Greg Reid]

Yeah, you can get it at any auto body supply house. It ain't cheap. The last can I bought, I almost fell out in the floor when he rang it up.
3M brand '05917 Weld Thru II'... It was damn near $30 for a 20oz rattle can.
Here, this is easier.... https://www.autobodytoolmart.com/pro...hoCZcEQAvD_BwE

[tjs72lemans]

That's about all I've heard of and used is weld thru primer by 3M.

[PontiacJim1959]

This may sound funny, but I use the hi-heat barbecue black, ie the high heat paint used for your outdoor grille. Paint is going to burn, no way around it, but the store bought spray bomb worked pretty good for me and burned off minimally, then just clean up the burned paint and re-spray. Just spray, let it dry a day or 2, then weld.

Just a consideration.

[dataway]

Thanks Greg ... that sounds like the ticket.

[rwfisher]

I've used SEM copper weld and it is a little cheaper than 3m, covers well and works well. Also comes as brush on if you prefer that

[dhutton]

Use it sparingly, a very light coat or your weld will be garbage.

Don

[Greg Reid]

Be aware, it's not actually a primer. You have to remove it from any surface that will get paint. For that matter, the instructions say to remove it from any spot where you've punched a hole to simulate a spot weld. Plug welds actually...remove it from the middle of the hole.
By the way, after looking at the can, it's not 20oz.....It's only 12.5oz for damn near $30.

[dataway]

I actually ended up getting this stuff. Solely based on reviews.

Seymour 20-1675 PBE Professional Primer, Self Etching/Weld Through Gray

[tjs72lemans]

Like most people that use weld thru primer, it's protection in an area that can't be prepped once welded. This was this poster's issue. So, no reason to worry about paint.

[Greg Reid]

Well yeah, that's true and that's all it's really for..but the word 'primer' ...which appears nowhere on the can by the way....might lead some to think it's ok to leave overspray on an outer surface.

[First Bird]

I've used Upol Weld Thru primer. It worked well

[dataway]

I was looking at the UPol stuff, its very highly rated by the customers.

[bkmont]

Originally Posted by First Bird

I've used Upol Weld Thru primer. It worked well

Same here.

[chiphead]

Upol copper weld thru works great and no zinc fumes

[dataway]

Since I haven't started the project yet ... I ordered some of the Upol also.

[MUSLCAH]

Originally Posted by rwfisher

I've used SEM copper weld and it is a little cheaper than 3m, covers well and works well. Also comes as brush on if you prefer that

Yup...same here....then aftah welding I make some access holes and blast in the 3M cavity wax ..with the long tubes and 360 degree spray heads...works slicker than snot on a door knob.

[Formulabruce]

Some info, "Weld -Thru" means "Induction Welded" , Not Mig welding. These primers don't burn up, they melt around the spot weld to give it corrosion protection.
I have used when plug welding, but that is not the true purpose of this primer. It was never designed to Burn up.
/\/\ Cavity wax is good stuff.

[dataway]

My major concern is on the back side of a MIG plug weld. So it should be ideal for me, or at least better than nothing.

[dataway]

Just read the instructions on the U-Pol "Weld #2" copper primer ... says it's suitable for resistance spot, MIG and TIG. Find it hard to believe you could TIG weld through any coating at all, it's certainly not very tolerant to any kind of contamination.