Best weld through primer?

[chevyshawn]

Needed some recommendations on some high quality weld through primer. Thanks

[dhutton]

They all suck imho. Use a high quality epoxy primer and scrape it away where you plug weld. A drill bit with the end flattened works well to remove the primer in the plug weld hole.

Don

[chevyshawn]

Thanks Don! l've used vht epoxy paint in a rattle can in the past and used a small dremel wire wheel to take the paint out of the spot weld holes before welding. Is the vht epoxy paint alright for this or does it need to be primer?

[dhutton]

I only use epoxy primer. I don’t think rattle can epoxy is anywhere near equivalent to a quality 2k epoxy primer. SPI is my favorite epoxy primer FWIW.

Don

[chevyshawn]

Thank'ya sir. I'll check out the SPI

[astroracer]

Agree 110% with Don. "Weld thru" primer doesn't do much but catch on fire when welding and you still need to go back and reprime all of the welds so it really doesn't do anything a good epoxy won't.
Mark

[sccacuda]

U-Pol is a very good weld through primer. If anything, your really only protecting the inside of the joint you are welding, as I assume everyone would go back and clean/epoxy the outside. As far as epoxy, doesn't get much better than Axalta (old Dupont) 2580CR. Even my hardcore PPG friends use it.

[astroracer]

While we are on the subject I will say it is imperative to protect the back side of any welded joint. Whether it is a patch panel, new panel or a welded seam you have to get to the backside to prime and protect it where ANY welding was done. The heated metal will rust quicker then the rest of the panel so it has to be protected otherwise it will rust through in a few short years.
Mark