has anyone used it and do you think it really works? what kind do you like the best?

I think its waste of time.....I call it burn through primer. Makes it hard to make a nice clean weld. The heat alone from welding by any rattle can primer is going to burn up. I like try to seal/prime up any of the metal after the welding is done.

I used it. It was kinda expensive $20 a can. It only took one can.

It is for between the over lap of the two panels being welded.

If you are butt welding the panels you dont need it.

I will use it again.

I've used it where I'm making repairs where panels mate or overlap. When I'm plug welding, I'll use it on the mating surfaces, and just scratch it off through the hole that I'm plug welding to help get a good arc. All I've tried is the 3m Weld Thru Primer. It's supposed to have a lot of zinc in it.

The 3M primer works good, has lots of zink in it. I use it all the time

Works great but make sure you grind off excess before you prime and paint because primer and paint peels off of it. Ask me how I know .

I dont weld without it. I bought eastwoods "bloxide", one of the few products from eastwood that really works for me. If you weld without it, wake up the next morning, and you can see rust all around the weld area. I dont scratch any of this stuff off before the weld. This primer has aluminum in it, so I guess it is conductive to the mig wire. Its nice becuase you can brush it on where you need it. I've been doing a lot of fab work on my project so I buy the metal sheets from lowes, home depot, etc. in the 8x16 or whatever size and degrease them, scotchbright pad em, then coat them with this stuff. I have sheets from last year that are ready to weld with no surface rust on them.

I use U-Pol. Expensive but the can actually sprays 2 years later.

The U-pol#2 is excellent... no spattering welds, etc. I've paid as much $25 per can, but it's out there for much less if you search.

Rick

I just used some made by Crest Products, zinc based. Works fine and seems like the metal is protected much better than regular primer.