Like a fool, I bought some SEM Zinc weldthrough primer to apply to some metal pieces we had to weld. “Great! This is a primer and we can weld right through it. Kill two stones with one bird!”. After reading the confusing information on the can, and based on Chris @tygaboy ’s experience we decided to sand that stuff off from the general areas we were about to weld. Afterwards, as I was about to start painting, I found out that you also have to remove it from any areas where paint will be applied! So why the hell even apply it in the first place???
I spent/wasted a bunch of time researching the issue on the web and, as usual, there is all kinds of contradicting info out there: “Yes, you weld right through it, no problem.” “I would never weld anything to that crap.” “It’s a primer so just paint right over it.” etc.
Finally I found this fairly authoritative video from 3M. I say authoritative because since it is put out by a major manufacturer, they have liability hanging over their head so the odds are they are going to make sure that what they say is at least not completely wrong. Here the guy explains the correct use of it. And in the process, he clearly admits that it is neither “weld-through” nor “primer”
Live and learn
I spent/wasted a bunch of time researching the issue on the web and, as usual, there is all kinds of contradicting info out there: “Yes, you weld right through it, no problem.” “I would never weld anything to that crap.” “It’s a primer so just paint right over it.” etc.
Finally I found this fairly authoritative video from 3M. I say authoritative because since it is put out by a major manufacturer, they have liability hanging over their head so the odds are they are going to make sure that what they say is at least not completely wrong. Here the guy explains the correct use of it. And in the process, he clearly admits that it is neither “weld-through” nor “primer”
Live and learn
