RichardB Posted November 24, 2020 Share Posted November 24, 2020 Feeling a bit confused on whether to use this or not between panels for spot welding. The idea of having the zinc there to provide cathodic protection seems good, especially when you see how quickly metal goes rusty after it has been welded. Having repairs rust from the inside out doesn't seem particularly appealing. Some don't appear to like it though and believe it produces a poorer quality weld when used. Has anyone experienced that? Link to comment Share on other sites More sharing options...
ed_h Posted November 25, 2020 Share Posted November 25, 2020 If you are talking about true resistance spot welding, using a "weld through" primer in the joint is endorsed by many, but not all, of the current car manufacturers. I haven't seen any problems using it. Ed Link to comment Share on other sites More sharing options...
RichardB Posted November 25, 2020 Author Share Posted November 25, 2020 Thanks Ed, good to know. Yes proper spot welding with electrodes as opposed to using a MIG etc. Link to comment Share on other sites More sharing options...
zetecspit Posted November 25, 2020 Share Posted November 25, 2020 Remember weld thru primer comes in zinc and copper. A friend who was a bodyshop man for 50 years reckons one is better for mig, the other for proper spot welds. Also it has poor adhesion, and the way it works is misunderstood. I "think" it sort of melts a bit and seals around the weld. But it isn't a general primer, and it is only part of the rust protection system. 1 Link to comment Share on other sites More sharing options...
Nick Jones Posted November 25, 2020 Share Posted November 25, 2020 Don’t do much spot welding...... I use Upol #2 weld through elsewhere and it seems to work. In fact any zinc rich primer seemed to weld through ok. Apart from the Toolstation stuff, which is more reluctant. IIRC, you can also get weld through seam sealers specifically intended for spot welding seams. 2 Link to comment Share on other sites More sharing options...
RichardB Posted November 25, 2020 Author Share Posted November 25, 2020 I'd be happy with a gooey zincky mess . I don't really worry about unpainted seams so much that haven't been touched by the welder, as those will be seam sealed or have cavity wax on top of them. It's just the immediate area of the weld itself that concerns me as it'd be so frustrating to have it bubble at the seam after it's back on the road (as some previous repairs on the car have done). I wonder which is better for which type of weld. I'd guess copper for spot and zinc for MIG? Link to comment Share on other sites More sharing options...
zetecspit Posted November 25, 2020 Share Posted November 25, 2020 6 hours ago, RichardBaines said: I wonder which is better for which type of weld. I'd guess copper for spot and zinc for MIG? toss a coin? I will give the chap a call... Link to comment Share on other sites More sharing options...
ed_h Posted November 25, 2020 Share Posted November 25, 2020 I've only used zinc, but notice that for plug welds, the primer still acts as a contaminant. I get better results if I clean primer from the weld hole. It wouldn't survive in that immediate area anyway. Ed Link to comment Share on other sites More sharing options...
RedRooster Posted November 25, 2020 Share Posted November 25, 2020 1 hour ago, ed_h said: I've only used zinc, but notice that for plug welds, the primer still acts as a contaminant. I get better results if I clean primer from the weld hole. It wouldn't survive in that immediate area anyway. Ed I do the same,easiest with a flattened off drill bit. Link to comment Share on other sites More sharing options...
ed_h Posted November 26, 2020 Share Posted November 26, 2020 5 hours ago, RedRooster said: I do the same,easiest with a flattened off drill bit. Yup. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now