weld thru primers?

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barbee6043

barbee6043

barbee 6043
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I have used it couple decades ago, I clean the metal I will weld good cleaned metal, plap disc ed, cleaned it with phosphoric acid sol. I read about the weld thru primer stuff now, is it anything more than a self etch primer???? Welding the wheel opening and the inside edge of outer wheel housing. 62 Lancer! (of all things!) ha
THIS is HER car, and it better look good till one of us kicks the bucket!
 
I use it - it seems pretty similar to ordinary primer. Supposedly it has a high zinc content to make it more conductive. It still burns and stinks like any other primer.
 
I've used weld through primer. It's different than regular primer in that it's specifically formulated to not contaminate weld - or so I've been told.
 
"Weld through" it is not. You still need bare metal to weld. Prep your area, paint it with a weld through primer of your choice and then remove the primer in the area to be welded. For example where I was spot welding I took a drill bit and just hit it to remove the paint. I used the SEM Copper brush on stuff.
 
Google it...There is a lot about it good and bad out there. As well, some discussion regarding the latest "stuff" on the market. Lots of misconceptions regarding this stuff and how to properly use it.
 
marksmopar1 said:
Google it...There is a lot about it good and bad out there. As well, some discussion regarding the latest "stuff" on the market. Lots of misconceptions regarding this stuff and how to properly use it.
Click to expand...

That Google is one some bich!! I did learn things I did not know. I can get to the inside of my panels, and I will just DA the in between layers and coat with Ospho. The do my usual epoxy primer, bah and more bla.. Thanks guys
 
I use it as described above where you "clean" the hole. I use a spot drill bit. The style that looks more like a little end mill with a tiny point. Some brands of weld-thru are better then others and some are total junk. U-pol is my choice but not cheap, Medallion if I can find it, 3M brand I don't like, and the $6 can of "cold galvanizing compound" leave on the shelf at Lowe's. They all seem to contaminate the weld to some degree even when you clean the hole. In terms of long term durability and corrosion protection I haven't noticed really any difference on cars I've seen long term between prepping with weld-thru or just taking a spot bit and cleaning the e-coat off the underlying panel in the hole. If you have to prep between panels to clean up the drilling and whatnot it's better then nothing I suppose.
 
I spray the whole seam and let it dry. If im plug welding I clean the areas where I will be welding and it seems to work good. It does burn a little but does not appear to affect the weld quality.
I was using a zinc based type but the price more than doubled when I went to buy another can. I found some "copper weld" and it was priced around $20 a can. I think SEM makes it. Seems to work just as good.
 
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