Experiment with weld through primer

S

Senile Old Fart

I have a lot of time on my hands and can not do much with it.

I remember a thread about weld through primer (wtp) a while back.

I have had good results with U-POL zinc weld through primer.

Others have posted they get a lot of spatter when using these types of primer.

I did a small experiment yesterday to see why some have this problem and some don't.

What I discovered is if I did not follow the directions of ONE coat of primer then yes I got spatter until a puddle forms on the primed area.

Makes sense to me , as mig is very ground sensitive and also does not like to "dig".

I think from my small test the main problem with the use of wtp is using to much of it, a case when more is not better.

IF you want to use more than one coat , or use a non wpt then a cone shaped wire brush spun with a drill motor will quickly clean the primer out of the hole you are going to plug weld and let you have a nice clean start each time.
 
I attended an I-CAR class where the subject was brought up. It was said that 3M recommends that the primer be removed from any area that is actually going to be welded ..... then why is it called weld through and not weld around .... LOL

I agree 100% with you that one coat is all that should be used, especially with the 3M product. Also using a little higher heat setting when welding through this primer works for me.
Personally I hate the 3M product. Rarely do you get to use the entire can before it stops up and becomes useless.
I have been using a product by Autokote that in my opinion works really well. It is a true weld through primer and is red oxide in color and can be primed over with other primers.
Most paint companies that I'm familiar with will not guarantee their product if it is sprayed over the 3M brand of WTP.

Primer-1.jpg
 
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