Weld through Primer ?

[Snollygoster]

I am slowly getting the hang of welding (thanks in a large part to this forum). I'm welding mainly patch panels in a vw beetle so its been tricky but hugely rewarding when done. I have recently been told to use weld through primer. Does anyone use this product and if so, does it have any effect on the weld and settings ? Cheers

 

[mike 109444]

I have not used any of the "weld through primers" but do use the stuff on the left of pic. This is, for the same amount as you get in most of the weld through primers tins (400ml) much cheaper and seams to work well. It drys very quick and does not seam to effect the welding to much (if plug welding I do just scrape off some of what I can see through the hole, just to get an easier start but not totally necessary). It does seam to withstand the heat from the welding very well.
At £3.99 if you buy 3 or more or £4.49 for 1 or 2. The weld through is usually about £8 +.
If the rear of the patch won't see daylight then I usually give it 2 coats (dry in aprox 5 to 10 mins for 2nd coat) It is touch dry in no time.

 

[pondy]

I have used upol weld through primer on a beetle im restoring. On plug welds It looked abit rougher than I had hoped but I plan to use a snall finger wire wheel on a drill to clean the holes before welding.
I can see the appeal of it, said beetle has had a quarter panel in the past and the joggled edge on the inside is corroded as its bare metal exposed.

 

[BrokenBiker]

not having ever used this stuff i must ask, what is it for? Is it just to protect metal that is unable to be painted after welding?

 

[pondy]

From what I can work out its for joggled joint and overlapped joints were you cannot paint after welding on automotive use etc. Spray it on and let dry, when welding it melts but reforms when cools down. May be wrong though?

 

[steveo3002]

doesnt melt and reform , usualy a zinc type spray that you use on hidden overlapping joints that would otherwise be bare metal- just like a burn resistant silver paint

from when ive seen cars at work come back for further repairs it still lets the metal rust but its better than nothing , try and drown it in cavity wax where possible

 

[Snollygoster]

So just to get this correct.....you don't actually "weld through" this ? You only use it in places where you can't put primer after the weld has been made ? ie overlapping and joggled areas ?

Cheers

 

[BrokenBiker]

you still weld through it. Basically you spray it onto areas that will be inaccessible after welding, then weld thee new panel in and go over the whole lot with normal primer or paint. The weld through stuff is used so you don't have to clean back before welding as far as i can work out

 

[steveo3002]

say if you was fitting a new sill , the flanges would be ground back to bare steel , you would use the weld through primer along the flanges for "some" protection instead of none

 

[Rocketman]

Like said it's the only protection you will be able to get into hidden joints. better than nothing for sure. As there is no better alternative for general restoration/repair work we are pretty stuck with it.

 

[Spot the welders dog]

Aside from the products advertised functions; I find its reflective properties useful in poor light conditions to highlght any area to be welded.