Weld Through Primer

[andyofcolumbusmerkur]

Multiple people have recommended SEM products on this forum. So here are some pictures of my results using their weld through primer. It is the basic version as they have another higher temp weld through primer. I didn't want to drill holes in the mower deck and have bolts inside the chute collecting grass. So I thought welding this chute blocker directly to the top would be a better plan. Plus it gave me a chance to practice with my HF inverter flux core machine before I use it on any vehicles. This primer would be perfect for someone welding on a fender for example. You wouldn't want bare metal underneath or inside of some hard to access area. You also wouldn't want to use regular primer as this would cause problems with the welding arc. I thought about grinding to bare metal, welding, and then painting over top. But as you can see in the photo there are all these holes for mounting to different types of mowers. Water would sit in these holes and would eventually get in there and attack the welds. Especially since the mower stays out in the elements Spring/Summer/Fall. The low temp product is suppose to burn away near the weld, but then flow back into that area when it cools. The higher temp version is more expensive and I couldn't find it near me anyway. The one I used was about 20 bucks for the can.

[my8950]

not sure exactly what is going on here, but it looks good!

[andyofcolumbusmerkur]

not sure exactly what is going on here, but it looks good!

Lol. It is neat stuff because you can paint both sides, then clamp it together for welding. It has zinc in the paint for conducting electricity.

[brokencase]

OK Andy, I'm in process of doing some small rust hole repairs on a Triumph GT6. There are a small holes just behind the rear wheel wells.

My planned approach is to grind away the rot and get down to bare metal. Then cut out a piece of sheet metal to fit behind and then MIG or TIG it in.

How would I use weld through primer in this application? I thought cleaning down to bare metal is best to avoid contamination of the weld. Does this stuff enhance the welding is some way like flux?

I guess I'll search the web and see where an how it is used...

[brokencase]

OK, after some research I see, this is good to put between any overlapping surfaces to prevent future corrosion.

In your case the chute bracket has a large overlapping surface area with the chute.

So in my case I might want to spray around the edge of the patch and on the inside edge of the hole, but on the exterior where I am welding I still want bare metal.

I think this stuff would be really handy for cases where you are spot welding in a replacement fender or panel.

[andyofcolumbusmerkur]

If it is only a small hole behind the wheel well then possibly you can get access to it from all sides. If there will be some overlap or impossible to reach areas then use the SEM zinc or SEM copper. I remember just welding right though the stuff and it didn't seem to cause any issues with contamination. That is something to think about however. Probably not something you would want to use welding together a bicycle frame for example. Another idea might be to use some space aged panel bond product. You wouldn't need to worry about warping the metal. I was also watching some of these videos for a product called muggy weld. There stuff is pricey but it is amazing the things people are doing with it.