never weld before

I seen several examples of spot welding but what confuses me is when you spot weld are the seams between the welds filled with filler or do you weld the seams closed?

Everytime I see a pic of spot welding, I see first the spot welds and the little open seems between the welds. Then the next picture
it shows a nice smooth piece of metal. Where the welding took place the metal looks much shiner as if the metal was grinded to close the seams. Is that what happen, or once the spot welds are done, then you weld rods along the seam to close everything.

How does it work.
thanks

 

<cr>
Sounds as if you are talking about two different processes.

Spot welding involves lapping two pieces of metal together, applying pressure, and then applying electricity. Where the metal is pressed together (at the most, about a 1/4" spot), the molten metal melts together.

In panel repair (i.e. patching over a rust hole), you will sometimes see intructions to "spot weld the patch on". This is an entirely different process than just described above. A less confusing term would be to "tack weld the patch on". A tack weld is just a short weld that is used to hold the pieces together until it gets a full weld.

From what I get from your question, it sounds as if the patch was tacked on and then welded completely. The weld is then ground flat before the final filler (aka Bondo) work.

 

The factory spot welds panels on. Some people also call it spot welding when you put in a new panel and just weld the new one in the same spots as the factory did, but the factory uses a welder like aekisu said. I believe its called a resistance spot welder. When I put in a patch, I weld the seam solid, but not one continous weld. The right term would be skip weld. You weld a short section in and then weld another area away from you last weld so you do not build up too much heat in the area and cause a bunch of warpage.

 

I was basing it on the first sticky "Patch panel/rust repair" in this forum. The poster has some pictures showing his example. one pick you see where he has spaced out welds, then the next picture shows everything all smoothed out. But what i'm understanding he "tacked" weld the panel first then did a full weld. He just did not show the picture of the full welds, am I correct?

 

Are you doing patch work? If you are just get the panel bonding glue thats out now. Most shops these days are using it on door/roof skins and you also get an extra seal to keep moisture out so the patch will last for a while.

 

You are 100% correct. He tacked in the panel (pic 4), welded it solid, and used a grinder to remove the welds (pic 5). Pic 6 is after the filler & paint work.

 

Gotcha!! I'm clear now.