Was able to tack original '35 door skins to 3/16" flat stock but 85 year old metal can be iffy when blasting/grinding/sanding, etc. So, best method to knock down the welds while being conscious of this? Flapwheel, grinder, ?. Thanks guys.
https://www.eastwood.com/1-2-mini-b...sfgxZhrkYhImRns0yItvuf2xE8KS-er0aAv9oEALw_wcB These little belt sanders work great for knocking down welds, you can concentrate on just the weld and not grind the metal around them.
When grinding welds and spot welds I have found it best to use a cutoff wheel to grind the weld at 60 degrees to the seam, then grind it across that pass at 90 degrees to the first. Then a light pass with a sanding disc will bring the weld flush with the panel without touching the surrounding surface.
If possible, touch up the backside too, so yo can do further hammer-and-dolly metalwork on the panel.
3m makes a 3" disc that fits on a cutoff wheel that is made for grinding of welds.Its about 3/16 to1/4 inch thick and really goes to town.I'll get the part number..
The cut off wheel works well. Its thin enough to flex some as you grind........lightly. I like a 6" adapted to an electric 90 degree grinder. Very good control. You need to wear a face shield if you use the side of a cut off wheel. You will actually be kinda using the edge and the side. The edge will quickly get the mound down close and the side will flexibly dress it down the rest of the way. Here is what I use. I get them by the box on Ebay.
As mentioned above, these 3M discs are by far the best method of knocking down MIG welds. If it stops cutting like it did when it was new, turn it around and keep grinding. They are not cheap but they are the best. They also last a pretty long time. https://www.amazon.com/dp/B0002SRLF...olid=3EBJEH4CC0R6U&psc=0&ref_=lv_ov_lig_dp_it
I welded with "easy grind" wire, used a cutoff wheel on a Dremel tool, and finished up with 3M discs.
Did you find that easy grind wire to be enough easier to make it worth looking for? Friend who is a body man said he didn't see much difference.
Haven't used a cutoff wheel to grind a weld in the 2 years since I bought a belt sander. Can't imagine going back to them. Work great for grinding through spotwelds on multiple layers, too.
I had a "ol what the hell" moment and bought the easy grind when my welding supply guy said he sells a lot of it. Cost was 7 bucks a pound! While it seems to grind a little easier, not much difference from cheaper wire. I did notice that the weld puddle was a little flatter at the same amperage/wire speed/gas.
7" electric grinder with fresh grinding discs. I move around alot so as not to generate too much heat. Very time consuming but it works for me. Yes, eye and ear protection required
I use a small (3 inch) cutoff wheel in a pneumatic tool, I try to be "surgical" and only take down the weld, none of the metal surrounding the weld. It's noisy. I wear both ear protection and a face shield. I am a crappy welder so the grinder and I have lots of together time.
The thing about removing the spot weld mounds is that you need to do it somewhat quickly. The cut off wheel will slice thru the mound quickly and impart less heat and possible warpage. Then you only dress a small mound down. Any type of grinder that has to grind the whole mound down generates more heat into the panel.
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