I've been grinding welds with the aluminum oxide wheels I get in a bulk pack from HF and always dread doing it. It's slow and it's a drudgery. A buddy showed me one of these wheels and it is amazing by comparison. Knocks the welds down extremely fast and runs cool - no discoloration in the metal. Is anyone else using these?

Interesting seems you get what you pay for ! I found 10 for 54.00 claim they run cooler last longer and leave smoother grinds

The biggest difference I've found is moving to high quality abrasives. 3M Cubitron made all the difference over the HF-level stuff.
And I've used those wheels but found they didn't offer me the level of control I wanted.

I follow this process:
- 3 inch air angle grinder w/ Roloc backer pad
- 3M Cubitron abrasives
- Start w/36 grit, use a steep angle and cut only weld material. Go SLOWLY. I used a "long-ish blip, blip" to keep accurate control over the cutting. Once "close" to the parent material:
- Switch to 80 grit. Shallower angle, same go SLOW approach.
- Once the edge of the weld starts to show a blend with the parent material:
- Switch to 80 grit on a DA to do final blending.

The 3M stuff cuts so quickly, I have yet to experience heat-related distortion.
Pics of a recent repair using the above approach. Hope this helps.

Also, a while back @McMark posted a vid of his technique when doing sheet metal repair. Maybe he'll point us at it...

I think this is the video you're talking about:


https://www.youtube.com/watch?v=z5YEjjqgF_k

That's the one. A GREAT tutorial!
Thanks, Teach!

Thanks for the tip! I stopped buying any sanding/grinding supplies from HF a long time ago because the quality is , but didn't know about those Pferd wheels. I've used mostly DeWalt because they are available locally. They aren't anything special but way better than the HF wheels at least.

+1 on 3M Cubitron. Money well spent except for their 36g 3/8" sanding belts. I may have gotten a bad batch but totally worthless whereas the 80g belts are magic.

In our production shop we use Zirconia resin fiber disks. Cheap and replaceable.

A small disk lasts about 2 days and a big disk about a week.

We use a 36 grit on a 7" disk to knock down a 2" weld and then a 50grit on a 4.5" disk to give it the final finish before an 80grit DA.

I find that this is the best and fastest way to grind down a weld with minimum heat absorption to the panel.




For my house I have a cutoff wheel and then a 60grit flap disk which I should change to a 36 grit.


I find the flap disks to be the most universal for grinding/finishing as they are very forgiving and great for when im one handed upside down or whatnot. I typically go through one a year.

Another 1 for Cubitron.

Cubitron is very very nice wheel.. We use 1000s of wheels at work 3m is the gold standard.. It also has a really cool history as to how they discovered it.