by Jason Becker
Every welder at one point or or another in their career, has put in a bad weld. I myself am no exception. Whether you're just starting out, or you've been at it for 20+ years, it's going to happen.
Mistakes are common, but what separates the professionals from the rookies, is the ability and knowhow of being able to repair them. Today we were joined by John Thompson with Pferd abrasives who recommended a few of their products to help make weld repairs and material prep easier.
In previous videos, we have discussed in depth what welding discontinuities are and how they are caused. But sometimes they just happen, and when they do, you should know how to safely and effectively repair them.
Abrasive selection is an important factor when dealing with weld repairs, since repairs cost 300% more in time and money compared to production without a repair, you want to decrease your time performing the repair. Having the right wheel can do just that, not to mention, there is a safety consideration as well. Using the wrong wheel to remove a bad weld or discontinuity can have serious consequences.
Back when I didn't know any better, I would use a 1/4" hard wheel on its side to clean out a root pass. As we show in this video, it's not only ineffective but it's also a safety issue and a cost issue. The wheel is not designed to be used that way and as a result, the integrity of the wheel will become compromised and could separate during improper use. Additionally, it can wear much faster due to the lack of reinforcement on the side of the wheel, so you are now wasting time and resources to repair the weld. The proper wheel would be an 1/8" hard rock that is designed for face and edge grinding. The wheel is designed to be used on its side. This allows the user to get into a groove and clean it out very fast and effectively thus saving time and money.
This wheel would also be my go to on a fillet weld because I would need to do some edge grinding on that as well to make a repair. A 1/4" hard rock would be ineffective here as well and just create more work trying to get it to cut into a 90° corner.
Don't get me wrong, the 1/4" wheel has its time and place. I prefer to use it to flush and blend welds, prep materials, and remove surface contaminants. Thats what it was designed to do and thats the application that it works best at.
The last wheel we discuss is the flapper wheel, these wheels are great but they are always used incorrectly. Because they do so well at removing stock quickly, a lot of people use them to remove mill scale. This will actually cause the wheel to glaze over and and not be able to remove material at all. The flapper does a great job at removing and blending welds, polishing surfaces and beveling plates. We show in the video how fast we are able to put a decent bevel on some 3/8" plate in a short amount of time.
At the end of the day, we want you to be able to work safely and effectively. While you're here, make sure to check out the Grinder Safety Video we just did where we discuss safe use of each wheel as well as the proper abrasive for different tasks. As always, than