An angle grinder is one of the most important welding prep supplies a welder
can have in a shop because grinders are versatile and extremely useful for
quickly prepping or finishing welds. Whether you’re preparing metal before
welding or finishing a weld by removing slag, learning how to use an angle
grinder will save time, materials, and, if you’re welding professionally,
customers (especially since you can quickly clean your welds and metal work
pieces).
Removing Contaminants with an Angle Grinder
Before welding, you will need to prep your material. This is very important and is not a step that is always followed by home hobbyists. It will immensely improve your results. This can be done with a simple steel brush, but using an angle grinder can eat away slag, rust, and paint buildup. Always be sure to not over-prep the metal. This will cause thin spots that will weaken your work piece.
Finishing Metal with an Angle Grinder
A common way to remove slag from your weld would be with a chipping hammer, but a better way would be to process it with your grinder. Have some finesse while doing this so you don't chew into your new weld. We would recommend doing a 3" pass on scrap metal, then testing out the slag removal there first.
Heavy Duty Sanding with an Angle Grinder
The best way to smooth out pockmarked and gritty metal would be with an angle grinder. Sometimes using sandpaper is very ineffective and more often times than not will rip through your paper and ruin your gloves. At the least, you can work on getting the big stuff off, then get out the sandpaper later.
Cutting Metal with an Angle Grinder
When cutting through metal, a lot of times using an angle grinder with the correct cut-off wheel will be the best bet. When you are building out your shop, you want the most versatile tools, and situations like these are where Metabo Angle Grinders shine. You may not get the cut quality of a chop saw, but you can always cut the metal then finish it with the same grinder. If you get one of the Metabo "Quick" Series Grinders, switching from disc to disc is a breeze. All you have to do is click a button!
Safety with an Angle Grinder
Like any power tool, you must exercise extreme safety while using an angle grinder. Common mishaps with an angle grinder include: sending sparks towards your face, getting your cut-off wheel stuck and getting jerked by the grinder, or getting too close to a moving disc.
We recommend cutting then prepping all of your metal on the same day. This will ensure that you are in your groove and will allow you to be more efficient. For long grinding days, I would recommend you get a dedicated grinding face-shield like the Optrel Clearmaxx or the Lincoln OMNIShield.
If you are looking for dual-purpose protection, plenty of welding helmets currently are outfitted with an easy-switch "grind mode". These are the best for situations where you are constantly needing to switch back and forth between weld and grind modes. Some best sellers are the Lincoln Viking 3350 and the ESAB Sentinel A50. If you are looking for a more economic version, you can go with the ESAB Savage A40.