Grinding Techniques

I come from an electronics background and I’ve just been getting into welding and fabrication with my $80 harbor freight arc welder.

As you may be able to infer, my welds often come out sub-optimal.
In order to make my projects just a little bit prettier I picked up a couple of grinding wheels and sanding pads for my angle grinder.

I’m looking for it to be mostly flat without destroying the strength of the piece.
My hypothesis is that I need to start with coarse grit and work my way up from there.
I also think that the abrasive surface should be pretty flat, almost parallel, to the surface I’m trying to blend the welds into.

What should I do in terms of technique to get the best result?
Do you have any other advice for someone who knows nearly nothing about welding?
When I get home from college, will welding on jack stands hurt me?

Thanks All,

Congrats on new learning a new skills!

Don’t be too hard on yourself. Be proud of your sloppy welds. We all start somewhere.

Grind with a course flap wheel to remove as much weld without digging into your base material. After you made it flat as possible with a grinder use a Dual Action sander to blend the material and your weld.

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If your new to grinding i would try a 40 or 60 grit flap disc (pherd or norton, walter). It offers great control of the amount of material being removed and still achieve a good surface finish. A palm sander with 100 grit will blend the rest if a finer finish is necessary.


Here’s a cool video on Just Grinding! Most importantly have fun building!

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Thats great your expanding your skill set. To get great results from learning grinding technique and maintain weld strength starts with your joint set up. On a corner joint you want a nice 90 deg angle between your parts so you get a nice fillet when ground there is still material in your joint. On a flat joint you should bevel opposing joints and or gap your so you get that same fill material that will stay after grinding.

When it comes to grinding technique you always want to use the largest flat section on the grinder. That will promote a level surface during grinding. I’ll say to never use the edge of a grinder cause it will make the surface wavey and its a bad habit to develop. There is a place for grinding on edge and that comes with experience. Key is keeping that grinding disc flat as possible that will give the best finish. When it comes to abrasives its a personal choice. I run fiber discs with a backing pad. in my opinion they cut the flattest and sharpest. Flapper discs are super forgiving and work great.

As for welding on jack stands is hard to unravel but yes if you have a vehicle safely supported you’ll be just fine. I do it every single day. If your talking about welding to a jack stand I don’t know about that safety. It all boils done to your own common sense about your safety.

I always use a flapper wheel with a plastic backing as it starts to wear u don’t start scratching up the part ur trying to sand + u can trim the backing down as it wears and use bout all of it up !