Grinding Inside Tight Angles

[Northwoods]

You mean with gas? I have a Hobart 140, so it came with all the stuff, but I just haven't bought a tank. One of my big issues is that I end up only needing to weld something maybe 3-4 times a year, so I always seem to be starting fresh. My welds start out crappy, then by the last weld of the project, they improve to poor. 

Most of the stuff I do is farm related, so it doesn't have to be pretty, plus most of it doesn't involve tight interior angles. The welds on the utility trailer I found busted and buried in brush when I moved here and welded back together look almost adequate because of the easy to get to, mostly horizontal surfaces. This current project (target stands) is my first project where I wanted it to look good but also had difficult (for me) angles and tight working space.

I also have a little ESAB stick welder, but have hardly touched it. What I really need to do is practice a lot more and a lot more frequently.

Or hire my son to do it for you.  He's top in his welding class right now.  It's only an 8.5 hour drive to your AO.

[tokugawa]

If it just needs to be clean for paint, use a small flap wheel. If it needs to be smooth and flush, use a small angle grinder to get as much as will fit in the corner, and get the rest with a die grinder. Belt file would probably work ok too.

[Bogie]

Somewhere, in one of my toolboxes, I have some small curved files. You'll have to comb
clean 'em after using them on that sort of thing, but...

[Hawkmoon]

Harbor Freight has a little hand grinder like a Dremel Tool for less than ten bucks.  The beauty of that is the kit comes with an incredible array of little grinding, polishing, and drilling tools for it.  Surely one of those would be suitable for removing the ugly if you're patient.

This one? https://www.harborfreight.com/07-amp-rotary-tool-kit-80-piece-58999.html

Oh, dear God no! I have one of those. "Under-powered" doesn't begin to describe it. It's essentially useless. And the abrasive on the various grinding tips is very soft -- Ben would go through dozens of the trying to clean up welds on a stand like that.

[zxcvbob]

This one? https://www.harborfreight.com/07-amp-rotary-tool-kit-80-piece-58999.html

Oh, dear God no! I have one of those. "Under-powered" doesn't begin to describe it. It's essentially useless. And the abrasive on the various grinding tips is very soft -- Ben would go through dozens of the trying to clean up welds on a stand like that.

I have one of those; I think mine is Bauer brand instead of Warrior.  It works great on plastic, which is what I got it for.  I tried to use it on soft steel once and it was useless, mainly because the motor would stall if I applied any pressure.

[dogmush]

If you are trying to remove steel with a rotary tool, you need a carbide bit.  I posted a set above.

Dremel and Dremel-esque abrasive stones won't work.  They are not designed for hard metals like steel.

[230RN]

Boy, I'm battin' zero on my suggestions lately.

<snif>

[tokugawa]

Grinding-
One of my jobs as a kid was in a structural steel fabrication shop. They were making staircases for a high rise.
 Along with 2" steel tube handrails and all the rail to post welds. Nobody wanted to grind welds.  I did a good job. 7" Milwaukee angle grinder, first with a hard wheel to remove the bead, , then a soft to blend. Doing a good job on work no-one else wants to do is job security. I developed forearms like Popeye.
After about a month of 8 hrs a day, I begged the foreman to put me on something else, anything else, for a few days to regain my sanity. He was a wise guy, but he knew what I meant.
Open shed, New England winter work. Working around heavy stuff is educational. Got to the point after a while if a pencil rolled off a desk, I would jump back before it hit the floor...

[Cliffh]

Die grinder and attachments

Just remember face shield and those shards a burr bit throw are attracted to your eyes.

Had a sliver from a die grinder get past the safety glasses.  Sucked having a doc remove it from my eye.

I keep a die grinder with an assortment of bits for cases like yours.  Only thing I've found that works well.

I understood this to be a “grinder and paint will make me the welder I ain’t” assignment

Cut to plan, file to fit, paint to hide.

[French G.]

I grind a lot, tons of fancy stuff with the goal to look never welded or ground, usually unpainted. But the high points have been hit. For your stuff learn to put down welds that don't need grinding. My only advice is to put away that little wire feed welder. Way easier to make structurally sound welds with your stick welder. 6011 is your friend.

[zahc]

Welds should not be ground to make them look better. They should only be ground to completely redo them. Ground welds cannot be inspected. They should only be wire brushed or maybe sandblasted.

These are what I use to grind inside welds to make them look better:

https://benchmarkabrasives.com/products/1-2-x-1-1-2-x-1-8-tapered-cartridge-roll-aluminum-oxide-10-pack

[Cliffh]

Welds should not be ground to make them look better. They should only be ground to completely redo them. Ground welds cannot be inspected. They should only be wire brushed or maybe sandblasted.

These are what I use to grind inside welds to make them look better:

https://benchmarkabrasives.com/products/1-2-x-1-1-2-x-1-8-tapered-cartridge-roll-aluminum-oxide-10-pack

Things may have changed since I was inspecting welds on US Navy submarines in the '80s and 90's, but... 

We were able to inspect many of the welds after grinding.  There were times when the welder would put in a couple passes, grind them, we'd inspect, they'd weld some more, grind, repeat until complete.  We'd also find a defect, grind until the defect couldn't be detected, the welder would then continue welding.  Pressure hulls welds would be ground flush after welding was completed, then we'd inspect the weld.

Granted, die penetrant inspections weren't as reliable after grinding since the defect may have been hidden by material being deposited over it to the point the die couldn't get into the defect.  But magnetic particle and X-ray/radioisotope (ir-192 and co-60) inspections didn't mind if the weld was ground or not. 

ETA:  Wire brushing and sand blasting were not allowed before the die penetrant testing.  Those methods are almost guaranteed to hide defects that are open to the surface.