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TIG cup grinding

Posted: Fri May 28, 2010 3:01 am
by jakeru
I was welding a tricky joint that needed more tungsten stick-out than I had a cup to enable (the largest cup I had was a size 8, gas lens type.) The largest the local welding supply had for my torch (a type 17) was a 10, non-gas lens, which I bought but it didn't do the trick. I figured I needed about 3/4" of stick-out for my joint...

I managed to modify my gas lens cup into a large (size 11-12) "shortie" by grinding out a gas lens cup. I tried grinding it on the bench grinder, which kind of worked, but left a bit of a ragged finish and wore down the grinding stone by about as much material as was removed from the alumina cup.

I finished the cup grinding with a diamond rotary burr, of the 1/4" arbor variety, with a head diameter of about 3/4". (I bought it previously to grind on stone.) This wasn't real fast either, but it did leave a nice finish and didn't wear out the tool at all. I kept it misted with a water sprayer during the grinding... and kept the grinding speed down so the water wouldn't immediately get slung away. I think a carbide burr would have worked too.

I was pleased that it worked so well, as I was able to get good shielding gas coverage out a lot further than any other cup in my posession allowed - I tested a full 3/4" stick-out on flat aluminum, (with I think 20+cfh), and I got a nice shiny weld puddle, free of black smut. No other cup I owned came close. This might be an OK setup for titanium...

Also, the tapered shape near the tip of this "custom" cup could be a useful feature, as it could allow you to get the cup a little closer to an angled obstruction.

I will consider doing more similar "cup modifications" in the future if I need something that I done have, or they don't make... For getting into a tight joint that the cup is bumping against something... I will consider just grinding down the cup now! New cups only cost about $1.30 - $2 ea, so I figure they are cheap enough to experiment and if it doesn't work out, no big loss.

Thought you might want to know this trick!

Re: TIG cup grinding

Posted: Sat May 29, 2010 2:12 pm
by jakeru
Although the large diameter gas lens setup was working for my tricky weld joint, its fatter base was limiting my range of motion (reaching into a tube welding the inside) compared to a standard collet body, so I tried a different approach.

I ground another tig cup (this one a #5, standard collet body) so I could get up close to a very tricky weld joint (welding inside a bent tube) without having to stick the tungsten way out. I ground off one edge of the cup, at about a 45 degree angle as you can see below, so I could get the tungsten in closer without having it stick out so far from the cup.

The angle ground cup did the trick! I had to build up some aluminum 4043 material inside an aluminum intake manifold runner tube. I couldn't even see the puddle when I was welding; I had to stop and stick a small mirror up into the tube to see it. I added filler rod down into the tube from the other end. The ground cup allow me to get it done! :)

The local welding supply who helped me brainstorm how to do this, thought it wouldn't be possible without a (not cheap) "micro" TIG torch.

Re: TIG cup grinding

Posted: Tue Jun 22, 2010 11:31 am
by speedfreak87
I have a stupid newbie question, and I don't know why my teacher didn't discuss this, but what does the gas lens do exactly?

Re: TIG cup grinding

Posted: Tue Jun 22, 2010 2:22 pm
by jpence38
Check this link out ................http://www.weldcraft.com/2008/01/gas-le ... s-for-tig/