Breaking Ceramic Cup

MotoEngineering · Tue Mar 15, 2016 6:19 pm

When welding 1/4 inch (6.4mm) Aluminium with AC TIG using a gas lens and 3/32 ( 2.4mm) Tungsten the Front often breaks off my Ceramic Cup. I'm using a no. 7 Cup with a 3/32 Electrode 2% lanthenated with about 1/4 inch stick out, A nice little bit of balling at the tip and about 15cfh of Argon flow at about 150 amps AC. I've bought what I think are good quality cups but about the first 3/16'' or 4mm of the cup just drops off in a perfect ring, no impact, no dropping of torch. What are the possible causes and solutions for this? All replies greatly appreciated.

LtBadd · Tue Mar 15, 2016 7:57 pm

Is this only with one particular weld or any weld?

If the weld is in close quarters then it's the heat buildup breaking the cup. If you're doing a lap or outside corner then that seems strange, however a larger orifice may help, I always use a #8

Kevin_Holbrook · Tue Mar 15, 2016 8:36 pm

Do you have this style torch ?

: 20160315_202531.jpg (34.93 KiB) Viewed 4043 times

Are you using both Teflon insulators ?

MinnesotaDave · Tue Mar 15, 2016 10:11 pm

I bet Kevin Holbrook is correct - you are likely missing the extra little insulator.

I was missing it when I got my first gas lens/cup and the front popped off like you describe because it tightened against the front of the gas lens.

I've also been told there is a large one piece that will take the place of the two in combination.

hey_allen · Wed Mar 16, 2016 12:18 pm

I found one at my local welding supplier, who primarily stocks CK parts.

For my 26 torch, it used part number 3GHS. Their online catalog has pictures of the lineup on page 53 if you want to see the differences.

MotoEngineering · Thu Apr 07, 2016 4:56 am

Hi Guys thanks very much for your replies. I was only using one of the white insulators. I found initially when I put both on I had trouble clamping the electrode. But obviously I will now use both insulators. I really appreciate the feedback, it's great to have really good information from experienced professionals, I hope I can add to this great forum. Cheers

GreinTime · Thu Apr 07, 2016 5:49 pm

I didn't even know there was a setup that used 2 insulators, learn something new every day!

Sent from my SM-G900V using Tapatalk

MinnesotaDave · Thu Apr 07, 2016 7:25 pm

MotoEngineering wrote:Hi Guys thanks very much for your replies. I was only using one of the white insulators. I found initially when I put both on I had trouble clamping the electrode. But obviously I will now use both insulators. I really appreciate the feedback, it's great to have really good information from experienced professionals, I hope I can add to this great forum. Cheers

Sometimes the tungsten doesn't clamp down because the collet body is not screwed in all the way.

Always loosen the back cap a little before screwing in the collet body - it has to tighten all the way and bottom out.

hey_allen · Fri Apr 08, 2016 12:35 pm

If you are only using a gas lens, you can also get a longer single insulator, from CK at least.
I was chasing a leaky torch and replaced the insulator stack with a single as part of my attempt at tracking the leak (which turned out to be just a junk knock off torch body...)

For a 26 style torch, the combined insulator is a 3GHS.

exnailpounder · Fri Apr 08, 2016 7:16 pm

News Flash....Cups break!
Everything has only so many hot/cold cycles in them until they give.

Fri Apr 08, 2016 7:38 pm

exnailpounder wrote:...
Everything has only so many hot/cold cycles in them until they give.

Including people...

Steve S

MinnesotaDave · Fri Apr 08, 2016 10:48 pm

exnailpounder wrote:News Flash....Cups break!
Everything has only so many hot/cold cycles in them until they give.

While that is true, when not using the correct insulator they can break within the first hour - that's a little too fast

Only a bipolar cup should snap that quickly

exnailpounder · Sat Apr 09, 2016 2:49 pm

If you read the OPs post, he is welding 1/4" aluminum which means hes probably at around 200 amps or more and using a #7 cup with 1/4" stickout. He doesn't say how long of a bead he is running but with 1/4" stickout he has the cup right ontop of the puddle. Of course it's going to overheat and crack off. Longer stickout and a bigger cup and maybe bump up the flow a little might help. Just my opinion.

Kevin_Holbrook · Sun Apr 10, 2016 2:00 am

exnailpounder wrote:If you read the OPs post, he is welding 1/4" aluminum which means hes probably at around 200 amps or more and using a #7 cup with 1/4" stickout. He doesn't say how long of a bead he is running but with 1/4" stickout he has the cup right ontop of the puddle. Of course it's going to overheat and crack off. Longer stickout and a bigger cup and maybe bump up the flow a little might help. Just my opinion.

he was missing an insulator adapter for the gas lens.

if you don't use the second insulator adapter or use a one piece insulator for a gas lens setup

when you screw the cup on ,it will bottom out on the gas lens.

MinnesotaDave · Sun Apr 10, 2016 8:20 am

Kevin_Holbrook wrote:
exnailpounder wrote:If you read the OPs post, he is welding 1/4" aluminum which means hes probably at around 200 amps or more and using a #7 cup with 1/4" stickout. He doesn't say how long of a bead he is running but with 1/4" stickout he has the cup right ontop of the puddle. Of course it's going to overheat and crack off. Longer stickout and a bigger cup and maybe bump up the flow a little might help. Just my opinion.
he was missing an insulator adapter for the gas lens.

if you don't use the second insulator adapter or use a one piece insulator for a gas lens setup

when you screw the cup on ,it will bottom out on the gas lens.

Yep, that's exactly what happened to me - screwed it on without the proper second insulator (or correct thicker one piece) and the cup bottomed out on the gas lens - broke real fast - just a few 9"-12" beads.

Put on the right stuff - 230 amps AC and no problems