MIG welding stainless w/ C25?

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08-30-2012, 02:18 AM
EmptyNester

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MIG welding stainless w/ C25?

I'm still new at this but I have seen that you should use tri-mix gas and different wire with stainless, but........

I have/typically use C25 and ER70S-6.

I have four small welds to do (each about 1"). I need to weld a tab onto each side of my gantry cross tube.

Attachment 7758

I can have a friend of my brother's do it, but it will take about a week and there's always the concern that the instructions get garbled in the hand-off.

Given that this isn't going to have a significant load on it - can I do it with C25 and ER70S-6?
08-30-2012, 02:23 AM
performance

Quote:

Originally Posted by EmptyNester

I'm still new at this but I have seen that you should use tri-mix gas and different wire with stainless, but........

I have/typically use C25 and ER70S-6.

I have four small welds to do (each about 1"). I need to weld a tab onto each side of my gantry cross tube.

Attachment 7758

I can have a friend of my brother's do it, but it will take about a week and there's always the concern that the instructions get garbled in the hand-off.

Given that this isn't going to have a significant load on it - can I do it with C25 and ER70S-6?

It'll weld, but it will be brittle, and definitely not stainless.

You could use pure argon if you have it to at least make it better, with some stainless 2 lb roll of wire...but this is a job for DC tig.
08-30-2012, 02:44 AM
EmptyNester

Quote:

Originally Posted by performance

It'll weld, but it will be brittle, and definitely not stainless.

You could use pure argon if you have it to at least make it better, with some stainless 2 lb roll of wire...but this is a job for DC tig.

I'm not really concerned about the weld not being stainless. I believe stainless is only needed where the carriage rides.

I've been looking for an excuse to get a TIG unit and learn to do TIG - this just doesn't seem like a good enough reason by itself. (But, I can always hope I'll win one in the contest.)

I know this is a hard question to answer, but "How brittle is brittle?". If you didn't have a TIG unit, would you use MIG for this application (a CNC gantry)?
08-30-2012, 03:02 AM
Rambozo

Quote:

Originally Posted by EmptyNester

I'm not really concerned about the weld not being stainless. I believe stainless is only needed where the carriage rides.

I've been looking for an excuse to get a TIG unit and learn to do TIG - this just doesn't seem like a good enough reason by itself. (But, I can always hope I'll win one in the contest.)

I know this is a hard question to answer, but "How brittle is brittle?". If you didn't have a TIG unit, would you use MIG for this application (a CNC gantry)?

Pre-heat the parts and slow cool (throw a heat proof blanket or something over them), and you shouldn't have any cracking. Like you say the strength required is minimal. You might need a little paint to keep the rust away, and any steel MIG welding near stainless can contaminate the stainless so you might get some small rust pits later. Tray to cover as much as you can before you weld. But all of that is really a cosmetic issue as you don't even need stainless in this application at all. Are you running stainless or ceramic bearings? If not, you may even end up with some rust lines where the bearings ride, because of contamination. I'm guessing that you selected stainless to avoid rust in the first place.

Of course if you clamp the tabs on with vise grips you could probably send them out to have those welds done with little chance of error. But there is the waiting part. :mad:
08-30-2012, 11:51 AM
everlastsupport

Quote:

Originally Posted by EmptyNester

I've been looking for an excuse to get a TIG unit and learn to do TIG - this just doesn't seem like a good enough reason by itself. (But, I can always hope I'll win one in the contest.)

Make sure you clear over or paint it, it will rust.

Also, have you looked at the Everlast Power ARC 140ST and 160STH, for the price and what you get, that is a deal for a DC TIG. If you paid to have it welded, that would be a major % of the 140 cost.
08-30-2012, 02:58 PM
Brian Ski

Harbor has some wire... http://www.harborfreight.com/0023-in...oll-42921.html

Pretty expensive for a 2lb roll. Wasn't sure if you have one close by. If you were close I would let you borrow my spool. I thought it was a lot cheaper than that.
08-31-2012, 12:20 AM
EmptyNester

Quote:

Originally Posted by Brian Ski

Harbor has some wire... http://www.harborfreight.com/0023-in...oll-42921.html

Pretty expensive for a 2lb roll. Wasn't sure if you have one close by. If you were close I would let you borrow my spool. I thought it was a lot cheaper than that.

Thanks for the offer Brian. Maybe I'll stop by and visit when I go to see my daughter at Purdue :)
08-31-2012, 12:23 AM
EmptyNester

Thanks for all the feedback.

I guess at this point I'm convinced that I should wait the extra couple days to get it welded by an expert. Specially given all the other effort I"ve put in to this table.

Fortunately, I won't have to pay to have it done. So that will buy me time until I either win a TIG unit or decide its time to buy one.
08-31-2012, 12:30 AM
zoama

Quote:

Originally Posted by EmptyNester

Thanks for all the feedback.

I guess at this point I'm convinced that I should wait the extra couple days to get it welded by an expert. Specially given all the other effort I"ve put in to this table.

Fortunately, I won't have to pay to have it done. So that will buy me time until I either win a TIG unit or decide its time to buy one.

You could rent a small dc tig machine for a day or two to practice and get the work done. The welds you need to make will be fairly easy and help you decide if you'd like to buy a tig machine.