Welding stainless to copper

Fittings,,,Parrots, Packing., Tooling.

Moderator: Forum Mods

Welding stainless to copper

Postby ozone39 » Fri Dec 25, 2009 9:53 am

Happy holidays to everyone. Not sure if this info has been posted before, but if not here's a little tech tip. Welding stainless to copper. Little more involved than doing a torch braze joint, but it looks a lot better and you end up with a cleaner product. First thing is tooling. You will need a TIG torch to do this. I used the most basic scratch start unit on the market, no foot peal or anything fancy, it's a Miller 140 power inverter (it's the size of a lunch box). Next is joint preparation, I welded a piece of 1 1/2" sch 40 s.s to a piece of 1 1/2" type L copper. A straight cut is absolute on each piece. The copper is easy, just use a tubing cutter. The stainless needs a pipe cutter (you'll find them on a pipe threading machine), do not try and use a tubing cutter on pipe. Or you can use the tubing cutter to score a cut line around to pipe in order to give you a straight line to cut bay mechanical means (saws all,band saw, grinder w/cut wheel, lathe, hack saw and so on). Next is cleaning the ends, I used emery cloth. Next is welding. I set my TIG torch to electrode negative, used an 1/8" 2% thoride (marked red) electrode and ground the tip at a 1 to 4 ratio and ran 110 AMPS with Argon gas set at 10 CFH. Focus the puddle on the s.s (it is thicker) and will take more heat, form the copper puddle into it. Tack one side, push the joint back together (it will pull apart when the weld cools) and then tack the opposite side. I then ran a perimeter weld in less than a minute. If you do not have the equipment a local welding shop should be able to do use the procedure I listed and do the same. One thing to keep in mind when ever you braze or weld these joints it is good practice to back purge the pipe with an inert gas. This will eliminate oxidation from forming on the inside. This is a standard practice in all food grade process pipe. Once the joint is welded let it cool naturally, do not quench the joint in water. now you have a good looking water tight joint. A guy could step it up and chuck it in a lathe and use a sanding disk on a grinder to feather out the joint.
Attachments
TIG JOINT NO3.JPG
TIG JOINT NO2.JPG
TIG JOINT NO1.JPG
thinking inside the box is for squares....
User avatar
ozone39
Trainee
 
Posts: 634
Joined: Sat Dec 12, 2009 9:14 am
Location: Big Sky Country

Re: Welding stainless to copper

Postby ozone39 » Sat Jan 16, 2010 9:11 am

here's a picture of a welded joint that I chucked up in my lathe and ran a sanding disk on.
Attachments
DSC02575.JPG
thinking inside the box is for squares....
User avatar
ozone39
Trainee
 
Posts: 634
Joined: Sat Dec 12, 2009 9:14 am
Location: Big Sky Country

Re: Welding stainless to copper

Postby MashMan » Sun Jan 17, 2010 1:10 am

Hiya Ozone39, yep done a stack of this myself and it works great. just curios as to what filler rod you used on your third pic from the top, copper inside stainless?
I've found I need to concentrate more heat on the copper as it disipates heat a lot faster than the stainless.

Thanks,
MM.
MashMan
 

Re: Welding stainless to copper

Postby Ayay » Sun Jan 17, 2010 3:40 am

Thanks for the post. I'm getting a TIG sooner than later and this is valuable infomation. A scratch-start may be financiallly much better than an expensive auto-start.
cornflakes...stripped and refluxed
User avatar
Ayay
Master Distiller
 
Posts: 1607
Joined: Tue Sep 16, 2008 1:25 am
Location: Planet Erf...near the bottom.

Re: Welding stainless to copper

Postby ozone39 » Sun Jan 17, 2010 8:05 am

If filler rod is needed I used a .s.s 316 (304 would work just as well) 1/16" diameter grade rod. It's a little tricky at first getting the two molten puddles to join, but once they acquire each it is a little more smooth sailing from there. I found it is a little easier when the s.s side is thicker. I get the puddle started on the s.s side then do what they call a whip stitch, I pull the puddle then push it back into the copper side, the thinner the material the faster the whip needs to be (amperage needs to be adjusted accordingly) . I have a scratch start unit and it works fine, you will have to clean you're electrode more often with scratch start. Thermal dynamics has a sweet ass unit that has the high frequency start in it and AC tig (welds aluminum), that will probably be one of my next purchase.
thinking inside the box is for squares....
User avatar
ozone39
Trainee
 
Posts: 634
Joined: Sat Dec 12, 2009 9:14 am
Location: Big Sky Country

Re: Welding stainless to copper

Postby exon » Sun May 01, 2011 1:44 pm

Thank you!

...I better read this twice. or thrice?
Best
exon
I am a pathological liar and functional illiterate.
exon
Swill Maker
 
Posts: 167
Joined: Sat Jan 08, 2011 8:35 am
Location: Left Coast

Re: Welding stainless to copper

Postby DIYhooch » Mon May 16, 2011 11:34 pm

Thanks so so much for posting this, especially the photos, each one is easily worth it's "thousand words".

This thread has me wanting to get a tig welder BADLY, I have contemplated it a couple of times and started looking into it but I always get lost in the details regarding AC/DC and all the functions etc etc. No one can ever give me a good answer because as soon as I mention I want to weld copper they just get a blank look on their face.

I have been using my dad's old fashioned arc welder for 20 years (the welder is actually 60 years old, man they did build things to last back then, the welding torch even has its original bakelite handle) and it still goes fine, have welded heaps of steel with that, I have also done a fair bit of oxy / acetylene cutting, welding, brazing but really want to try tig as I think it is my answer for still making as I am kinda tired of soldering/brazing plus I can start to make some stainless steel items I have wanted for a while but couldn't do with the oxy/acetylene.

I had a few questions I was hoping could be answered, the only things I will be wanting to weld are stainless/stainless copper/copper stainless/copper copper/brass stainless/brass:

- What welder do you recommend AC or DC, what functions etc etc?
- What sort of budget would I need for a 'decent' brand tig that would do the job, and having said that what are 'decent brands' these days (I have no idea)?
- Can you use one shielding gas for all the metal combinations I mentioned (stainless/stainless copper/copper stainless/copper copper/brass stainless/brass)?

Thanks very much.
DIYhooch
Novice
 
Posts: 43
Joined: Thu Dec 06, 2007 8:06 pm

Re: Welding stainless to copper

Postby squidd » Tue May 17, 2011 8:26 am

DIYhootch,

Can't answer all your questions, but suggest you have a look at Everlast Welders.
Check their Forum for both plusses and minusses, and to ask your Q's.

No affiliation, etc.

squidd
squidd
Swill Maker
 
Posts: 223
Joined: Sun Nov 30, 2008 8:49 pm

Re: Welding stainless to copper

Postby mash rookie » Tue May 17, 2011 8:50 am

DIYhooch wrote:Thanks so so much for posting this, especially the photos, each one is easily worth it's "thousand words".

This thread has me wanting to get a tig welder BADLY, I have contemplated it a couple of times and started looking into it but I always get lost in the details regarding AC/DC and all the functions etc etc. No one can ever give me a good answer because as soon as I mention I want to weld copper they just get a blank look on their face.

I have been using my dad's old fashioned arc welder for 20 years (the welder is actually 60 years old, man they did build things to last back then, the welding torch even has its original bakelite handle) and it still goes fine, have welded heaps of steel with that, I have also done a fair bit of oxy / acetylene cutting, welding, brazing but really want to try tig as I think it is my answer for still making as I am kinda tired of soldering/brazing plus I can start to make some stainless steel items I have wanted for a while but couldn't do with the oxy/acetylene.

I had a few questions I was hoping could be answered, the only things I will be wanting to weld are stainless/stainless copper/copper stainless/copper copper/brass stainless/brass:

- What welder do you recommend AC or DC, what functions etc etc?
- What sort of budget would I need for a 'decent' brand tig that would do the job, and having said that what are 'decent brands' these days (I have no idea)?
- Can you use one shielding gas for all the metal combinations I mentioned (stainless/stainless copper/copper stainless/copper copper/brass stainless/brass)?

Thanks very much.

You will need an AC/ DC machine only if you want to weld Aluminum at some point. It welds with AC.

Steel, Stainless and Copper weld with DC. I am about to head out to my shop for a few hours of MIG welding steel. I will get a lot done.

MIG.s are fool proof these days. Auto darkening hood, point and shoot.
One hell of a lot easier than it was when I grew up stick welding. Just gave away my old stick welder. Hadn’t used it in years.

TIG is sometimes called "Gentlemen’s welding" for the delicate precise welds you can do with it and its versatility if you have an AC/DC rig.

If you are not going to do a lot of welds and want very nice work that doesn’t require much finishing afterwards. Buy a TIG

Different metals require different gas for best results. Most will weld okay with argon used on your TIG

Read my post this morning on welding copper in the Novice section.

Mash
User avatar
mash rookie
Site Donor
Site Donor
 
Posts: 2226
Joined: Tue Dec 07, 2010 8:20 am
Location: Pacific Northwest

Re: Welding stainless to copper

Postby Grumpy365 » Fri Jun 10, 2011 7:28 pm

I have access to a tig (the same model used in the pic). It's been a while since I have used a tig and I need a refresher.

1. Can I use 80/20 mix gas I have on my mig? I don't remember if tig is always pure argon or if that's just for aluminum.

2. My copper pipe is ACR, it's thicker than my SS ferrel. Can I successfully whip stitch it if I puddle the copper and whip it into the SS?
Grumpy365
Novice
 
Posts: 10
Joined: Mon May 23, 2011 6:41 am

Re: Welding stainless to copper

Postby ozone39 » Sat Jun 11, 2011 5:46 am

I generally use 100% Argon for general carbon and stainless steel welds (works well on Aluminum too). In the photos above I used 100%Ar. When I TIG copper to copper I switch over to Helium (also known as heli-arc)..Helium runs hotter...Here is a post about shielding gases that explains all:

http://en.wikipedia.org/wiki/Shielding_gas
thinking inside the box is for squares....
User avatar
ozone39
Trainee
 
Posts: 634
Joined: Sat Dec 12, 2009 9:14 am
Location: Big Sky Country

Re: Welding stainless to copper

Postby rebucklives » Sun Aug 07, 2011 2:20 pm

Test specimen for a 16 ga Copper / 12ga SS 304 butt weld using pulsed GTAW and ER308L filler. Weld was cleaned up by electro-polishing. I've got some ERCu (deoxidized copper) filler rods coming in next week so I will try a few other test joints to see how they work and post them for users to look at along with some of the weld parameters.
Attachments
DSCF0493.JPG
rebucklives
Novice
 
Posts: 2
Joined: Tue Jul 20, 2010 9:40 pm
Location: The State of Jefferson

Re: Welding stainless to copper

Postby heynonny » Mon Aug 08, 2011 7:31 am

Here is a good site for welding questions, no mockery from dumb questions. A lot of good info and answers from welders:

http://forum.weldingtipsandtricks.com

You should register for max benefits.

Main page is:

http://weldingtipsandtricks.com

I have an 'Arcmaster 185' from Thermalarc, pricey, but sweet, , , -hey-
User avatar
heynonny
Bootlegger
 
Posts: 303
Joined: Fri Jun 06, 2008 7:17 am
Location: SoCal

Re: Welding stainless to copper

Postby CyBaThUg » Sat Dec 01, 2012 3:08 am

Did u use a filler rod or just fused it together
CyBaThUg
Novice
 
Posts: 10
Joined: Tue Jul 17, 2012 11:12 pm

Re: Welding stainless to copper

Postby johnhopper1957 » Sat Dec 01, 2012 4:57 am

You can do either using filler is easier though, I usually fuse but have used stainless filler and add it on the stainless side of the weld pool. That said I have used copper filler as well. I would stay away from butt welds on thin stainless to copper unless you have had experience with dissimilar metals. Expend your copper, slide in your stainless and focus your arc on the copper, once the weld pool forms drag it into the stainless being mindful of torch angle.

Several different methods, do a few test runs and when you are comfortable to for it :)

viewtopic.php?f=15&t=30142&start=12 for a copper to stainless weld.
johnhopper1957
Swill Maker
 
Posts: 149
Joined: Fri May 27, 2011 4:38 am


Return to Still Related Hardware



Who is online

Users browsing this forum: No registered users and 3 guests