Soldering Stainless steel

[wyzazz]

Yes, and it works just fine. I don't know about the long-term issues with dissimilar metals, but they solder together without any issues.

-Joe

I doubt Copper (or Brass for that matter) would be reactive enough to make much of a difference when soldered to Stainless Steel. Where's John Palmer when you need him??

 

[BrewBeemer]

Where's John Palmer when you need him??

Why do you need him?

 

[wyzazz]

Why do you need him?

Because he is a Metallurgist, it would be nice to pose the question to him.

 

[Scut_Monkey]

I doubt Copper (or Brass for that matter) would be reactive enough to make much of a difference when soldered to Stainless Steel. Where's John Palmer when you need him??

Because he is a Metallurgist, it would be nice to pose the question to him.

I was listening to a Brewstrong podcast yesterday and Palmer was discussing the reactions between dissimilar metals. If I remember correctly he suggested that it would not be a great idea to use an aluminum fitting on a stainless kettle but on an aluminum pot it's fine. Other than that he did not think copper or brass fittings would be a problem in stainless or aluminum kettles.

His reasoning behind this was that placing an aluminum fitting (high corrosion potential) within a stainless kettle (low potential) will corrode the fitting quickly. However, aluminum fittings in an aluminum kettle spreads the potential corrosion over a large area and is not a problem.

I'm sure I miss quoted him but this was the just of what he was saying.

 

[BrewBeemer]

Because he is a Metallurgist, it would be nice to pose the question to him.

Sorry not totally impressed, I learned thru a machine shop with a welding and fab department 35 years ago at NASA Ames Research. It must not be an exclusive "metallurgist" only knowledge thing provided one has the ability to look listen and learn.

 

[wyzazz]

Sorry not totally impressed, I learned thru a machine shop with a welding and fab department 35 years ago at NASA Ames Research. It must not be an exclusive "metallurgist" only knowledge thing provided one has the ability to look listen and learn.

Didn't say he was a Metallurgist to impress anyone, nor did I say that the knowledge was exclusive to that field. (That would be a silly assumption.) Not sure what you're getting at here, but it seems you're attempting to discount something I've said or maybe something Palmer has said?

Help me out here, I'm grasping at straws.

 

[BrewBeemer]

No disrespect Danny my reply wasn't aimed at you or to be taken wrong.
After working with many "propeller heads" at the Berkeley and Livermore Rad Lab plus the Sandia test facility
i've learned how to work around these odd thinking.

 

[wyzazz]

Understood, just was a little confused.

Your thoughts on the dissimilar metals being soldered together? Any issues with longevity?

 

[BrewBeemer]

Understood, just was a little confused.

Your thoughts on the dissimilar metals being soldered together? Any issues with longevity?

Examples, a 3/4 hp vertical mount well pump bronze impeller inlet stub, sandy soil wears this inlet stub OD to pump base ID over years of service dropping pumping efficiency.
Machined down the stub then soldered on a SS sleeve, machined to a tight clearance to pump base, going on 35 years no problems plus SS a gummy material vs bronze.
A commercial grade hot tank for boiling heads and blocks the high dollar bronze pump was worn down internally and not pumping as new. Machined out the body then soldered in a sleeve tightening up the internal impeller clearances tighter than factory new. It's pumping hot caustic chemicals daily 5 plus years under high heat conditions. The bronze finish is now black.
Granted this is in extreme conditions so is a $2K pump head.
Not to sound like a wise ass, with a Bridgeport mill and lathe on the property I can fab, repair or weld items considered junk. It ain't junk junk until I say it is.

 

[itsme6582]

Examples, a 3/4 hp vertical mount well pump bronze impeller inlet stub, sandy soil wears this inlet stub OD to pump base ID over years of service dropping pumping efficiency.
Machined down the stub then soldered on a SS sleeve, machined to a tight clearance to pump base, going on 35 years no problems plus SS a gummy material vs bronze.
A commercial grade hot tank for boiling heads and blocks the high dollar bronze pump was worn down internally and not pumping as new. Machined out the body then soldered in a sleeve tightening up the internal impeller clearances tighter than factory new. It's pumping hot caustic chemicals daily 5 plus years under high heat conditions. The bronze finish is now black.
Granted this is in extreme conditions so is a $2K pump head.
Not to sound like a wise ass, with a Bridgeport mill and lathe on the property I can fab, repair or weld items considered junk. It ain't junk junk until I say it is.

So does this all mean you don't see an issue arising or that you would avoid it.

 

[BrewBeemer]

So does this all mean you don't see an issue arising or that you would avoid it.

I have found no problems with what they called dissimilar metal bonding with soldered joints. Even brass to brass or copper to copper soldered joint with soft solder can be ripped apart if enough force were applied.

 

[wyzazz]

So does this all mean you don't see an issue arising or that you would avoid it.

In a nutshell, it's a non-issue.

 

[Quaffer]

I'd like to add my bit to this otherwise most excellent thread. I just did my first dimple solder today. I decided to start with the grant because it is the least expensive vessel should things go wrong. The grant needs a bottom drain with a Camlock male. I will be installing a 1/2" half coupling. Here I have cut a hole with a 1/2" conduit punch (7/8" dia) and pulled a dimple with the tool set up as shown. I use a 1/2" bolt so a 1-1/16" socket for 1/2" square drive makes a great self-centering receiver. The remaining pieces on the bolt are just spacers for the long bolt. It is so long because I hope to later pull dimples and pull in couplings in one step, like Green Monti. Notice the piece of 1/2" copper pipe with masking tape on top of the grant.

After having pulled the expansion piece partially through, i reassembled the tool to pull the half coupling through. The piece of 1/2" copper pipe with masking tape is a snug fit inside the coupling which centers it on the bolt. Parts go on the bolt from left to right.

I put the nut in a vice which made it a lot easier to work the wrench with both hands.

The joint has flux and a solder ring is in place, almost ready for heat.

Before I put in the solder ring I filled the dimple with flux. It works like a spirit level so I can modify the mounting of the grant until it is plumb.

After applying heat with a MAPP gas torch. The solder has flowed through the joint and a bead shows up around the coupling. This alone verifies that the joint is sound and leak free. The inside of the joint is now mostly an esthetics issue, which is still worth doing right. By the way, notice the buildup of hardened flux in the threads.

Here's the stuff I used; Stay-Clean liquid flux applied with an acid brush, and Stay-Brite #8 solder.

The flux in the threads was hard to get out with just flux on a rag. I eventually used a 1/2" NPT tap to chase the threads out; the flux had turned to almost glass in there. The tap pulled out crunchy flakes.

Here's what the inside joint looked like after cleaning with flux, then soap and water. There is more solder than I would have liked. I think next time I'll use 75% of a ring and cut it in half to spread it around a little. Also there are stains remaining which do not look so hot. I tried to remove them with a green scrubby pad. It started to remove the stains but it scratched the metal surface so I stopped.

The solution to the flux stains turned out to be Bar Keepers Friend on a wet paper towel. I had an unopened can sitting around since I read rave reviews about BKF here on HBT. It did not let me down, I am a fan too now. The scratches you see are from the green scrubby. There are some faint marks left from the flux which I believe are etched into the surface so they will not come out. Removing the flux sooner may reduce these etchings.

That's it for me. Thanks all who have contributed to our common knowledge.

 

[bbognerks]

Word of warning on the dimple tool. Check your bolt and nut every once in a while to make sure they are in good shape. I had done about 20 fittings with this nut on the hardned bolt from McMaster. After pulling a half coupling through, when I was trying to back the nut off, it jammed. That's right, I could back it off about 1/4 inch from pulling it through and then it wouldn't move at all.

I spent the next 45 minutes cussing, dremeling, hammering, and wedging it off the bolt so I could finish soldering the coupling. Managed to bruise the tip of my thumb in several places where I missed the punch I was using to wedge it apart. Fun times.

 

[klyph]

Ya, I used up a handful of stainless nuts. As soon as one started binding a little, I chucked it and grabbed a new one.

 

[itsme6582]

Finished my keggle a couple of weeks ago but I just managed to get the pics on the PC.

I cut the top of the keg off with an angle grinder and then dimpled and soldered a coupler in place. The whole process was incredibly easy. There really is no reason that someone with no experience and just the slightest bit of common sense couldn't do this. Here's a [ame="http://www.youtube.com/view_play_list?p=40264571DF6C6DD1"]playlist[/ame] of how-to videos I watched beforehand. Nastalgia's dimpling and soldering video was definitely the most helpful. I put the keg tool together mostly with borrowed parts from work. I ordered the reducing coupler and 1 in coupler from McMaster. I actually ordered the wrong 1 inch coupler. I ordered a threaded one. The threads were not an issue. These pics are before final cleanup. The discoloration on the coupler came off right away with a little BKF. It looks brand new again.

I ordered a ball valve kit and a side-pickup tube kit from Bargain Fittings. All stainless and < $50. The Bargain Fittings coupler fit into the dimple sort of loosely but not enough that I hammered the dimple in, as discussed in earlier posts so I could get a tight fit. While soldering, some flux seeped through because it wasn't CH tight. That's what the discoloration is.

Altogether, I finished this project for a hair under $100.

 

[Quaffer]

Beautiful joint! I did one on an old abused hole on my keggle last night, and yours is far better. My keggle split when I pulled the dimple and I had a dickens of a time to get it tight. I'll do a fresh one tonight.

 

[itsme6582]

Quaffer: I'm not sure how to prevent the splitting. Maybe pull slower? I pulled out about halfway through to check the progress before I finished. What about lube? I didn't use anything fancy. I used a little olive oil. I think Nostalgia uses WD-40 in his video. Also, on your grant, I think you could have gotten away with a little less solder.

 

[Quaffer]

Quaffer: I'm not sure how to prevent the splitting. Maybe pull slower? I pulled out about halfway through to check the progress before I finished. What about lube? I didn't use anything fancy. I used a little olive oil. I think Nostalgia uses WD-40 in his video. Also, on your grant, I think you could have gotten away with a little less solder.

I used WD40 and went slow. I think it split because of metal fatigue or something.

Years ago I had tried to braze a 1/2" male copper adapter to this hole, and it was a struggle with futility. In retrospect I probably used the wrong flux; I picked the first one on the shelf basically. It was white powder that burned into black peanut brittle and soot. I attempted repairs which held up for one or two brews until I finally gave up and went weld-less. I think I must have done something to the material then to make it split now; too much heat or too many heating cycles. The brazing rod needed a much higher temperature then the solder I use now.

I ended up using two rings of solder last night because it was leaking out through the crack. Finally I flipped the keg over and capped the crack with solder, and so far so good. I will test it with heat this weekend to see if it is going to hold up.

 

[Quaffer]

There was one more thing about that half coupling. I checked it twice, still the "genius" pulled it in backwards. Luckily I had a 1/2" NPT tap. I am now the owner of the world's shortest full coupling. :cross:

The next full coupling went in without issue. HLT only needs a dip tube and a sight glass now.

Then I cut my brand spanking new Bayou 15.5 gallon kettle and put in a full coupling. Easy peasy. The thin metal of this pot stayed hot a lot longer than did the keggle. I let it cool for almost two minutes then tried to brush of the joint with flux. The solder was still liquid and I messed it up. It is still sound but not as pretty as could have been had I been patient.

 

[Fletch]

Ya, I used up a handful of stainless nuts. As soon as one started binding a little, I chucked it and grabbed a new one.

There is no earthly reason to use stainless bolts or nut for this tool, and you discovered the best reason NOT to use them. SS nuts are much softer than carbon steel. Stick with carbon steel and use lube on the threads.

FWIW, I had ordered the other parts from McMaster, including the large SS coupling to use on the outside as a mandrel. I promptly lost it before the first use (fell out of my truck, it appears). I just took the reducing fitting to HD and picked up a 1" NPT black iron coupling. Works just fine, costs about $10 less.

 

[itsme6582]

There is no earthly reason to use stainless bolts or nut for this tool, and you discovered the best reason NOT to use them. SS nuts are much softer than carbon steel. Stick with carbon steel and use lube on the threads.

FWIW, I had ordered the other parts from McMaster, including the large SS coupling to use on the outside as a mandrel. I promptly lost it before the first use (fell out of my truck, it appears). I just took the reducing fitting to HD and picked up a 1" NPT black iron coupling. Works just fine, costs about $10 less.

I almost completely agree with this 100%. The reducer should definitely be stainless. I think the large coupler should be stainless too but a non-stainless large coupler would probably be fine. The other parts definitely don't need to be stainless. In fact, they probably shouldn't be just as you said.

 

[GreenMonti]

There is no earthly reason to use stainless bolts or nut for this tool, and you discovered the best reason NOT to use them. SS nuts are much softer than carbon steel. Stick with carbon steel and use lube on the threads.

FWIW, I had ordered the other parts from McMaster, including the large SS coupling to use on the outside as a mandrel. I promptly lost it before the first use (fell out of my truck, it appears). I just took the reducing fitting to HD and picked up a 1" NPT black iron coupling. Works just fine, costs about $10 less.

I almost completely agree with this 100%. The reducer should definitely be stainless. I think the large coupler should be stainless too but a non-stainless large coupler would probably be fine. The other parts definitely don't need to be stainless. In fact, they probably shouldn't be just as you said.

If the large coupler is not SS then one should plan on polishing the area since a good deal of pressure is being applied and the iron will impart to some degree on the surface. That will lead to some rusting.

If the area is polished and the iron is removed then there shouldn't be an issue. Just be aware.

Prost

 

[orangehero]

I used a 1" iron pipe fitting for the outside and a brass pipe fitting (1/2" FNTP to 3/4" FGH) I ground down for making the dimple. Worked fine, no rust after a quick cleaning.

 

[Boerderij_Kabouter]

Finally got around to making some progress on my rig last night. Did my first couple fittings. The regular, dippled, pulled through coupler are crazy easy and pro looking even on my first try. The element nut was a different story... wow. That was tricky. It took me two tries to get it done and I had a blob of solder run away on me. I'll need to do some filing and buffing to get that off, but it is functional and decent looking. I found it much easier to do a regular solder with the element nut that try to use the wraps under the nut.

Thanks for the guidance everyone.

 

[slakwhere]

i have done a couple of couplings for a buddy at 1/2" using this method and it's fantastic! a hole saw on my drill press was much easier than a step bit, and i think i'll be going Greenlee punch for the ultimate in ease.

anyone know what size taper coupling i would need to solder in a 1" half coupling for an electric element? i've seen the nuts soldered right to the vessel but it seems a pulled through half coupling would be easier to solder and possibly a bit stronger...

 

[Flomaster]

i have done a couple of couplings for a buddy at 1/2" using this method and it's fantastic! a hole saw on my drill press was much easier than a step bit, and i think i'll be going Greenlee punch for the ultimate in ease.

anyone know what size taper coupling i would need to solder in a 1" half coupling for an electric element? i've seen the nuts soldered right to the vessel but it seems a pulled through half coupling would be easier to solder and possibly a bit stronger...

best thing is get the 1" coupling and measure the OD then you know what size hole you need to drill

-=Jason=-

 

[milldoggy]

Had one handy, measured around 1.5 inches on my tape, not caliper here

 

[slakwhere]

best thing is get the 1" coupling and measure the OD then you know what size hole you need to drill

-=Jason=-

damn you and your logic!

guess i'll place a bargain fittings order and then figure out what size hole saw and tapered conduit i need

 

[adivito]

While its being discussed, quick question on coupler for the element. Has any had an issue or successfully used the coupling since one is nps and the other is npt?