First SS to SS solder + check out this weld spud

[humbledore]

First I am working on converting a 1/4 barrel to 110V electric. Jimbo's thread on his build has been amazing and inspirational for sure.

Quick sidebar for those of you thinking of soldering a fitting onto your keg. Have you seen these weld spuds? They are like a half-coupling with a nice weld collar. Pretty cool. I may order some.

I got some 1" locknuts from bargainfittings.com (great place). Today I did a practice run on an old junker keg, I did not yet have my harris stay-brite #8 or harris stay-clean flux, they are on the way. So keep that in mind. What I did have was plain old plumber's solder and some flux from McMaster that states it is for stainless steel, copper, and some other metals. So I figured it was good enough for a first go.

Oops, hit submit too quick. Here is how I started out with an outline of solder. Not a good idea with a hex nut, maybe it works better with the right flux and a round fitting. Repeat, don't do this with your solder! I learned from this.

I used a pipe nipple wrapped in teflon to keep it centered in the hole. Teflon to make sure the nipple didn't get soldered in.

[corene1]

We use those all the time at work , here they are called Bonny Flanges. The local steel supply house has boxes of them. It makes installing a pipe outlet quick and easy. Never thought of using them with solder, it would make an extremely strong connection with silver solder . I have always welded them in place. Very clean installation though. I am using one in my electric conversion also.

[humbledore]

Okay first go around did not go well. Even though I sanded the heck out of the keg and the nut, the solder would not stick. I am pretty sure a better flux would have helped this. I finally took the nut off, then tinned (coated with solder) the entire keg surface that might touch the locknut. So when it cooled it was a pool of solder. If I had to do it again I would do the same to the locknut face, try to get solder to stick to the face before I even tried to attach it. Anyway with enough heat from the old mapp torch and multiple dosings of flux I got it on there:

Cleaned it up a bit and stuck in the heating element for a water-tightness test. Here is it with the keg filled to the top with water. no leaks yet. I guess I will find out more when I heat and or boil in it.

Bottom line it is not pretty but seems to be water tight. It is possible to do with half-ass flux and solder. Hopefully the next one will be cleaner with the right flux/solder.

[humbledore]

We use those all the time at work , here they are called Bonny Flanges. The local steel supply house has boxes of them. It makes installing a pipe outlet quick and easy. Never thought of using them with solder, it would make an extremely strong connection with silver solder . I have always welded them in place. Very clean installation though. I am using one in my electric conversion also.

Yeah the only drawback that I see is that it requires a minimum hold size of 1 9/16 to 1 5/8". I could not do that with a step bit. But honestly the step bit kind of sucked, maybe a bi-metal hole saw the right size would be the way to go.

[S-Cackalacky]

Great idea using the pipe nipple to hold the nut in place while soldering. I don't understand what you meant about the way you wrapped the solder around the nut being a problem. What problem did it cause?

S-C

[corene1]

First I am working on converting a 1/4 barrel to 110V electric. Jimbo's thread on his build has been amazing and inspirational for sure.

Quick sidebar for those of you thinking of soldering a fitting onto your keg. Have you seen these weld spuds? They are like a half-coupling with a nice weld collar. Pretty cool. I may order some.

I got some 1" locknuts from bargainfittings.com (great place). Today I did a practice run on an old junker keg, I did not yet have my harris stay-brite #8 or harris stay-clean flux, they are on the way. So keep that in mind. What I did have was plain old plumber's solder and some flux from McMaster that states it is for stainless steel, copper, and some other metals. So I figured it was good enough for a first go.

Oops, hit submit too quick. Here is how I started out with an outline of solder. Not a good idea with a hex nut, maybe it works better with the right flux and a round fitting. Repeat, don't do this with your solder! I learned from this.

locknut1.jpg

I used a pipe nipple wrapped in teflon to keep it centered in the hole. Teflon to make sure the nipple didn't get soldered i

locknut2.jpg

How did it work? There are a couple of tutorials on soldering stainless here. When I do it I have a little different approach. I clean the parts to be soldered and apply flux to them, then I tin them. Meaning I apply a coat of solder to each piece making sure it bonds to the metal, I don't bond the two pieces at this time. I then clean them and put another coat of flux on the pieces and put them in place then I heat them gently and apply a little more filler solder when the base solder starts to flow. That will give a nice solid connection.

We must have been posting at the same time! Good Job!

[humbledore]

S-C, I didn't take a pic. When things go to hell I never rememer to do that. The solder stuck to the keg OK but would not stick to the nut. So when I pulled the nut off there was solder everywhere but where it needed to be. [EDIT - the solder did not wick up underneath the nut.] I had to go back and really gouge and file the nut face and the keg surface to get the solder to stick. If I had to do it over with this same flux/solder I would say sandpaper didn't rough the surface up enough. I would use a file.

Corene tinning the surfaces (both) would definitely be the way to go. Much easier then. Plus I may take a hammer to the keg face to flatten it. This seems to have worked without doing that, but the solder did not want to fill the gap. Maybe higher silver would have done better, but it is watertight right now.

[S-Cackalacky]

Corene, could you describe your tinning process? I've done it with copper by simply wiping the excess solder away with some steel wool. Would that be a way to do it with ss as well?

Thanks,
S-C

[Jkhippie]

Boy, am I glad to see a psoitive outcome here. I have the same nut and I was worried I'd need more heat than a MAPP torch. Still wanna see your final result.

[acfixer69]

Tinning the nut is going to be a bigger hurdle for the novice then face value.

AC

[Jimbo]

Happy to see you got it to solder up finally. Nice work. ya the step bits suck. They work but even with a drill press and cutting oil I had to fight it. I might have work hardened one. Man at one point it wouldn't go any further. I used a cone shaped grinding stone chucked up to get past that point. Then back to the step bit.

[S-Cackalacky]

I found this video on Youtube that demonstrates the strength of a ss to ss soldering - http://www.youtube.com/watch?v=YqDdkzVDvRY" onclick="window.open(this.href);return false;" rel="nofollow . The video is boring as hell, but serves to demonstrate how well it bonds.

S-C

[corene1]

Corene, could you describe your tinning process? I've done it with copper by simply wiping the excess solder away with some steel wool. Would that be a way to do it with ss as well?

Thanks,
S-C

It is really pretty simple. If I were to do the same connection as done above. I would use a file to clean both surfaces as well as the edge of the nut so as not to get any glue or by products from any type of abrasive. They can sometimes keep the solder from wicking properly. I would use a light coating of paste flux on the nut and the area on the keg. I would then use my torch and reach in heat the keg from the inside while rubbing my solder on the outside. When the paste starts to liquefy it is getting close and when the solder flows, back off with the heat so as not to get the stainless too hot and burn it. The solder should flow evenly where ever the flux is. Then I would do the same process with the nut. I would then clean the surface of both with warm water and a rag. Then I would run my file across the top of both pieces just enough to rough them up a bit. I would put a light coat of fresh flux on both pieces and set them in place. Using my torch , I would start to heat them making sure that I didn't get either piece too hot. I would probably apply my heat more to the nut than the thin keg material. When the flux starts to wet keep an eye on the solder. as the solder starts to get shiny I would start to add a tiny bit more filler solder and work it gently around the fitting.
One note would be, Although the nipple keeps the nut centered it also acts as a heat sink pulling heat away from the nut making it hard to control the heat evenly. Joining something thick to something thin is more difficult than joining pieces of equal size. Remember always keep the heat moving slightly never hold it in one spot for more than just a second, Be gentle with the heat.

Just watched the video posted. The above method was for using basic lead free solder. If I were to use silver I would just clean both surfaces, flux them well and do single step solder joint.

[humbledore]

Tinning the nut is going to be a bigger hurdle for the novice then face value.

AC

You could be right, I was just thinking about how keeping the solder out of the threads might be tough.

[humbledore]

Happy to see you got it to solder up finally. Nice work. ya the step bits suck. They work but even with a drill press and cutting oil I had to fight it. I might have work hardened one. Man at one point it wouldn't go any further. I used a cone shaped grinding stone chucked up to get past that point. Then back to the step bit.

Yeah it took a while. The bigger the hole gets the harder it is to make progress with the step bit. And I was using a cheap corded drill.

[corene1]

Tinning the nut is going to be a bigger hurdle for the novice then face value.

AC

You could be right, I was just thinking about how keeping the solder out of the threads might be tough.

Just keep the flux out of the threads and the solder will not go there. Solder follows the path of the flux and it doesn't take much flux to clean the surface.

[humbledore]

Tinning the nut is going to be a bigger hurdle for the novice then face value.

AC

You could be right, I was just thinking about how keeping the solder out of the threads might be tough.

Just keep the flux out of the threads and the solder will not go there. Solder follows the path of the flux and it doesn't take much flux to clean the surface.

I will try this when I get the better flux later this week and post again.

[bellybuster]

hate to be "that guy" but those joints look like they'll just come apart with a light tap. The rounded edges are a dead giveaway. With the Harris Stay Clean you will see a huge difference, the solder will flow and become one with the SS. I did no tinning prior to soldering.
http://www.youtube.com/watch?v=BBZPocvN ... fA&index=8

[humbledore]

Yep I did see your video, good work. That is where I got the idea for the solder ring. Good to hear that the stay clean will do the trick cause the stuff I had made me work for it. Attempt #2 should go better.

[bellybuster]

the difference with the Stay Clean is night and day. You will instantly have 100% confidence in the joint just by seeing the solder flow the way it should.
I am putting half couplings into 3 kegs this week in my brewery rebuild.

[Halfbaked]

What ever Belly says on the stay clean is fact. I seen his work on utube and you couldn't ask for anything any cleaner.

[humbledore]

Here is the intended victim of attempt #2...a guy I know hit the motherload of decommissioned kegs...1/6's, tall and short 1/4's and halfs. I got a couple of real clean ones cheap. I wonder if this paint will be a problem, I'll probably need to sand it clean in the area of the fitting.

[Jimbo]

Nice score Humbledore!

Im just finishing the first run with my setup. Ill post up some stats in my Electric Build thread shortly.

[S-Cackalacky]

Thanks Humbledore for starting this thread. This is one of three that I will have bookmarked for reference when I start working on my electric keg - yours, bellybuster's, and Jimbo's. I also found a Youtube video about soldering the "spud" into a keg - http://www.youtube.com/watch?v=LIkvP55UbxM" onclick="window.open(this.href);return false;" rel="nofollow . He's soldering to a flat surface - don't know how much more complicated it would be on a curved surface.

I already have one of the 1" ss locknuts, but I might go with the half coupling used by bellybuster for the simple reason that it might be easier to deal with because of the curved surface.

S-C

[humbledore]

Glad it could be of use, SC. The half coupler would be a good way to go as per belly's video, very clean. Now I got the 1" locknut and full coupler at bargainfittings.com. The locknut weights 2.8oz, the coupler comes in at a half pound! That is a big chunk of metal. The half coupler will be more manageable.

[bellybuster]

Here is the intended victim of attempt #2...a guy I know hit the motherload of decommissioned kegs...1/6's, tall and short 1/4's and halfs. I got a couple of real clean ones cheap. I wonder if this paint will be a problem, I'll probably need to sand it clean in the area of the fitting.

new-quarter.jpg

I've been looking for one of those for quite awhile now to use as a thumper. very hard to come by.

[humbledore]

I've been looking for one of those for quite awhile now to use as a thumper. very hard to come by.

PM me, the odds that you live anywhere near me are small but if you do I can set you up with one.

[Poitin]

He's soldering to a flat surface - don't know how much more complicated it would be on a curved surface.
S-C

Here he is soldering to a curved surface 1/4 keg.

http://youtu.be/RhZM6yGf7iw" onclick="window.open(this.href);return false;" rel="nofollow

[S-Cackalacky]

He's soldering to a flat surface - don't know how much more complicated it would be on a curved surface.
S-C

Here he is soldering to a curved surface 1/4 keg.

http://youtu.be/RhZM6yGf7iw" onclick="window.open(this.href);return false;" rel="nofollow

Thanks, I thought I had seen that version before. Actually, after viewing the video, the curve of the keg surface doesn't really look like it would be that much of a problem.

S-C

[bellybuster]

those spuds are really nice, wish I didn't have a stock of half couplings already.