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Soldering Stainless steel

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BargainFittings

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First attempt. I did not let the flux sit very long on the fittings before soldering it with a propane torch.

I used regular lead free plumbing solder.

I'm quite surprised how well it worked. I think I overheated the fitting. Obviously there is way too much solder on there. You can see where the flux had not wetted the steel. The solder kinda bunched up around it.


NOTE: this is a damaged nipple. I don't sell ugly stuff like that! :)
 
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BargainFittings

BargainFittings

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I just took a hammer to it. I beat the tar out of that washer and it just bent a little.

Did not budge the solder joint.

I really am impressed!
 
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Oatey brand lead free plumbing solder. Harris brand - stay clean liquid flux. Good for copper, brass, stainless steel etc. Not good for aluminum.

It is very caustic and you must not breathe the fumes. I need to get an insert for my respirator rated for it.

Hard to hold my breath and solder :)
 

GreenMonti

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Oatey brand lead free plumbing solder. Harris brand - stay clean flux. Good for copper, brass, stainless steel etc. Not good for aluminum.

It is very caustic and you must not breathe the fumes. I need to get an insert for my respirator rated for it.

Hard to hold my breath and solder :)

The solder I have, the flux I don't. I was going to buy the Harris solder and flux for stainless for my diffuser. I didn't want to spend another 65 dollars on the solder and I never asked about the flux. So I welded it instead.

That's the white or the black flux you used?
 

Swagman

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If you don't mind like to stick my two cents in.

I have used silver solder for several years, some for fittings on stainless steel gas tanks, and a few custom fittings for brewers. There are several good brands myself I like sta-brite solder and acid.

For a tool I have found that a large very large Iron the one I have a present is 150 watt. I found better control and less of change of overheating like with a torch.

Just my two cents

Swagman:cool:
 

Brewmoor

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I used this (safety Silv 45) to braze my fittings into my kegs. I used a oxy-mapp torch. Seemed to do the trick. I tried one with jewelers oxy-acetlyne torch but it seemed to get too hot.

I tried your aproach with a thermowell I was trying to make and it failed. I could not get the solder to stick. I must not have been using the right flux.
 
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BargainFittings

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Secret is the flux. The stay clean actually etches off the oxide layer and allows the solder to wet the steel. Very slick.

I think I will try my hand at soldering a kettle tomorrow.

This is where I got the inspiration:

Guy sounds a little like
 
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Brewmoor

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That torch he is using is the same jewelers torch I have. Chances are he is using oxy-acetlyne. He heats those parts up pretty quick.

I will try the stay clean next time. See if I have better luck.

This video was one of my inspirations too. It was the reason I decided to braze my fittings instead of paying a welder. Here is another good one.

 
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wilserbrewer

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+1, I have seen some very clean work using silver solder. Since the solder is not as strong as a weld, of course, it is best if the fitting has a larger shoulder on it, or better yet the fitting should be threaded into the kettle, and then soldered for additional strength and water tightness. Skotrat does it here.

http://www.skotrat.com/go/default/brewing-info/keg-conversion-101/
 

wilserbrewer

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For a tool I have found that a large very large Iron the one I have a present is 150 watt.
Swagman:cool:
At the risk of questioning the resident genius/guru....with all due respect Swag, might that iron be 1500w? 150w sounds awfully small?
 

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It's good to see someone is actually trying to make real functioning bulkheads. I'm sure everyone can see how that configuration completely takes the nipple's threads out of the potential leak path. You put a gasket between that washer and the inside wall of a cooler and you're golden.

I've done silver soldering with a plain old propane torch and then tried with just MAPP gas on the same torch. Both got it done just fine. The trick with flame, I think, is keeping it off the flux. If you burn it off, the joint will suck. I learned to heat the parts and avoid the flux. Literally, with the right solder and acid flux, it's as easy as sweating copper fittings.
 
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It's good to see someone is actually trying to make real functioning bulkheads. I'm sure everyone can see how that configuration completely takes the nipple's threads out of the potential leak path. You put a gasket between that washer and the inside wall of a cooler and you're golden.

I've done silver soldering with a plain old propane torch and then tried with just MAPP gas on the same torch. Both got it done just fine. The trick with flame, I think, is keeping it off the flux. If you burn it off, the joint will suck. I learned to heat the parts and avoid the flux. Literally, with the right solder and acid flux, it's as easy as sweating copper fittings.

Bobby, I have actually taken your point of view to heart and tried to find a reasonable solution. I'm not sure soldering or brazing is going to fit the bill due to the labor involved. There is definitely some motor skill involved in the process too.

I know most people find the fittings I sell to be a reasonable and cost effective solution to seal their coolers. I have had fewer than a handful of people ask about solutions for a leak and most of the time it comes back to either the hole is too big or the nipple in the set was the wrong length.

I'm going to sacrifice my first attempt to a 5 lb sledge hammer and see what it takes to drive the washer off.
 

BrewBeemer

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It's good to see someone is actually trying to make real functioning bulkheads. I'm sure everyone can see how that configuration completely takes the nipple's threads out of the potential leak path. You put a gasket between that washer and the inside wall of a cooler and you're golden.

I've done silver soldering with a plain old propane torch and then tried with just MAPP gas on the same torch. Both got it done just fine. The trick with flame, I think, is keeping it off the flux. If you burn it off, the joint will suck. I learned to heat the parts and avoid the flux. Literally, with the right solder and acid flux, it's as easy as sweating copper fittings.
As stated above by Bobby_M;
Clean your stainless parts nice and bright before soldering, use cut muriatic acid as flux and stainless will solder as good if not better than clean copper. I've been using an old torch run with natural gas and compressed air plus it's hot enough to do silver soldering. I've silver soldered a couple cracked 10" antique clock bells, dressed them to not see the repair plus they ring again. Overheating with O/A is easy to do unless you move the heat away quickly or cause a total recleaning before resoldering again you have to keep on top of what your doing, be ready and fast with O/A.
 

Bobby_M

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Bobby, I have actually taken your point of view to heart and tried to find a reasonable solution. I'm not sure soldering or brazing is going to fit the bill due to the labor involved. There is definitely some motor skill involved in the process too.

I know most people find the fittings I sell to be a reasonable and cost effective solution to seal their coolers. I have had fewer than a handful of people ask about solutions for a leak and most of the time it comes back to either the hole is too big or the nipple in the set was the wrong length.

I'm going to sacrifice my first attempt to a 5 lb sledge hammer and see what it takes to drive the washer off.
No doubt. I know thousands of brewers are happy with typically sold weldless solutions but I guess the idealist in me just wants to see it done better somehow. I will only sell sightglass kits where I can put the gasket between the compression fitting and the kettle wall with no other parts. The fact that I'm not trying to make a real busi
 
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BargainFittings

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Ok I followed through and soldered a stainless and a brass fitting (wondered if that would work) into one of my kettles. Its the thinnest wall kettle I own. Both holes were tight enough to almost thread into so I just cleaned them real well, fluxed inside out and the fitting and soldered it like it was copper!

Seems very sturdy even without any backer inside on the thread. The only thing that would worry me is if someone dry fired a kettle. As long as there is liquid in it the solder should stay put.



 

Brewmoor

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That looks good.

Should be pretty strong too. Unless you drop your kettle, there should not be much directional force on the fittings.
 

CodeRage

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I think I am going to be ordering me some flux soon brother!

Thanks for taking the time to show us ;)
 

wilserbrewer

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I just took a hammer to it. I beat the tar out of that washer and it just bent a little.

Did not budge the solder joint.

I really am impressed!

Yea agreed, myself and perhaps others tend to think of solder as a soft metal of little strength. How quickly we forget that it is "metal" and if well bonded can make a pretty damn tuff connection. Nice work BF.
 

Reelale

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The only thing that would worry me is if someone dry fired a kettle. As long as there is liquid in it the solder should stay put.
Would dry firing liquify the solder again? I didn't know you could solder stainless without silver solder. I'll have to remember this. But I've had zero problems with the weldless fittings I purchased from you, so I'm good. Those solder joints look pretty good to me. Everything I try to sweat or solder always ends up looking like a piece of coral.
 
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BargainFittings

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Would dry firing liquify the solder again? I didn't know you could solder stainless without silver solder. I'll have to remember this. But I've had zero problems with the weldless fittings I purchased from you, so I'm good. Those solder joints look pretty good to me. Everything I try to sweat or solder always ends up looking like a piece of coral.
If you got it up to the melt temp of the solder it would. I would think the plastic handle on the valve would burn before that and alert you :)
 

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Looks pretty good! I played around with an oxy acetylene torch, some SS keg tops, standard plumbing soder and some copper fittings. Out of 10 attempts I was only to make one sweet looking joint. I was using the harris stay clean liquid flux too. I think the oxy acetylene torch may have been too hot though. I did not sand the area before hand so that may have been an issue. But, you have indeed inspired me to try it again. How long did you let the flux sit on the SS soldered? I was recently playing with the harris stay clean flux, plumbing solder and a propane torch and I was soldering all kinds of stuff in the basement, so I need to give it another go.
 
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BargainFittings

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How long did you let the flux sit on the SS soldered?

I actually lightly sanded around the kettle hole and wet each contact point well with the flux and waited less than a minute before soldering it. The fittings I just dunked them in a small container I put the flux in. I just rolled them around to be sure they had flux all over them.

Another thing is I heat each of the couplings from inside like that video link I posted. I put a small bead of solder around the joint... basically I tinned it, applied more flux and then worked the torch over and around the outside to work the solder down a bit. Running the heat under the fitting will wick the solder down some.

On a threaded fitting you have to watch carefully or the solder will fill the threads quickly!
 
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BargainFittings

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Installed a half coupling.

Cleaned up the kettle a bit and center punched it.


Drilled out 1/8" hole


Drilled out to 7/8"


Finished out hole to diameter of half coupling. Did not measure it.
 
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As you can see I got a VERY tight fit on the fitting.



Inside shot of fitting



Solder barely wicks through to other side.



Outside before cleaning it up fully

 

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I will be attempting this with solder and SS close nipples for all my keggle holes. I have 10 years experience with lead-free and high temp silver solder, in an application where it must look flawless on brass.

I have a couple questions:

In order to thread in a 1/2" SS nipple, what hole size should I start with before the tap?

What tap size does this require? 1/2" is inner size, not thread size correct?

As my heating will be electric, I'm assuming that even soft solder would be sufficient with the nipples threaded in.

Thanks in advance, I'm just a little confused about sizes as all my plans so far have involved going weldless.
 
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You will need a fairly thick wall vessel to create a thread. I drill my holes one size under the final fit and just keep tweaking the hole with the step bit until it almost fits. I use a grinding stone on my drill to clean up the edges and widen the hole slowly until the nipple will screw in.

I lightly sand around the hole. Flux the fitting and and a half inch around the hole and solder the fitting in.

1/2" nipples will fit tight in a 13/16" hole. If you thread the hole you will need a 1/2" NPT Tap.
 

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What would you think about using a 45% or 56% silver solder rod with the flux on the rod?

I know it's more expensive than the plumbers lead free, but in your opinion would you get a cleaner joint with less solder fill? Not to mention that high content silver solder is much better with dissimilar metals. Also with the flux core the joint would only need to be cleaned set and then heated in preperation for the solder.

Ideas, opinions, Corrections?
 

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What would you think about using a 45% or 56% silver solder rod with the flux on the rod?

I know it's more expensive than the plumbers lead free, but in your opinion would you get a cleaner joint with less solder fill? Not to mention that high content silver solder is much better with dissimilar metals. Also with the flux core the joint would only need to be cleaned set and then heated in preperation for the solder.

Ideas, opinions, Corrections?
I used the silv 56 rod on my kettles. I think techinally I was brazing. You need a bit hotter flame and longer face time with the material. I liked using it. Just about as easy as using solder and sweating connections.

Use the 56. I don't think the 45 meets our qaulifications for higher gravity liquids. I can't remember. When I was looking around there was a reason I went with the 56. Higher percentage of silver but, There was another reason too.

Here is the stuff I used:

http://www.airgas.com/browse/product.aspx?Msg=RecID&recIds=69750&WT.svl=69750

With this flux:

http://www.airgas.com/browse/product.aspx?Msg=RecID&recIds=246456&WT.svl=246456

All FDA approved.
 

Brewmoor

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Should work great. That is what I use to solder copper. I used MAPP/OXY for brazing with the Saftey-Silv 56. I think you would prefer it to propane for any job.
 
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