Silver solder cracks

[sha1]

I have recently fitted my stainless steel fermenter with a solder-on tri clamp flange.
I have read in several places that silver solder joints in the 'homebrew industry' last for one to two years before cracking, however i could not find evidence, nor reports on the severity of such cracks. Are they like cracks and failures from crevice corrosion? Are they cracks caused by thermal fatigue of the joint? Are they catastrophic? Are they hairline cracks that just slowly let fluid out?
Anyhow, i will be thankful if you share here some stories and maybe pictures of failures of silver soldered joints, and some info on the environment in which the joint was, for the sake of learning to spot and maybe prevent such cracks in the future.
Stories of exceptional joint strength are welcome too.

Thank you,
Sha1

 

[wilserbrewer]

I have read in several places that silver solder joints in the 'homebrew industry' last for one to two years before cracking....

I do not believe this claim at all, just my opinion. I would like to read these claims if you can link them. Was this the opinion of a welder? While silver solder is perhaps not as strong as a weld, I can't believe this would be an issue if used with reasonable care.

 

[sha1]

the '1 to 2 years' figure can be seen here -
http://byo.com/hops/item/1516-tlc-for-stainless
"Our limited experience says silver solder is effective, but may crack after a year or two of homebrewing service."
There are more concerns on the corrosion resistance of soldered joints in stainless here -
www.voc.uk.com/net/docs/13.2/13.2-439-31.pdf
and brazed joints here -
http://www.lucasmilhaupt.com/en-US/about/blog/2013/3/interfacial-corrosion

 

[wilserbrewer]

Our limited experience says silver solder is effective, but may crack after a year or two of homebrewing service."

Your original post left out the bolded words, I feel they change the statement measurably.

Well your 1st linked article also says this about welding...

The reason TIG is preferred is that you can weld aluminum, stainless steel or even titanium if you have the skill, the correct gases and the correct filler rod. Smaller, thinner welds put less heat into the welded metal and cause less problems with warping or changes in molecular structure that might lead to corrosion or cracking.

So had you chosen to have the fitting welded, you could be worried about the same potential issues of corrosion and cracking that seem to concern you with the solder, since it does say "less problems", therefore there are obviously "some problems".

It's a big internet out there, you can always find some bad news if you look hard enough. In my opinion, the homebrewing environment is not that harsh, I feel there are better things to worry about than corrosion and cracking of your soldered fitting, especially considering the large surface area of a soldered on tri-clamp....just my opinion.

 

[matc]

I have a keggle with 4 soldered fittings on it (2x1" locknut btw) that i've been using for 3 years now wihtout any problems. It's electric though so maybe the thermal shock is less. Anyway, i'm always checking the solders before using it.

 

[sha1]

You are right, I agree. The problem of corrosion and mechanical failures always exists, and it is probably not of the highest concern to the homebrewer.
However, as their limited experience led them to mention that such failures are possible, I was wondering if that was true and what failure rates and modes are expected - from personal interest in metallurgy, and fear of future problems with soldered stainless in future project, in cold or hot environments(after all it is not welded superduplex stainless).

 

[GotPushrods]

I've silver soldered many dozens of fittings. None have failed in over 5 years. Come to think of it none look any different than the day they were soldered.

But then my regular brewing process doesn't involve repeated beatings with a large hammer. If that's somehow in your process, there could be some legitimate concern.

 

[Stealthcruiser]

I would "think" , that any cracking issues with a soldered homebrewing setup would be from the occasional minor impacts that the soldered fittings would see in storage and handling.

Not from any thermal shock issues or the like.

 

[LarMoeCur]

I've had one solder fail in my 15 years of using SS. And it was my fault. I kicked the ball valve trying to get something from in my garage. Surface area is your friend when soldering. Unlike like welding where you are melting the same metals together. Soldering you are filling in the space between the metals with a different metal. The more area you have the better the solder will hold and be less likely to fail.

 

[wilserbrewer]

Very true! With enough surface area soldered, you can beat the fitting with a 2 lb hammer and not have it crack, the vessel will bend and distort before the solder cracks.

Solder, weld, or weldless with gaskets, all have shortcomings.