Silver Soldering tri-clamp ferrules to CSST

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Silver Soldering tri-clamp ferrules to CSST

Post by jimmayhugh » Sun Aug 09, 2020 11:23 am

I don't have an indoor workshop, so when I'm working on a project it's usually on a makeshift table using sawhorses and a table top I made out of 2x4s and 1/2" particle board. I also have to set it up on the side of my house away from the dogs, especially when I'm using materials that may be toxic. Every thing I do is done using hand tools, and my eyes are not as good as they used to be. I'm also limited as to when I can do the work, since I don't tolerate 110+ degree heat as well as I used to.

As a result, some of my finished products are not necessarily perfectly square or level. Also since I use tri-clamp connectors for everything, getting exactly the right length for a given product is a challenge.

My latest project is a sight level for my electric keg boiler, so I can prevent the liquid level from getting too low and causing the 5500W element from burning out.

To that end, I bought a 300mm (about 12") sightglass from aliexpress. Naturally the sightglass is just that much off to allow a fit using standard length spools.

I happened to have some tri-clamp ferrules that can be silver-soldered to 1/2" copper pipe, and I also had some 1/2" CSST. After some careful checking, I determined that the CSST would just fit inside the ferrules.

I cut the CSST to length using a stainless steel tubing cutter, used some 400 grit sandpaper to rough up the CSST and the inside of the ferrules, cleaned it all up with some acetone, and was ready to silver solder.

I wrapped some 1/16" silver solder around several of the CCST valleys, shoved the CSST into the ferrule, moistened the whole thing with Sta-Brite liquid flux, positioned the CSST and ferrule so that the ferrule was hanging off the end of my work bench, and applied heat to the lowest part of the ferrule until the solder just started to flow. I then added a little more silver solder to the top of the ferrule and let it flow down into the interior of the ferrule. The result looks like this:


I still need to verify that the joints are liquid and gas tight, but the results look promising.

Now if things don't exactly match up, I have a little "wiggle-room" to get things mated up. :D

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Re: Silver Soldering tri-clamp ferrules to CSST

Post by Expat » Sun Aug 09, 2020 11:47 am

Like it! A good work around to a problem. Got a pic of the level glass in on your boiler?

You might also fill the CSST valleys with a bit of copper wire if you're not getting a positive seal with just the solder.

Current boiler and pot head
Cross flow condenser
Modular 3" Boka - pics tbd

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Re: Silver Soldering tri-clamp ferrules to CSST

Post by zapata » Fri Oct 02, 2020 5:23 pm

I'm a devout solderer cuz I'm too stubborn to learn how to weld, so I always love a good stainless soldering project.

What kind of solder are you using? Something relatively low silver I'd guess, maybe a 4-8%?

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Re: Silver Soldering tri-clamp ferrules to CSST

Post by Saltbush Bill » Fri Oct 02, 2020 5:27 pm

High silver content is what ive always used.... and the right flux.
The flux you use or can buy seems to vary country to country a bit.

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Re: Silver Soldering tri-clamp ferrules to CSST

Post by Swedish Pride » Fri Oct 02, 2020 11:21 pm

the right flux is key.
I've used lead free plumbers solder exclusively and for me it works fine, no leaks caused by stress on joints.
Don't be a dick

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