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Soldering question, but not distilling-related

PostPosted: Fri Sep 14, 2018 12:53 pm
by Hefty
Hi all,
Hope this is ok to post here. Mods, please delete if not ok.
I'm new here and in the planning stage of my first pot still, but I also have another project that will require some form of soldering or brazing and I can see there is a lot of collective knowledge in this field here.

When I'm not drinking beer or rum, generally I'm drinking coffee. I also camp a lot. I want to make a stovetop steam wand out of an old moka pot. I could buy a Bellman but I'm not going to pay that much for something I already have 95% of the parts and know-how to make myself. (this is also why I homebrew, and hopefully soon distill, too!)
The device will just be the bottom half of a moka pot with the filter removed and a length of tube with a small ball valve and steam nozzle soldered to the inner spout of the top half. I've bought a 4 bar relief valve because I won't get enough steam pressure through the wand without triggering a lower pressure one.

My question is:
Would soft solder be strong enough to join this steam wand tube to the pot for this higher pressure application?

I have what I need for soft soldering, but if hard soldering/brazing is needed I'll just need to do a little extra planning to get access to a hotter torch and buy some hard rods.

cheers,
Jono.

Re: Soldering question, but not distilling-related

PostPosted: Fri Sep 14, 2018 2:35 pm
by warramungas
I think you might struggle to get some to 'ok' your build.
I don't know metal strengths, brazing welding etc, but if you want to build a pressure vessel that's a specialty area.
Still run at atmospheric pressure, or a smidge above. If you want to make something that can go up to 4 bar you want to know what you're doing.
Water will boil at 144 degrees c at 4 bar and if you have a leak or blow a hose off at that temp you've got a nice little schrapnel maker.
I would caution strongly against making anything you think might contain that amount of pressure.

Re: Soldering question, but not distilling-related

PostPosted: Fri Sep 14, 2018 3:15 pm
by Hefty
That's a fair call. I knew it raised the boil temp, but I didn't know it was that much!
I might have to rethink the idea.

Cheers,
Jono.

Re: Soldering question, but not distilling-related

PostPosted: Fri Sep 14, 2018 8:44 pm
by Joycy
Soft solder can be ok under 3 or 4 bar of pressure and 100C heat when done right but if not done 100% it will crack. Honestly, I wouldn't make anything myself at home that is getting up to 4 Bar but if you are adamant on making it, I would silver solder it for strength

Re: Soldering question, but not distilling-related

PostPosted: Fri Sep 14, 2018 10:19 pm
by RC Al
RC's don't try this at home kids answer. :law-policered:

There's some You Tube vids on diy steam cleaning - put coil of copper on a blow torch, feed pressurized water into the back of the coil, nice steam pressure out the other, a multitude of safety issues, but I think built properly, barely more dangerous than a gas torch alone...

The principles of that setup could be transferred to what you are trying to do, no hot vessel, no joins, but slow reaction time to turn off though

Re: Soldering question, but not distilling-related

PostPosted: Sat Sep 15, 2018 10:20 am
by Professor Green
warramungas wrote:I think you might struggle to get some to 'ok' your build.
I don't know metal strengths, brazing welding etc, but if you want to build a pressure vessel that's a specialty area.
Still run at atmospheric pressure, or a smidge above. If you want to make something that can go up to 4 bar you want to know what you're doing.
Water will boil at 144 degrees c at 4 bar and if you have a leak or blow a hose off at that temp you've got a nice little schrapnel maker.
I would caution strongly against making anything you think might contain that amount of pressure.


:text-+1:
Unless you're a boilermaker and you know what you are doing, this kind of caper has disaster written all over it.

Cheers,
Prof. Green.

Re: Soldering question, but not distilling-related

PostPosted: Tue Sep 25, 2018 7:59 am
by Squid boy
I'm a boilermaker but also hold a boiler ticket, rule #1 if any vessel is designed to operate under pressure it should have a safety valve.

Re: Soldering question, but not distilling-related

PostPosted: Tue Sep 25, 2018 8:10 am
by Squid boy
Sorry did not finish last post, should have 2 safety v/v & qualified pressure welder, as mentioned I'm a boilermaker but not qualified to weld at these pressures.