Soldering Stainless - things I've learned

[Adr_0]

For anyone looking at soldering stainless, I have finally (after 6-7 attempts) had a bit of a win and can give some pointers. I have been using the Cigweld 965 stuff from Bunnings (10g or so coil):
http://www.bunnings.com.au/cigweld-15g-acid-core-soft-silver-solder_p5914026

1. On my angle grinder, I put a 'fine' flap disc to softly grind around the solder area without taking a lot of metal out. Works an absolute treat.
http://www.bunnings.com.au/josco-100mm-120-grit-extra-fine-abrasive-flap-disc_p6320415

2. Ezi Weld and Comweld GP Silver Brazing Flux don't work. Although the GP Silver Flux (from Blackwoods) has a much higher melting point, it still crusts up and fails to do anything. Cross these both off the list. I hear that Comweld 965 works well but I couldn't find it anywhere.

3. Apparently MAPP torches are a little bit too hot. I got one from Bunnings for brazing aluminium and it works great, but I did wonder if there was too much heat getting in there. So instead I got a $24.95 propane pencil flame torch (Also from Bunnings) which apparently has a lower temperature. Works a treat... just not upside down or sideways. The pencil flame was great, but unfortunately not working on its side makes it pretty useless. Cross that one off the list.

4. I read somewhere that zinc chloride is the ticket for stainless. In my desperation I got the Bakers soldering fluid from Bunnings - looks like zinc chloride, but for some reason I left it aside. Finally used it today - make sure it's the fluid not the paste as I'm sure the paste will crust up - and it is magic. This is the stuff to use. It should be available at Bunnings, but if not Blackwoods have it - again the fluid, not the paste.

5. After a light grind with the flap disc, I started to put some heat on the surfaces. I then dabbed some Baker's fluid with a paper towel (a dropper would be best) and finally got the solder to stick. Beauty.

I need to touch it up a bit but that seems to be the right combination for soldering stainless, with all the consumables and equipment readily available. If you can get a pencil flame propane torch that will work upside down, that should work very well.

No idea how strong the joint will be but it's a great option to join stainless and keep it all pretty stainless.

 

[sp0rk]

From everything I've read on some other forums, EZI-WELD 801 is the bomb for soldering copper or stainless (and has been working for me)
This video from Bobby at Brew Hardware has been a great help while I've been building some stuff
http://www.youtube.com/watch?v=LIkvP55UbxM

 

[Adr_0]

Awesome video, yep the key is definitely getting heat in when the base metals are thick, and you need the right flux.

Looks like these fluxes are all appropriate:
-Comweld 965
-Ezi-Weld 801
-Bakers Soldering fluid

The Ezi-weld 602 is no good though.

As the three above all have zinc chloride, ammonium chloride and hydrochloric acid. Not sure on paste vs fluid, but I would definitely add the paste once it reaches temperature, rather than apply direct heat to the paste.

As in the video, cleaning before is a very good idea and this can be done with the fluxes. Wipe them off if you are using paste, then reapply once you get to temp.

 

[pilgrimspiss]

I did my apprenticeship making stainless steel wine tanks here in W.A.

:icon_offtopic:

Not sure of your backgrounds but you 'd be surprised how easy TIG welding is. If you can solder with a torch and flux you'd LOVE TIG welding lol.

Bit of a pricier option but a great investment of skills. Something like this would be fine for anything you come across in home brewing.

http://www.ebay.com.au/itm/NEW-Rossmark-WS-220-220Amp-DC-Inverter-TIG-ARC-MMA-Welder-Stick-Welding-/141205061618?pt=AU_Welding&hash=item20e07a3ff2&_uhb=1

https://www.youtube.com/watch?v=Ds6cLG3ThDY

I've always avoided soldering stainless due to heat input, and TIG welds are sooo pretty!!

Cheers
Matty.

 

[sp0rk]

I think the cost is the main difference here, I was a TIG welder/design trainee in a past life so I've got the skills, but now being an underpaid IT slave, I just can't justify the cost of an argon bottle, decent welder and having a sparky put in a 15A feed to my shed (though this will be happening soon hopefully)
However for around $100 I can buy a MAP kit with a decent torch and for under $50 I can get good solder and flux and be off soldering in my bits and pieces