# Soldering Stainless Steel



## Yorg (31/5/10)

Have seen and read a fair bit on soldering stainless steel over on Homebretalk.
Seems like a great alternative to sanitary/unsugared TIG welds.
The key to it seems to be the flux, but all the recommendations are for US brands.
Anyone tried it and have recommendations for solder and flux that are available here?


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## kegpig (31/5/10)

plenty of fluxes available here any industrial supply place and then a good grade of blue tip solder should do the job


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## praxis178 (31/5/10)

Yorg said:


> Have seen and read a fair bit on soldering stainless steel over on Homebretalk.
> Seems like a great alternative to sanitary/unsugared TIG welds.
> The key to it seems to be the flux, but all the recommendations are for US brands.
> Anyone tried it and have recommendations for solder and flux that are available here?



Not of the top of my head, but I'll take a look in my BOC consumables guide first thing tomorrow for you. I do recall that you should use high silver content solders, and fluoride bearing fluxes, but that's just a vague memory from before TIG came into my life.


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## chappo1970 (31/5/10)

A cold shivver just ran the length of my spine... 

Ok you are looking for a product call "weld all" or HTS-528. I have used and it is excellent for the job. BUT you need to heat to 1400 degrees and get it just right so you don't blow the base metal away. However it flows brilliantly and is perfect apparently for tight fittings like what we use in brewing.

Then there is a product that is 56% silver and is much like silver solder except the silver content is obviously much higher. Normal silver solder is about 4% to 15%. It's called #3105 from Microflame IIRC? Again the melting point is around 1200 degrees IIRC. But it will require a flux.

Both these types of rods are not cheap around $50 for 4 rods. However 4 rods will go a fair way.

Any *GOOD* industrial welding supply place should stock either one.


Goodluck


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## praxis178 (31/5/10)

Chappo said:


> A cold shivver just ran the length of my spine...
> 
> Ok you are looking for a product call "weld all" or HTS-528. I have used and it is excellent for the job. BUT you need to heat to 1400 degrees and get it just right so you don't blow the base metal away. However it flows brilliantly and is perfect apparently for tight fittings like what we use in brewing.
> 
> ...



Thanks Chappo for saving me the reading I'd 'ave had to do tomorrow!  I can still check things if required, but that sounds very like what I remember.

As an aside I've also used 92% silver solder on SS, flows well but is rather brittle for some reason, so is OK in a pinch for unstressed joins, but still good flux and high heat required.....


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## chappo1970 (31/5/10)

Thomas J. said:


> Thanks Chappo for saving me the reading I'd 'ave had to do tomorrow!  I can still check things if required, but that sounds very like what I remember.
> 
> As an aside I've also used 92% silver solder on SS, flows well but is rather brittle for some reason, so is OK in a pinch for unstressed joins, but still good flux and high heat required.....




 Wholly crap 92%!!! Would have been a bit of a of fun, no? I reckon your dead on with how brittle it would be.

Do you remember what the other stuff was? IIRC is was 40% silver 3% nickle and ? Would friggin stick anything to anything and remained pretty supple. The old noodle ain't as good as it used to be. Must the water, wouldn't be the beer.


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## MHB (31/5/10)

There are two quite different processes called soldering one is soft soldering the other called hard solver soldering, is perhaps better known as Silver Brazing

The key to all soldering is surface preparation and the right flux and temperature

For soft solder you need: -
Propane torch with a good hot intense flame
Phosphoric acid
A zinc chloride based flux
Lead free (tho leaded works but we are talking food grade) Solder usually about 95% tin and balance silver

Clean thoroughly steel wool or a brillo pad, paint the surface where you want the solder to go with phosphoric acid and warm it gently, coat the same area with flux, warm the area you want to solder evenly, slowly bring the temperature up, keep rubbing the tip off the solder on the surface until it starts to "wet" the surface, then flow the solder onto the surface, it will be drawn to the heat so apply the solder just away from the heat and let it run.
When you have a nice even joint remove the flame and DON'T MOVE THE PIECE, the solder goes through a crystalline stage if you move it the joint will fail.

For Silver brazing
Oxy torch
Silver Solder Flux - from the same guys that are about to roger you rotten for the solder.
Cadmium free silver solder (the best is 45% + Ag and your arse will sting when you pay for it)

The process is similar to the above but it's a lot hotter and you don't need the phosphoric acid

Free Tips
Do some practice don't over heat it's the solder in the joint that does the work not the stuff on the outside that you can see. Find some schmuck who can TIG and pay him

MHB


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## mika (31/5/10)

I've used the Eutectic products before and liked them, not sure that this was the one we used, but it would work. Still on the pricey side though.

Eutectic link


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## chappo1970 (31/5/10)

MHB is dead right. Sorry I only think in braizing terms not solder.

I like Mika's option plus a good quality Map Torch should do the job.

Personally TIG is the only way.


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## praxis178 (31/5/10)

Chappo said:


> Wholly crap 92%!!! Would have been a bit of a of fun, no? I reckon your dead on with how brittle it would be.
> 
> Do you remember what the other stuff was? IIRC is was 40% silver 3% nickle and ? Would friggin stick anything to anything and remained pretty supple. The old noodle ain't as good as it used to be. Must the water, wouldn't be the beer.



Yep was fun (runs like water) and pricey is putting it "nicely" to say the least.

Don't recall off hand, like I said I can look it up, that's how long it's been since I did that kind of stuff, lot of beer through the liver since them days. BTW water makes you rust, so I don't touch the stuff! :icon_cheers: 

Oh yeah the reason I like TIG, the consumables are for the most part cheap, and don't go off. Pity about the gas though. LOL


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## Thirsty Boy (1/6/10)

I've soft soldered a couple of stainless bits together... not too hard at all. I just used a propane torch, silver solder, acid and a zinc chloride flux. Which is just what MHB said. But thats not soldering sockets into pots or anything...just joining a coupe of nuts and bolts together. I reckon I might take quite a bit of practice before I let myself loose on an expensive stainless pot.

Soft solder is all thats needed for any brewing application I can think of... OK you might not want to soft solder your brew stand together (but you probably could) - I've tried breaking apart soft soldered brass/copper bits I've done for my brewery.... I can swing off them so I think that they aren't exactly going to be accidentally knocked off as you pass. I often wondered why more people don't solder instead of weld... its so much more doable than welding if you don't have a tig... and homebrewers do like to do stuff themselves.


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## Yorg (2/6/10)

Thanks guys, yes it was the lower temp stuff I was referring to.
I have been soft soldering brass and copper, and like TB, find it works great and is plenty strong for the required application.

MHB, that's great info. Can you go one better and name solder and flux products?

Mika, the link is for a US site. Are you saying their products are available here? Where?


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## MHB (3/6/10)

I haven't brought any for years but last time I just went to BOC and they had to order the solder in for me, it's in their catalogue Just ask for "Food Grade" make sure it's the Cadmium Free, they will have a recommended flux to go with it.

The Lead free soft solder I have always picked up at my local hardware store, it's in a little coil in the plumbing section, the packaging makes it pretty obvious it's the lead free one, as does the price.

TIG is really a much better option, pay if you have to but a good TIG weld is for life. Solder joints often crack due to the different expansion rates of the different metals, might take a couple of years.

MHB


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## brettprevans (3/6/10)

just pull out the arc welder, use a stainless welding flux and have at it! it will of course splutter everywhere, but thats what angle grinders are for 

well my advice is solid if you cant get someone to TIG it for you.

I should post up a pic of the most recent mod to my kettle....had an annoying long thermowell cut out then just filled in the hole with weld. will grind off the small splatters on the weekend.


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## sjp770 (2/6/14)

Whats the Pro's and cons of using a stick welder on Stainless? I have inherited an old welder with a big bunch of stainless rods.


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## Martrix (2/6/14)

Yorg said:


> Have seen and read a fair bit on soldering stainless steel over on Homebretalk.
> Seems like a great alternative to sanitary/unsugared TIG welds.
> The key to it seems to be the flux, but all the recommendations are for US brands.
> Anyone tried it and have recommendations for solder and flux that are available here?


whats an 'unsugared' weld? :blink:


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## sp0rk (2/6/14)

Martrix said:


> whats an 'unsugared' weld? :blink:


Sugaring is oxidization around the weld, which is remedied by shielding with argon, which is called purged welding or unsugared welding
The other way to do it is weld at low amperage, but that can run the risk of not getting a hot enough weld pool and not having good penetration leading to a crap weld that may or may not stick for long


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## Rdyno (2/6/14)

If only mig's were good at stainless.


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## Ducatiboy stu (2/6/14)

Rdyno said:


> If only mig's were good at stainless.


They are if you use stainless wire.


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## Rdyno (2/6/14)

Ducatiboy stu said:


> They are if you use stainless wire.


Yea I just returned from an hour on youtube watching stainless mig welding lol.


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## Ducatiboy stu (2/6/14)

Soldering stainless needs the correct solder flux. Its THE most important thing


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## booargy (2/6/14)

you haven't given it a go yet may be surprised how easy like colouring in just cover the weld in nice neat circles.


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## pist (2/6/14)

Yorg said:


> Have seen and read a fair bit on soldering stainless steel over on Homebretalk.
> Seems like a great alternative to sanitary/unsugared TIG welds.
> The key to it seems to be the flux, but all the recommendations are for US brands.
> Anyone tried it and have recommendations for solder and flux that are available here?


MHB is correct on the solder cracking...its doable but wont last. In applications where heat is to be applied over and over I'd go with having it welded.
TIG welding is much smoother and neater if done well...and more likely to be sanitary if done right. If you can't do it...pay someone its much harder than it looks.
I welded mine myself using MIG and stainless wire


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## Ducatiboy stu (2/6/14)

And pots a super thin which makes it even harder.


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## Maheel (2/6/14)

i played around with it here (solder)

http://aussiehomebrewer.com/topic/64450-soldering-stainless-adding-ss-fittings-to-keggles/

in the end even though i have "free" access to solder/oxy/mig/tig and a full workshop of goodies i reckon it's easier to just go weldless

each to their own but


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## Martrix (2/6/14)

sp0rk said:


> Sugaring is oxidization around the weld, which is remedied by shielding with argon, which is called purged welding or unsugared welding
> The other way to do it is weld at low amperage, but that can run the risk of not getting a hot enough weld pool and not having good penetration leading to a crap weld that may or may not stick for long


Ahh, Cheers for that. I'm ordering some BOC Stainshield gas and stainless wire for my MIG in a few weeks. Considered a TIG but sticking with my mig setup right now is the cheaper option. Can't be that much harder than normal steel


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## glenos (2/6/14)

just don't this; http://www.dhhs.tas.gov.au/peh/alerts/public_health_updates/kingston_sheetmetal_stainless_steel_tank_update

Stainless steel water tanks soldered with a 50% lead solder.


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## Maheel (2/6/14)

some bunnings stock "aquasafe" solder with no lead
it's twice or 3X the price but much safer than oldschool 60/40 lead solder that they also sell

i have checked with the aqusaafe makers and it is also cadmium free


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## Ducatiboy stu (2/6/14)

You want silver solder.


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