Nickel/ Silver brazing of stainless?

I've got an oxy-acetylene rig, but no TIG. I plan on trying Nickle/ Silver brazing. Does it flow out like regular braze, only on stainless? I know regular braze don't work...

Okay, it looks like it worked. I sawed a brass 1/4 pipe coupling in half, rather than using a half-nipple, That way, I have lots of area, for strength. I filed a clean spot on my kettle, and filed the edge of the brass half-coupling clean. Then brazed it on, using a slightly oxidizing flame, to burn off any oils. I haven't drilled the center hole yet- until I leak tested it with a quick-disconnect screwed in, and spray any-damn-soapy-stuff. It's tight, I'll go ahead and buy a valve, Vana. Not as neat as regular braze, it didn't seem to want to flow as well. Next time, I'll try some silver SOLDER. probably neater, nearly as strong? I may put the valve on with a steet Ell, to keep it in close to minimize the sticky-out-ness. Oh, this was on my shop built stainless 9 gallon pot, 16ga, 48" circumfrence by 15 deep, because that's how big the cut off was, 20 years ago when I needed a big pot of beans.

Or should I put the valve on a stright piece of pipe, to get it away from the fire? Who has burnt up a valve?

As you found, you can braze stainless with a nickel alloy, but it's a bit difficult. The same properties that make stainless non-corrosive also make puddle flow-out or "wetting" a bit of a challenge.

You can gas weld stainless with stainless TIG filler rods available at most welding supply shops. I prefer 309 rods for general purpose work because they allow the flexibility to join dissimilar metals (like stainless to mild steel). You'll need a good penetrating flux or inert back-gas capability to get a clean weld (else you run the risk of crystallizing or "sugaring" the back side of the weld).

As far as welding the valve - I wouldn't recommend it. Check out this fitting from Homebrew Heaven

Yuri_Rage said:

As far as welding the valve - I wouldn't recommend it. Check out this fitting from Homebrew Heaven

Click to expand...

Yes, Yuri. that IS a coupling. Saw it in half, and you have a half-coupling. Stick one on the outside of a kettle, and you can screw the valve into it. Now go back and read post #2 above.

Oh, and Yuri, pipe threads are tapered. Be sure to solder/braze/weld the correct end to you kettle. That's the inner end, where the other half of the coupling used to be. I used a brass coupling with a hex sectrion in the middle, so I couldn't screw it up. And the hex had lots of area for welding.

I guess you could drill a bigger hole in the pot, and stick a whole coupling half way through, then weld/solder/braze, and you would have a fitting inside for um...filters, etc. But I wanted to try it before I commited my kettle to having a hole. AND, It would be hard to clean under the inner end, right near the bottom of the pot.

EDIT: I was too harsh the first time.

I wasn't questioning your method, merely suggesting that you might find that welding rather than brazing would be an acceptable means of achieving your goal.

Yes, I know that's a coupling. Yes, I read your post, but you used a brass coupling rather than the stainless one I saw the other day at the aforementioned website.

Yes, I'm well aware of tapered pipe threads, but that's good info for anyone who wants to try and replicate your project.

Hey, I think we misinterpeted some. When I asked about burning up a valve, I meant from the heat of the cooking fire. The wort soaks up most of the heat, but should I put the valve on a longer nipple to get it out from the pot? I do know that commercial stcok pots come with valves right near the pot.

I thought your second post, with the nipple pic, was from a new poster, one of those guys who didn't read the preceding posts...

casebrew said:

Hey, I think we misinterpeted some.

Click to expand...

Fair enough - just trying to be helpful.

I understand the valve issue you're talking about now. One of my brew pots came with a ball valve that screws in pretty close to the side of the pot at the bottom. The o-ring is high-temp, and I think it's a metal to metal seal internally, so I don't have to worry too much about overheating it. Still, I wouldn't weld the valve directly to the pot, though I understand that's not what you were asking about.

OK - I just used some silver brazing solder, white paste flux to braze, and benzomatic MAPP gas to braze a 1/2" stainless steel thread to my keggle. It was so easy I would recommend anyone to try it.

need to pay attention to the alloy metals in silver solder, most of the mid range alloys contain cadmium which is toxic. The safety silv 56 material by harris is cadmium free and nsf approved. With the 56% silver and stay-silv flux anyone with a propane turbo torch can silver braze stainless parts together.

kladue said:

need to pay attention to the alloy metals in silver solder, most of the mid range alloys contain cadmium which is toxic. The safety silv 56 material by harris is cadmium free and nsf approved. With the 56% silver and stay-silv flux anyone with a propane turbo torch can silver braze stainless parts together.

Click to expand...

Is this on the right track? 1/16" seems small to me, but I'm no expert.

McMaster
76955A72
Cadmium-Free Extra-Strong Silver Alloy 1145-1205 Deg F Melting Range, 1/16" Wire, 1-oz Coil
In stock at $25.55 Each

Ag Cu Zn Sn %
56 22 17 5

That is the same alloy as harris safety silv 56, the 1/16" dia. is normal size in 1 Oz. coils.

I dont remember the specifics, but a brewer on the green board utilized a threaded male coupling, not a nipple, but half nipple and half female coupling, sorry don't know the exact fitting name. What he does is to drill and tap the keggle and screws in the fitting. The he merely silver solders the joint to make it watertight. This seems like the best alternative to SS welding in that the joint is mechanicly strong yet also bonded well w/ the silver older