Anyone tried silver BRAZING on stainless

[jleiii]

I have a few SS projects I want to do, and regular soldering is not working too well for me on screen/mesh.
I use a silver based brazing paste in my business, where we braze SS to brass using a standard propane torch. I've been doing this for years and it works very well. The paste has an aggressive flux, and it flows out beautifully. There is a cleaner to dissolve the leftover flux, so that's not an issue.

The material we use is SRA Silver Brazing Paste STL-1205-655 which is 56% Ag, 22% Cu, 17% Zn, 5% Sn, and melts at 1205F. Plumbing silver solder is similar but uses bizmuth instead of zinc. None of the other silver brazing products from SRA use bizmuth, and I suspect that it's used to bring the melting temp way down, to around 450F. The MSDS does not address food safe, or any post application warnings - just warnings about the issues of application.

The brazing paste is super simple to use. It comes in a syringe and you squeeze out a bead, heat with a propane torch and rinse the flux off.

Does anyone have experience using this type of material in a 'food safe' situation, i.e. a brew pot?

 

[P-J]

I would not use it:

http://en.wikipedia.org/wiki/Bismuth

I would reccoment using Stay Brite

 

[Brad2287]

I have not used that product but I have brazed all of my stainless. I used saftey silv 56 and it works perfectly with the correct flux. I did use an oxy/acetylene torch with a brazing tip for this. Here is the information.

Typical Application:**Suitable for use in the food processing industry. Silver color is excellent match for stainless steel and silverware applications.

I would err on the side of caution for anything not listed as food safe.

Sent from my EVO using Home Brew mobile app

 

[Brad2287]

Also the stay bright does work very well with the liquid flux and is easy to use with a propane torch. The braze is stronger but for homebrewing use I am not sure if that matters much. All of these can be found at airgas or possibly similar retailers.

Sent from my EVO using Home Brew mobile app

 

[jleiii]

I would not use it:

http://en.wikipedia.org/wiki/Bismuth

I would reccoment using Stay Brite

Bizmuth is in typical Plumbing solder, not the stuff I have. But I'm not sure what your point is about bizmuth: "unusually low toxicity" sounds like a good thing.

Brad2287 - saftey silv 56 is the exact same thing as I have, so if the Harris version is food safe, then mine has to be as well. Thanks

 

[jleiii]

I finally had a chance to test this silver brazing paste, and it worked beautifully. It flowed out and filled in the mesh layers making a solid bond.
I had some higher temp material too, and that was a total fail. I think it's flux is less aggressive than the 1205. Time to ramp up to project scale.

 

[ScubaSteve]

You should post pics of what you're doing. Brazing mesh sounds interesting....I had wondered the same thing.

Spot welding is probably the most commonly used process with mesh. Anything with a flame is likely to overheat/melt the wires due to their small mass....not what you want to do with SS.

 

[Zuljin]

I've used brass to braze repair steel lawnmower decks and other lawn equipment. This has little to do with the brewing application yall are talking about. I just want to say that proper brazing is easy to learn, and done properly can make a strong and lasting bond.

 

[P-J]

I use Harris Stay-Brite-8 Silver solder along with their Stay-Clean Liquid Flux with great results every time.

I suggest that if you might be interested in this you will want to read the product descriptions in the links I posted.

A common propane torch is all you need to use it.

P-J

 

[jleiii]

I use Harris Stay-Brite-8 Silver solder along with their Stay-Clean Liquid Flux with great results every time.

I suggest that if you might be interested in this you will want to read the product descriptions in the links I posted.

A common propane torch is all you need to use it.

P-J

P-J,

I'm not disregarding your suggestions at all, but I already have the brazing material, and don't need/want to buy something else that I don't need. As a business owner and 40+ years of DIY I always try to work with what I have, or modify it (I have a number of metal working machines) to fit my needs. Sometimes it ends up not as cost effective though!

The brazing paste also works with a propane torch or butane pencil flame burner.

I certainly appreciate the suggestions.

 

[jleiii]

You should post pics of what you're doing. Brazing mesh sounds interesting....I had wondered the same thing.

Spot welding is probably the most commonly used process with mesh. Anything with a flame is likely to overheat/melt the wires due to their small mass....not what you want to do with SS.

ScubaSteve,

Once I have a tangible thing to show, I'll post it. I'm working on a hop screen basket for my boil pot. Sure I could buy one, but whats the fun with that?

 

[jleiii]

Here is the finished product. I forgot to take more pics.
The metal is 1/2" stainless strip that I bent in half then flattened with the mesh inside. The ends were cut so they overlap to make the joint, then brazed the entire length with a butane pencil burner.
Then I rolled it into a ring, brazed the ring at 1 end to hold it, clamped it to a pipe, and pulled the mesh seam tight. I then tacked a few spots along the mesh, then filled in between, then went over the entire length again. I had to press the 2 edges of the mesh together to ensure they were flat, and the relative mass of the mesh vs the pipe kept it from sticking to the pipe. Once the seam was done I joined the ends of the second end.
Then I stood it up on a square of mesh and brazed all the way around the ring. I trimmed the mesh as close as I could, then used an angle grinder to smooth it off. I found a few small spots that did not fuse, so I had to touch them up. Finally I added 2 strips at the top to form a hook over the rim of the pot.

Can't wait to try it. I will pre-boil it a few times to help ensure no traces of flux are left.

I will probably use the silver solder on projects in the future. The higher temp for the brazing was a little tough to maintain while it flowed out. I did not have any issues with burning the mesh, although it glowed pretty good a few times. The butane was great for the mesh, but not enough for the stainless strips.

 

[Stealthcruiser]

Nice!
I'm thinkin' on making one, but using rivets to put it together with, ( 'cause thats what I have!).

 

[jleiii]

I did a boil test and was concerned it was too close to the bottom, and may use the long strips to elevate it some. Once it reached a full boil there was significant turbulence inside which went away once I lifted it. There is about 1/4 inch between it and the pot bottom. Could be a scorching concern under it so I'll have to see once I brew with it.

Not sure rivets will cut it. You'd have to use an awful lot to avoid gaps where the hops will escape.

 

[Stealthcruiser]

True that........I was meaning rivet on a strip of stainless as need to close the gaps, as in a strip from top to bottom, where you brazed from top to bottom.

It would necessitate an "inner frame", and the strips to make the screen captive on the outside.

 

[ScubaSteve]

I know this thread is about silver brazing, but you might have better luck with plumbing solder and a burly soldering iron. You should be able to keep the heat pinpointed enough to tack it like a spotwelder. That high content silver solder is too damn expensive.

I TOTALLY understand the desire to build it yourself, but there are a few vendors around here who can make you a basket for less than what you've probably spent...and it'll look professionally made...not to mention it will have been fabricated using much less heat so you know the mesh will remain "stainless".

 

[jleiii]

I know this thread is about silver brazing, but you might have better luck with plumbing solder and a burly soldering iron. You should be able to keep the heat pinpointed enough to tack it like a spotwelder. That high content silver solder is too damn expensive.

I TOTALLY understand the desire to build it yourself, but there are a few vendors around here who can make you a basket for less than what you've probably spent...and it'll look professionally made...not to mention it will have been fabricated using much less heat so you know the mesh will remain "stainless".

I tried plumbing solder and my 100w iron (burly+), and was not happy with the results. I suspect the flux I was using was not aggressive enough.

The SS mesh cost was about $6 (1/6th of a 36x36 sheet @ $40) and the 3 stainless strips were $1.09 each. That's under $10 total. As I stated to start I had the brazing material already. I use it in my business, and 1 tube lasts longer than the shelf life. The last batch dried up with more than 1/2 left, but that was a cup we put into a syringe. I bought the syringe this time.

I will stop at the welding shop were we get our gases, as they are a Harris distributor and see what the cost is for the aggressive flux, if they even have it, so I can try the solder again.

I priced Hop Baskets, and my $10 one saved me lots of money, plus I get to make it myself. It's 4" dia x 15" tall. Helps justify all the tools I have at my shop, too. This is one of many beer projects I'm working (or worked) on. Sure, I can buy these things, but what fun is that?

Here's another one I'm working on - a self contained bottle washing/sanitizing station. This is the part that supports the bottle necks. It's made from scavenged 2.5" PVC conduit cut into 16" lengths, milled on 4 sides to form flats, cut into 2.5" pcs then cemented together. In this shot I'm milling one side flat. I'll post more in another thread.