Stainless steel question

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baer19d

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What kind of stainless steel are beer kegs made of? Is it 304 stainless? Also does anyone know if a flux core wire is made for this kind of stainless and if so where can I buy it? Thanks, Mike
 

lehr

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I wouldn't weld a keg with flux core wire you really need to back gas your welds when you weld a keg it will make a mess on the inside otherwise.

Pat
 

humann_brewing

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I am trying to put a couple in a keggle using a propane torch and some silver solder prepping it with some liquid flux.

I don't have the ability to tig weld so I thought this should work for stainless steel. What do you think?
 

Sawdustguy

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I am trying to put a couple in a keggle using a propane torch and some silver solder prepping it with some liquid flux.

I don't have the ability to tig weld so I thought this should work for stainless steel. What do you think?
Silver soldering absolutely works providing you have the right flux and your torch gets hot enough.
 

humann_brewing

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Silver soldering absolutely works providing you have the right flux and your torch gets hot enough.
Well I went to the welding shop as I had to refill the CO2 anyways. I got a kit with liquid flux and a small amount of solder. I told the workers silver solder and that is what they gave me so who knows.

I have this torch:



I got a blue tank with it but it sounds like I should get the yellow tank for this job.



MG9 - 16.92 oz. Fat Boy Max Power Propylene Fuel Cylinder (MG9)

* Ideal for medium to heavy soldering and brazing
* Flame temperature in air = 3600 F
* 20% more fuel (than standard 14.1 oz cylinders)
* Recyclable
* Lower profile
 

kladue

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I have used the SafetySilv 55% silver- no cadmium type silver brazing material for thin wall stainless connections, the lower silver percentages will often contain toxic levels of cadmium as an alloy component to reduce melt temperature. You will need StaySilv flux to go with the silver filler material, a white paste that you apply to both the inside and outside of work area to keep metal from discoloring. The Mapp gas torch is more than adequate for the silver brazing, the main thing to watch for is keeping the metal temperature no hotter than the dark red color, hotter and the chrome starts to oxidize and will not accept solder. If you overheat an area, cool it down and sandpaper it back to clean metal, apply paste, and try again. If you have the top from keggle conversion, practice on that then do the keggle.
 

humann_brewing

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I have used the SafetySilv 55% silver- no cadmium type silver brazing material for thin wall stainless connections, the lower silver percentages will often contain toxic levels of cadmium as an alloy component to reduce melt temperature. You will need StaySilv flux to go with the silver filler material, a white paste that you apply to both the inside and outside of work area to keep metal from discoloring. The Mapp gas torch is more than adequate for the silver brazing, the main thing to watch for is keeping the metal temperature no hotter than the dark red color, hotter and the chrome starts to oxidize and will not accept solder. If you overheat an area, cool it down and sandpaper it back to clean metal, apply paste, and try again. If you have the top from keggle conversion, practice on that then do the keggle.
I am beginning to think I was sold the wrong type of solder. I remember it saying contains no silver yet all this stuff says that it should while working with stainless steel.

Is there any main chain store I may have that would sell Harris products like StaySilv and SafetySilv?
 

kladue

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There are 2 types of silver bearing solder, the low temp ~430-450 degree alloy that is mostly tin, and the high temp brazing alloy.
If you have the low temp solder you should have a clear liquid flux to go with it. Prep solder joint with sandpaper to take off the oxide coat on the stainless and apply coating of the liquid flux and heat metal gently and test for solder melting. You may have to apply the flux and reheat area until solder flows over work area. Place coupling or fitting that has been prepped the same way and apply heat until solder melts and add more solder to fill gaps.
With the high temp silver brazing prep area with sandpaper to remove oxide coating, apply white paste flux at joint and outwards at least 1/2" to protect the stainless, match work area flux application on inside to protect that side. If you want you can make a ring of the solder and place it in joint then heat until solder flows, of feed it by hand. The high temp silver solder will follow the heat, so if the area you heat is not where you want the solder to go be forwarned that it will migrate to hotter area. The main trick to this is applying the heat to the thickest/highest mass item first then sweep flame onto thinner material while trying not to overheat work area.
 

Brewin_Bob

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I'm looking around YouTube. Is there a good how-to video or write up on how to silver solder a coupling onto a repurposed keg?
 

humann_brewing

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There are 2 types of silver bearing solder, the low temp ~430-450 degree alloy that is mostly tin, and the high temp brazing alloy.
If you have the low temp solder you should have a clear liquid flux to go with it. Prep solder joint with sandpaper to take off the oxide coat on the stainless and apply coating of the liquid flux and heat metal gently and test for solder melting. You may have to apply the flux and reheat area until solder flows over work area. Place coupling or fitting that has been prepped the same way and apply heat until solder melts and add more solder to fill gaps.
With the high temp silver brazing prep area with sandpaper to remove oxide coating, apply white paste flux at joint and outwards at least 1/2" to protect the stainless, match work area flux application on inside to protect that side. If you want you can make a ring of the solder and place it in joint then heat until solder flows, of feed it by hand. The high temp silver solder will follow the heat, so if the area you heat is not where you want the solder to go be forwarned that it will migrate to hotter area. The main trick to this is applying the heat to the thickest/highest mass item first then sweep flame onto thinner material while trying not to overheat work area.
Thanks for the info, I will try and track some of this down, the closest weld shop didn't have much selection in this department.

Also, are you suppose to solder the inside of the keg and if so how in the hell would you do that?
 

kladue

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The you tube video shows the low temp solder method, the high temp is nearly identical, and no you do not need to solder inside of keg. The reason to apply solder flux to inside is keep stainless from changing colors and oxidizing when heat is applied to outside.
 

humann_brewing

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The you tube video shows the low temp solder method, the high temp is nearly identical, and no you do need to solder inside of keg. The reason to apply solder flux to inside is keep stainless from changing colors and oxidizing when heat is applied to outside.
Thanks, I was going to flux this inside of the keg, just not sure if it needed the solder too. So yes or no? I am confused by your sentence "and no you do need to solder inside of keg."
 

humann_brewing

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Sorry for the confusion, should have taken more time to proof response before submitting it.
Great! What I got yesterday was a Stay Brite Kit with Stay Brite Solders and Stay CLean Liquid Soldering Flux. I am not sure of the percentage of silver to tin in it but I do know there is not much of it. I am not even sure I could do this one job with this amount.

Would like lowes or HD care this type of solder?

Sorry for sound ignorant, but I am a newbie here.
 

kladue

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If you have the StayBrite8 you are good to go, sandpaper area where you want to solder, apply thin coat of liquid flux on the outside only as the stainless will not get overheated like brazing temperatures cause. Heat joint area gently by sweeping torch flame across area, and test with solder when flame is directed away from joint area. You may have to reapply the flux a couple times to get stainless to accept solder, apply flux then rub solder across area to coat metal with solder, you could use a dry rag to wipe away excess solder if necessary. When solder has covered entire joint area prep fitting the same way to get the solder to adhere to the fitting, then position prepared fitting and apply heat until solder melts and fill any gaps by applying more solder. When joint cools, wash flux off and scotch brite the surface clean.
 

Brewin_Bob

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Thanks, kladue. Naturally, I'll get some scrap metal to test technique with first.
 

starsailor

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Hi, I'm thinking of using silver soldering on my keggle to stop the leaks the crop up frequently using nuts and orings. Locally I've found 2 silver solders and I curious if anyone has any experience with them or any comments regarding their suitablity or food safety. The 2 silver solders are:

1. Forney Self Fluxing Silver Solder
6% silver (no mention of other metals in the alloy)
20,000 PSI tensile strength
400-700 degree F temp range
product number 38116

2. Alpha Fry Silver Solder and Flux
98% tin 2% silver alloy
8,000 PSI tensile strength
450 degree F melting point
zinc chloride flux tube
product number 53982

Any info would be a great help!
 

starsailor

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Hi, I'm thinking of using silver soldering on my keggle to stop the leaks the crop up frequently using nuts and orings. Locally I've found 2 silver solders and I curious if anyone has any experience with them or any comments regarding their suitablity or food safety. The 2 silver solders are:

1. Forney Self Fluxing Silver Solder
6% silver (no mention of other metals in the alloy)
20,000 PSI tensile strength
400-700 degree F temp range
product number 38116

2. Alpha Fry Silver Solder and Flux
98% tin 2% silver alloy
8,000 PSI tensile strength
450 degree F melting point
zinc chloride flux tube
product number 53982

Any info would be a great help!
OK, aftre some searching online I found the Forney website with product description here:
Welcome To Forney Industries
and MSDS here:
http://forneyind.com/msds/ms38116.pdf

The summary is that Forney claims this silver solder is food safe and non toxic and the MSDS backs that up showing only silver and tin in the solder, and especially no poisonous chromium or lead. Also, from the MSDS, there is zinc chloride and ammonium chloride in the flux core. That's pretty much the same flux you would apply in paste or liquid form if it weren't self fluxing wire anyway.

At around $10 I'm going to give it a try on some stainless scraps to see how well it works. I'll report back how it goes...
 

Hoplite

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Please check out, Kent White (the Tinman) at www.tinmantech.com.

A friend does aircraft welding on many different metals including Stainless Steel. He is a follower of Kent White. He says you must flux the front, back and the rod. Use neutral flame.

The Keg should be 304. TM technologies, sells the flux you need and a booklet on OXY Acetylene Stainless Steel welding. That is the only place I can find the info and the flux.

I just ordered both for a keg project of my own. Good Luck!
 
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