A friend of mine brews his own beer and he has purchased a 20 gal stainless tank. He wants me to weld a 3/4 stainless pipe coupling at the bottom on the side to screw in a drain valve. The tank metal is too thin to arcweld (for me) and I don't have TIG. I'm wondering if it would be OK to braze the fitting in or would this set up some sort of galvanic action caused by the chemicals in the beer?
Engineman
It will be difficult to braze it. If you get it too hot you will get oxide growth on the backside.
There are many weldless fittings available. They do cost a little more than the welded fitting, but easy to install and then you dont' have to worry about sanitary welds, etc.
Where are you? If you are close to me, I would gladly help a fellow brewer.
JW
Some examples of a weldless fitting.
JW
Silver solder.
Often used for such things as oxygen system parts and food contact stuff.
Cheers Trevor Jones
Bummer -
Wish I were local again - have TIG and Stainless tig filler.
How about a MIG ? - did you get a MIG from another friend(had a machine shop) ?
- I should have... Bummer.
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member
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The friendly experts on this live in rec.crafts.brewing.
Silver brazing is routinely used on stainless used in food and dairy applications. Be sure that the rod you use is cadmium-free. Most rod available at retail stores is Cd-free these days.
Another good material is Harris Staybrite, a 430F solder that is mostly tin with a little silver. It's much stronger than ordinary soft solder, food safe, works very nicely on stainless with good color match.
You can silver braze it. Just make sure that you use a food safe grade of silver solder. There will be some galvanic action though. When I repaired restaurant equipment as a sideline, for a well known drive in chain, it was common to find this sort of joint. Soft solder, such as silver tin silver bearing solder will also work. Stainless welding rod, should also be certified food safe.
Steve R.
Use a food certified stainless welding rod and a oxy/acet torch. With a light touch, it is no more difficult than soft soldering (which obvously would not work in this application.)
Still, practice on a few scrap pieces before you turn the torch loose on an expensive tank.
Harry C.
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