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Story and pictures by Randy Mosher
Republished from BrewingTechniques' November/December 1997 issue.
Last week Randy topok us through some initial steps in Part one and two of this series. If you missed it, just click here...
Welding Tips
 Once you learn the fine art of melting metal together, you will have to confront a few more of stainless steel's bad personality traits. Because stainless steel conducts heat poorly and expands at a high rate when heated, it tends to warp badly when welded. Unfortunately for brewers, this effect is most noticeable on thin sheet metal. A number of things can be done to improve the situation.
- Make sure your parts are as closely fitted as possible before starting to weld. A 1/16-in. gap is really too much to bridge.
- Tack your weld every two inches or so to give yourself a loose seam. This will keep distortions limited to a small scale. When working with sheet metal, go along your tacked seam and tap the metal back into alignment before welding. Then do the same again after welding, using a second hammer as an anvil on the back side.
- Keep your torch moving as fast as possible while still penetrating fully. If you screw up a section, don't dwell on it. Just keep moving, and go back and fix it later.
- Use a backing bar. Commercially made copper bars are designed with holes and fittings designed to flood the backside of the weld with the argon shielding gas used in the torch; but these are expensive and may be not be available in your shop class.
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Even a plain copper bar 1 in. or so wide and 1/8 in. or more thick will provide physical support and draw heat from the weld zone. The stainless will not stick to the copper. Another aid is a material called Solar Flux B, a gray powder that can be mixed with alcohol and brushed onto the back of the weld. With or without backing bars, the flux keeps the back of the weld cleaner and less prone to blow through.
Silver brazing can also be used to join stainless. This technique requires a good propane or MAPP (methylacetylene-propadiene) gas torch, some cadmium-free silver braze (not solder), and the appropriate flux. The joints must be absolutely clean and fit very closely so the gap between the parts is small. Silver braze is very thin and liquid when molten and will not fill gaps. Smear the parts with flux, clamp or wire the parts in place, and heat. Add the brazing rod when the flux turns watery and the joint is just turning red-hot; the procedure is similar to sweating a pipe fitting. Brazed joints will suffice admirably for most brewhouse tasks, but the process doesn't work well for joining overlapping sections of sheet, which is why I'd stay away from this technique when it comes to constructing fermentors.
For another perspective on home welding, see "A Primer on Welding Stainless Steel" by Jeff Donaghue in BrewingTechniques 2 (5), pp. 52-54 (September/October 1994).
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RESOURCES
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Back issue liquidation sale
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Randy Mosher is a beer author/lecturer and freelance graphic designer based in Chicago. A BJCP-certified national judge and a home brewer since 1984, Mosher has made presentations to a number of national and regional homebrew conferences and writes on beer and brewing topics for a variety of beer and home brewing magazines. He also serves on the board of advisors for BrewingTechniques magazine and is the author of The Brewer's Companion, an advanced homebrew reference guide published by Alephenalia Publications of Seattle.
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Here are some HBA favorites: |
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 BrewMaster: The Craft Beer Game: If you appreciate good beer, you'll love BrewMaster: The Craft Beer Game. Using mechanics similar to the classic card game rummy, players combine cards to produce six beer styles including ale, stout and Belgian. In doing so players will use some of the 90 beautifully crafted cards representing real beer ingredients. No beer knowledge is necessary, as this is not a trivia or drinking game. Indeed it is the perfect game for settings involving beer and non-beer fans alike. A Perfect Holiiday Gift!
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Rocky's South Paw Swankey:: Pennsylvania Swankey was a common style in this state before being lost due to Prohibition. The term "Swankey" comes from the German "schankbier", meaning a beer of lower than usual gravity. This historic and very American style was brewed to be a session beer (a tasty, low gravity, low alcohol beer that one could sip for an entire evening of socializing without becoming too inebriated or too full). In terms of body and color it's similar to an English Mild Ale. It's hopped just enough to balance the malt sweetness with American varieties and flavored with aniseed. Our recipe suggests 1/8 oz. (approximately 1.25 tsp.) of aniseed as a starting point. This will give your beer a very subtle licorice character. You can pump it up if you like but be forewarned, a little bit goes a long way and the licorice flavor is not for all tastes. (Starting Gravity: 1.026 - 1.030) (Finishing Gravity: 1.006 - 1.010) (24 IBU's) |
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Bridget's Love Potion Saison: Saison beers are distinctive specialty beers from the Belgian province of Hainuat. These beers were originally brewed in the early spring for summer consumption, though contemporary Belgian saisons are brewed all year round with pale malts and well dosed with Belgian hop varieties. Lively carbonation ensues from a secondary fermentation in the bottle. The color is classically golden orange and the flavors are refreshing with citrus and fruity hop notes. (Starting Gravity: 1.066-1.070) (Finishing Gravity: 1.014-1.018) (Approximate Alcohol content: 6.5-7.2%) |
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Catherine the Great Imperial Stout:: Dark black example of a beer originally made specifically for export. Essentially a black barley wine it has high hop bitterness, flavor and aroma. The high hop flavor and aroma, though unusual for the stout style, are required for an Imperial stout. |
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Chappaquiddick Ale:: Chappequiddick Ale is a Boston style ale that is characterized by a malty body and medium bitterness with a very clean finish devoid of yeast characteristics. It will be medium to dark amber in color. A refreshing ale with the hues leaning towards tan. An excellent session beer! (Starting Gravity: 1.042-1.048) (Finishing Gravity: 1.007-1.013) (Approximate Alcohol Content: 4.0-4.5%) (35 IBU) |
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St. Nick's Holiday Ale:: St. Nick's Holiday Ale is a delightfully spiced ale with accents of cinnamon and vanilla. Mildy hopped with nice honey flavors balanced by the nutmeg and clove. This Amber colored malty ale will really warm up your winter nights. Brew early to make the Holidays! (Starting Gravity 1.070- 1.075) (Finishing Gravity 1.011 - 1.016) (Approximate Alcohol Content: 7.0-7.5%) (25 IBU) |
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