Welding

[rightwingnut]

I'm going to get the guys at my local metal shop to weld fittings onto my SS kettles. Is there a special material they should use to keep it food-grade? Are there any undesirable materials? What should I ask them?

 

[Janx]

I *think* stainless welding is all food grade and it's all good, but I'm really not sure. Someone on this board must know definitively...

I've never asked for anything special...maybe that's why my brain has been feeling more sluggish

 

[seven77]

I don't weld, but I've seen a few friends. Normally they try to get that "quarter roll" appearance, so the weld looks like a stack of quarters. I'm sure this method would be harder to clean, because bacteria could stay in the creases of the weld. I've seen a few guys who weld without the creases, just one smooth line. I don't know if this is any stronger or how much harder it is to weld, but I would think it would be easier to sanitise.

Just my 2 bits.

 

[Uncle Fat]

I'm no welder, but from what I've read, there is a difference between a normal weld, and a sanitary weld. A sanitary weld is done in an oxygen-free environment. They use nigrogen to purge the oxygen. I think this eliminates the pitting that can occur in a weld making it easier to sanitize.

 

[rightwingnut]

Is that a specialty I'd have to search around for, or can most shops do a sanitary weld?

 

[DyerNeedOfBeer]

The weld you need is not uncommon... as a matter a fact, its quite normal. The equipment commonly used on stainless welds surrounds the arc with gas which eliminates pitting. If you convey your usage to the shop who is doing the work, they should have no problem providing you with the right weld. Just make sure its not a muffler shop Not that they aren't good welders, but they would probably not have stainless rods or experience with stainless welding. Just ask the shop if they do stainless and if the answer is yes, tell them you want a smooth weld to facilitate cleanliness and you will be fine.

 

[rightwingnut]

Good deal...Thanks. The owner of the shop was my football coach as a kid, and knows my family an' all that good stuff, so I'm good to go.

 

[chuggs]

The "stack of quarters" is indicative of a Tig weld. The dip=dip motion of the filler rod makes the tell tale shape. You could go back over it without the filler and lay down the weld a bit if you wanted to. Most Tig welders use Argon for an inert gas. Stainless Steel requires the use of "Back-gassing"...ie. There are two flow regulators...one passes Argon through the Torch...surrounding the electrode...and keeping oxygen away from the weld on the front surface. The other regulator is used to make sure NO oxygen is present on the back surface. If you don't have the back gas going...you'll wind up with Chromium Oxide on the back surface of the weld. Looks like Burnt Sugar. And it will be impossible to keep from rusting. It can usually be taken off with a grinder...but better to back gas from the start if you have the choice.

I'm waiting to get a splitter valve for my Argon tank...and a second flow regulator so I can weld all the fittings on my keggles.

I don't worry about bacteria...If you keep them clean...and you're heating them up over a fire anyway...there's not much that will grow on the weld. The threads inside the couplling would be the problem spot if there was one.

If you want small qty's of Stainless Steel filler rod...you might check:

TigDepot.com

 

[kladue]

Have the shop "TIG" weld the coulping to the keg, if the do not want to back gass( fill keg with argon) to prevent sugaring get them to use solar flux or superior #9 flux on inside. After welding a pass with SS brush on a 4" grinder will knock the residual flux off. If their welder is really adept challenge them to back weld inside surface of the coupling connection while protecting the outside surface with the backup flux. Back welding the inside will make for a smooth surface to cleanup, no crack to catch material in.