MIG Braze 304 SS to copper

[Fourlix]

I have a great big old stick machine, a bumblebee ac/dc. I think it was made by Miller. Is it possible to add a high frequency and use it for TIG?

[Fourlix]

I am seeing on welding forums that for stainless, and I presume copper, a scratch start TIG set-up can be easily rigged on this old Bumblebee AC/DC....Since I already have gas bottles and flowmeters, all I need is a TIG torch with a gas valve.... Worth trying.

[Southernhighlander]

You can use scratch start on stainless and copper. Just make sure that you use the Ceriated Tungsten electrode and not the Thoriated tungsten electrode. You can sharpen the tungsten with a 4" grinding wheel or a bench grinding wheel but you should not use those wheels for anything else. Chem sharp powder works really well for sharpening electrodes for stainless and copper. We mainly use chemsharp here. You can find the chemsharp powder on the internet. It works great and you don't end up putting any dust in the air like the grinding method. To remove the weld tint from the welds you can use Bradford Derustit's wonder gel. You just wipe it on the weld bead and leave it for 15 minutes and then you just wash the weld with soapy water and the black weld tint magically wipes away leaving a shiny stainless weld bead. The wonder gels primary ingredient is a very strong acid so fallow the directions carefully. You will also need to passivate the tank after all of the welding is done. You can use nitric acid for that, or you can use the wonder gel.

[Fourlix]

I found a TIG torch with a gas valve, 17, for $84. Not sure what that comes with, probably not much. That's a pretty easy entry fee....Santa might need to deliver a late Xmas present....

[Fourlix]

Southern Highlander,,,,THANK YOU for those great tips....

[Cali_Shine_Distillery_co.]

the only thing i wanted to add... if y'all don't mind....is that silicon bronze is rated for water with a ph of 7.0 and there isn't much wiggle room

this is what i found when doing my research

From the Food Code 2009>FDA Food Code 2009 Chapter 4

4-101.14 Copper, Use Limitation.
(A) Except as specified in ¶ ( of this section, copper and copper alloys such as brass may not be used in contact with a food that has a pH below 6 such as vinegar, fruit juice, or wine or for a fitting or tubing installed between a backflow prevention device and a carbonator. P
( Copper and copper alloys may be used in contact with beer brewing ingredients that have a pH below 6 in the prefermentation and fermentation steps of a beer brewing operation such as a brewpub or microbrewery.

So what the we came to as a conclusion in our distillery is that silicon bronze is okay for fermentation but due to the ph of distilled spirits which should be an "8" we don't use it for our joints on anything to do with distillation.

am i wrong here???? if so maybe you could explain to me why???????

[Southernhighlander]

Cali_Shine_Distillery_co

The Copper Use Limitation is for the copper in the silicon bronze. Copper salts are not good for you and acids as well as solvents pull them out of the copper. As long as the copper is in the up side of the vapor path then there are no worries. The copper molecule is to heavy to be carried upwards by the ethanol vapor. If there is copper in the line arm and in the downside of the vapor path, especially the condenser then those copper salts will be carried over into the spirit. Of course we all know many, if not most, stills have some copper in the downside of the vapor path, even copper condensers, so it is a fact that most distilled spirits have some copper salts in them. However, most people do not consume enough distilled spirits to be poisoned by the copper salts. The copper salts are of course green. Distilled spirits with really high levels of copper salts will have a slightly blue tint. Of course you can only see the blue tint before it goes into the barrel. More copper salts are carried through from the condenser than any other part of the still, because liquid ethanol picks up more copper salts than ethanol vapor. If you keep the condenser tubes clean then there will not be enough copper salts to matter, but if you let them get really green and nasty you will see that very slight blue tint in your condensate if you look closely enough.

Of course we all know that some copper is necessary to remove the sulfides from the spirit, however that can be done by having the copper in the upside of the vapor path. My rule of thumb, as far as designing and building stills, is that copper is okay as long as there is no copper in the condenser. That is not to say that I will not sell a customer a copper condenser. I have and I still will if that is what they want. However, I always suggest and I prefer to build the final condenser from stainless.

It is not the copper in the silicon bronze that actually worries me. It is the other things in it. I have researched it and I have not found anything that is conclusive either way. We rarely use silicon bronze anymore, but when we do we make sure that it will have no contact with the ethanol.

[Fourlix]

Building a copper condenser is SO much easier than building one out of stainless....Even a copper coil in a bucket of cold water will work....But stainless? Hokey smokes Batman,,,,and then there is the issue of heat conductivity, the copper is going to transfer the heat so much better than stainless. Hmmm. Forget about the coil....How about stainless tubing inside a copper cylinder with copper end plates?

[Silk City Distillers]

It's about time that copper condensers go the way of the dodo (if they haven't already) - for the reasons mentioned above.

Some light reading...

The Impact of Copper in Different Parts of Malt Whisky Pot Stills on New Make Spirit Composition and Aroma (PDF) @ Wiley Online Library

ETHYL CARBAMATE FORMATION IN THE PRODUCTION OF POT STILL WHISKY (PDF) @ Wiley Online Library

ETHYL CARBAMATE FORMATION IN GRAIN BASED SPIRITS (PDF) @ Wiley Online Library

ETHYL CARBAMATE FORMATION IN GRAIN-BASED SPIRITS (PDF) @ Wiley Online Library

Ethyl carbamate kinetics in double distillation of sugar cane spirit (PDF) @ Wiley Online Library

Ethyl carbamate in pot still cachaças (Brazilian sugar cane spirits): Influence of distillation and storage conditions @ ScienceDirect

Ethyl carbamate in cachaça (Brazilian sugarcane spirit): Extended survey confirms simple mitigation approaches in pot still distillation @ ScienceDirect

Metals in alcoholic beverages: A review of sources, effects, concentrations, removal, speciation, and analysis @ ScienceDirect

Quality of illegally and informally produced alcohol in Europe: Results from the AMPHORA project. @ ResearchGate

Production and Composition of Cider Spirits Distilled in "Alquitara" (PDF) @ Journal of Agricultural and Food Chemistry

[HedgeBird]

Of course we all know that some copper is necessary to remove the sulfides from the spirit, however that can be done by having the copper in the upside of the vapor path. My rule of thumb, as far as designing and building stills, is that copper is okay as long as there is no copper in the condenser. That is not to say that I will not sell a customer a copper condenser. I have and I still will if that is what they want. However, I always suggest and I prefer to build the final condenser from stainless.

We are in the process of replacing (and enlarging) our copper shotgun style condenser with an all stainless one. I am a convert to the copper up and stainless down setup and would also strongly recommend that for anyone buying or building a still. I built my own still and as such wish I would have done a number of things different. Number one is the stainless and not copper condenser, number two is the lack of CIP in the column/plates, number three is the flange connection system I used and number four is the pain in the ass sight glass mounts I made. Thats probably about all my regrets actually, and the only one I plan to fix/change is the condenser.