Copper working

[MudDan]

Would it be possible to weld or braze copper? I have a small supply of copper parts, wire, and fittings and was thinking to be able to attach(weld-braze) to each other to form an effective reflux column. I seen how adding turbulence within the column can be effective. So if I had a cold finger and took some copper wire and wrapped it around could I heat it to the point of adhering, or is it just going to melt and distort my copper? I was thinking of using my MAP gas and Oxygen torch.
And another metal question while I'm at it... I work in a foundry, making copper alloy bars. I had a thought of casting my own base for the column. I can machine and grind it down to just about any size. Are there ANY metals(beyond lead) that I should be aware of using? I am thinking of using a basic 954 Aluminum bronze(copper, aluminum, iron, manganese) but am going to try to use 955 which also has nickel for added resistance to corrosion. 955 is a bit harder to obtain. Unfortunate for me I work with mostly leaded alloys. But I still have access to many other metal combinations.

Thanks for your time...
MidRange

[Buccaneer Bob]

Is there some reason why you can't just use lead-free plumbers' solder and sweat things together like everybody else?

This technique doesn't limit you to pipes-and-fittings. You can sweat-together pretty much any two pieces of copper that touch each other.

As far as metals are concerned, a lot of guys say "only use copper or stainless for stills".

Of course, you do need to use appropriate solder for copper-to-copper or copper-to-stainless (some guys have had success with this) and appropriate brazing rods for copper-to-stainless, stainless-to-stainless, etc.

So tin, silver, etc., in small amounts are acceptable.

Most frown on aluminum because it is not nearly as chemically inert as some people think. There are situations where the stuff will dissolve quite quickly, i.e. "galvanic corrosion".

Obviously, lead is not good, and there is lead in varying amounts in a lot of bronzes, with the possible exception of brass plumbing fittings (regulations in some countries have outlawed lead in plumbing fittings).

Some guys place faith in "pickling" potentially leaded bronzes (brasses).

But other guys just don't trust it.

Some guys use a little non-stainless steel. It's not overtly harmful, since we need iron in our diets to live, but you don't want rusty booze, so use non-stainless steel sparingly.

Overall, I would say look at the plumbing industry as a guideline for what's safe and what's not, and you should be okay.

One thing to consider: Working in a foundry, you are in a rather unique position. If either you or your employer could produce a pure copper 2-inch tri-clamp ferrule, there would probably be a pretty fair niche market for it. Most guys who need one have to fabricate something themselves, but there are a lot of hobby/home distillers who seem to have money coming out the wazoo, and they would pay a pretty fair price for something pre-made. Ask around, and find out what some of these guys are looking for. There's a market there for somebody who's a little bit industrious. Just a thought.

[NcHooch]

Soldering is easy and most folks have the tools to solder with lead-free plumbing solder, or silver solder. You can TIG weld copper as well, but that requires special equipment and skills . I'd try an avoid the leaded alloys and stick with either copper or stainless.
hope that helps,

[MudDan]

I really didn't think about using the solder due to transfer of heat, or in this case cold for good reflux action. The better contact my copper has with itself, the better the flow of heat away from the gas which will in my theory be most efficient. Like the tighter you pack your copper mesh in the better, but not just for more surface area, the better contact with your cooling copper parts as well... Just what comes to mind when dealing with copper for me.
As for the bronze or brass... Well, I am in a foundry where we make "Green" metals as well as lead free metal alloys. I can make a bronze adapter of any sort with a real 0% lead spec. As far as making money, we are in casting not machining. I could provide the bar stock to a machinist who wanted specific sizes or specs on the alloy. Right now we are about to try a 10" brass solid round in a horizontal casting machine... We have a spectrometer on site, so keeping it clean is easy.
So what metals are actually safe? Many that I see in this forum could have many elements. The ones that may be common are:
Copper(just for the sake of mentioning the element)
Lead*
Nickel
Iron
Sulfur
Chromium
Zinc
Cobalt
Manganese
Aluminum
Silicon
Antimony
Phosphorus
Tin
I am sure I am leaving something out. Out of these common alloy ingredients, which may pose a threat?

Nickel in certain forms can be dangerous... But this is essential for the creation of stainless steel
Much of brass or bronze color comes from zinc, or aluminum.
Silicon although not a metal is still an ingredient I add often for hardness.
Sulfur... Well, it ruined about 3000 pounds of my metal today. Set me back 6 hours... I know sulfur is there! Zinc will make you sick, flu like symptoms when it releases ZO2. Icky stuff, milk is the foundry remedy Haha.
Cobalt... I can't remember what is toxic about it... My brain sends a red flag when I think cobalt... Maybe dangerous in molten form? Might be safe and I just fried my brain a lil too much in highschool. But really, when it comes to cooling I keep in mind that heat is what transfers... Not cold. So you are not really adding cold... You are taking heat away. Heat is energy, just like electric... Copper is the best choice because its conductive nature. Wires to radiators, all copper. The transfer of energy is unmatched. So I am going to try and get these cooling copper parts welded if possible to be like cooling fins act.
Really I hoped to build a pot still... But with my lack of desire to drink and my enthusiasm for liquid fuel I think a reflux is certainly more suitable for my needs. I hope in a year I will be pulling jars of 98%. That should keep the mower going, and maybe the dirtbike? We'll see in another topic... MudDan out! Thanks for the tips, Imma learnin'!

[skydivemd]

I really didn't think about using the solder due to transfer of heat, or in this case cold for good reflux action. The better contact my copper has with itself, the better the flow of heat away from the gas which will in my theory be most efficient.

...I hope in a year I will be pulling jars of 98%. That should keep the mower going, and maybe the dirtbike? We'll see in another topic... MudDan out! Thanks for the tips, Imma learnin'!

MudDan - not to be rude, but it's time to review the Parent site because, well, ya have ah bit more learnin' to do.
Such as... If you are pulling 98% off of a still, it will most likely be a vacuum still. The maximum you will be able to distill off of an atmospheric pressure reflux/fractionating column still will be approximately 96% because ethanol and water form an azeotrope....

Any of the forum "Old Timers" will tell you that lead-free silver solder works in their builds and will work in yours.
The gap the solder has to bridge between well-fit copper pipes will be on the order of ~0.005 inch. It is there to hold things together and make it water/steam tight.
Was it Rad who said, and I'm paraphrasing here, that, "Theory doesn't mean shit in the face of real world numbers."
Consider how inefficient things are anyway. If you believe that welding will make a real-world, significant, and measurable difference, then TIG welding is the highly specialized and costly process you need. Otherwise, consider investing in a good roll of solder...

Best of luck, and let us know how things progress.

[MudDan]

Yes this is all based on theory... But something I think is worth trying. Not for fitting the pipes together. Those pieces fit snug and have a lot of surface area shared making the transfer of energy almost as efficient as possible. I am talking about extending the copper itself.
You know in the foundry I have got the same response for my ideas. They say if they have the casting procedure down and we are making money why change? Because my scientific theory has improved the quality and rate of production so significantly they pulled me off the line and made me the boss. I now run the show. And when those guys said "we have been making these bars for 20 years". I corrected them, and reminded them that we have been forging copper alloys for 3000+ years... But this nerd can still seem to add new innovation to this once standard industry.
98%... Ok so I am 2% off... I would be happy with 96%, but if I hit 98% you owe me a dollar.
I do feel if I was to attach fins to the copper tubes, the best results would be from the best contact with the cooling copper. Maybe it won't be much, but I would bet a paycheck it would be a noticeable difference.

[MudDan]

P.S. but I am not spending the money on a tig... If torches don't do it... Neither do I.

[whiskeytripping]

Muddan, the heat transfer you are talking about is not even worth you worrying about. The column is going to fill with a vaporized steam of alcohol, not to mention, even if the "cold" sneaks in because it is not fused right just adds to the reflux, SO were back to being back at the 95% numbers, and at that proof you cannot drink it. SO, just be happy with what we all have to work with and make some drink

[skydivemd]

If you know best, that is OK. You have something in mind that you want to try so I say "go for it. "
Plenty of members who had an idea and saw it through have made valuable and occassionally poignant contributions to the volume of knowledge available for all HD members.

And there is nothing wrong with innovation. Just so long as you've made darn sure you understand exactly how and why things have come to be done the way they are. Once you know the "accepted" way, and the previously tried alterations and results, then you proceed enlightened and not stabbing in the dark.

Oh, should you get 98% ABV from your still at STP, I'll give you $2

[rad14701]

MudDan, if you do a bit of research you will find that alcohol open to the atmosphere will stabilize at 96.5%, at most, not 98%... And some folks rationalize that to be because at anything above that that the alcohol evaporates, which is false... If you were to get your hands on truly high proof alcohol and leave it open to the atmosphere you would find that the %ABV would drop and the volume in the vessel would increase because the alcohol will absorb water out of the atmosphere which is why the %ABV drops... So, even if you could manage to produce alcohol above 96.5% ABV the %ABV would rapidly drop back to the 95% - 96.5% range...

[Prairiepiss]

I think the heat transfer ability you would get would be voided by even a shite breeze over the column. But if you feel it a noble experiment go for it. But I have been working on copper welding with a oxy acer. Torch. And I think you will be pushing it with a mapp oxy torch. And use a lot of gas. It can be done. Not easy to get the hang of. I'm still working in it. And real easy to f up a part quick. But if you get it right it does look good. And you will still need to have some solder around to fill pin holes that you will differently get in a weld.


Edited to add. The only reason I'm experimenting with it is for looks and wow factor. Not for thermal reasons. Solder both soft and hard work perfectly fine. I do prefer hard for as many joints as I can use it.

[MudDan]

Muddan, the heat transfer you are talking about is not even worth you worrying about. The column is going to fill with a vaporized steam of alcohol, not to mention, even if the "cold" sneaks in because it is not fused right just adds to the reflux, SO were back to being back at the 95% numbers, and at that proof you cannot drink it. SO, just be happy with what we all have to work with and make some drink

I don't think you understood my goal... I mentioned I was not a drinker, so let's wipe out you mentioning that alcohol at that proof is not for consumption. Moving on to the heat in the column... Yes, more reflux is my desire. It's why people pack the column with mesh... Surface area that comes into contact with the vapors. My goal is to take this principle and see if my idea works to make a high quality distilling machine that has not been used before. The plus, might start a whole new line of stills in my name, or maybe just have a still that works well. In either case I see no damage done. I am now thinking of insulating the column outside to keep vapors from condensing on the column, I may even try to apply heat. As for the reflux cooling, one day I may take an A/C unit apart and start cooling using refrigerant.

And for the record... I do understand that many things, some not mentioned in this forum, have been tried. All sorts of attempts to make something better... Easier... More productive.... Less dangerous. I know... Almost everything has been done... Open your mind and maybe you can take pride in saying "I did that. I went outside that box, tore it up, and this better machine is the result." Feels good man, try it sometime. Or just live life believing everything is already known, and no further knowledge remains waiting to be discovered.

[MudDan]

If you know best, that is OK. You have something in mind that you want to try so I say "go for it. "
Plenty of members who had an idea and saw it through have made valuable and occassionally poignant contributions to the volume of knowledge available for all HD members.

And there is nothing wrong with innovation. Just so long as you've made darn sure you understand exactly how and why things have come to be done the way they are. Once you know the "accepted" way, and the previously tried alterations and results, then you proceed enlightened and not stabbing in the dark.

Oh, should you get 98% ABV from your still at STP, I'll give you $2

Initially 98% as an intended to be way over, an exaggeration I thought would be understood. But knowing how close to that I might be able to come is exciting.
Thank you for the words of encouragement.

[MudDan]

I think the heat transfer ability you would get would be voided by even a shite breeze over the column. But if you feel it a noble experiment go for it. But I have been working on copper welding with a oxy acer. Torch. And I think you will be pushing it with a mapp oxy torch. And use a lot of gas. It can be done. Not easy to get the hang of. I'm still working in it. And real easy to f up a part quick. But if you get it right it does look good. And you will still need to have some solder around to fill pin holes that you will differently get in a weld.


Edited to add. The only reason I'm experimenting with it is for looks and wow factor. Not for thermal reasons. Solder both soft and hard work perfectly fine. I do prefer hard for as many joints as I can use it.

I was just mentioning the column and insulation and maybe even the application of an external source of heat to the column... You read my mind! A bit of cold air could throw your reflux/equilibrium all out of whack. I've even considered trying to make the inside column wall modified to cause a dripping and turbulence within.
Thanks for the heads up on the difficulty taking a torch to copper tubing. I figured it would be tough due to the low melting point. Iron is easy to control because it hardens so fast after the heat is dispelled. Before you get it to actually melt, its shape is lost all around the area. I'll see if I can get the hang of it. I am pretty good with molten metals. After all, my job is to have 2400F on one side, and 6 inches on the other side of a graphite die have 300F. It takes a "feel" for the metals to start this process. Overall not all that hard once the procedures are in place.
I think the mapp/oxy might work out only because the incredibly small torch that creates such a small flame. My torches at work are large, common cutting torches. But I may try that as well if the mapp does not work so well. After that, on to a new tactic Haha.

[Prairiepiss]

I think I kinda see what your thinking. But you really haven't layed it out good enough for me to be sure.

Are you trying to make your own packing from bits and pieces? What is your end goal if you don't drink?

Maybe some kind of diagram would help us understand what you are trying to do.

Adding heat to a column is kinda counter productive. Mater of fact the experimenting that spawned from LWTCS thumper. Has shown sings that a thermal barrier between the boiler and column can possibly aid in separation within the column. But a temp gradient is still needed for separation to happen efficiently.

[MudDan]

Not bits and fragments, but rather a netting of deliberately cut and placed copper to both catch the vapors, and insure it flows down the center of the column rather than down the walls. I think of how the more complex copper configuration the better results. A double wound is better than a single... Triple wound... You get it. Addition of cold fingers... Yet another cool surface that is significant for its lower shape, dripping down the center.

In my head I envision something like the fins on a radiator welded to copper pipe with cold water flowing. The fins are angled to provide constant movement with only small spaces for the hot vapor to travel. This is how the higher and cleaner alcohols are achieved, in my theory. Water will be the first to condense, so the more efficient the reflux in the column, the better the results of your distillation.

But, one thing I have to say... I could be full of shit, for I have not distilled anything more than a glass flask and a tube to get distilled water.