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Solder or Brazing plates


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I have a question about securing plates to the wall of a copper column and bubble caps to the plates. Will using silver or regular solder (Lead free of course) be sufficient to secure the copper plates to the wall and the bubble caps to the plate, or would one recommend silver brazing instead? Brazing in a 6''x2' section of pipe does not seem very feasable because it would probably cook your arm in a matter of seconds, and I cannot even begin to think about getting a good line of sight.

Will solder or silver solder be strong enough? If I use ROHS certified solder will that ensure approval by the regulatory agencies? Is a high silver solder preferable to a low silver solder? Will ethanol after time eat away at the solder or is this not even an issue?

Logic says that silver solder will be more than enough to keep plates/caps in place for years to come. Soldered joints I see used quite often, but there is no harm in making certain. I have always used silver solder in most of my applications.


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Either solder or brazing will work, but do it in couplings and then assemble them.

Personally I'd go with tri-clamp sections, check out Still Dragon, or get a column already designed. With all that said, the bubble plate system has not worked for me with out the liquid management valves. So i use a packed column.

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Braze or silver the caps to the plates. Soft solder plates to the column. You have to use 2 widely different melting points or the whole thing will fall apart while installing the plates in the column.

As for assembling. Cut the column into 12 inch sections.put a plate in each end 3in. from the end. Heat from the outside not the inside.

Assemble the sections with copper bands or modified copper connectors. 3 sections will give you 6 plates, each 6in apart Vary your lengths to suit your needs, but this makes a nice 3 foot plated section.

And yes you will need cooling management valves to make it work. You have to 'make it rain' to fill the plates properly.

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Before I explain my still build, I would like to ask two stupid questions. What exactly do you mean by cooling managment valves, and where can I get more information? And can I use ROHS certified silver solder 56% which we have an enormous amount of? I know that normal lead free solder is much cheaper, but I have always preferred using silver which I have a quantity of. We will use a small mapp gas torch to do this.

I am using some components from Still Dragon including the copper caps, downcomers, plates, sight glasses and ferrules. I have purchased a 6''x10' copper type L pipe which was cut into 2' sections and a 1' section to be made into a dephlegmator with 12 1/2'' copper pipes. I would have cut it into 1' sections like you suggested, but for aesthetics we are hoping to keep them 2' with 4 plates each. The company that runs Still Dragon has already done the surface area calculations and figured out the proper flow rates and surface area required for each plate. We are being kind of lazy and simply taking their plates, caps (9 per plate) and the downcomers (3 per plate) they make and using a different column material. One thing to note is that the 12 hole plates were a little larger than 6'' because they were made to be held in by a gasket which actually reduces their suface area by a slight amount. This same amount of surface area will be reduced for my column by a machinist friend who will be shinking the radius of the plates slightly with a lathe so they can fit in the pipe. These plates are to be held in by 4 1/8'' holes drilled into the side of the pipes with small 1/8'' copper rods inserted about 1/4'' for the plates to rest on, they will be soldered to the outside and sanded over for eventual polishing. I have a CIP system that I am building utilizing a pressurized SS beer keg and TC SS rotating CIP balls for each plate. The plates will be disabled with a 3/4'' copper pipe that leads directly to the plate on the side of the still with a 3/4'' SS ball valve for each. The sight glasses (Still Dragon ones with a brass flange that has no contact with the vapor) will be attached to 3'' SS ferrules that will be brazed into the column. The column is to be held together with 6'' SS ferrules and for the time being held together with SS tri clamps. I am eventually going to have chrome plated or polished SS flanges made to hold them together for aesthetics only.

This column is going to be fed by the boiler from a 2'' copper pipe. The column is not going to be attached to the boiler because I don't think it will be as easy to access it. An idea I have been toying around with is using SS solenoid valves to control the CIP and plate disablers instead of using regular manual ball valves to ease operation even further. That is just an idea, nothing cemented yet.

If you notice anything in my explanation that sounds stupid or plain wrong, please alert me. I honestly never thought about melting the things clean off when sealing the plates in. Instead of a normal downpour for the plates, the downcomers will supplement this function.

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Well, that build is far more advanced than your initial post eluded to. Sounds great and expensive.

On your build the coolant management is your delph. You need to control the coolant delph temp. Too cool and you have reflux constantly, little to no output. Too hot and the cuts aren't compressed well. Control the cooling with ball valves to balance flows between condenser and delph if using single water feed line.

Excellent site for your build info is homedistiller.org/forum . Look in the column stills area.

And you might as well get an Oxy/Acel torch set. The copper is going to such the heat too quick for mapp in the size you are doing. Will also be cheaper in the long run instead of a bunch of throwaway mapp cylinders.

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  • 4 weeks later...


The bubble caps and downcomers you're planning to use should work great, just remember to put all the downcomers on one side of each plate and stagger the location of the downcomer cluster (IE, put them on opposite sides of the column for each plate)

For your plate disablers, I'd advise against automated valves, you'll find with experience that it's really not necessary, and a pain to fine valve diaphragms that are ethanol safe over long periods of time. There are motorized ball valves that would do that job and are ethanol safe, but they would be cost prohibitive to control for the small ease of use benefit that they'd offer.

Regarding dephlegmator control as porter has commented, some distillers use simple ball or needle valves to regulate water flow to the dephleg, and others use automated solutions. There are various ways of doing this, and the system that I build has simple solenoid operated diaphragm valves managing water flow to the dephleg. This allows you to manage reflux and thereby abv/product profile by controlling the amount of distillate that is returned to the plates as reflux, and the amount of distillate that is allowed to continue to the product condenser as takeoff.

Regarding your plan on securing the plates in the column, you'll want to solder them in, not simply rest them on pegs in the column as it seems that you're planning. The silver solder you're talking about will work fine, as would standard lead free plumbing solder. The only problem with using low temp plumbing solder is that if you plan on attaching your ferules after you've soldered in the plates you'll have issues with the plates becoming desoldered. For this reason I'd suggest you solder the plates in with the silver solder you've got, and then useing a lower melting point solder to secure the flanges that you'll be using. If you're using stainless ferrules to secure the column sections together then you might consider a copper/stainless TIG joint... This could be done by a competent TIG welder that's familiar with fusing dissimilar metals.

Either way, best bet is to consider order of operation regarding assembly, and use the highest melting point solder you've got available to assemble the first parts of the build, and use lower melting point solder for the subsequent portions (or use localized heat/welding methods such as TIG for all parts)

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I suggest using flow meter for the dephlamator (gph). And most of all use an Independent water line to feed it. If you share a line it will mess with the flow.

Depending on the dephlegmator control setup you've got, an independant feed is not needed. You can source the water off the product condenser to feed the dephlegmator. This allows for preheated water that limits thermal shock and instability when using an automated flow control system that cycles water flow to the dephleg via PID logic controlled water valves.

This works great in the systems that I produce, and I believe that Sherman also uses this logic in his fully automated distillery control solutions.

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If you are using a "closed loop", if you trim (control flow) to a load, you need to bypass the remainder available back to the main return line. As far as flow meters go, they are pricey and usually are used to secure a fixed flow rate. Flow regulators (either electronic or pressure actuated) come in two or three way varieties, the two way being less expensive, but you still need to add the bypass line, like you automatically have for the three way valve. With small diameter valves, the three way is a space saver as well. If you are running with city water, you obviously will have a wider swing, summer to winter- closed loop you can reset your reservoir tank or chiller op stat to a higher tempp if it is too cold for ya.

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  • 2 weeks later...

I believe on flow meters. I don't use digital. I like the nice plastic ones with the ball or weight. I don't think automatic valves are needed either, maybe for some people.

I use city water for the condenser and dephlamator. Each unit has its own feed and discharge line. It is truly precision control. When you try to run two or more units off of one feed line and one discharge line you open your self up to more likely fluctuation problems.

That's my two cents.

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Sounds like a fun build! The first thing I would change with my design/build, if doing it over again, is to put all internal plates (both my four valve plates and two dephlamator plates) at seems in the column instead of trying to slide the plates down inside the column and attaching them from the inside. You probably wont have as many issues if you are using 6" factory pipe, buy my column is 11" rolled plate and not perfectly round. Getting the plates in place and level (without banging the @#$% out of them) was a huge pain. Brazing plates a foot and a half down the inside of an 11" tube with the oxy/acetylene torch was beyond a pain. On the final condenser I still need to build I am just going to cut the tube at each spot a plate goes, and then braze or weld the slightly too large plates from the outside.

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I have just as of 3 hours ago finished brazing all of the plates. The 9 bubble caps and 3 downcomers are now in and all they need is a good brushing and cleaning. The plates got a little warped but that doesn't matter, but first one did and we just banged it back into shape really quick. We are using Harris 56% silver brazing alloy.

Below is a dephlegmator design I found, and I am actually copying it! I bought 3 extra plates and I'm milling them down this week. For a few dollars extra its worth it.

(Not my picture, I'm just copying)


This is what the sight glasses will look like. I have cut the ferrules so they are flush with the pipe. I will be silver brazing them in either tomorrow or Monday. They are being held in place by an aluminum angle I bought at Home Depot. Everything I'm adding will be flush down the pipe tube, even the CIP system which will be modular.

(My table in the morning... Not my pills)


I now understand everything that must be done. I forgot to mention that I am adding a plate disabling system but I have opted to use copper pipes running straight to the plates. These pipes will have a TC connection on the side of the still where a TC ball valve attaches and can be turned on and off. Easy to clean, easy to operate. Pretty penny though.


I didn't want to make another post, so I'll post it here. All 4 sections now have pate holes drilled. What you see are copper rivets which will be soldered from the inside and polished outside. Say what you want about it but I don't really mind them! At least it's different to say the least.


The copper rivets are in 4 points around the plate which balances on it. Now it's time to take all the plates out, braze in the CIP ports in the back, then braze in the front 4 window ferrules.


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