Column Attachment

[AlZilla]

Hello,

First time still builder here and my first hurdle.

I'm building a 2" copper column (Type L) and have an 8 gallon stainless drum for a boiler. The barrel has a 2" bung (I need to verify that it's actually NPT since the barrel is of European manufacture).

Nothing is available locally. I live in Hooterville and pretty much every uncommon thing needs to be ordered.

It looks like I can find a 2" C x MIPS Male Adapter. It should solder onto the column and then I could thread it into the barrel, sealing it with either PTFE tape or the flour paste mixture I've seen recommended. I could just disassemble to clean between uses.

THE QUESTIONS: Is this a good way to do it? What other options are there?

Thanks for any help.

[Samyguy]

most likely 2" pipe thread , pipe thread is pretty much world wide, if I'm wrong I'm sure some one will point it out.
Tri-clamps are an option, cost is alot more than pipe tread. tri-clamps are more convenient.

[still_stirrin]

The problem with threaded joints, especially between a stainless steel female thread and a copper male thread is that the thermal expansion rates of the two metals is different. As a result, a threaded joint may have a tendancy to leak as the system heats up.

Also, the larger the threads...2” standard pipe threads versus smaller threads...will expand greater proportionately. You may find that assembly and disassembly gets increasingly more difficult with usage.

For this reason, tri-clover (TC) joints are preferred for this type of service. Fortunately they are common in the commercial industry such that internet sales make them accessible worldwide. Adding a TC ferrule to a stainless vessel is best accomplished by TiG welding. A TiG welded joint will be strong and easily support the loads imposed by a column and reflux head, including the product condenser.

Likewise, a TC ferrule can be soldered (provided you have the proper materials...flux & filler) or TiG welded. However, pay attention to the diameters of the ferrule’s tube section.

What I’ve found is that 2” type L copper has such a thick wall that the ferrule won’t easily slip inside the pipe. For my column, I used 2” DWV pipe which has the thinnest wall of all copper piping and the ferrule easily slips inside the pipe allowing me to solder the stainless ferrule to the pipe.

Summarizing, the threaded joints will work, but it is not the “ideal joint”. If it is all you have available, then use it. But be prepared for the challenges ahead. Flour paste can “band-aid” a lot of these problems.
ss

[AlZilla]

most likely 2" pipe thread , pipe thread is pretty much world wide, if I'm wrong I'm sure some one will point it out.
Tri-clamps are an option, cost is alot more than pipe tread. tri-clamps are more convenient.

It did turn out to be a 2" pipe thread. Glad it wasn't something bizarre!

[AlZilla]

I had not considered the different expansion rates. Very good point.

If I'm understanding correctly, a stainless TC on the barrel AND column is the best solution. I can solder the column side. I'd have to hire out the tig welding, which is no problem. What about a threaded ferrule for the barrel side? That would avoid both the expansion issue and the welding.

Thank you for your help.

The problem with threaded joints, especially between a stainless steel female thread and a copper male thread is that the thermal expansion rates of the two metals is different. As a result, a threaded joint may have a tendancy to leak as the system heats up.

Also, the larger the threads...2” standard pipe threads versus smaller threads...will expand greater proportionately. You may find that assembly and disassembly gets increasingly more difficult with usage.

For this reason, tri-clover (TC) joints are preferred for this type of service. Fortunately they are common in the commercial industry such that internet sales make them accessible worldwide. Adding a TC ferrule to a stainless vessel is best accomplished by TiG welding. A TiG welded joint will be strong and easily support the loads imposed by a column and reflux head, including the product condenser.

Likewise, a TC ferrule can be soldered (provided you have the proper materials...flux & filler) or TiG welded. However, pay attention to the diameters of the ferrule’s tube section.

What I’ve found is that 2” type L copper has such a thick wall that the ferrule won’t easily slip inside the pipe. For my column, I used 2” DWV pipe which has the thinnest wall of all copper piping and the ferrule easily slips inside the pipe allowing me to solder the stainless ferrule to the pipe.

Summarizing, the threaded joints will work, but it is not the “ideal joint”. If it is all you have available, then use it. But be prepared for the challenges ahead. Flour paste can “band-aid” a lot of these problems.
ss

[30xs]

I did a quick search on eBay and found this if it’d work. It at least gives you an idea of a simple way to get from NPT to tri-clamp.

https://rover.ebay.com/rover/0/0/0?mpre ... 2315772763" onclick="window.open(this.href);return false;" rel="nofollow

[NineInchNails]

Hello,

First time still builder here and my first hurdle.

I'm building a 2" copper column (Type L) and have an 8 gallon stainless drum for a boiler. The barrel has a 2" bung (I need to verify that it's actually NPT since the barrel is of European manufacture).

Nothing is available locally. I live in Hooterville and pretty much every uncommon thing needs to be ordered.

It looks like I can find a 2" C x MIPS Male Adapter. It should solder onto the column and then I could thread it into the barrel, sealing it with either PTFE tape or the flour paste mixture I've seen recommended. I could just disassemble to clean between uses.

THE QUESTIONS: Is this a good way to do it? What other options are there?

Thanks for any help.

Usually most every hardware store has PVC fittings. You should have no trouble trying to attach a 2" PVC fitting into your keg to confirm the type of thread.

I'd just thread in a stainless 2" NPT x 2" Tri-Clamp to your keg. I wouldn't worry too much about thermal expansion differences. Just load up on the teflon tape and screw it in tight. I wouldn't over think it unless you run into an issue later on.

[AlZilla]

Thanks guys for the help. I have a copper NPT fitting on the column for now. Winter closed in here in the frozen north and even semi-outdoor activities not involving snow machines pretty much ground to a halt. I managed to boil water as proof of concept and it seemed to work fine, though more testing is needed. The plan is to go to the stainless Tri-Clamp fitting above on the barrel and a copper version on the column to save screwing and un-screwing over and over.

The weather has finally broken and the snow has melted enough to expose the tops of the 48" fences so it won't be long now.