4" VM Build

[Salt Must Flow]

I've been using a 3" VM (Vapor Management) for quite a few years, but recently decided to upgrade to a 4" VM still. I just started ordering in some parts. Here's the plan for the VM head. The only welding for the VM head will be to weld the 2" ferrules to the 1-1/2" gate valve. I'm not sure if I'm going to place that centering plate below the reflux condenser or just above the sight glass.

4 Inch VM Head 01.jpg

1-1/2" stainless gate valve.

1.5 in Gate Valve.jpg

4" x 4" x 2" Short Tee I bought on AliExpress for $38.23 free shipping. It went on sale so I had to snatch it up quick. Only took 6 days to arrive.

4 in Tee.jpg

Just for scale, this pic shows 2", 3" then the 4" tee. 4" is BIG

2 3 and 4 Tee.jpg

For the reflux condenser, I plan to do a double wound coil of copper tubing. 1/2" copper tubing on the outside and 3/8" copper tubing on the inside. Using 2" PVC pipe and 3/4" conduit as mandrels appear to give the most evenly spaced coils. The tubing will be filled with salt prior to winding the coils and the salt cleared using water pressure.

Reflux Condenser Drawing.png

I'm shooting for a 6' tall column packed with Lava Rock. If I need to go taller I can, but 6' is the plan at the moment. I've been shopping around for 4"x 24" spools, but they're so darn expensive, even from China. I may know a guy who has 4" stainless dairy pipe. If so, I'll have it cut and have ferrules TIG welded. I also found a local listing for 4" stainless dairy pipe online for $15 per foot.


I plan to purchase the copper tubing and winding the reflux condenser this weekend. In another week or so I plan to place one last China order for the rest of the parts, ferrules, clamps, gaskets, sight glass and 6"x4" Tri-Clamp reducer.

[GrumbleStill]

Nice one SMF, will be keeping an eye on the build and interested to see how it runs.

As for the 4” pipe spools, have you checked out local exhaust / muffler shops?

[MooseMan]

I was going to say the same, if you happen to have any performance auto shops near you, give those a look in for 4" SS tubing.

I found it pretty easy to rattle the sand out of my coils when I did mine, before purging the last of it with water.

Look forward to seeing the build develop SMF.

[Bushman]

I may know a guy who has 4" stainless dairy pipe.

That is what I use on my CM still. I was lucky enough to have one of the members send me one for $50 plus shipping. The beauty of the dairy pipes is they come with ferrules on both ends.

[Salt Must Flow]

Nice one SMF, will be keeping an eye on the build and interested to see how it runs.

As for the 4” pipe spools, have you checked out local exhaust / muffler shops?

Thanks a LOT GrumbleStill and MooseMan! That will be a HUGE cost savings and something I never would have considered. I really appreciate you guys mentioning that. I see they even sell 304 stainless straight pipes on Amazon. It's a fraction of the price of sanitary pipe, has the same OD and only slightly smaller in ID which shouldn't be a problem. The tiny lip on the inside of the welded ferrules may snag on rolls of copper mesh, but I can grind to taper the transition to eliminate that.

The guy who TIG welds for me has a precision band saw and can easily cut the pipe square. His company fabricates race car tube chassis so this is a piece of cake for him to weld everything straight.

[Salt Must Flow]

I was going to say the same, if you happen to have any performance auto shops near you, give those a look in for 4" SS tubing.

I found it pretty easy to rattle the sand out of my coils when I did mine, before purging the last of it with water.

Look forward to seeing the build develop SMF.

I'm definitely going to use salt to fill the copper tubing. I've had perfect luck winding different size coils in the past using salt without kinks or wrinkles. The thought of using sand scares the hell out of me My luck, the sand won't come out. I've heard of people using sand, I don't doubt it works, but since salt dissolves with water, it's guaranteed to come out. I calculated the volume of the copper tubes and it requires less than 1 quart of salt to fill them both. Since each length is only 10', they will be very easy to fill completely from end to end.

[Salt Must Flow]

I may know a guy who has 4" stainless dairy pipe.

That is what I use on my CM still. I was lucky enough to have one of the members send me one for $50 plus shipping. The beauty of the dairy pipes is they come with ferrules on both ends.

I also lucked out when I built my 3" VM years ago. A friend gave me a LOT of 3" dairy pipe for free. I intended to use dairy pipe again, but since 4" 304 stainless exhaust pipe is so darn cheap in comparison, I can't imagine using anything else now. It's sold on Amazon and even polished too!

[Salt Must Flow]

Thanks to the recommendation to use 4" 304 stainless exhaust pipe, I've mocked up the lengths to be cut and TIG welded. These are the ONLY parts to be welded for this new build.

2" Tri-Clamp Ferrule and 2" Short Ferrule
4" Tri-Clamp Ferrules
4" 304 Stainless Exhaust Pipe 48" Long

4 in Mockup Welds.png

[Salt Must Flow]

I just found this listing for two pieces of 47.3" stainless pipes for $60.99. That's a $21 cost savings over the previous link I listed. The wall thickness is 17 gauge/1.4 mm/0.0551181" which is a little bit thinner than the other pipe which is 0.0625" thick. I can't imagine that being a problem though.

To create three 24" long Tri-Clamp spools, each pipe needs to be cut to 22.31" long and the welded ferrules make up for the rest of the length. 47.3" lengths should work out just fine. Saving money every day

[MooseMan]

Wow that's pretty damn cheap for that length of SS in 4" eh!

I don't think the gauge will be an issue at all, so long as the welder is skilled and practiced, and it will be covered with insulation once completed so low risk of denting.

All looking good man.

[GrumbleStill]

Good to hear that the tip worked out SMF (well at least so far - proof is always in the pudding), and be keen to see how it ends up.

Truth be told, I was actually doing a bit of research on a suggestion you made about SS welders / welding supplies when the 304 exhaust option popped up.

Have fun & stay safe.

[Salt Must Flow]

I think I'm going to save a few bucks on parts & welding by modifying my mock-up a little bit. I don't think I need three 2' spools. I'll just go with two 3' spools. That will eliminate a significant amount of welding.

4 in Mockup Welds 02.png

[Salt Must Flow]

Good to hear that the tip worked out SMF (well at least so far - proof is always in the pudding), and be keen to see how it ends up.

Truth be told, I was actually doing a bit of research on a suggestion you made about SS welders / welding supplies when the 304 exhaust option popped up.

Have fun & stay safe.

That's alright because a good tip is still a good tip no matter how or when it was discovered Sourcing the pipe for the 6' column was the only thing I hadn't finalized at the time. I'm absolutely thrilled now because the alternative costs were bothering me.

[Salt Must Flow]

I just finished winding the copper coils filled with salt. 10' of 3/8" OD tubing and 10' of 1/2" OD tubing.

Copper Coils 01.jpg

By the way, I was NOT able to use the 0.922" OD conduit as the mandrel for the 3/8" copper tubing. It was just slightly too small and started to wrinkle the tubing a bit. I had to step slightly up to 3/4" PVC pipe (1.125" OD) and it worked perfectly.

Reflux Condenser Drawing.png

I will be drilling two holes through a 4" Tri-Clamp end cap and threading them using a 3/8" NPT thread tap. These brass elbows will be installed through those holes. I just drilled out these elbows using a 7/16" drill bit and threaded them using a 1/4" NPT thread tap.

Brass Elbow 01.jpg

These copper adapters will be installed on the underside of the 4" end cap and the reflux condenser will be soldered to these copper adapters. These are for 'water in' and 'water out'.

Brass Elbow 02.jpg

[acfixer69]

Gona have fun with the threadin stainless NPT is aggressive.

[Salt Must Flow]

Gona have fun with the threadin stainless NPT is aggressive.

You're right, it's not to drill & thread relatively large holes. I have successfully drilled a hole through an end cap and tapped it with a 1/2" NPT thread tap before. It went well by taking it slow and using a LOT of lube. I figure I shouldn't have any issue drilling & tapping with a 3/8" NPT thread tap. I do have a plan B and a plan C if I do work harden the stainless.

Plan B: I can drill or use a Die Grinder to open up the holes a bit more and try to get 'just enough' depth of threads to screw the elbows in. These connections are just holding the elbows for 'water in' and 'water out' through the end cap so I don't need the full depth of thread as you ordinarily would for a typical connection under pressure.

Brass Elbow 03.jpg

Plan C: I can Die Grind the holes open just enough to insert the elbows and silver solder them into the place.

[MooseMan]

Fantastic results on the coils, they look real neat and tidy.
It's very apt that you used salt to pack the copper, considering your username!

Nice idea with the fittings through the end cap too, will make a lovely neat and secure fit.

I can attest to acfixers comment on tapping SS, especially the thickness of an end plate, it's horrible stuff to work on with hobby level tools.

Can I suggest something?
I've had this job go easier in the past by using a larger tapping drill.
I don't have sizes to hand right now but whatever the recommended tapping drill size is, go a few thou bigger if you have the bit sizes, and the tap will have a much easier job of it.
And go stupid slow and wet with the drill so you don't work harden the hole walls whilst drilling.

Then, depending how slack the brass fittings are, just run some solder down into the thread on assembly.

[Salt Must Flow]

Fantastic results on the coils, they look real neat and tidy.
It's very apt that you used salt to pack the copper, considering your username!

Nice idea with the fittings through the end cap too, will make a lovely neat and secure fit.

I can attest to acfixers comment on tapping SS, especially the thickness of an end plate, it's horrible stuff to work on with hobby level tools.

Can I suggest something?
I've had this job go easier in the past by using a larger tapping drill.
I don't have sizes to hand right now but whatever the recommended tapping drill size is, go a few thou bigger if you have the bit sizes, and the tap will have a much easier job of it.
And go stupid slow and wet with the drill so you don't work harden the hole walls whilst drilling.

Then, depending how slack the brass fittings are, just run some solder down into the thread on assembly.

I certainly will. The elbows just need enough thread to screw into place.

I've drilled & tapped 1/4" NPT and 1/2" NPT through end caps so 3/8" shouldn't be an issue. I am aware and have experienced issues with drilling stainless though. Like you said, go slow.

[Yummyrum]

SMF , to keep drill and SS cool , I’ve found making a moat out of blue -tack ( you could probably use plastacine too ) works really well . Have a hose dribbling water into the moat and there is no heating what so ever as long as you go slow and push hard wirh the drill

IMG_0900.jpeg

BTW , nice work on the coils . I’m concidering something similar and your mandrel experience was great .

[shadylane]

@ Salt Must Flow

I'm thinking, the centering plate is going to restrict vapor from getting to the RC, so more will be going out the valve. This could be a limiting factor when running lots of reflux for neutral.

[Yummyrum]

That crossed my mind too Shady . I guess SMF will be seriously bending those petals down though

[Salt Must Flow]

@ Salt Must Flow

I'm thinking, the centering plate is going to restrict vapor from getting to the RC, so more will be going out the valve. This could be a limiting factor when running lots of reflux for neutral.

Yeah I always place that thing on top of the sight glass, but I drew it up there. It will probably end up where I normally put it. The gate valve controls the take-off rate so it shouldn't make any difference other than perhaps how many turns on the knob vs where that plate is located.

[acfixer69]

I remember this discussion from years ago, over years of use the centering plates were not needed and were too restrictive to be of value. Proper insulation of the packed section did the trick of distributing the returning product thru the media. Energy travels from hot to cold so with the column insulated and retaining heat centering is not needed.

[Salt Must Flow]

I remember this discussion from years ago, over years of use the centering plates were not needed and were too restrictive to be of value. Proper insulation of the packed section did the trick of distributing the returning product thru the media. Energy travels from hot to cold so with the column insulated and retaining heat centering is not needed.

The ONLY purpose of using this plate is to direct the reflux down through the center of the sight glass like a large stream rather than allowing the reflux to run down along the glass. I've been using this plate for years on my 3" VM. It works perfectly, other have used it and zero negative affects. Even at 3000W at full reflux, it functions perfectly. It's not even restrictive like the plates people used to use many years ago.

Centering Plate.jpg

I was just toying with the idea of placing it above the tee rather than below it.

[acfixer69]

I remember this discussion from years ago, over years of use the centering plates were not needed and were too restrictive to be of value. Proper insulation of the packed section did the trick of distributing the returning product thru the media. Energy travels from hot to cold so with the column insulated and retaining heat centering is not needed.

The ONLY purpose of using this plate is to direct the reflux down through the center of the sight glass like a large stream rather than allowing the reflux to run down along the glass. I've been using this plate for years on my 3" VM. It works perfectly, other have used it and zero negative affects. Even at 3000W at full reflux, it functions perfectly. It's not even restrictive like the plates people used to use many years ago.

Centering Plate.jpg


I was just toying with the idea of placing it above the tee rather than below it.

By all means use it. Just know it will slow vapour speed to reflux condenser, if that is not a problem use it.

[shadylane]

The ONLY purpose of using this plate is to direct the reflux down through the center of the sight glass like a large stream rather than allowing the reflux to run down along the glass.

I'm thinking, only passive reflux is going to run down the sides of the RC and sight glass.
Active reflux will drip off the end of the RC coil and fall straight downwards.
Maybe put the sight glass on top with the coil inside of it, so you can see the liquid reflux.
That way the sight glass isn't occupying space that would be better used for packing.

[Salt Must Flow]

This is the best pic I could get of it in use. Works great. Without it, reflux just runs along the glass and it's annoying to look at blurry glass. I very much prefer to see 100% of the reflux pouring straight down through the center of the sight glass.

Centering.jpg

[Salt Must Flow]

The 4" stainless exhaust pipe just arrived! It was very well packaged and not so much as a scratch on them. The description claimed each piece is 47.3", but they're both 47". This will not be a problem. The pipe is definitely NOT too thin. It's plenty thick and a great value for the price. It's not polished at all on the interior, but it doesn't have to be.

4 in Pipe 01.jpg

4 in Pipe 02.jpg

4 in Pipe 03.jpg

4 in Pipe 04.jpg

The polish is so nice that it's hard to get a decent pic. At the moment I intend to use two pieces of this 2" rubber foam pipe insulation and Velcro strap. Unfortunately it's not 'split' insulation. So far I haven't found any 2" 'split' pipe insulation which would make it MUCH easier to install and the seams would mate perfectly. I may have to flatten it securely on a table, slide a marker flat across the table to draw a straight line on the insulation and then I can split it using scissors. So far that's the plan.

[MooseMan]

That tubing could be a great cost effective answer for a lot of people what want to build a 4" column, so you are the pioneer here!

On the insulation, do you have access to a bandsaw? Table saw?
Both would provide a different solution but could make things a little easier and neater.

You could even, if you want to get ingenious, find a short bit of pipe that the foam just fits inside, melt a Stanley blade across one end and "Pull" the foam through to split it.

[Salt Must Flow]

That tubing could be a great cost effective answer for a lot of people what want to build a 4" column, so you are the pioneer here!

On the insulation, do you have access to a bandsaw? Table saw?
Both would provide a different solution but could make things a little easier and neater.

You could even, if you want to get ingenious, find a short bit of pipe that the foam just fits inside, melt a Stanley blade across one end and "Pull" the foam through to split it.

I'm really happy with the pipe. I honestly don't think I'd want it to be any thicker either. It's noticeably heavier than my 3" pipe. This thing will be a BEAST and heavy once fully assembled and filled with 4 gallons of Lava Rock. Imagine the combined weight of the pipe, packing, clamps, sight glass, tee, reflux condenser, elbow and shotgun condenser filled with water!

Wow the thought of using a table saw freaks me out I think it would just tear it apart. That insulation is very flexible, floppy rubber foam like neoprene. Similar but not quite like wet suit material. It isn't at all rigid so you can't push or pull it down a table saw in any straight manor. My though is, as long as I can lay it flat on a flat surface, I should be able to draw a straight line on it. I should be able to cut it along that line easy enough.