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.