rwmingis
Well-Known Member
Hi everyone,
After a lot of deliberation, I recently bought one of those Rubbermaid drink coolers and converted it to a Mashtun. (they're hard to find, but I found some at Spacepac Industries in Wollongong, $174.00 pickup) I originally just put a simple bulkhead fitting on it similar to those kewler kitz fittings, but found it let the valve rotate and flex an awful lot. Probably not a big deal, but I didn't like clamping so hard on the plastic cooler (the 174 dollar plastic cooler!) with metal fittings so that it wouldn't flop around. Also, the flexible pickup tube from the false bottom would get pinched when under the grain bed in hot wort which caused me a bit of strife. So I went back to the drawing board and came up with this one. It uses all off the shelf parts that you can easily find at bunnings. The one exception is the 2mm copper plate which I got at A & E metals in Sydney.
Seems to work a treat, with the adjustable pickup, you can have little to no deadspace in the mash tun. With the 2mm copper plate, it creates a very stiff mounting for the bulkhead fitting, which provides a lot more support for the valve. The tabs on the 2mm plate are adjustable to make a better fit. By adjusting the length of the pickup tube, you can actually lock the false bottom between the tabs and the pickup, making a very rigid mounting. For the seals, I just used an idea I got from someone's post on this site where you cut up one of those silicone baking trays to make gaskets. The 1/2" copper tube passes right through the threaded brass hollow rod, which means there is less chance at clogs due to grain bypassing the false bottom at the very beginning of the sparge. The copper tube is soldered at each end of the brass hollow rod using bushes cut from the ends of a 1/2" copper butt fitting (or elbow fitting). The OD of the butt fitting fits perfectly inside the brass hollow rod, and obviously, the ID fits the 1/2" copper tube. Lucky I suppose. The other lucky thing is that elbow at the end of the pickup fits the hole in the false bottom with a half mm annulus, so no grain gets through, but it's still easy to insert. A sectional drawing is below:
You can bend the rigid copper pipe by using a vise and a mapp gas torch. You will also need the mapp gas torch for the silver solder, as lead solder might be a bit dodgy in the acid wort. You can't silver solder using propane, especially connections this big.
As for the tapered flanged nut on the outside of the mash tun, I just put a normal flanged nut on a threaded barbed fitting which would fit in my drill chuck. Once you get it spinning, you can either sand it, or use a dremel tool until you get the right profile for the nut edge so that it fits nicely in the recess on the mash tun. I did actually put a gasket on this nut as well, not for sealing purposes, but to protect the plastic, and create more friction so that the valve won't twist.
The only other thing that I can think of is that the fitting that the valve connects to is a threaded reducer with threads on the outside and the inside. I just drilled the insided out with a 1/2" bit which the copper pipe could then fit through. Everything is then silver soldered together.
This an issue i've given a lot of thought, and figured that it might benefit you all if I shared it. If you need dimenesions or have questions, feel free to email me, or if you make one or find an improvement, I'd love to see it. A full size drawing is attached (pdf)
Cheers,
Rob
View attachment Mash_Tun_Pickup___Bulkhead_Fitting.pdf
After a lot of deliberation, I recently bought one of those Rubbermaid drink coolers and converted it to a Mashtun. (they're hard to find, but I found some at Spacepac Industries in Wollongong, $174.00 pickup) I originally just put a simple bulkhead fitting on it similar to those kewler kitz fittings, but found it let the valve rotate and flex an awful lot. Probably not a big deal, but I didn't like clamping so hard on the plastic cooler (the 174 dollar plastic cooler!) with metal fittings so that it wouldn't flop around. Also, the flexible pickup tube from the false bottom would get pinched when under the grain bed in hot wort which caused me a bit of strife. So I went back to the drawing board and came up with this one. It uses all off the shelf parts that you can easily find at bunnings. The one exception is the 2mm copper plate which I got at A & E metals in Sydney.
Seems to work a treat, with the adjustable pickup, you can have little to no deadspace in the mash tun. With the 2mm copper plate, it creates a very stiff mounting for the bulkhead fitting, which provides a lot more support for the valve. The tabs on the 2mm plate are adjustable to make a better fit. By adjusting the length of the pickup tube, you can actually lock the false bottom between the tabs and the pickup, making a very rigid mounting. For the seals, I just used an idea I got from someone's post on this site where you cut up one of those silicone baking trays to make gaskets. The 1/2" copper tube passes right through the threaded brass hollow rod, which means there is less chance at clogs due to grain bypassing the false bottom at the very beginning of the sparge. The copper tube is soldered at each end of the brass hollow rod using bushes cut from the ends of a 1/2" copper butt fitting (or elbow fitting). The OD of the butt fitting fits perfectly inside the brass hollow rod, and obviously, the ID fits the 1/2" copper tube. Lucky I suppose. The other lucky thing is that elbow at the end of the pickup fits the hole in the false bottom with a half mm annulus, so no grain gets through, but it's still easy to insert. A sectional drawing is below:
You can bend the rigid copper pipe by using a vise and a mapp gas torch. You will also need the mapp gas torch for the silver solder, as lead solder might be a bit dodgy in the acid wort. You can't silver solder using propane, especially connections this big.
As for the tapered flanged nut on the outside of the mash tun, I just put a normal flanged nut on a threaded barbed fitting which would fit in my drill chuck. Once you get it spinning, you can either sand it, or use a dremel tool until you get the right profile for the nut edge so that it fits nicely in the recess on the mash tun. I did actually put a gasket on this nut as well, not for sealing purposes, but to protect the plastic, and create more friction so that the valve won't twist.
The only other thing that I can think of is that the fitting that the valve connects to is a threaded reducer with threads on the outside and the inside. I just drilled the insided out with a 1/2" bit which the copper pipe could then fit through. Everything is then silver soldered together.
This an issue i've given a lot of thought, and figured that it might benefit you all if I shared it. If you need dimenesions or have questions, feel free to email me, or if you make one or find an improvement, I'd love to see it. A full size drawing is attached (pdf)
Cheers,
Rob
View attachment Mash_Tun_Pickup___Bulkhead_Fitting.pdf
