50 Litre Thermo Pot Mashtun conversion

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Eclipse9101
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50 Litre Thermo Pot Mashtun conversion

Post by Eclipse9101 » Thu Jan 21, 2016 1:05 pm

Thought I would put up a few pictures of my recent mash tun build to help any fellow brewers out incase anyone has a build planned for the future.

Parts Used:

50 litre thermo pot from bergland
thermo pot bottom drain kit from brewbuilder
ptfe tape
51mm starrett tct holesaw
angle grinder with SS cutting disc
dremmell
3, 6 and 11mm cobalt drill bits
21mm qmax cutter


I started out by marking the centre point from inside the pot. I then drilled a 3mm pilot hole from the inside of the pot through both skins. After checking both holes lined up vertically I cut a 51mm hole in the outer skin from underneath the pot. The starrett cutter made easy work of this. I would recommend these to anyone thinking of doing a conversion like this!

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Note - I didn't use any cutting oil or water, just metal on metal. A few short bursts and careful pressure and the drill was through in seconds.

after carefully removing the insulation i drilled a 6, followed by an 11mm hole back through the inside skin.

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Next, after carefully measuring up where I wanted the ball valve on the front of the tun I drilled another 51mm hole with the starrett cutter. This time it was as close to the bottom lip as i could get. Directly inline with where the tap was going to be fitted.

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I had to actually cut down the pilot drill bit which is part of the starrett tct cutter. This was so I could drill the 51mm hole in the outer skin without the pilot drill doing through the inner skin!

I then layed out my length of stainless threaded pipe which would connect the ball valve to the elbow fitting on the underside of the pot. I lined this up exactly where It needed to be and proceeded to mark it either side and cut with the angle grinder.

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Then I used the dremmel with a standard cutting disc to carefully cut out a section of the lip from the inner edge. I then measured up where the ball valve would need to be mounted in order for it to be in line with the 90 degree elbow on the underside. I then used the qmax cutter to punch out the 21mm hole in the outer bottom rim.

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I then punched out the inner centre hole with the qmax and checked the fittings. The elbow would not quite fit in as the outer hole was slightly too small. So I used the dremmel to carefully cut 2 small sections away between the circle edge and the channel where the tube would be.

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I now proceeded to dry fit everything together to check it fitted properly. Unfortunately the deck drain fitting was a few threads too long to screw all the way into the elbow under the tun. I screwed 2 hex nuts onto it leaving about 3 threads exposed, clamped it in a vice and used the angle grinder to cut off the excess threads. When I removed the 2 hex nuts this cleaned up the end of the threads nicely:thumb:

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And finally all fitted!

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Update:
Instead of udibg the spacer washer I decided to grind the inner threads out of a 1/2" hex nut. This is now used like a washer and sits up against the pot with the ball valve screwed up tightly against it. I prefer the look of this to a big washer :D



Hopefully this helps a few people out!

I would also like to say a big thank you to everyone who helped me and gave me some sound advice along the way.
Attachments
IMG-20160121-WA0024.jpeg
IMG-20160121-WA0029.jpeg
IMG-20160121-WA0031.jpeg
IMG_20160121_184845.jpg
Hex nut with threads ground out
Last edited by Eclipse9101 on Sun Jan 24, 2016 5:13 pm, edited 2 times in total.

Haydnexport
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Re: 50 Litre Thermo Pot Mashtun conversion

Post by Haydnexport » Thu Jan 21, 2016 6:33 pm

Thanks for the great pictures, i'm planning on a thermo hlt and a thermo mash tun in the near future , both 80l , what false bottom are you going for?

Eclipse9101
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Re: 50 Litre Thermo Pot Mashtun conversion

Post by Eclipse9101 » Thu Jan 21, 2016 9:41 pm

Haydnexport wrote:Thanks for the great pictures, i'm planning on a thermo hlt and a thermo mash tun in the near future , both 80l , what false bottom are you going for?
I went for the brewbuilder false bottom. I have just fitted the 3 piece ball valve tap tonight aswell. I decided to grind the threads out of a 1/2" bsp hex nut with a dremmel. Then used this as a spacer washer between the tun wall and the ball valve. Lots of PTFE tape on the threads. The ball valve only screwed on about 2turns but its solid. Have leak tested again and everything looks good!

beatts

Re: 50 Litre Thermo Pot Mashtun conversion

Post by beatts » Fri Oct 07, 2016 3:45 pm

Hi,
How did you tighten the elbow onto the Deck seal fitting?

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barneey
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Re: 50 Litre Thermo Pot Mashtun conversion

Post by barneey » Fri Oct 07, 2016 5:41 pm

As the op hasn't visited the forum for over 2months, I thought I could answer the question for him.

There are 2 internal lugs with in the deck fitting, find something to jam in-between these & simply screw the fitting into the elbow.

It is also possible to conceal all the pipework.

ciderhead
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Re: 50 Litre Thermo Pot Mashtun conversion

Post by ciderhead » Sat Oct 15, 2016 9:26 pm

big screwdriver will do it and get extra torque with vice grips or adjustable spanner on the blade of the screwdriver

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Rogermort
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Re: 50 Litre Thermo Pot Mashtun conversion

Post by Rogermort » Tue Oct 18, 2016 1:33 pm

Has anybody worked out how to fit a temperature probe into one of these and if so, whereabouts to best fit it? Or do most users simply trap a flexible lead under the lid when sealing it down with the clamps?

brew like a dog

Re: 50 Litre Thermo Pot Mashtun conversion

Post by brew like a dog » Thu Oct 27, 2016 5:55 pm

I have just converted my 50 litre thermopot to a mash tun using your method above. Your method works well. Many thanks :)
Last edited by brew like a dog on Fri Feb 17, 2017 1:07 am, edited 1 time in total.

brew like a dog

Re: 50 Litre Thermo Pot Mashtun conversion

Post by brew like a dog » Fri Nov 04, 2016 2:39 am

beatts wrote:Hi,
How did you tighten the elbow onto the Deck seal fitting?
I used a 'stainless steel multi purpose plumbing tool' :)

Fil
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Re: 50 Litre Thermo Pot Mashtun conversion

Post by Fil » Sat Nov 05, 2016 5:01 am

Rogermort wrote:Has anybody worked out how to fit a temperature probe into one of these and if so, whereabouts to best fit it? Or do most users simply trap a flexible lead under the lid when sealing it down with the clamps?
fwiw for my thermopot FV i dropped a long SS thermowell through the lid along with the hex coil..

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for my mash tun i simply close the lid over the probe lead ;)
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ist update for months n months..
Fermnting: not a lot..
Conditioning: nowt
Maturing: Challenger smash, and a kit lager
Drinking: dry one minikeg left in the store
Coming Soon Lots planned for the near future nowt for the immediate :(

braindead
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Re: 50 Litre Thermo Pot Mashtun conversion

Post by braindead » Tue Jan 31, 2017 11:30 am

How much did the tools for this conversion cost you.
My thermo is coming on Friday
I have the basic drill and grinder.
Just talking about the
51mm starrett tct holesaw
SS cutting disc
3, 6 and 11mm cobalt drill bits
21mm qmax cutter

ciderhead
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50 Litre Thermo Pot Mashtun conversion

Post by ciderhead » Tue Jan 31, 2017 1:24 pm

When drilling I found a punch from a nail creates an accurate location to stop a drill bit sliding around, I would also recommend some kind of lubrication, I use water or a few squirts with lubricating oil to stop stainless hardening, big pressure low drill speed also works best

Fil
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Re: 50 Litre Thermo Pot Mashtun conversion

Post by Fil » Tue Jan 31, 2017 2:55 pm

with the uber thin skins in a thermopot be prepared to puncture the skin with a nail/screw.. fwiw i use an old cross head jewelers screwdriver with the intention of puncturing the skins, its the initial puncture that wears down drill bits. so a sharp knock to puncture the skin is helpful.

standard jobber hss drill bits are fine to use, but invest a fiver in a tube of cutting grease, a wee dab on the drill point is sufficient to let a cheap hss drill bit slice through much thicker SS ;) and step up the hole size .. stepped drill bits are great upto 12-12mm diameter after which they can catch and shift the work piece dangerously if not securely clamped in place.
If the drill is not slicing through easily pulse the trigger rather than just drilling on and risking overheating the work point.

imho no need to be too careful about the thermopot base skin, no one will ever see it, I used a dc rotary hand tool to chop mine ;) For minimising deadspace with a forward tip perhaps consider an off centre/front mounted bottom drain ,cheaper too ;).

if your using a full sized thru the hull skin fitting for the drain hole an angle grinder with a thin SS cutting disk is Very useful to chop a few inches off the length, However for fine tuning the length a belt sander is the tool needed, fwiw i had to grind down with the belt sander both the skin fitting and the elbow into which it threaded. leaving 2-3 thread turns only on the skin fitting.

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after belt sanding a small file is useful to open up the start of the thread, and remove the thin trailing remnant of the last thread removed. Then working the piece in and out of a another fitting to set the thread opening/start.

ebay a few M20 ss washers as you may need to bulk out the extension of tube/nipple extending thru the base rim..

enjoy the build ;)
ist update for months n months..
Fermnting: not a lot..
Conditioning: nowt
Maturing: Challenger smash, and a kit lager
Drinking: dry one minikeg left in the store
Coming Soon Lots planned for the near future nowt for the immediate :(

braindead
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Posts: 5
Joined: Mon Jan 30, 2017 6:44 pm

Re: 50 Litre Thermo Pot Mashtun conversion

Post by braindead » Sun Feb 05, 2017 12:27 pm

Does anyone have the tools for cutting lying around and not in use. I see other forums share the tools but the Op disappeared.
Thanks

brew like a dog

Re: 50 Litre Thermo Pot Mashtun conversion

Post by brew like a dog » Thu Feb 09, 2017 2:44 am

braindead wrote:Does anyone have the tools for cutting lying around and not in use. I see other forums share the tools but the Op disappeared.
Thanks
The cost of the tools does add to the cost of the conversion.

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