daggermark
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- Jun 30, 2020
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Hey everyone, I'm new here and looking for some advice on how to make my cool-box mash-tun watertight. I've done 3 all-grain batches so far, so pretty much a novice! Hoping this is the right place for my first question...
As the title suggests, I've converted a cooler into a mash tun, and drilled a hole through it for a nipple/ball-valve. But I really struggle to get a proper seal on it. I've watched a bunch of similar conversions and it seems the answer tends to be - stuff loads of ptfe tape round it, which doesn't seem right to me!
Firstly, I guess its worth noting I'm from the UK, so all my fittings are BSP.
I started out with a BSP parallel-thread nipple, as I thought it would be easier to tighten it down to the specific wall-width of my cooler. As you probably know, parallel thread isn't watertight, so you have to stop water entering the thread in the first place. I tried to put a compression coupler on the end of the nipple inside the tun, with a fibre tap washer inside it. Fine - no water entering the thread. The next problem is getting it to seal against the wall of the cooler - I put an o-ring between the coupler and the wall of the tun, but the rim of the coupler isn't wide enough to retain the o-ring, and it deforms when tightening the nut on the outside - leaky tun.
I then tried to put a metal washer between the coupler and the o-ring, to give more surface area. Trouble with that, liquid could get down between the metal washer and the metal coupler, onto the thread, and so once again I have a leak.
So I moved to a barrel-nipple - these are tapered thread, so it doesn't matter if water enters the thread as the nut will always tighten down to form a seal. This was easier on the inside - just tighten a flanged backnut onto the nipple, put an o-ring next to it, easy. But on the outside, its another story. The barrel nipple has to be exactly the right length to get a seal, as far as I can tell. Too short, and you cannot tighten the outer nut enough to prevent back-flow leaks. Too long, and you cannot tighten it enough to pull the o-ring against the inside-wall of the tun.
Any ideas? Is loads of tape really the way forwards?
As the title suggests, I've converted a cooler into a mash tun, and drilled a hole through it for a nipple/ball-valve. But I really struggle to get a proper seal on it. I've watched a bunch of similar conversions and it seems the answer tends to be - stuff loads of ptfe tape round it, which doesn't seem right to me!
Firstly, I guess its worth noting I'm from the UK, so all my fittings are BSP.
I started out with a BSP parallel-thread nipple, as I thought it would be easier to tighten it down to the specific wall-width of my cooler. As you probably know, parallel thread isn't watertight, so you have to stop water entering the thread in the first place. I tried to put a compression coupler on the end of the nipple inside the tun, with a fibre tap washer inside it. Fine - no water entering the thread. The next problem is getting it to seal against the wall of the cooler - I put an o-ring between the coupler and the wall of the tun, but the rim of the coupler isn't wide enough to retain the o-ring, and it deforms when tightening the nut on the outside - leaky tun.
I then tried to put a metal washer between the coupler and the o-ring, to give more surface area. Trouble with that, liquid could get down between the metal washer and the metal coupler, onto the thread, and so once again I have a leak.
So I moved to a barrel-nipple - these are tapered thread, so it doesn't matter if water enters the thread as the nut will always tighten down to form a seal. This was easier on the inside - just tighten a flanged backnut onto the nipple, put an o-ring next to it, easy. But on the outside, its another story. The barrel nipple has to be exactly the right length to get a seal, as far as I can tell. Too short, and you cannot tighten the outer nut enough to prevent back-flow leaks. Too long, and you cannot tighten it enough to pull the o-ring against the inside-wall of the tun.
Any ideas? Is loads of tape really the way forwards?