Cooler mash tun leaking bulkhead

[SanPancho]

built 5 gal cooler tun for neighbor. Bought it at HD, red rubbermaid 5 gal. Had a morebeer bulkhead on hand, supposedly the one they use in their cooler tuns.

Their site says to drill it out to 7/8. Tight fit. Bulkhead has to be screwed in thru the cooler walls. We filled it with water, no leaks. Unfortunately after an overnight mash we noticed the cooler had bubbled out the size of an acorn in the rear at bottom.

Bulkead leaked, cooler has liquid in the bottom. Ugh. Pierced the bubble to drain. Disassembled, cleaned, reassembled, filled halfway with water. You can see a couple tiny little bubbles come off the bulkhead. Swapped silicone gaskets. Left washer off. Etc etc.

No luck. no matter what we do it leaks.

Is it the bulkhead? The offbrand “igloo” cooler? Whats the solution on getting these suckers sealed up with no leaks?

 

[IslandLizard]

I use silicone caulk to seal my bulkhead to a rectangular Coleman Xtreme cooler.

The hole and thus the bulkhead is under a slight angle with the side, so it's about impossible to get it to seal perfectly. I put a piece of reinforcing tube inside the hole so I have something solid to tighten the nuts to, but I still get a few drips. The silicone caulk takes care of that. The caulk is in the hole and on the inside between the cooler body and the silicone washer/seal.

I have to redo the silicone job every few years or so, mostly because I can't seem to keep my feet off the valve.

 

[IslandLizard]

Although I use transparent caulk, I wonder if that blue "RTV silicone" is food safe and can be used.

I've only used that RTV stuff once to seal and hold a crankshaft seal in place. A $5 seal, $7 for the tube with RTV silicone, and 3 hours of work to get the crankshaft pulley and timing belt cover off and back on. At least I replaced the timing belt at the same time while I had access.

 

[SanPancho]

I use silicone caulk to seal my bulkhead to a rectangular Coleman Xtreme cooler.

The hole and thus the bulkhead is under a slight angle with the side, so it's about impossible to get it to seal perfectly. I put a piece of reinforcing tube inside the hole so I have something solid to tighten the nuts to, but I still get a few drips. The silicone caulk takes care of that. The caulk is in the hole and on the inside between the cooler body and the silicone washer/seal.

I have to redo the silicone job every few years or so, mostly because I can't seem to keep my feet off the valve.

So the silicone is under your gasket? Does it spin when you tighten it down?

 

[IslandLizard]

So the silicone is under your gasket? Does it spin when you tighten it down?

Yes, it's under the gasket as well as in the hole to prevent any leaking into the foam space.

It does tend to spin when tightening, so just hold on to the valve to keep it all in place while tightening the nut. But don't over tighten it, as it will keep compressing the foam wall more and more. Even after the silicone has all set up, I still have to be careful not to inadvertently rotate the valve/bulkhead assembly at some point. There is a reasonable resistance to rotation, but it's not 100% perfect either. It's been working fine for 5 years like that.

This is when I built it, there is a lot more silicone under and around that red gasket now.

 

[SanPancho]

got it. ordered some silicone from amazon. says food grade and safe to 350F. hopefully i didnt compress the cooler wall too much by tightening it.

the cooler was only like 20 bucks to begin with, might be best to just start over. there was quite a bit of wort that came out when i popped the little bubble.

 

[IslandLizard]

got it. ordered some silicone from amazon. says food grade and safe to 350F. hopefully i didnt compress the cooler wall too much by tightening it.

the cooler was only like 20 bucks to begin with, might be best to just start over. there was quite a bit of wort that came out when i popped the little bubble.

Aquarium grade silicone is food safe. Then again how much exposure is there to the small amount of silicone if it weren't quite?

I think the cooler is fine as is.
You can drill a small weep hole in the bottom to drain off any wort or water that accumulates in the foam space. Store the cooler under a slight angle with a wad of paper towel under it, so it drains out through that weep hole while not in use.

Use some acetone (not nail polish remover, it may have oils in it) to degrease the area where the silicone needs to adhere to. And a little fine sanding there to remove the gloss will give better adhesion too.

If it still feels flimsy and loose, maybe insert a short piece of hard plastic tube in that hole, between the cooler walls, as a spacer. Insert from the outside, and against the inner shell, leaving the hole on the inner shell as is, the same diameter for the bulkhead to go through.
And again, use silicone to keep it in place and seal.

 

[SanPancho]

10-4 on the acetone and the sanding. But not on the pipe insert. Not entirely clear on that part.

 

[Lorne Lemaire]

i would like to suggest you just use a rubber bung drilled to drain hose size stuffed into drain hole inside cooler and outside you could use white plastic hose "pincher" to control flow just like a valve. this works very well and is trouble free.

 

[mkopec1]

The problem with these coolers is they are meant to keep stuff cool, not hot, and are not rated for temps of mashing. So the plastic gets pliable, including the foam insulation, while hot. So the trick I always found in a bulkhead is to use a single continuous threaded coupling of pipe, not the one that is threaded on both sides, if you know what I mean. Then over time You will have to tighten this bulkhead because when the plastic gets pliable while hot, this can come loose (plastic and foam moving). The one thats threaded on both sides, instead of a continuous thread does not allow you as much leeway to tighten when stuff gets loose over time.