hole in cooler too big for oring seal?

I just got a 70qt Coleman Xtreme cooler(marine version) and I'm getting ready to make my mash tun. When I removed the drain assembly I realized the hole is about an inch in diameter. A 1/2" nipple is real sloppy in there. Do you think an oring will seal my weldless bulkead or will I need to get one of those flat silicone washers. Anyone else have this issue? I was expecting to have to drill that hole out so a nipple would fit, then it would be nice and tight. Just wondering what others suggest. Thanks

I just got some of the flat rubber washers from Lowe's that were the right diameter to cover the hole and still allow the valve to pass through. Making your own tun involves some trial and error

Yeah, the trial and error wouldn't be so bad if I didn't live in BFE. 2 hours to a hardware or grocery store so I do much of my shopping for specialty items online. I make my town trip once every month or two, and if I can't find what I need when I'm there it's too bad jim...I was assuming the washers I use need to be high temp food grade, etc. I was mainly asking to see if others had encountered this same issue and what ended up working for them. With my lag time of ordering and shipping it could be weeks(or worse) before I get it dialed.

I have a similar sized hole on mine. I have a female 1/2" ball valve with a 2" nipple to go through the interface. Inside the cooler I am going from the nipple to a 1/2" FPT copper fitting that's forms into a 1/2" pipe to attach to my manifold.

To get a tight fit I got some food grade gasket material (around 3/32 thick), and three stainless washers. Two of my washers we're 1.5" in diameter, the third was 2" o.d. Add all of them up and I got a great seal. I used the washers and a exacto knife to cut the gasket material. The third washer is to make up the gap.

Sorry no picture but hopefully the description helps. I tried using the original plastic fittings that came with my cooler as gaskets but the continually leaked.

sligo, where did you get the food grade gasket material? All your washers are on the inside? thanks for the tips

jmh286 said:

I just got some of the flat rubber washers from Lowe's that were the right diameter to cover the hole and still allow the valve to pass through. Making your own tun involves some trial and error

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I did that on one of mine as well. I also did one where I simply cut up an old neoprene mouse pad and made my own.

Have any young kids at home? Baby bottle silicone nipples make a great flanged gasket.

Revvy said:

I did that on one of mine as well. I also did one where I simply cut up an old neoprene mouse pad and made my own.

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That is a great idea!

So what I'm understanding here is that it's not necessarily the size of the hole you're trying to seal that matters, but getting good coverage of the hole with the right material.

Yeah, the gasket was the funny one. I got that as scrap from my job. I used two of the washers on the outside, the larger diameter washer was the one resting against the cooler, and just one on the inside. Both inside and outside had gaskets cut to match the washers.

I know on my 50 quart coleman extreme, the 1/2" coupler was quite smaller than the hole. I went ahead and bought a 3/4" coupler which fits quite snuggly in it.

then reduce from 3/4 to 1/2" for the ball valve? or did you get a stainless 3/4 ball valve and reduce at the barb?
thanks

worthogg said:

then reduce from 3/4 to 1/2" for the ball valve? or did you get a stainless 3/4 ball valve and reduce at the barb?
thanks

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I did a 3/4" -> 1/2" barb, no ball valve on the outside since the 50 quart version can't use that because of clearance. You will want to have either 1/2" or 3/8" barb at the end just so you don't have a huge hose.

So you could do 3/4" coupler -> 3/4" ball valve -> (3/4" -> 1/2") barb. Up to you.

Or do a 3/4" coupler -> (3/4" -> 1/2" reducer) -> 1/2" ball valve

Just depends how long you want it

So I just went and found a 3/4" stainless nipple I had laying around from another project. The hole on my cooler is almost exactly the same size as the nipple. I was able to actually thread the nipple right into the the hole. With an oring and washers there's no way this would leak. My only concern is that the o.d. of stainless washers would be so big that I would have to grind the bottoms off in order to clear the bottom of the cooler. Not a big deal I guess. Not thrilled about all the fittings needed to reduce down to 1/2", but if I can find a 3/4" ball valve I'll go the 3/4 to 1/2" barb route on the outside. 3/4 to 1/2" bell inside for my SS screen. This in turn means using 1" PVC I guess as a spacer on the outside. Not sure if this is the route I want to take or not.

anyone have a link to silicone washers that fit over 3/4" nipples?