Plugging a 1" BSP hole

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chris2012
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Plugging a 1" BSP hole

Post by chris2012 » Wed Mar 06, 2019 7:30 pm

I'm thinking of using:

https://www.bearingboys.co.uk/Hexagon-B ... P1-24892-p
https://www.bearingboys.co.uk/Hexagon-B ... C1-24928-p

But then I'm not sure what to use o-ring wise, I'm looking at:

https://www.bearingboys.co.uk/Imperial- ... 10-43493-p

I'm thinking BSP 1" has a minor diameter of 30.291mm so the 28.30mm of the o-ring might be ok? But that's just a guess.

Is there a relation between the BS o-ring number, and the thread of the pipe you use with it?

Cheers!

Carnot
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Re: Plugging a 1" BSP hole

Post by Carnot » Wed Mar 06, 2019 8:37 pm

Be careful here. Make sure that the flange has an o ring groove otherwise you are likely to find that the ring will squash out. A Groove will trap the o ring in position. The other option, one I have done many times, is to use a Dowty seal, preferably a stainless one.

https://www.ebay.co.uk/itm/DOWTY-BONDED ... ctupt=true

Not cheap but these are about the best that you can get.

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Kev888
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Re: Plugging a 1" BSP hole

Post by Kev888 » Thu Mar 07, 2019 12:33 pm

If the hole truly is 1" BSP (i.e. with 1" BSP female threads) then that plug would work. But they are designed to seal around the threads (such as with PTFE tape or sealing compound) not seal against their flange - so the O-ring etc would't be needed and may not even work.

The flanges on that kind of plug are minimal - just intended for spanners to grip not intended to make an area to seal against. Also, the threads are usually tapered (rather than parallel) intended to get tighter when screwed in - they frequently won't screw in far enough for the flange to butt up to the female part if made accurately (poorer accuracy nuts, such as cheap brass types, can sometimes be sloppier and stand a better chance of allowing it).

By your links though, I wonder if you actually just have a plain hole of some kind, not a threaded/BSP one, and are expecting to use the plug with a back-nut to screw up tight to the vessel wall. If so then for the reasons mentioned it can be a matter of chance as to whether the tapered plug will screw in far enough to pull tight enough; sometimes they will, sometimes they won't. In that case, a plug with parallel threads and wide flange - i.e. designed to work in this way - might be a safer bet, such as this kind of thing:
Image
with a plain or flanged back nut like this:
Image
and some kind of seal such as a silicone washer or dowty type of thing between plug flange and vessel wall.

Those plugs and nuts are available in potable grade brass from most standard plumbing hardware places such as toolststion for a pound or two. I don't recall seeing them in stainless though, they probably exist but it isn't a common way for stainless plumbing to work.
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chris2012
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Re: Plugging a 1" BSP hole

Post by chris2012 » Thu Mar 07, 2019 2:21 pm

Thanks a lot both of you!

It's to plug a hole cut with a 32.5mm hole punch.

That brass fitting looks really good, i'm slightly wary of using brass, in the acidic wort though :(

I'll investigate if there's something similar in SS.

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Kev888
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Re: Plugging a 1" BSP hole

Post by Kev888 » Thu Mar 07, 2019 2:54 pm

Yeah stainless is nicer, though it can still rust in the wrong conditions (which brass never will). There are increasingly plastic plumbing fittings around too, which might be another avenue to look down.

FWIW, brass will normally survive well enough in things like mash tuns and boilers, unless your cleaning potions are too aggressive for it. There's not much of a health concern in this situation either, 'if' it is plumbing brassware intended for UK potable plumbing applications - they don't stick loads of lead and stuff in it (as is often done with general purpose brass).

I tend to avoid using brass in fermenters, though. Partly because of the cleaning & disinfecting potions I use on those, and partly because I'm more wary of of contact with the beer, which is lower pH than the un-fermented wort and in contact for a long time.
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Re: Plugging a 1" BSP hole

Post by chris2012 » Wed Mar 13, 2019 4:19 pm

Being somewhat cheap and wanting to use SS, I decided to take a shot at the blanking plug and cap, and some silicone washers, needless to say I can't seem to get the cap to squish the silicone washer down well at the moment. So I'm wondering, could the following work:

Blanking plug ----> keg -----> silicone washer -----> SS washer ----> blanking cap

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Re: Plugging a 1" BSP hole

Post by chris2012 » Wed Mar 13, 2019 4:37 pm

Just ordered some dowty washers on ebay, and some ss washers, will have a play, and report back!

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Kev888
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Re: Plugging a 1" BSP hole

Post by Kev888 » Wed Mar 13, 2019 6:03 pm

chris2012 wrote:
Wed Mar 13, 2019 4:19 pm
Blanking plug ----> keg -----> silicone washer -----> SS washer ----> blanking cap
EDITED to correct:
If the dowty washer doesn't work on the plug flange then yes, trying it on the other side may have some mileage. Certainly it sounds like you need the extra packing by the stainless washer you mention, to get enough clamping force.

However with the plan above, the silicone washer seals the keg to the stainless washer, which isn't sealed to anything. So you'd likely need to bodge it up with sealant or similar to prevent wort getting between washer and plug threads (that would also be useful in preventing wort getting into any void between plug and cap). That said, if everything is just right then sometimes an O-ring might squidge into the threads enough to avoid the need for sealant at our low pressures. But it needs to all come together unusually well to rely on that.

Another possibility would be for the stainless packing washer to be on the plug side. IF the cap has enough of a ridge for the dowty washer
Last edited by Kev888 on Wed Mar 13, 2019 11:00 pm, edited 1 time in total.
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Re: Plugging a 1" BSP hole

Post by Kev888 » Wed Mar 13, 2019 11:00 pm

(Just to mention I'd mistaken your proposed order of fitting, so have now corrected my last post)
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Re: Plugging a 1" BSP hole

Post by chris2012 » Sun Mar 17, 2019 6:49 pm

Thanks a lot, both of you, works great now!

I ended up doing:

blanking plug --- dowty washer --- keg ----- dowty washer ------ cap

Image
Image

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Re: Plugging a 1" BSP hole

Post by Carnot » Mon Mar 18, 2019 6:21 pm

That looks a nice neat job. I think you made the right choice. Fit and forget.

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