Air Tight Connection Between John Guest Adaptor And CO2 Reg

[ChrisA]

I am using a John Guest female adaptor (3/8" OD tube X 3/8" BSP - part number PI451213S) to connect the gas tubing to my regulator however I am concerned about leaks due to the regs male thread being to short to connect with the rubber seal. As you can see in the photo below the bottom of the adaptor hits the brass nut before reaching the rubber washer inside the adaptor.





I initially went round the local plumbing merchants and DIY shops looking for an identical washer to the John Guest one and was planning to stack multiples, however the closest match I could get was an O ring. (Left is the John Guest washer and right is the O ring)



I thought that this would sort the problem but unfortunately when I tighten the adaptor the O ring curls and drops into the center of the reg tube. I then tried to cut down a couple of larger washers but these had the same problem



The only other idea I have had is to shorten the adaptor by cutting off 3-4mm but I don’t have a vice or angle grinder so I am at a bit of a loss.

Whatever the solution I will always be using lots of PTFE tape to wrap around the tread but wondered what everyone else was doing to get a tight seal at the join?

Cheers Chris

[jaroporter]

what reg are you using? i messed around for ages with the same issue with the common parweld welding regs. finally convinced myself that it did actually just mate with the washer (i think). PTFE is designed for tapered threads, not parallel/washer connections so i'm not sure if that helps.. pretty sure mine doesn't leak, have you tightened it fully and tested it?

[ChrisA]

Sounds like we have the same regulator http://www.parweld.co.uk/product/regula ... gauge-co2/



No I haven't tested it yet but have wet the end of the reg and then tightened the adaptor fully and then unscrewed but the washer is still dry so i know its not connecting. My other cause for concern is that I am able to hand tighten it so over time could see this causing a problem.

Did you need a spanner to tighten yours?

[Wonkydonkey]

Apart from using Ptfe, which would do the job in most cases. The only other drastic action would be to cut a bit of the JG fitting off. So as to shorten the thread a bit.. If you see what I mean

[ChrisA]

Do you have a similar setup @WonkeyDonkey? What did you end up doing?

Did you need a spanner to tighten yours? Is it possible to get different thicknesses of PTFE as I have wrapped loads round it and it is still not ultra tight.

[jaroporter]

yeah that's the one. think i may have given a slight tweak with a spanner but wanted to be careful as it's plastic. your water test sounds like there's a fair gap though..

[deanrpwaacs]

I have been looking at keg set up . Isnt there an adapter to go onto the co2 reg then you fit the john guest fitting ?

[ChrisA]

I have been doing a lot of googling and haven't came across one yet.

I was hoping that someone had found one and could recommend a compatible component?

[Dave S]

get yourself a little table clamp vice and cut a bit off the JG with a junior hack saw.

[Wonkydonkey]

I have been looking at keg set up . Isnt there an adapter to go onto the co2 reg then you fit the john guest fitting ?

Yeh that's what I got.

[jaroporter]

mine isn't here with me so i can't check exactly what i did, but in the absence of a better plan i'd be tempted to forget sealing with the washer and use maybe a couple of turns PTFE (just a couple of turns) to pull it in tight. then test it with the gas.. mine is tight and doesn't leak. though hacking a bit off the end may actually be that 'better plan'..

be interested to see about this adaptor, never heard it mentioned before.. ?

[Wonkydonkey]

The long reply is, I brought a reg off ebay and brought a few adapters, 1 fitted and noot that long ago it fell over and broke... I improvised with another fitting I had... While I got another fitting, but I got what you got and could see the same probs,. So I have left it as it is, it's not broke anymore... So I won't fix it just yet, but when I do I will cut off the end and... That's so the seal meets before the end meets. Which is what I was suggesting. And there is the gas Ptfe which is thicker. It's yellow container, as the White is for other stuff and thinner.. But with the gas type "less is more" well to much is to much.
This is what I had. I think it was 1/4, but don't quote me on it. I brought 3/8 2nd time and was wrong


It was a swivel adaptor which can be made up from an elbo and a threaded straight conector.

[ChrisA]

As I don't have a work bench I have just ordered some of the thicker gas PTFE online and will test it. Hopefully this will work but failing that I will resort to buying a bench and shortening it.

@WonkeyDonkey how may wraps of the thicker tape would you recommend? Two?

If in the meantime anyone could post a photo and some details about a connector that would be appreciated?

[ChrisA]

Thanks for all your help guys!

[Wonkydonkey]

I just measured the thread on the adaptor that I used to replace the broken one, in the above pic it's 12.2mm. I guess you can work it out from there. But I think you can easly mod your conector just with a bit of coarse sand /Emory paper, going around and around. Or a small hacksaw, 5mm off the end is more than enough , more like 3mm thou.

Edit:Gas Ptfe, 1 and a bit but not more than tow layers, as it ends up choo-ing it up