UK: Fuel meter supplies

[Biopyro]

So I've got some free time for once this summer, and I've decided to build another cannon. Nice, reliable advanced combustion. I've secured an offcut of 110mm rated PVC from my favourite supplier, now I just need to sort my meter.
I was thinking,

Gas > hose (attached with jubilee clips) > 15mm BV > tee with gauge > 15mm copper >15mm BV > elbow threaded into chamber wall.

Anyone got any suggestions for it?

The main part I don't like is the tee with gauge will need an adaptor, as the gauge is 1/4" and I can only find 15 x 1/2" x 15 tees. I know this will give me grief, so does anyone know where I can get some simpler parts?

[qwerty]

Do you realy need the gauge? and a good supplier of fittings ect is HIE Plumbing.

[POLAND_SPUD]

yeah, do you really need a gauge ?? most regs come with a gauge... if you are going to use regs for propane then you don't really need a gauge

[spudamine]

He doesn't mention using a reg, maybe planning on using the torch head as a needle valve to slow the flow enough to meter with the BV?
As for the plumbing you could just use BSP ballvalves and galvanised fittings to make the whole meter with no compression joints, BES sell pretty much any galvanised fitting imaginable, including nipples of various lengths, for the meter pipe.

[Biopyro]

Yeah I was planning just to use a torch head instead of a reg, couldn't find anywhere here selling a torch head converter, so I thought I'd do it this way. Is there anywhere to buy an adaptor?

[spudamine]

Yeah I was planning just to use a torch head instead of a reg, couldn't find anywhere here selling a torch head converter, so I thought I'd do it this way. Is there anywhere to buy an adaptor?

I've never seen one in the uk, I just bung a hose on the end, worked to fuel my hybrid.

[Biopyro]

As in blowtorch > hose > reg > BV > etc?

[spudamine]

yes but without the reg. the flow out of the torch head is so low you can just open the BV, wait for the meter to fill to the correct pressure then shut the BV. as long as you make sure that no liquid propane can get to the meter I would trust this over a cheap reg. other bonus is you don't need to chop up/dismantle your torch head so you can keep it for soldering or melting lead or whatever...

[Biopyro]

So you're using a gauge in the meter pipe ala my original plan, or calculating using the vapourization pressure of butane?

[Biopyro]

Ok so now I'm pretty set on trying to capture the rare "tank to BSPT" (British standard pipe thread), but I have a sneaking suspicion my blowtorch may already be threaded, thing is it's really stuck, and I don't want to force it. Is this a glued threaded joint or something tougher?

[SpudBlaster15]

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[Biopyro]

Didn't want to budge, even with heat applied.

Luckily, I have found a gas bottle adapter in the UK
From either here or here

This means I just need a 1\4" needle valve. The plan from there is to use a tyre valve on the cannon, and a female chuck on the meter system so it's detachable.
Good idea? Will i lose a lot to leakage?

Update:
The needle valve was no problem, got it from BES ltd, but turns out that part adapted a blowtorch to a 1/4" thread, not a gas cannister.
Desperate, I ended up buying a blowtorch and attaching it to the system with silicone hose (PVC was leaky crap) and a jubilee clip.
Works a treat since the blowtorch head has diameter 10mm, same as the ID of 10mm hose, and the blowtorch was only about £8 from ebay.