Help with fittings please!?

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joshywin
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Thu Aug 23, 2012 11:26 am

So I'm making a pneumatic gun using an old fire extinguisher from the tip/dump. I managed to disassemble it okay but when it came to finding the right fitting, i'm clueless! I measured the diameter and the ID is 28mm. I looked for fittings of the internet and it came up with BSP fittings. I went to a local plumber merchant and he told me it was a metric fitting therefore BSP won't fit. So I searched the internet but I am so confused, I can't find any "28mm metric fittings". If anyone could help me with the situation I'd be grateful. All I'm wanting is something I can screw into the top and attach to some copper pipes. Fire extinguisher model: Annex I Directive 97/23/EC.
Can anyone help, it's only my first proper go at making one and I apologise in advance for my terrible knowledge on the subject.
I'm only 14 :P
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jackssmirkingrevenge
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Thu Aug 23, 2012 11:50 am

joshywin wrote:Fire extinguisher model: Annex I Directive 97/23/EC.
Sounds more like the specs it was made to than the actual model number.
I'm only 14 :P
We could tell by the unnecessary bold text :D

As to your problem, this is some advice I had given in another thread, links might be dead:
Reducer: http://www.ebay.com.au/itm/2PCS-1-2-Mal ... ter-Reduce r-Brass-/250881413920?pt=LH_DefaultDomain_0&hash=item3a69b29320

(make sure the exposed thread is compatible with whatever you want to hook the tank up to!)

Epoxy for setting up the mould: http://www.ebay.com.au/itm/Araldite-AB- ... -minutes-R apid-GIFT-/270682624949?pt=LH_DefaultDomain_0&hash=item3f05f113b5

Epoxy for filling the mould: http://www.ebay.com.au/itm/Loctite-Mari ... ater-Sets- 50min-/250888044070?pt=LH_DefaultDomain_0&hash=item3a6a17be26

This would not be my first choice though, I would be more confident using something like this if you can find it cheaply, perhaps locally: http://www.ebay.com/itm/EPOXY-RESIN-MAR ... H-IMPACT-3 2-OZ-KT-/280255931847?pt=LH_DefaultDomain_0&hash=item41408e25c7
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hectmarr wrote:You have to make many weapons, because this field is long and short life
joshywin
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Thu Aug 23, 2012 1:28 pm

Thankyou, I'll try using the epoxy method.
Roughly what PSI would you estimate the epoxy could handle holding before giving way?
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jackssmirkingrevenge
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Thu Aug 23, 2012 2:14 pm

joshywin wrote:Roughly what PSI would you estimate the epoxy could handle holding before giving way?
If done well with proper epoxy I would trust it to 500 psi or more.

I have to emphasise "if done well" though ;)
hectmarr wrote:You have to make many weapons, because this field is long and short life
K8TOW
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Sat Sep 29, 2012 7:47 pm

i have used a fire extinguisher before and i use a 3/4 black iron from the extinguisher to the sprinkler valve from mcmaster-carr.then i use brass after that.
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