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Fridge compressor help

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Fridge compressor help

Unread postAuthor: Dave_424 » Sun Dec 14, 2008 11:23 am

hey guys, I have decided to build a fridge compressor and have a few questions

1. Will a normal quick connect hold the pressures? I had thought it would as long as it isn't used to hold back the pressure, just to connect to cannon

2. What size fitting will fit on the pipes from the compressor?

and 3. How long roughly would it take to fill a 2.2cm x 100cm chamber to 300 psi?

Thanks Dave
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Unread postAuthor: POLAND_SPUD » Sun Dec 14, 2008 11:45 am

1. yeah it should hold the pressure.. mine is rated to 35 bar but I have to use a ballvalve to release the pressure before disconecting (as the pressure rise it's harder to disconnect/connect...)

2. I use 1/2" malleable iron and brass fittings... I have 2 Ts joined thoghether with a pressure gauge, BV used to relief pressure and a quick connect fitting...

the part that joins the fittings with the compressor is made from two 1/2" male-female adapters with a rubber seal in between... as I thighthen them the seal 'wrapps' around the air outlet... I hope you know what I mean... it's basically a homemade compression fitting... it works surprisingly well

3. it depends on your compressor.. each model might have different power and output... mine would do it in about 2.5 minutes
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Unread postAuthor: Dave_424 » Sun Dec 14, 2008 1:38 pm

ok thanks

do you think that a 6mm or 8mm compression (I live in the UK so it is metric) fitting, really cranked down would be sufficient.

Do you know what size the pipes are, which would be closer 8mm or 6mm?

Thanks Dave
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Unread postAuthor: john bunsenburner » Sun Dec 14, 2008 1:42 pm

Why not solder it, cheeper and more relyable, from what i know compression fittings are hard to make air tight, oh and : YAY I AM NOT ALONE IN USING METRIC!!!
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Unread postAuthor: Dave_424 » Sun Dec 14, 2008 1:54 pm

yeah that had crossed my mind, but I don't have any soldering equipment which will cost me about £30.

Compression fittings are EASY to get air tight, just wrap and olive (or fennel i think it is called in other places) with some teflon tape (PTFE tape in the UK) and then crank down the nut.

has worked every time for me, even if it leaks just tighten it more. Never failed.

My question still stands, what fitting would be closer, 8mm or 6mm?

Dave
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Unread postAuthor: john bunsenburner » Sun Dec 14, 2008 2:26 pm

It depends on you compressor, or do you think they ar all the same, come on use common sense... Get a ruler or another way to mesure and do it your self. We are all happy to help but noth with something you can easyly do your self while we cannot!

Gettign back to soldering: I have noticed soldering tools are really useful, even thoug my right hand is covered in burns(im practising) it is really useful. I made a aluminium piston and i made a triggering system for hammer valve(this includes the hammer valve). It is much cheeper in the long run and i have found good soldering torches for around 10CHF(20pounds). These things are ussually life time investments unlike compression fittings.
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Unread postAuthor: Dave_424 » Sun Dec 14, 2008 2:44 pm

well yeah, of course i don't think they are all the same
I havent got the compressor yet and was wondering what I would need to order

no need to flame at me, there is logic in my madness :P

Dave
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Unread postAuthor: john bunsenburner » Sun Dec 14, 2008 4:10 pm

im not flaming at all just a little critisism. I would not really go out and buy a compressor unless you have to(like her ein switzerland) go to a dump or a fride repair shop and ask, or ask relatives and friends anything from an AC to a freezer works... Once you have it messure it and then onc eit is up and running then you can be proud you made it your self.

I bet there is more logic in your madness than in mine so be proud(i heated a copper rod this morrning then i put it down and when i picked it up i forgot what part was heated, it hurt pretty bad(after all 900°C is no fun)).
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Unread postAuthor: POLAND_SPUD » Sun Dec 14, 2008 4:44 pm

6 or 8 mm who knows - it depends entirely on the size of copper pipes on that particular compressor you'll get.... my homemade 'compression fitting' works just fine you might try it yourself
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Unread postAuthor: Dave_424 » Sun Dec 14, 2008 5:56 pm

ok guys, sorry i might have seen the bottom of my pint glass too many times

Ok i get it, i will try to pick up a compressor from either some friends or go to the dump.

will keep you posted on my progress.

Dave
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