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#Post#: 92555--------------------------------------------------
woud it be a reckless idea to...
DIR By: seriesewan
Date: September 5, 2014, 10:13 am
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use a Co2 fire extinguisher as a source of shielding gas for mig
welding?
are the fitments standard? could i simply unscrew the nozzle &
put a regulator in its place then wire the release handles
together to turn on the gas supply?
#Post#: 92559--------------------------------------------------
Re: woud it be a reckless idea to...
DIR By: Serious Series
Date: September 5, 2014, 1:13 pm
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Hardly worth the effort as it will not hold much CO2.
Net search says they are pressuised to about 850 psi thats about
50 volumes of the internal capacity , normal welding is 4l/m to
12l/m depending on conditions.
Estimate the volume and do the calcs.
Best welding result is usually with an Argon CO2 mix.
There is a hobby company selling cylinders with no rental.
#Post#: 92562--------------------------------------------------
Re: woud it be a reckless idea to...
DIR By: Doug_T
Date: September 5, 2014, 1:45 pm
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I suppose theoretically it would work, but practically?
Well let's just say having seen pictures of what happened when a
CO2 extinguisher got leant on without the safety pin in and the
plastic horn whipped up and mangled the poor chaps face then I'd
probably not be trying it. Sure you might have a reg on it, but
that only puts control on the low side - you're talking of
having the handles squeezed permanently together which gives you
no control on the high side, and 100% of the high side pressure
hitting the reg immediately.
Don't want to sound like a Hi-Vis Nazi, but really it's not a
great plan; trapped pressure really is one of the things you
don't want to mess with. It doesn't take much volume of anything
to cause trouble if there's a lot of psi / bar involved.
#Post#: 92566--------------------------------------------------
Re: woud it be a reckless idea to...
DIR By: nickjaxe
Date: September 5, 2014, 3:19 pm
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Its somthing I have thought about...I use CO2 from a pub gas
bottle...filled to 50 bar or 725 psi...lasts forever...
I have to fit an adapter to my CO2 bottle to be able to fit a
reg...I just use an old oxygen reg...I think the treads maybe
the same size...if you can get it for nowt go for it as long as
you have a reg fitted....
HTML http://www.ebay.co.uk/itm/Single-Stage-2-Gauge-Co2-Mig-Welding-Regulator-With-Adaptor-For-Pub-Gas-Bottles-/161396310002?pt=LH_DefaultDomain_3&hash=item2593f83ff2
or this,
HTML http://www.ebay.co.uk/itm/MIG-Gas-Regulator-Pub-Bottle-C02-Welding-Welder-Female-CO2-Push-Fit-4mm-del-hose-/291107777288?pt=LH_DefaultDomain_3&hash=item43c7602b08
More costly than the adapter I use but I cant see one,
Dont think I would bother with pub types bottle being so cheap
and inexpensive to fill.
Nick.
#Post#: 92567--------------------------------------------------
Re: woud it be a reckless idea to...
DIR By: kev
Date: September 5, 2014, 3:32 pm
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Why not just do it properly, it's cheaper than you think with
rent-free cylinders.
HTML http://www.hobbyweld.co.uk/
#Post#: 92572--------------------------------------------------
Re: woud it be a reckless idea to...
DIR By: GlenAnderson
Date: September 5, 2014, 4:34 pm
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You can rent mini sized bottles from BOC now, £20 a year and £20
a fill iirc. Hobbyweld is fine, but it is supplied at a lower
pressure than BOC, so you need to bear that in mind when
comparing prices.
You can weld using the CO2 from a fire extinguisher. One issue
is that it's not an ideal shielding gas, another is that there
isn't a great deal of gas in them compared to a pub bottle of
the same size, and far less than a proper welding one. The
physical issue is that the outlet of a fire extinguisher is
liquid fed, in other words there's a pipe going down to the
bottom of the cylinder, drawing the contents from the liquid,
rather than gas fed like welding bottles where there's no pipe.
This is because fire extinguishers are designed to be carried
and moved around in use, and the liquid feed gives a constant
performance. This isn't a factor in welding, but it's also the
reason why your welding bottles must be used upright. You may
well find your regulator either won't perform properly or
freezes up on a fire extinguisher if you don't use it with the
bottle upside down. To be honest, unless you can get out of date
CO2 extinguishers free or extremely cheaply it's not worth the
aggro of sorting out adaptors.
#Post#: 92574--------------------------------------------------
Re: woud it be a reckless idea to...
DIR By: Sunny Jim
Date: September 5, 2014, 5:20 pm
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I have had my pub gas bottle for over 30 years now and it is
still half full. You bought the bottle then just paid for
re-fills (if it ever ran out!).
I have a regulator and a heater on it. You will never get such a
neat weld as with the proper Argoshield, but they will be
perfectly strong.
Sunny Jim
#Post#: 92582--------------------------------------------------
Re: woud it be a reckless idea to...
DIR By: nickjaxe
Date: September 6, 2014, 5:00 am
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Hobby weld looks interesting...no prices unfortunately...I like
the NO rent idea...is the deposit refundable????
#Post#: 92603--------------------------------------------------
Re: woud it be a reckless idea to...
DIR By: Richard
Date: September 7, 2014, 10:05 am
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is the deposit refundable?
yes
SH><.
kind regards
I just think shagging that sheep is so irreverant
mind you BOC at £20 a year is quite good it was £100 a year when
I had a bottle!
#Post#: 92605--------------------------------------------------
Re: woud it be a reckless idea to...
DIR By: seriesewan
Date: September 7, 2014, 2:54 pm
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thanks for the advice I think i will leave the fire
extinguishers as they are & look into hobbyweld or renting an
argoshield bottle from boc :)
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