BOC gas cylinder rental avoidance
George Bray
BOC cylinder rental in the UK. I share some of the contributors'
frustration.
Does anyone know how to 'decant' a gas like nitrogen, CO2 or oxygen
from one of the BOC cylinders into some other vessel? i.e. in order to
return their precious cylinder and thereby stem the expense,
especially if one only uses a little gas every so often.
Would it be possible to use a cylinder like those used for camping
gaz?
Can you purchase a valve which will allow gas to flow into the
cylinder for recharging? Or can these cylinders be recharged through
the existing valve? Pub cylinders might offer another alternative, as
could recovery cylinders used for automobile air conditioning work.
Any other suggestions?
Before anyone starts registering safety concerns, I'm interested in
establishing how it might be done before assessing whether it is
feasible or advisable.
The other problem is the transfer process. Simply connecting two
cyclinders of equal volume together would presumably result in at
least half the gas remaining in the BOC cylinder. It might still be
cheaper to throw away half the gas in order to avoid the extortionate
cylinder rental charges over a long period of several years. Anyway,
perhaps you need a compressor or some other pump in the air line, plus
a pressure gauge to ensure the receiving cylinder was only charged up
to its safe operating limit.
Regards
George
R L Driver
"George Bray" <GeorgeB...@hotmail.com> wrote in message
news:f888ed61.03081...@posting.google.com...
so rusty as they used to be a bottle of argoshield now lasts me about a
year. If I remember correctly I pay about £30 a year for the bottle , and
about 40 for a refill. Ok its not cheap , but its not unreasonable.
My insurance now costs me ( no I've never claimed in 20 years ) about £2000
odd a year , presumably this is to help pay for new houses for you and your
neighbours after you have blown up you entire street. Have you any idea how
reactive pure oxygen is? Have you any idea why the bottles are so heavy ,
it is because the metal is about an inch thick. Bottles are supplied (
depending on product) at about 300 bar, camping gas liquifies at about 10
bar , you are dealing with serious pressure. Please try not to blow or
freeze off all your limbs, or you will no longer be able to use a keyboard.
A suitable candidate for the Darwin Awards her.
steve the grease
Andy Dingley
<sNtOeSv...@ntlworld.com> wrote:
>steve the grease
Hopefully "steve the greaseless", if you're handling oxygen !
As to the hazards of refilling cylinders, even propane:
http://www.tennessean.com/local/archives/03/08/37656667.shtml?Element_ID=37656667
Alex
Bray) wrote:
>I've just read previous postings related to the extremely high cost of
>BOC cylinder rental in the UK. I share some of the contributors'
>frustration.
>
>Does anyone know how to 'decant' a gas like nitrogen, CO2 or oxygen
>from one of the BOC cylinders into some other vessel? i.e. in order to
>return their precious cylinder and thereby stem the expense,
>especially if one only uses a little gas every so often.
>
>Would it be possible to use a cylinder like those used for camping
>gaz?
>Can you purchase a valve which will allow gas to flow into the
>cylinder for recharging? Or can these cylinders be recharged through
>the existing valve? Pub cylinders might offer another alternative, as
>could recovery cylinders used for automobile air conditioning work.
>Any other suggestions?
>
>Before anyone starts registering safety concerns, I'm interested in
>establishing how it might be done before assessing whether it is
>feasible or advisable.
>
It is possible, however you are going to need adaptors, high-pressure
hoses, valves etc etc. You're dealing with pressures up to 4000psi
here, and mistakes are very very dangerous, usually fatal. I have seen
(locally) the result of oxy cylinders going bang, and the result is
not unlike a bomb exploding.
The bottom line - forget it. Pay the rental and get on with it.
Alex
Andrew Todd
> BOC cylinder rental in the UK. I share some of the contributors'
> frustration.
Eh? I pay about £30 PA from BOC which I don't think is too bad.....
Neil
>
>
>
I use pub cylinders. Get friendly with a local landlord, and he will often
just swap the cylinder for as little as a tenner. I also find the half
height cylinders so much easier to move around.
Neil
Iain Miller
> BOC cylinder rental in the UK. I share some of the contributors'
> frustration.
>
> Does anyone know how to 'decant' a gas like nitrogen, CO2 or oxygen
> from one of the BOC cylinders into some other vessel? i.e. in order to
> return their precious cylinder and thereby stem the expense,
> especially if one only uses a little gas every so often.
Have you tried Calor instead of BOC? I've had CO2 bottles from them & there
is no cylinder rental - just turn up & take away a bottle of gas - £13 for a
3.5kg bottle of CO2 IIRC.
Kylie Longstocking
>>Eh? I pay about Ł30 PA from BOC which I don't think is too bad.....
> Sounds like Ł30 per year is cheaper than a funeral?
>
> I use pub cylinders. Get friendly with a local landlord, and he will often
> just swap the cylinder for as little as a tenner. I also find the half
> height cylinders so much easier to move around.
Be careful as pub gas is sometimes a mixture of CO2 and Nitrogen as I
discovered when my welding suddenly started looking like pigeon poo.
I currently buy pure CO2 from a fire protection agent at about 15 quid a
bottle. The only catch is he's very careful about checking the date
stamps on the cylinders. If I take too long finishing one I can get
charged 22 quid to have the cylinder pressure tested and restamped.
But wasn't the thread originally about oxygen?
Neil
> discovered when my welding suddenly started looking like pigeon poo.
> I currently buy pure CO2 from a fire protection agent at about 15 quid a
> bottle. The only catch is he's very careful about checking the date
> stamps on the cylinders. If I take too long finishing one I can get
> charged 22 quid to have the cylinder pressure tested and restamped.
>
> But wasn't the thread originally about oxygen?
>
I thought the thread was about gas cylinder rental originally
" I've just read previous postings related to the extremely high cost of
BOC cylinder rental in the UK. I share some of the contributors'
frustration.
Does anyone know how to 'decant' a gas like nitrogen, CO2 or oxygen
from one of the BOC cylinders into some other vessel? i.e. in order to"
snip
The bottles I get are pure Co2 although the boc ones are, I believe, often
called "argoshield"? and maybe contain someting else pertinant to decent
welding?
Neil
Andy Dingley
<dozyp...@yahoo.co.remove.uk> wrote:
>The bottles I get are pure Co2 although the boc ones are, I believe, often
>called "argoshield"? and maybe contain someting else pertinant to decent
>welding?
Argoshield (or Coogar, if you shop elsewhere) are tri-gas mixes that
are suitable for MIG welding. You can't MIG weld with CO2 and MAGS
welding with it isn't possible on typical home wire-feed equipment.
Kylie Longstocking
> The bottles I get are pure Co2 although the boc ones are, I believe, often
> called "argoshield"? and maybe contain someting else pertinant to decent
> welding?
Uh-oh, I was steering clear of that particular can of worms.
Suffice to say that some folk reckon they can MIG weld decently with
pure CO2, while others insist it isn't possible. I'm happy with the
results I get, but haven't tested them scientifically.
Andy Dingley
<oss108n...@bangor.ac.uk> wrote:
>Suffice to say that some folk reckon they can MIG weld decently with
>pure CO2
By definition, you can't MIG with CO2. At the best, you're using dip
transfer MAGS, which is a different process. Unless you're using a
pulsed supply, you're also unlikely to get a good weld out of it.
Kylie Longstocking
> On Tue, 19 Aug 2003 12:43:34 +0100, Kylie Longstocking
> <oss108n...@bangor.ac.uk> wrote:
>
>>Suffice to say that some folk reckon they can MIG weld decently with
>>pure CO2
>
> By definition, you can't MIG with CO2. At the best, you're using dip
> transfer MAGS, which is a different process.
OK, point taken.
> Unless you're using a
> pulsed supply, you're also unlikely to get a good weld out of it.
It comes down to personal definition of a "good" weld. As I said, some
of us are happy with our results even if it may have taken us longer to
reach the necessary skill level. I've certainly seen worse
"professional" welding.
The question is whether the cost saving is justified in relation to the
extra effort. Personally, I find that it is, but wouldn't necessarily
advise a beginner to struggle along the same route.
TVS
> BOC cylinder rental in the UK. I share some of the contributors'
> frustration.
I've got two bottles from Air Products and have found them cheaper than BOC.
Its worth shoping around. Toby
Restoredclassic
>> BOC cylinder rental in the UK. I share some of the contributors'
>> frustration.
The easiest way to avoid rental is to befriend a local garage and get him to
swop the cylinders for you whenever you need it....The hardest bit is obtaining
the original cylinders.....but that`s not altogether impossible , is it?
R L Driver
"Restoredclassic" <restore...@aol.com> wrote in message
news:20030819175510...@mb-m29.aol.com...
I bet you wouldn't like it if BOC came round and " borrowed" some of your
tools.
steve the grease(less) see above
Andy Dingley
<oss108n...@bangor.ac.uk> wrote:
>It comes down to personal definition of a "good" weld. As I said, some
>of us are happy with our results
This is a shame. If most "amateur" welders swapped their gas, they'd
get much better welds.
And an automatic hat, and some deliberate _practice_ would help even
more. Get a wheelbarrow full of scrap, in pieces no bigger than 6"
square plates. Start welding them together in pairs, and don't stop
until the whole thing is solid. Then throw it away. The idea that
somehow you can take a rusted-out strut mount and fix it properly with
your first-ever weld seems a little odd, when you think about it in
isolation - yet it's how so many people start out.
Kylie Longstocking
> On Tue, 19 Aug 2003 14:25:48 +0100, Kylie Longstocking
> <oss108n...@bangor.ac.uk> wrote:
>
>>It comes down to personal definition of a "good" weld. As I said, some
>>of us are happy with our results
>
> This is a shame. If most "amateur" welders swapped their gas, they'd
> get much better welds.
Ah, but those who have mastered welding rust to rust with the wrong gas
end up as highly skilled welders!
> And an automatic hat, and some deliberate _practice_ would help even
> more. Get a wheelbarrow full of scrap,
Or in layman's terms, a Morris Marina.
> in pieces no bigger than 6"
> square plates. Start welding them together in pairs, and don't stop
> until the whole thing is solid. Then throw it away.
Well yes, but only after driving it around for a year or two.
> The idea that
> somehow you can take a rusted-out strut mount and fix it properly with
> your first-ever weld seems a little odd, when you think about it in
> isolation - yet it's how so many people start out.
True, but the MOT tester is there to see that it's all good and solid.
My point is, that many people get all their practice on old bangers that
really don't matter, before graduating to proper restoration of classics
that do. Or at least, that's how it was in my day...
Chris Bolus
Sorry, explain that to me in more detail Andy?
Most MIG welders seem to be supplied with straight CO2 (in rip-off size
bottles!).
Maybe it's just that I've practiced a lot in welding rust to rust (!),
but I know I can make a really good weld with catering grade CO2 (which
I get from a local gas supplier at £11 a bottle). My standards are high
and I've never had a weld break
--
Regards, Chris (Please take out my car to reply by email)
----1961 Austin A40 Farina----1966 Triumph Herald Estate---
--1969 Riley Elf--1965 Wolseley 16/60--1965 Hillman Minx---
-------1972 Mini Clubman estate------1957 Standard 8-------
---- Website at www.b0lus.com ----
********** Please don't email in HTML! **********
Andy Dingley
<ch...@FARINAb0lus.com> wrote:
>>By definition, you can't MIG with CO2. At the best, you're using dip
>>transfer MAGS, which is a different process. Unless you're using a
>>pulsed supply, you're also unlikely to get a good weld out of it.
>
>Sorry, explain that to me in more detail Andy?
Being a vaguely competent wire-feed welder requires you to understand
the process. It's simple stuff, but if you don't know what it's meant
to do, you'll never know what's going wrong when it does.
There are four ways to get metal from the gun to the workpiece; spray
transfer, dip, globular and pulsed transfer.
Spray transfer is the best. Droplets are melted on the tip of the
wire, "pinched off" by the magnetic field and fly freely across the
gap. The noise is a quiet hissing, because many droplets are in flight
simultaneously. You can only obtain spray transfer by using a high
voltage and (importantly) a high wire speed. This is why you need to
learn on thicker material, with the dials turned right up. Spray
transfer is a hot process, so it's hard to use if you're working
vertically (the pool runs away), but you can usually manage on
aluminium or thick steel, because of the heatsinking effect. Small
machines may not have the power to get into the spray transfer regime
at all. Using CO2 as a shield gas, especially at low voltages, may
also prevent it working.
Dip transfer is used for thin steel, where the heat of spray transfer
would be excessive. The wire feeds, contacts the workpiece and the tip
melts off, breaking the circuit. Repeat. The noise is more staccato
than spray transfer, as you can hear the rapid cycling process.
Penetration isn't as good as spray transfer, so be careful using it
for structural fabrication in vertical runs.
Globular transfer is the most popular process for small amateur
welders, but it's WRONG ! If (especially with CO2) spray transfer
never quite gets going, or dip transfer is cycling too slowly, then
the droplets hang on the end of the wire to form a large blob (bigger
than the wire), then fly off together. This half-cooled blob hits the
workpiece and sticks, but there's inadequate heat in the workpiece and
no penetration. Welds are ugly "pigeon crap" and have no strength.
Pulsed transfer is a solution to globular transfer, without the high
heat of spray, but you need a welder than can pulse the current
rapidly to force droplet formation. These are only found at the high
end.
To weld thin steel well, you need to use dip or pulsed transfer. If
you're welding moderately thin steel (clean 18 gauge) then even a
cheap set ought to run dip with CO2 quite happily. To weld really
thin steel, then you _need_ pulsed transfer.
The tricky bit is where the steel is "a bit on the thin side".
Although you could use CO2, you can equally well use Argoshield. The
margin of error with CO2, where your good dip welds turn into bad
globular welds is that much narrower. A good welder probably slows
down, but a less skilled welder starts to make poor welds.
If you're welding heavy gauges, then you can't use CO2. Full stop.
If you try it, you'll get poor transfer, poor penetration and weak
welds.
>Most MIG welders seem to be supplied with straight CO2 (in rip-off size
>bottles!).
CO2 makes a fine welding gas for thin metal, where you're competent to
do it. You can't say that CO2 is simply _wrong_, as if they'd supplied
a cylinder of nitrogen. It's also cheap.
But CO2 is harder to use than argon or tri-mixes, and it's inflexible
as you can't use it for heavy stuff. Why make things harder for
yourself ?
>and I've never had a weld break
So how do you know they're good welds ? It's a basic technique to do
nick-break tests from time to time, to check that your welds really
are that good.
Welding up rusty old sills isn't rocket science. The stresses are low
(that's the joy of monocoques) and the holes tend to appear in the
least stressed corners. But try repairing a wishbone, or replacing a
chassis leg, and you're into a whole different ballgame.
Chris Bolus
<din...@codesmiths.com> wrote:
>On Wed, 27 Aug 2003 22:58:21 +0100, Chris Bolus
><ch...@FARINAb0lus.com> wrote:
>
>>>By definition, you can't MIG with CO2. At the best, you're using dip
>>>transfer MAGS, which is a different process. Unless you're using a
>>>pulsed supply, you're also unlikely to get a good weld out of it.
>>
>>Sorry, explain that to me in more detail Andy?
>
>Being a vaguely competent wire-feed welder requires you to understand
>the process. It's simple stuff, but if you don't know what it's meant
>to do, you'll never know what's going wrong when it does.
>
>There are four ways to get metal from the gun to the workpiece; spray
>transfer, dip, globular and pulsed transfer.
>
<snipped good stuff>
Thanks for that, now I know what you meant. I was in fact taught welding
as a factory apprentice, but it didn't run to MIG (well it was 20 years
ago!), so I do know something of the theory & techniques, just not MIG.
I do now! I was taught by guys who weld pressure vessels!
>If you're welding heavy gauges, then you can't use CO2. Full stop.
>If you try it, you'll get poor transfer, poor penetration and weak
>welds.
For heavy stuff I drag out the old faithful stick welder!
>
>But CO2 is harder to use than argon or tri-mixes, and it's inflexible
>as you can't use it for heavy stuff. Why make things harder for
>yourself ?
Maybe it's just what I'm used to, but when I ran out on a Sunday and my
wife bought one of those little bottles of argoshield I found it more
difficult.
>
>
>>and I've never had a weld break
>
>So how do you know they're good welds ? It's a basic technique to do
>nick-break tests from time to time, to check that your welds really
>are that good.
By reference to the times when I've had to undo my welds. They _are_
strong!
>
>Welding up rusty old sills isn't rocket science. The stresses are low
>(that's the joy of monocoques) and the holes tend to appear in the
>least stressed corners. But try repairing a wishbone, or replacing a
>chassis leg, and you're into a whole different ballgame.
I did the chassis sections on my old LandCruiser (sitting under the
jacked-up back end). That was too heavy for my little MIG to cope and I
stick-welded it.
I have a "soapbox" that won competitions for three years, all welded up
out of 25mm and 20mm box sections. A downhill course in a field puts
huge stresses on the structure. Nothing ever broke - well not the welds
anyway. I bent the back wheels and ended up fitting caravan wheels to a
welded-up axle.