MIG Welding Gas from your Cars Exhaust

[mark]

do you guys think this is possible

what with the high price of bottle rental now and the gas and the
surcharge

i thought this may be possible



my car runs on propane

can I suppose, stick a rubber pipe up the exhaust ........have that
going to a vapour seperator.....then into a cheap compressor (who
knows ...a tire inflater maybe capable) ...........then into
bottles .........

how many Min's of hours welding can be/ maybe possibly held in a large-
ish bottle at 120 psi

you may get a slightly shitty weld .but who cares its almost free.

exhaust gas analysis of fuels

Exhaust pipe emissions [g/km]
Autogas (LPG)
Diesel
Petrol

Particulates (PM)
<0.001
0.040
0.001

Nitrogen Oxides (NOx)
0.04
0.40
0.06

Hydrocarbons (HC)
0.05
0.06
0.08

Greenhouse Gas (CO2)....or welding gas :)
170
170
190

Carbon Monoxide
0.3
0.5
0.6


all the best.markj

[David Littlewood]

In article

Post by mark
do you guys think this is possible
what with the high price of bottle rental now and the gas and the
surcharge
i thought this may be possible
my car runs on propane
can I suppose, stick a rubber pipe up the exhaust ........have that
going to a vapour seperator.....then into a cheap compressor (who
knows ...a tire inflater maybe capable) ...........then into
bottles .........
how many Min's of hours welding can be/ maybe possibly held in a large-
ish bottle at 120 psi
you may get a slightly shitty weld .but who cares its almost free.
exhaust gas analysis of fuels

[snipped]

Mark,

What I don't know about welding would fill a very large book, but I do
know something about combustion chemistry.

First of all, most of the exhaust gas would be nitrogen - it represents
about 79% of the air going in (or over 70% of the mixture) and, apart
from a trivial amount converted into NOx, it ain't going anywhere except
out the exhaust. AIUI, MIG welding uses CO2 or argon, the latter being
preferred, and since the latter is several times as expensive as
nitrogen, I deduce there must be a reason nitrogen is not used, probably
as it will form nitrides with some metals and hence local changes in
hardness. If I understand you correctly, you quote the exhaust figures
in g/km; in order to understand what you have got, you really need to
look at the gas concentrations in volume %. That would highlight the
glaring hole which is mostly the nitrogen.

Second, there will be some oxygen in the exhaust, from incomplete
combustion even if the mixture is exactly stoichiometric. This will
obviously be bad news for the weld.

Third, the mixture of water and NOx in the exhaust gas will not do the
inside of your pressure bottle a lot of good.

Fourth, the CO in the exhaust would not do you any good if you were
welding in a confined space. Some would get oxidised in the arc, but not
all.

Sorry to rain on your parade - and give it a go (with suitable
precautions), it might work...

David

[mark]

Post by David Littlewood
In article

Post by mark
do you guys think this is possible
what with the high price of bottle rental now  and the gas and the
surcharge
i thought this may be possible
my car runs on propane
can I suppose, stick a rubber pipe up the exhaust ........have that
going to a vapour seperator.....then into a cheap compressor (who
knows ...a tire inflater maybe capable) ...........then into
bottles .........
how many Min's of hours welding can be/ maybe possibly held in a large-
ish bottle at 120 psi
you may get a slightly shitty weld .but who cares its almost free.
exhaust gas analysis of fuels

[snipped]
Mark,
What I don't know about welding would fill a very large book, but I do
know something about combustion chemistry.
First of all, most of the exhaust gas would be nitrogen - it represents
about 79% of the air going in (or over 70% of the mixture) and, apart
from a trivial amount converted into NOx, it ain't going anywhere except
out the exhaust. AIUI, MIG welding uses CO2 or argon, the latter being
preferred, and since the latter is several times as expensive as
nitrogen, I deduce there must be a reason nitrogen is not used, probably
as it will form nitrides with some metals and hence local changes in
hardness. If I understand you correctly, you quote the exhaust figures
in g/km; in order to understand what you have got, you really need to
look at the gas concentrations in volume %. That would highlight the
glaring hole which is mostly the nitrogen.
Second, there will be some oxygen in the exhaust, from incomplete
combustion even if the mixture is exactly stoichiometric. This will
obviously be bad news for the weld.
Third, the mixture of water and NOx in the exhaust gas will not do the
inside of your pressure bottle a lot of good.
Fourth, the CO in the exhaust would not do you any good if you were
welding in a confined space. Some would get oxidised in the arc, but not
all.
Sorry to rain on your parade - and give it a go (with suitable
precautions), it might work...
David
--
David Littlewood- Hide quoted text -
- Show quoted text -

I was just going on what those results in the table ..said to me ..
co2 there is the dominant gas ...
...so is the table wrong ?

and to get rid of some of the nasties ...i could filter the whole lot
through those carbon granules you get from aquarium shops.

and wasn't planning on doing it in a confined area ..it would be well
ventilated ....more so, than most MOT garages that just have the front
doors open ......

The process of welding gives off lots off CO and other poisonous gases
anyway.

As for the stuff, that could rot the cylinder ...there's not much
sulphur in the gases from an engine run on lpg.......would the carbon
granules filter get rid of what there is left of any potential rust
agent . ?


all the best.markj

[David Littlewood]

In article

Post by mark

Post by David Littlewood
First of all, most of the exhaust gas would be nitrogen - it represents
about 79% of the air going in (or over 70% of the mixture) and, apart
from a trivial amount converted into NOx, it ain't going anywhere except
out the exhaust. AIUI, MIG welding uses CO2 or argon, the latter being
preferred, and since the latter is several times as expensive as
nitrogen, I deduce there must be a reason nitrogen is not used, probably
as it will form nitrides with some metals and hence local changes in
hardness. If I understand you correctly, you quote the exhaust figures
in g/km; in order to understand what you have got, you really need to
look at the gas concentrations in volume %. That would highlight the
glaring hole which is mostly the nitrogen.
- Show quoted text -

I was just going on what those results in the table ..said to me ..
co2 there is the dominant gas ...
...so is the table wrong ?

No (at least I have no reason to think it is), just incomplete - exhaust
analysis is looking at pollutant levels; nitrogen and oxygen are not
considered pollutants. (Though, with bureaucrats who consider stones dug
up from farmers' fields as taxable waste, you never know.)

[snip]

Post by mark
As for the stuff, that could rot the cylinder ...there's not much
sulphur in the gases from an engine run on lpg.......would the carbon
granules filter get rid of what there is left of any potential rust
agent . ?

Well, I was talking about NOx - which with water would produce nitric
acid and other nasties. Yes, carbon granules would probably absorb both
- until exhausted.

You would probably do better making your own CO2 from marble chippings +
acid though.

David

[ravensworth2674]

I'm not going to take issue with the chemists here but CO2 is a pretty
miserable Active gas in the Mig/Mag welding scene.
In my experience, it needs something like Argon to produce a smooth
weld.

There were others who increased their alcohol consumption to get CO2
bottles from their hostelries. The wiggly runs were from the alcohol
but the excess spatter was from the CO2.

All the rest- used ArgoShield

Norm

[p***@yahoo.com]

On Sun, 30 Nov 2008 15:12:56 +0000, David Littlewood

Post by David Littlewood
In article

Post by mark
do you guys think this is possible
what with the high price of bottle rental now and the gas and the
surcharge
i thought this may be possible
my car runs on propane
can I suppose, stick a rubber pipe up the exhaust ........have that
going to a vapour seperator.....then into a cheap compressor (who
knows ...a tire inflater maybe capable) ...........then into
bottles .........
how many Min's of hours welding can be/ maybe possibly held in a large-
ish bottle at 120 psi
you may get a slightly shitty weld .but who cares its almost free.
exhaust gas analysis of fuels

[snipped]
Mark,
What I don't know about welding would fill a very large book, but I do
know something about combustion chemistry.
First of all, most of the exhaust gas would be nitrogen - it represents
about 79% of the air going in (or over 70% of the mixture) and, apart
from a trivial amount converted into NOx, it ain't going anywhere except
out the exhaust. AIUI, MIG welding uses CO2 or argon, the latter being
preferred, and since the latter is several times as expensive as
nitrogen, I deduce there must be a reason nitrogen is not used, probably
as it will form nitrides with some metals and hence local changes in
hardness. If I understand you correctly, you quote the exhaust figures
in g/km; in order to understand what you have got, you really need to
look at the gas concentrations in volume %. That would highlight the
glaring hole which is mostly the nitrogen.
Second, there will be some oxygen in the exhaust, from incomplete
combustion even if the mixture is exactly stoichiometric. This will
obviously be bad news for the weld.
Third, the mixture of water and NOx in the exhaust gas will not do the
inside of your pressure bottle a lot of good.
Fourth, the CO in the exhaust would not do you any good if you were
welding in a confined space. Some would get oxidised in the arc, but not
all.
Sorry to rain on your parade - and give it a go (with suitable
precautions), it might work...
David

Sounds like a NoNo for welding but is it usable as a non
oxydising atmosphere in a small muffle?

[mark]

Post by p***@yahoo.com
On Sun, 30 Nov 2008 15:12:56 +0000, David Littlewood

Post by David Littlewood
In article

Post by mark
do you guys think this is possible
what with the high price of bottle rental now  and the gas and the
surcharge
i thought this may be possible
my car runs on propane
can I suppose, stick a rubber pipe up the exhaust ........have that
going to a vapour seperator.....then into a cheap compressor (who
knows ...a tire inflater maybe capable) ...........then into
bottles .........
how many Min's of hours welding can be/ maybe possibly held in a large-
ish bottle at 120 psi
you may get a slightly shitty weld .but who cares its almost free.
exhaust gas analysis of fuels

[snipped]
Mark,
What I don't know about welding would fill a very large book, but I do
know something about combustion chemistry.
First of all, most of the exhaust gas would be nitrogen - it represents
about 79% of the air going in (or over 70% of the mixture) and, apart
from a trivial amount converted into NOx, it ain't going anywhere except
out the exhaust. AIUI, MIG welding uses CO2 or argon, the latter being
preferred, and since the latter is several times as expensive as
nitrogen, I deduce there must be a reason nitrogen is not used, probably
as it will form nitrides with some metals and hence local changes in
hardness. If I understand you correctly, you quote the exhaust figures
in g/km; in order to understand what you have got, you really need to
look at the gas concentrations in volume %. That would highlight the
glaring hole which is mostly the nitrogen.
Second, there will be some oxygen in the exhaust, from incomplete
combustion even if the mixture is exactly stoichiometric. This will
obviously be bad news for the weld.
Third, the mixture of water and NOx in the exhaust gas will not do the
inside of your pressure bottle a lot of good.
Fourth, the CO in the exhaust would not do you any good if you were
welding in a confined space. Some would get oxidised in the arc, but not
all.
Sorry to rain on your parade - and give it a go (with suitable
precautions), it might work...
David

     Sounds like a NoNo for welding but is it usable as a non
oxydising atmosphere in a small muffle?- Hide quoted text -
- Show quoted text -

I don't know ...
No ones proved otherwise ...it could give good results ..

May be forced to try it when the next rental period is due

Looked up nitrogen and the exhaust gases .......seems that most of the
nitrogen in the air pases strait through the cars combustion process
unharmed unchanged ..
and nitrogen is as much as a semi inert gas as co2...thats according
to what research i could do .

and nitrogen is used as a MIG welding gas ..........particularly as a
a gas to fill tubing that is to be welded .

yes, i would like to carry on using argoshield ...but cant justify the
expense it costs when i only use one bottle a year.

I'm not arguing ..or saying to people.... do it my way ...
I'm just after constructive critisim...........which Ive had so
far .so alls well and good.
I didn't realize that the nitrogen was the dominant gas ....Dave put
me right on this ...and i did a bit more looking on google with that
in mind.

information for all

i don't know if people realize now ...........you cant do unrented
bottle swaps any more...since the new owners of boc's bottle business
(air-liquide) put into place a fool proof system.

so anyone that used to do this is in for a big surprise when or if
they task there bottle to be swapped.

all the best.markj

[ravensworth2674]

'Man in North Wales found in garage with car engine running and
rubber pipe on exhaust'

Just a thought, fellas- just a thought.

I was dying to write that

Norm

[Adrian Godwin]

Post by mark
yes, i would like to carry on using argoshield ...but cant justify the
expense it costs when i only use one bottle a year.
I'm not arguing ..or saying to people.... do it my way ...
I'm just after constructive critisim...........which Ive had so
far .so alls well and good.
I didn't realize that the nitrogen was the dominant gas ....Dave put
me right on this ...and i did a bit more looking on google with that
in mind.
information for all
i don't know if people realize now ...........you cant do unrented
bottle swaps any more...since the new owners of boc's bottle business
(air-liquide) put into place a fool proof system.
so anyone that used to do this is in for a big surprise when or if
they task there bottle to be swapped.
all the best.markj

A friend pointed this company out to me the other day ... anybody used them ?
(See Hobby Welding Gas)

http://www.adamsgas.co.uk/stat_ind_product.aspx?ctrl=argon


-adrian

[mark]

Post by Adrian Godwin

Post by mark
yes, i would like to carry on using argoshield ...but cant justify the
expense it costs when i only use one bottle a year.
I'm not arguing ..or saying to people.... do it my way ...
I'm just after constructive critisim...........which Ive had so
far .so alls well and good.
I didn't realize that the nitrogen was the dominant gas ....Dave put
me right on this ...and i did a bit more looking on google with that
in mind.
information for all
i don't know if people realize now ...........you cant do unrented
bottle swaps any more...since the new owners of boc's bottle business
(air-liquide) put into place a fool proof system.
so anyone that used to do this is in for a big surprise when or if
they task there bottle to be swapped.
all the best.markj

A friend pointed this company out to me the other day ... anybody used them ?
(See Hobby Welding Gas)
http://www.adamsgas.co.uk/stat_ind_product.aspx?ctrl=argon
-adrian- Hide quoted text -
- Show quoted text -

yup, looked into that ..and it works out the even more expensive, i
would use a few of those small bottles a year ...they hold 137 bar and
1.29 M3

where as my boc bottle holds 11.71 m3 at 230 bar

he has his prices on ebay

here

http://cgi.ebay.co.uk/Welding-Gas-CO2-Argon-Mix-9-4L-Rent-Free_W0QQitemZ200282812664QQihZ010QQcategoryZ11774QQssPageNameZWD1VQQrdZ1QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247

all the best.markj

[sparky]

What about letting the car run with the exhaust hose directed to the weld nozzle no tank no regulator just a 2 inches rubber hose near your weld in a well vented area of course

[Austin Shackles]

On or around Sun, 30 Nov 2008 05:38:35 -0800 (PST), mark

Post by mark
exhaust gas analysis of fuels
Exhaust pipe emissions [g/km]
Autogas (LPG)
Diesel
Petrol
Particulates (PM)
<0.001
0.040
0.001
Nitrogen Oxides (NOx)
0.04
0.40
0.06
Hydrocarbons (HC)
0.05
0.06
0.08
Greenhouse Gas (CO2)....or welding gas :)
170
170
190
Carbon Monoxide
0.3
0.5
0.6

where's the hydrogen oxide gone then?