|
Posted by Jack Bauer on August 7, 2007, 10:58 pm
Please log in for more thread options
I have asked this question and seen others ask, but have yet to read an
a answer that seems satisfactory.
If MAPP gas and acetylene have almost the same flame temp, MAPP has more
heat in it, MAPP gas is cheaper and safer to handle, and MAPP gas is
known as being as good or better than acetylene at heating, cutting and
brazing, then WHY, other than availability of the tanks and gas, would
MAPP gas NOT be used for welding? And be highly preferable to acetylene?
I did see someone comment that copper and MAPP gas could be explosive.
Is that true?
|
|
Posted by Grant Erwin on August 7, 2007, 11:14 pm
Please log in for more thread options
Jack Bauer wrote:
> I have asked this question and seen others ask, but have yet to read an
> a answer that seems satisfactory.
>
> If MAPP gas and acetylene have almost the same flame temp, MAPP has more
> heat in it, MAPP gas is cheaper and safer to handle, and MAPP gas is
> known as being as good or better than acetylene at heating, cutting and
> brazing, then WHY, other than availability of the tanks and gas, would
> MAPP gas NOT be used for welding? And be highly preferable to acetylene?
>
> I did see someone comment that copper and MAPP gas could be explosive.
> Is that true?
It's not anything to do with copper and MAPP. It's chemistry. There is a
lot more hydrogen available in the MAPP flame then in the acetylene flame, so
welds done with MAPP (or any other LP derivative) suffer from hydrogen
embrittlement.
Here is the section on fuel gases out of the notes from Ernie's gas welding
class:
Fuel gases:
Acetylene:
made from dripping water on calcium carbide, acetylene used to be user-
generated for everything from toy "carbide cannons" to household gas
installations which had an acetylene generator in an outbuilding,
generally a blockhouse about 100 feet from the main home with 3 walls
made of concrete blocks and the 4th wall (the one that faced away from
the house) made of wood so that if the acetylene exploded, the wood wall
would fail and the blast energy would be directed away from the home.
Acetylene generators were also used in industry and are still around as
quaint period pieces, but insurance practices now dictate that acetylene
production all be done in large plants. The welding gas industry would
love to see acetylene go away entirely because of the astronomical
insurance costs associated with handling it, but it is necessary for
welding as no other gas has its attributes of heat without excessive
amounts of elemental hydrogen being introduced into the weld metal.
very expensive fuel
only fuel gas appropriate for welding steel
Propane/Chemtane/MAPP/Propylene/Flameall: (LP gasses)
not suitable for welding, best choice for heating or cutting
use same regulator as acetylene
propane is a much cheaper gas than acetylene
Grant Erwin
Kirkland, Washington
Seattle Metalheads welding class facilitator
(Ernie Leimkuhler, teacher)
|
|
Posted by Don Young on August 8, 2007, 10:45 pm
Please log in for more thread options
"
> Here is the section on fuel gases out of the notes from Ernie's gas
> welding class:
>
> Fuel gases:
>
> Acetylene:
> made from dripping water on calcium carbide, acetylene used to be
> user-
> generated for everything from toy "carbide cannons" to household gas
> installations which had an acetylene generator in an outbuilding,
> generally a blockhouse about 100 feet from the main home with 3
> walls
> made of concrete blocks and the 4th wall (the one that faced away
> from
> the house) made of wood so that if the acetylene exploded, the wood
> wall
> would fail and the blast energy would be directed away from the
> home.
> (Ernie Leimkuhler, teacher)
One of my memories from about 1940 is of my uncle and cousins removing the
acetylene generator from the basement of a Kansas farm house. There was no
particular blast or fire protection evident. There was no electricity yet
and the gas had not been used for many years but there were still outlets
for acetylene lights in each room. I remember they dumped the generator and
it was full of the same carbide residue I remember my dad removing from a
welding acetylene generator some years later.
Don Young
|
|
Posted by Ernie Leimkuhler on August 8, 2007, 12:20 am
Please log in for more thread options
> I have asked this question and seen others ask, but have yet to read an
> a answer that seems satisfactory.
>
> If MAPP gas and acetylene have almost the same flame temp, MAPP has more
> heat in it, MAPP gas is cheaper and safer to handle, and MAPP gas is
> known as being as good or better than acetylene at heating, cutting and
> brazing, then WHY, other than availability of the tanks and gas, would
> MAPP gas NOT be used for welding? And be highly preferable to acetylene?
>
> I did see someone comment that copper and MAPP gas could be explosive.
> Is that true?
Besides Grant's quote from my seminar you will soon find MAPP
non-existent.
This has to do with one of it's constituent gasses.
MAPP is Methyl-Acetylene Poly-Propylene.
One of the gasses used to make MAPP is Propadiene.
Propadiene is now worth more to the plastics industry than it is to the
welding industry, so MAPP is being phased out.
In Seattle it is almost impossible to get in anything bigger than a
disposable propane torch sized can.
The replacements for MAPP are numerous.
I have used Flamal, Propylene, and Chemtane, and all work fine for
cutting, heating, and brazing.
They are all hotter than basic Propane.
Honestly I gave away my large acetylene tank in my shop 3 years ago, and
have never missed it.
|
|
Posted by Leo Lichtman on August 8, 2007, 3:27 pm
Please log in for more thread options
"Ernie Leimkuhler" wrote: (clip) The replacements for MAPP are numerous. I
have used Flamal, Propylene, and Chemtane, and all work fine for cutting,
heating, and brazing. They are all hotter than basic Propane.
>
> Honestly I gave away my large acetylene tank in my shop 3 years ago, and
> have never missed it.
^^^^^^^^^^^^^^
I'm trying to figure out what this all means. I notice you did not list
welding among the uses for Mapp gas equivalents. Yet you gave away your
large acetylene tank. Do you do all your A/C welding with a smaller tank?
Since I use acetylene for light welding jobs as well as heating and brazing,
and I use medium and small tanks, should I just continue what I am doing?
Can you weld with these other gases? Will they work in the same torches
that are made for acetylene?
Thanx for any info and clarification.
|
| Similar Threads | Posted | | MAPP vs MAP//PRO for welding? | September 5, 2008, 9:18 am |
| gas cutting versus hacksaw | July 2, 2007, 10:37 pm |
| ASME versus EN PQR comparison | October 17, 2007, 6:23 am |
| Lincoln SP series mig welders versus a retail version? | September 27, 2007, 5:09 am |
| Chemistry of acetylene. | March 5, 2008, 10:36 am |
| Oxy-Acetylene Equipment | March 19, 2008, 5:37 pm |
| How long does acetylene last? | March 20, 2008, 1:29 pm |
| Acetylene welding | September 12, 2008, 8:20 am |
| acetylene gauge pulsating | August 27, 2007, 11:40 pm |
| Acetylene to Propane Conversion | August 25, 2007, 10:01 pm |
|
|
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap
> a answer that seems satisfactory.
>
> If MAPP gas and acetylene have almost the same flame temp, MAPP has more
> heat in it, MAPP gas is cheaper and safer to handle, and MAPP gas is
> known as being as good or better than acetylene at heating, cutting and
> brazing, then WHY, other than availability of the tanks and gas, would
> MAPP gas NOT be used for welding? And be highly preferable to acetylene?
>
> I did see someone comment that copper and MAPP gas could be explosive.
> Is that true?