Thank you for all your comments and suggestions. I’ll try to respond
to all comments and also to provide a couple of points I’ve
discovered in wandering the web.
The internet has info about manufacturing and storing processes for
acetylene. Most acetylene used for welding is manufactured by mixing
calcium carbide and water under controlled conditions. More on that
and how it might affect flame color below.
Acetone and crushed rock are placed in the final storage tanks. Then
the acetylene gas is pumped into the tanks at 300psi; it goes into
solution / dissolves / in the acetone. When acetylene is dissolved in
the acetone it is much less likely to explode. The crushed rock
creates tiny spaces in which any explosion would occur, rather than
having a tank-sized large cavity available for the gas to explode.
Shannon, you commented in your 6/7 post that acetylene will burn
orange-yellow if not properly mixed with air. I agree. The air
intakes on my torch are recessed so they are less likely to become
dirty or blocked. My torches had always burned with a blue flame
until I got these two most recent tanks which have burned orange.
You also commented,
What I really think right now is that the concern is just a new full
acetylene tank and it is a compressed gas and does stratify a bit in
the tank. I’ve had new tanks spit out what I am assuming is acetone.
Burning some of that stuff off may be necessary.
So, based on your comment, I wonder if some tanks are now being
overfilled with acetone? Acetone burns with an orange-yellow flame.
Your suggestion to just burn this stuff off might be a very good
solution to my orange acetylene torch flame.
Atelier Hratch, you commented in your 6/7 post that the age of torch
heads or torch tips might affect the color of the flame. I’m not
sure the torch age would affect the flame. However a dirty brass tube
through the torch handle, or a dirty filter on the torch tip, might
affect the flame.
My torch head has a replaceable rubber tip seat at the top of the
brass tube which goes through the torch head. This rubber tip seat is
just below where the torch tip would screw in. I could not figure out
how to remove this rubber tip seat, so I have not soaked this brass
tube in a cleaning solution overnight. Others have posted in other
Ganoksin threads that they have cleaned this brass tube by soaking it
either in acetone or in their sonic unit overnight.
Each of my torch tips has a replaceable filter just above the screw
threads where the tip attaches to the head. Just above this filter
there is an orifice which narrows down the gas to a thin stream. The
filters need to be replaced regularly; the orifices need to be
removed and cleaned regularly. I had not done these things for my
torch tips, mea culpa.
My Goss torch support person sent me some new filters and one new
orifice for the tip which I had been using most frequently. Changing
the orifice and filter in my most-used tip made the flame steadier.
but it was still orange. I tried each of my tips on the second
"orange flame" tank; some had never been used before so their filters
and orifices were pristine. Each tip still created an orange flame.
This is when I took the tank back to the local shop and exchanged it
for one of theirs which had been on their premises for several years.
That flame burns blue.
Atelier Hratch, in your 6/8 post you commented that the orange flame
seems to burn cooler and to get metal dirtier more quickly as it was
being soldered. I’ve had that experience also. Perhaps, following up
on Shannon Dalton’s idea, acetone doesn’t burn as hot as acetylene.
Al Balmer, you posted on 6/7,
Remembering back to college qualitative analysis, the orange flame
sounds like there’s a sodium compound involved. Not a bad or unusual
thing, sodium is everywhere in trace amounts. However, that doesn’t
explain the temperature difference. Are you certain it’s cooler?
This comment led me in a completely new direction. If there is a
contaminant in acetylene gas, what might it be?
International standards dictate that contaminants in acetylene can
include hydrogen sulfide (max.25%) plus a combination of arsine and
phosphine (max.25%). Hydrogen sulfide burns with a pale blue flame.
Arsine is arsenic hydride; the arsenic in this compound burns a
bright blue. Phosphine has already gained fame as a component of
mustard gas. When it burns it produces a dense white cloud and is a
serious respiratory irritant.
Masks as we work with acetylene torches, anyone? wry grin.
Here I begin to speculate with absolutely no knowledge. very
dangerous! Feel free to comment.
Other unintended contaminants which might wind up in an acetylene
tank might be calcium or sodium.
Calcium (burns with an orange flame): Acetylene for welding is made
by combining calcium carbide with water inside a tank. This produces
a large quantity of acetylene gas and a calcium carbonate slurry.
Calcium carbonate is also known as slaked lime, and is frequently
sold for agricultural purposes. It is also used in a wide range of
other products from cosmetics to animal feed. It does not “burn” in
the traditional sense of the word. When heated, it is transformed
into calcium oxide and carbon dioxide; this transformation releases
extra heat as an orange flame.
My uninformed question: what if some of that calcium carbonate wound
up in the pressurized tanks (fillere) instead of in holding pools?
Sodium - (burns with a pure yellow flame): Internet research led me
to a book written by Chinese chemists called the ChemicalBook,
published in 2016. In this book, the Chinese chemists explain that
applying saturated brine rather than water to the calcium carbide
will slow down the reaction to create “a pure and smooth airflow of
My uninformed question: I don’t believe we are receiving acetylene
from China. But if a US company were to use saturated brine rather
than water to produce acetylene, is there any way sodium might wind
up in an acetylene tank?
At the present time, I have an acetylene tank which burns with a
blue flame. If my next tank burns orange, I’ll be back to square 1.
At this point, Shannon Dalton’s suggestion that the tank may contain
extra acetone seems to be the best possibility offered in this
Thanks again to all for your very thoughtful input,