Back to Ganoksin | FAQ | Contact

Acetylene flame color


Recently we changed an acetylene tank in the school I’m involved
with. We have 2 tanks and soldering stations set-up. The flame is
very yellow though still with a blue cone when using the new full

The other tank produces a bluish flame. Thinking something was not
working properly with the hose, handle or torch tip ( everything was
purchased new 1 1/2 years ago) I switched the entire set up (
including regulators) between the 2 tanks. The flame was still
yellow on the new tank. I’m a bit mystified.

Any would be helpful.


The flame is very yellow though still with a blue cone when using
the new full tank. 

Sounds like you’ve got what’s called a “spitter”. This means acetone
is getting or has gotten into the valve and is being sprayed out with
the acetylene gas. Two possible causes. One the tank was not upright
when it was transported. In this case this is a temporary situation.
The other is that there is too much acetone in the tank. In this case
I would return it to the supplier for another tank of acetylene. I
few years ago I had to change suppliers because all the acetylene
tanks I got from them were spitters.

Although you can still use a tank that is a spitter I can imagine
that the acetone is not good for the diaphragm in your regulator.

Rick Copeland
Silversmith and Lapidary Artisan


A yellow flame suggests that the oxygen isnt getting to the torch or
you have contamination of an oil of some sort. Neither is a good
sign. I would be inclined to send the tank back and tell them it is

Nick Royall



i heard that acetylene isn’t as “clean” as oxy/propane. true?

thanks bill g
ps some of my simpler torch work is on


Hi Beth,

Did your tank tip over or get laid on its side? Acetylene tanks are
full of a medium and are filled with acetone to dissolve the gas.
See: (pdf file)

It’s never a good idea to tip them over, and your delivery guys
should know this, but sometimes it happens. A loss of acetone could
explain the flame color.

Hans Rohner


Thank-you both Nick Royall and Rick Copeland for the I
sent one tank back already and when the second tank had the same
issue I started wondering what was going on.

Up in the north country of New Hampshire we don’t have much choice
who we get supplies from. I will talk with them again.

Beth Simon
Littleton Studio School