Propane regulator has been irregular

I have been having trouble with my Little Torch propane regulator.
The propane regulator has been irregular - The pressure fluctuates up
and down. I have the dial set at 5, however, the dial will go as low
as 2 and as high as 10. I am not sure what is wrong with my
regulator. I am fairly new at this and I’m at a loss of what to do.
Any suggestion from experienced torch users would be much

Thanks You,

Hi Naomi,

It might not be your regulator! My daughter experienced similar to
your described problem.

I caution you to take the following to your supplier of
welding equipment and use it only to form the basis of discussions to
help resolve your issue, Naomi Propane/LPG is very dangerous and you
need to check what I state below with the professionals that supplied
you the equipment. I am telling you this based on our experience with
our equipment which may well be different to yours.

A couple of things to have checked out.

Firstly the hose between the bottle and the hand piece needs regular
cleaning inside. The chemical in the propane (LPG) will contaminant
with the hose and produce residues which will cause irregular flame

Where we purchased our system from explained this to us and sold us
a small bottle fitted with a tight fitting tubular copper pipe gently
bent at 90 degrees, we are then able to squirt Shellite (Lighter
Fluid) down the hose to flush the hose.We removed the propane hose at
both ends then use the Shellite to flush out the hose. Shellite is a
very volatile liquid and needs to fully removed before you connect
the hose back up. Typically we blow at one end to remove any excess
Shellite then depending on the climate let the hose sit for a good
hour or so to allow the reaming Shellite to fully evaporate. Then
reconnect the hose.

Our supplier suggests the cleaning process be done once a week if
you use the system daily. If you only use in say weekly the supplier
suggested the excess Propane/LPG be let bleed from the hose system
and not to have the liquid gas sit in the hose thereby reducing the
contamination in the hose. You might be wondering where this built up
gas I mention comes from. in a system that as a normal bottle and
hand piece where you turn off the Propane/LPG at the bottle there is
no pressurised propane in the hose. In our system we have a safety
valve pressure sensing device fitted to our bottle which when you
turn the main tap off at the Propane/LPG with the safety device
fitted it retains a pressured with Propane/LPG in the hose, this can
take a good minute or 2 to be bleed out after you have turned the
main tap off assuming you have the hand welding valve fully on. More
on this later.

The other cause can be the bleed back valve which is fitted in the
hand piece, these are quite often the culprit. They can be replaced
however our supplier informed us these are a weak link however in a
basic stand system are required to remain fitted for flashback

Now please again seek some professional advise here with your
Propane/LPG welding equipment supplier this is very important and
take what I am about to tell you with extreme caution. Propane/LPG is
dangerous. That said the supplier of our equipment suggested we
remove this bleed back valve which prevents flash backs to the
propaneLPG cylinder, this was only done because our supplier had
fitted a safety device to the LPG cylinder that the hose connects
directly to that prevents the flash back, it also switches off the
LPG to the hose should the hose get damaged and it senses no back
pressure. Our supplier fully explained the dangers of not having the
bleed flashback valve without the special safety device fitted and
asked if we had only the one system so accidentally the hose and
fitting couldn’t be connect to a bottle without the bottle safety
device fitted. Once he confirmed this and was happy that we
understood the issues stated above he happily removed the back bleed
valve to the hand piece. Once these two measured were done then our
flame fluctuations disappeared.

Naomi check with you supplier who will know the rules and safety
regulations in your State and be guided by them… Hopefully the above
comments will help you with your discussions with them to more better
understand the issues you are experiencing and more quickly with
their assistance get them resolved.

Hope this is of some assistance. Have a Heppy New Year!


I have used propane to heat my house and two outbuildings for 34
years, and to fuel my blacksmithing forge, and to fuel my Hoke
torch, since 1991, and have never heard of the need to purge the
piping or hoses weekly or at all with lighter fluid. This sounds
extremely dangerous, especially if the flashback arrestor were
removed at the torch. Taking the arrestor off at the torch leaves the
entire hose or pipe vulnerable. The pressure regulator should be at
the tank. The problem of a wobbly gauge reading sounds as if the
gauge is clogged, and the usual culprit is the teflon tape that some
plumbers use on propane fittings. When a friend and I built our
forges, this stuff gunked up the jets totally. Get rid of it it. Do
not let anyone work on regulators except qualified techs.

all best,
John Neary
blacksmith, welder, jewelrymaker
Tesuque, NM

Hi John,

I agree with your comments. The issue with cleaning the hose
probably relates more to the fact that with flashback arrestor which
is fitted to the cylinder actually holds LPG in the hose unless you
bleed it out everytime you use the system.

This is where the contamination would probably come from. The folks
that we bought the gear from have been in business for 50 years and
are authorised gas agents. They know their stuff. I have a regulator

  • flashback safety device - hose - handpiece (minus the flashback
    arrestor) when you turn the LPG off at the cylinder the flashback
    /safety device retains the LPG pressure that was in the hose at the
    time of switching the LPG off therefore LPG sits in the hose. I am
    getting my daughter who uses the system to bleed out the retained LPG
    after she has turned the gas off at the cylinder.

We are finding that provided you do the bleed off after use the need
to clean the hose with shellite is not really required however from
time to time one forgets to bleed the hose (well that will be my
daughter (-: ) therefore the occasional flush out is required.

If Naomi system has a regulator that has a gauge which is
fluctuating the irregular flame still could be the flashback valve in
the handpiece and the varying amount of back pressure which would
reflect back to the meter gauge and show the fluctuation. Hopefully
Naomi has tracked down a gas hardware expert and her problem sorted.



I’m still doubtful about the need to ‘clean’ the hose.

Just because your gas supplier has been in business for 50 years is
no guarantee that they are correct. Years ago I plumbed a 6 bench
shop with O2/acetylene, maybe a max run of 75 feet. My plan was to
use heavy rubber torch hoses and standard threaded gas tees and
fittings. NO WAY the gas company said, they wouldn’t even sell me the
parts. Had to be copper tube with flared fittings (which was a lot
more work and far harder to get leak proof)

Only problem is that ‘Any contact of acetylene with high-alloyed
copper piping will generate copper acetylide, which is very reactive
and may result in a violent explosion’. Contact type explosive.

No buildings destroyed and no bodies but the gas people were just
plain wrong.

Demand Designs
Analog/Digital Modelling & Goldsmithing

Two days ago I flushed out my propane hose as Ian suggested. It
seemed to have worked, however, when I was soldering last night the
propane regulator started fluctuating again. It did not seem as bad
as it was but it still is fluctuating. I have my studio in the
garage which not insulated. I live in Southern California so it does
not snow but still gets cold at night. I was wondering if the
temperature could have something to do with it?

I also wonder if perhaps I need more pressure on my propane. I have
it set at 5 psi and I also have the oxygen set at 5 psi. Could the
pressure I’m setting it at be a problem?

Someone mentioned plumber’s tape around the propane value. Should I
unscrew the value and see if there is any tape in the way?

If anyone has anymore suggestions, please let me know. In the
meantime I have been trying to find an experience wilder who could
possible help.


I just got a Smith Little Torch for Christmas (actualy before
Christmas as an early present from my husband) with a propane tank.
I’m new to jewelry making and soldering so I don’t know what I’m
doing. After 2 weeks into using my torch (we had a lot of snow here
so I was home bound for 2 weeks with lots of time to practice), my
regulator also became irregular. I set both the propane and oxygen
tanks to 5 psi like the manual says then use the torch with no
problems, but here’s where things go wrong - if I turn off the torch
even for a brief time to say adjust the pieces I’m soldering and
then relight the torch, I’ll get a HUGE flame. Totally freaked me
out! The propane regulator pressure reads way to the end of the dial!
I reread the manuals cover to cover and they do recommend bleeding
the torch before and after use - but just a minute after using
it??? That didn’t seem right to me. Today I called the welding
supply center where I purchased the torch and they said the pressure
on the propane tank, once set should NOT change. They want me to
bring the regulator back so they can send it back to Smith. Hope this


Hi Naomi,

I’ve just discovered that I too have problems with my oxy/propane
set- up when the weather is cold. My tanks are outside when in use
(stored in a detached garage when not in use), with the hoses coming
into the house through the window. The weather has reached -5 degrees
Celcius on a few occasions over Christmas and I found myself unable
to solder due to a lack of pressure. The chap at the gas company said
that this is a problem with both propane and acetylene in cold
weather - and it makes sense.

When condensed into a cylinder, propane is a liquid. It is filled to
such a level as to leave a space above the liquid to allow room for
the liquid propane to evaporate and become propane gas - the propane
liquid is extremely volatile, having a high vapour pressure/low
boiling point, meaning that it is preferentially a gas rather than a
liquid at “normal” temperatures. At higher temperatures the partial
pressure of the gas in the cylinder will be higher than it is at
lower temperatures. By that I mean that at higher temperatures, the
propane will more readily form a gas but it is limited by the
confines of the cylinder (because for the liquid content to
completely form a gas, a very large volume would be needed and it is
simply not available). However, at lower temperatures, the liquid is
less volatile and more of it stays as a liquid rather than forming a
gas and because liquids are more condensed than gases, this tendency
is not as limited by the tank’s size and so it’s possible for a
significantly larger proportion of the propane than normal to be in
liquid form when the temperatures are very low (although the
temperature would have to be minus 42 degrees Celcius for all the gas
to have condensed to a liquid). I found that there was such little
pressure that I thought my propane tank was empty, when in fact it is
still virtually full!

I’m not sure whether or not your regulator is faulty or if it’s just
a case of the cold weather condensing your propane to the extent
that there is just not enough gas pressure. Unfortunately, there’s
nothing that can be done about the cold weather/low pressure problem

  • just solder on a warmer day - but hope that explains it to some



The chap at the gas company said that this is a problem with both
propane and acetylene in cold weather - and it makes sense. 

Don’t believe everything you hear.

While the temperature/pressure bit is true not all propane is the
same. Here in the US ‘propane’ sold in warm places has a lot of
butane (cheaper) in the mix, much lower lower vapour pressure. Cold
places get straight propane. My folks heated a cottage in northern
Vermont with propane even when it was -30 C.

I haven’t tested cold acetylene tanks but I do see a number of
welding company trucks with an O2/acet rig and long hoses. And the
tanks are gorilla sized so I presume they never leave the truck even
in mid winter.

Demand Designs
Analog/Digital Modelling & Goldsmithing

Cold places get straight propane. My folks heated a cottage in
northern Vermont with propane even when it was -30 C. 

What you say makes perfect sense also as it has to get down to -42
for all the propane to become liquid but still, when the temperature
dropped significantly on more than one occasion, I had no useable
pressure from my propane tank so what I said it true to some extent.
My hoses are going to a first floor window though (now I’ve moved my
workshop from downstairs to my own dedicated upstairs room) so the
elevated torch and its need for extra pressure may have something to
do with it also.