Pulsing Mini Torch Regulators

Hi Everyone, Just wanted to pass this by to see if others have had the
same problem. We have used the mini torch system and after years of
use, the Acy. regulator started to pulse when the torch handpeice was
lit. We use a 4 tip with the gas pressure at about 4 lbs. So after
bringing the regulators to a repair shop, having them lost and
replaced with brand new Victor SR 6-15 regulators, 6 months later the
gas regulator starts the pulsating thing again. AARGH. I called the
local Smith rep and he visited the shop. His opinion was that the
regulator was designed to hold higher pressure and running it at such
a low pressure was causing the regulator to continually try to shut
off. He is currently locating me the correct regulators to compliment
the handpeice and tip size we use and this should solve the problem.
My question and frustration is that 3 others that do home studio
contract work for us have the same set up (via Rio Grande) and can
most likely anticipate the same problem within time.

When I get the new regulators that are best suited for the minitorch
handpeice I will pass on the info. and the name of my supplier.
Until then, if I can find a moment, I am putting a call into Rio
customer service and see if anyone there has a better answer to my
‘throbbing’ question!!!


I have also had troubles with the regulators pulsing. I talked to
the local welding supply shop and they said it was due to a leaky
diaphragm. Well I had the regulator rebuilt and it worked fine for a
while but the pluses came back. I finally kicked up the pressure to
about 10lbs and the problem went away. The problem is that there in
not enough volume of gas flowing and with a low pressure, when the
regulator allows a little more gas into the system, it changes the
pressure. With the higher line pressure, you get more of a buffering
effect. I expect an accumulator, a secondary gas storage device,
might also smooth out the pulses.

Another point is that I expect it has a bit to do with the pressure
in the tank. Next time you bleed down your torch, watch the
secondary gage on the oxygen. As the tank pressure drops, the line
pressure rises.


I had a similar pulsing problem with a Presto-Lite rig I have for
casting. I thought it was the regulator also but suffered through. The
next bottle of acetylene I used it was even worse and then I started
getting a liquid dripping from the torch and burning like napalm. Very
scary. I called the gas company and they explained that the bottle had
too much acetone in the mix. The acetone is used to dissolve the
acetylene in and hold it in suspension as a gas. Anyway I took the
bottle back and had my regulator checked for damage. Haven’t had the
problem since… Check your acetylene supplier. Frank Goss

I don’t know how it is with acetylene but with propane you need a two
stage regulator since it begins as a liquid and is changing into a
gas. I had the same problem with my propane until I installed a two
stage regulator. Bill


Hello Navran,

> I don't know how it is with acetylene but with propane you need > a two stage regulator since it begins as a liquid and is changing > into a gas. I had the same problem with my propane until I installed > a two stage regulator.

The change from liquid to gas does not make it necessary that you use
a two stage regulator. The important thing it that you keep the tank
right side up on both propane and acetylene. If the tank it not right
side up the liquid will enter the regulator and cause problems.

Since propane is liquid in the tank, the pressure in the tank will
remain relatively stable, unless it gets cold. A propane tank is only
pressurized by the liquid turning to gas. This pressure is only about
100 psi. This effectively does the same thing as the first stage of a
two stage regulator.

Acetylene is a gas that has been absorbed in acetone and a filler
material. I has stored at a higher pressure. Think of it like Coke or
7UP. If you take off the lid it fizzes all over. Granted the pressure
is much higher. But the same thing happens inside the tank when you
open the valve. If you let the gas out too fast, the acetone will come
out with it. The tank size must be large enough to supply the amount
of gas that the torch needs without this happening.

Here is difference between a two stage regulator and a single stage. A
two stage regulator drops the pressure from the tank to a preset
pressure that is above your the intended pressure. For the sake of
argument lets say tank pressure is 2000, the preset first stage drops
it to 120 psi and adjustable second stage drops it to 3-15 psi

A single stage drops it from tank pressure to working pressure in one

The main reason to have a two stage regulator is to solve the
problems that arise when you have a fluctuating tank pressure.
Fluctuating tank pressures can be caused by using multiple torches at
the same time or high consumption.

I hope that I have helped.

Timothy A. Hansen
TAH Handcrafted Jewelry
web-site: www.home.earthlink.net/~tahhandcraft
e-mail: @Timothy_A_Hansen

If the regulator is pulsing it needs to have a new diaphram installed
by a profesional . David