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How do you know you're running low?


#1

Hi all.

I have been reading the Smith vs. Meco thread and now I have a
question. About March I bought a Hoke torch. It was terrible, flame
did not obey the controls, so I sent it back and got a Meco Midget.

It has been so easy to use until lately, the past 2 days it’s gotten
worse. I use propane and oxygen in tanks, a 3-lb propane and 20 sq
ft oxy.

The propane flame has been erratic. It smoothly turns itself down
while I’m using it, then when I re-adjust it, it turns itself up too
high after about a 5 second delay.

I am very careful not to force the valves off (though sometimes I do
tighten them hardish, to make sure they’re off, 'cause that old Hoke
popped a lot and I got into that habit, but just with thumb and one
finger). I swear I am being good.

I was sweat-soldering something last night and the flame shrank,
(the oxy sometimes blows it out) but my first instinct since I’m
concentrating on the work is to get closer to the work. I got closer
and closer and then the flame got wacky and scared me, but I think
this wackiness is just a side effect from holding the torch too
close.

I have my pressure set at the regulators about “2” for oxy and
started at “3” on propane when it was new, and now I set the propane
at about “5”.

Anyway my question is, could I be running low on fuel gas? What
should the 2nd gauges read (I admit I have not paid much attention
to whether they have changed)? I hope it’s something simple like
that.

Please tell me it’s not something serious I have to deal with.

FWIW I do bleed the lines and back off the needle valves at the end
of every work day. The hoses are the standard Meco stiff 12-foot
hoses.

Other than this recent thing, the torch has been a real pleasure. I
have used it about 3 days a week for about 2 months. The tip is the
middle size it came with, and clean as a whistle (I checked it).

I know I sound like a patient at the doctor. What do you doctors
think this could be?

Connie


#2

Connie,

it sounds more like a problem with the regulator than with the
torch. Of course, check whether or not you are not running of either
gas or oxygen first. If that is o.k. check if the nut on top of the
valve did not get loose. If that is o.k. too than it probably the
regulator. There is nothing really in construction of any torch which
can cause that. Wacky flame behavior means wacky supply of either gas
or oxygen. In your post you mention the following:

I have my pressure set at the regulators about "2" for oxy and
started at "3" on propane when it was new, and now I set the
propane at about "5". 

That may your problem right there. It is a very common mistake that
is made. You should not readjust your regulator on daily basis. Set
it once and leave it on that setting. When you done, just shut of at
the tank, do not touch the regulator. The membrane inside is very
finicky and if you re-adjust it all the time, it can begin to
malfunction, which would result in wacky fuel supply, and
consequentially in a wacky flame.


#3

C- somtimes the regulators get whacky i am having some trouble you
described with mine right now not holding the pressures that i set
them at they are about 14 years old and i should most likly take them
in for a rebuild. then not meaning to sound sarcastic here but… i
have seen someone who out of habit was stepping on the hoses or had
them pinched under the wheels of his office chair, oops - g


#4

Hi Connie

I use propane and oxygen in tanks, a 3-lb propane and 20 sq ft oxy. 

Some simple checks to make on your torch handle;

Press on the torch knobs and see if pushing or pulling will cause it
to change. Sometimes the torch will have an o-ring to prevent gas
from going around the shaft the adjustment knob and it could be the
o-ring moving, they do change over time.

If you get to close to your work you will get a pop in the torch
tip, it is because the tip is getting to hot when you move closer,
yes it is scary. You did get flash back arrestors for your setup when
you bought it didn’t you?

Your gauge settings are pretty meaningless unless you say what gauge
set you are using. Yes you could be running out of fuel, but your
setup instructions should have told you how the gauges work and what
to look for. The ones I am familiar with the first gauge right off
the tank is the high pressure gauge and tells the pressure of the
tank, the second gauge of the pair will tell you the pressure being
applied to your torch. If they become equal or even close to equal
you are out of that gas and its time for a refill.

The torch will become erratic if the fuel pressure gets low or the
oxygen pressure gets low, for the shrinking flame, I would say fuel,
if it were oxygen, the flame becomes oxidizing and goes out, usually,
not get smaller.

Hope this helps, if not, let me know what gauge set you are using
and I will look it up.

Terry


#5

Hi Connie,

I just had this exact problem recently with my propane tank. I use
the smith little torch and what you are describing is, to my best
understanding, a problem with the bladder inside the regulator.
There is this diaphram type piece inside that expands or contracts
depending on how much pressure you are turning your regulator valve
to. If this diaphram is stretched or worn then you will not have a
steady pressure. I bought a new regulator as I needed my tank right
away. If you bring the regulator into your local welding supply store
they may be able to fix it or send it out to have it fixed. Most
regulators that run around $80 - $100 will come with a 1 year
warranty. If you have not had your reg. this long then you should be
able to get it replaced through whoever you purchased it from. I
ended up getting a good deal on a new one at $65. It is an
acetylene/oxy reg., but apparently the acetylene/oxy and propane/oxy
regs. are the same. It works great and I have no movement when I turn
my torch on and no pulsing.

As a side note…Is your tank exposed to frequent cycles of warm and
cold?..I’m pretty sure my reg busted because of exposure to our
lovely new england winter weather. I kept the whole set up outside
at night and then brought it in during the day. I think this constant
switch to extreme cold was what busted up the diaphram. I am in a
new studio now and keep my small tanks inside…however there are
regulations for this type of thing. I happen to have a very lenient
landlord in a building with 4 or 5 other studio jewelers.

Another thing to consider (some other orchidian may have more info)
is that your not pressurizing the reg enough. Since you are using a
different torch from my smith little I would think there would be
some difference here…I know when I am using my #7 tip I pressurize
my regs up to 8psi for both my propane and oxy. this is only another
idea though and my experience with torches really only extends to my
smith. I would bet though that you have a busted reg…Good luck.
Hope this helped.

Shauna Gilardi


#6

Leonid,

You should not readjust your regulator on daily basis. Set it once
and leave it on that setting. When you done, just shut of at the
tank, do not touch the regulator. The membrane inside is very
finicky and if you re-adjust it all the time... 

Does this mean re-set it at the same place each time? Because I am
backing off on those needle valves every time I shut down for the
night, as I was instructed to do by the Welding Supply guy who sold
me the tanks and regulators.

He said that if I leave them there, the delicate needles will get
stretched to that place and lose their ability to adjust over time.

When I say needle valves I mean the brass revolving things near the
regulators that rotate to unscrew (back off) and tighten (turn
pressure up). Am I mistaken about this?

Terry Ogden wrote:

The torch will become erratic if the fuel pressure gets low or the
oxygen pressure gets low... 

Terry,

I think that answers my question, because the high pressure gauge on
the oxygen side is definitely lower than when it was new. From
memory, 500 to 1000 psi now. I think I just will need a new tank
pretty soon.

Connie


#7
I just had this exact problem recently with my propane tank. I use
the smith little torch and what you are describing is, to my best
understanding, a problem with the bladder inside the regulator.

I’ve just bought the smith little torch and regulators( last week),
firstly the torch handpiece was faulty - leaked LPG gas- so was
replaced, and now the oxy regulator doesn’t seem to be working. The
gauge that you adjust to ’ 5" by screwing in the handle ( not the
tank pressure gauge) loses pressure sometimes before I get the torch
lit, sometimes while the torch is lit, and when i flush the hose
before putting on the tip during set up. The LPG regulator is not
doing this, it stays steady at 5 once I have set it, whereas the oxy
goes to ‘0’. It also has made noises a couple of times, sounds like
something catching inside the regulator, not very loud. I managed to
solder a couple of things with it, with difficulty, but now can’t get
a steady flame,I don’t think there’s any oxygen getting though. I
have phoned the company I purchased it from and they are trying to
find someone who knows about this sort of thing, then will get back
to me, but i thought I’d ask here, any ideas? does it sound faulty?
is it me?

thanks in advance for any replies, Christine in sth Australia


#8
Does this mean re-set it at the same place each time? Because I am
backing off on those needle valves every time I shut down for the
night, as I was instructed to do by the Welding Supply guy who
sold me the tanks and regulators.

ou are correct. if you turn off the oxygen tank and elave the
preasure where it was last night, every time you turn the tank back
on the preasure SLAMS against the membrane.

Turn off the tank, bleed the line at the torch, turn back the
preasure valve.

next am turn on the tank, and reapply preassure.

be sure you tank is CHAINED to a wall. If it falls over and pops off
the valve it WILL become a missle.

Oxygen supply houses rebuild the valves very reasonable. if you
don’t OWN a spare, buy one and give the old one to the supplier to
rebuild. Always have 2.

David Geller


#9

Connie,

That is exactly what I mean. The regulator should be set once on the
pressure you normally use and left there.

Unless there are some changes to the design of the regulators since
then, do not do what you call “back off the needles”. Set it at the
pressure you want and leave it there.

When brass knob on the regulator is unscrewed, the membrane inside
seals off gas in the tank from the hose.

When you screw the knob in, the membrane under the pressure from the
screw is deflected from it’s normal position to allow some gas in the
hose. The material the membrane is made off is shall not deform just
because it is left in the same position, but if you constantly
re-adjust the knob, the effect is the same when you take a piece of
springy brass and start bending it backward and forward.

Pretty soon you will notice cracks in you brass and if you continue
it will break. That is what happening inside regulator when it
constantly been re-adjusted.

If his statement

He said that if I leave them there, the delicate needles will get
stretched to that place and lose their ability to adjust over time. 

is really true, it means that the regulator is of really inferior
quality. Bring it back and get a professional quality one.

I have been using mine since 1984 and I have absolutely no troubles
with it.


#10

I saw you folks talking about this and wanted to put in my 2 cents…
I had an oxy regulator (one of the cheap ones can’t rememeber the
brand) blow on me in my shop. I used it exclusively for casting. It
was cranked up to about 30 psi. I heard a big pop and then a loud
hiss. I don’t mess around with the pressure much just shut it off at
the tank when not in use. It was about 5 years old. Next regulator I
get will not be one of the cheap ones. It was my luck that it was the
oxy that blew and not the acetelyne. The guy I work with routinely
leaves a pilot on his soldering torch. (not anymore). Just wanted to
throw this in the mix. Gas is one of those dangerous things we do and
while it might feel good to get a regulator for $85 rather than $185,
in the long run it may not be the schmartest thing to do.

Stanley Bright
Owner


#11

OK I have a question I have a regulator tells me feul level there is
no pressure gauge and the helpful instructions of turn it to A or B
there is no A Or B on my tank lol Acetylene air torch prestolite

and I need to get a flashbk for it… THanks for the comment about
in and out of cold.

I am losing my studio and am worried about where I can store the
acetylene at home it would have to be an unheated workshed or an
unheated storage unit rented.

Is this safe? can the tank and regulator take the temperatures?

Just got kiln and everything and now I must be out by Sept 15

I will not give up! I finally got most of my equipment darn it.

I am going to clear out a tiny room at home to do wax work and flask
prep but the kiln and torch will have to be elsewhere for safety
probably a storage unit

Any input appreciated my biggest concern is safety and I will need
it for the kiln and acetylene torch.

Silver & Cameo Heritage Jewelry
www.corneliusspick.com


#12
Does this mean re-set it at the same place each time? Because I am
backing off on those needle valves every time I shut down for the
night, as I was instructed to do by the Welding Supply guy who
sold me the tanks and regulators. 

With all respect to Leonid, I have always heard from myriad sources
that this valve should be released at the end of each day to avoid
wearing out the diaphragm by leaving it stretched.

Noel


#13

This is a slightly different Question:

My wife uses a B tank for acetylene. We typically let the main gauge
go low and then exchange the tank. This time she had let the gauge
really go low and I wondered how much gas was left in the tank. I
used her small tip and bled the tank to near zero and it took about
10 minutes. I changed to the medium tip and went another 5 minutes. I
then changed to a large tip, the needle pegged on zero and we went
for another 5 minutes and then my patients ran out. Wow, much more
left dissolved in the tank than we ever knew. The welding supply guy
had no clue on how much gas could be left in the tank. By the way the
exchange cost me about $42.00. It keep going up!

Charles Friedman DDS
Ventura by the Sea


#14

We all hear different things from different sources. It is always
good to exercise some judgement in evaluating A
diaphragm is made of special alloy which was formulated to resist
deformation from static pressure. If pressure in tank could overcome
modulus of the material and that what will be required to stretch the
diaphragm, then the regulator would simply explode. In any regulator,
the modulus of diaphragm is higher than PSI rating of the regulator,
so the scenario of stretching the diaphragm is physical
impossibility. On the other hand, by backing off at the end of the
day and resetting in the beginning of the next day, causes work
hardening of the diaphragm and eventual and inevitable breakage.

Leonid Surpin


#15

Christine

I make initial adjustments on my gauges, and then open the valve to
finish, they will drop a little between no-flow and flow.

The hum in the gauge is normal, I have seen several that have done
it, but usually on higher flow values.

Overall, the gauge does sound faulty for all the symptoms you
describe, but try setting the pressure with flow from the tip and see
if that works.

Terry


#16

Teri

My dad has his outside or in a covered open shed year round in
Colorado at an elevation of about 5700’, I don’t see a problem, but
we seldom get -30F.

I run my kiln in the garage and I can open the windows when it is
operation, the garage is unheated. As of late, I have moved my
oxy/acet tanks into the house (basement), got tired of moving them
back and forth from the house to the shed, I do not see it as a
problem and I do have flash-back arrestors. They are secured and safe
in in the past where they have been so cold that frost coated the
entire setup to the point I could not read the gauges.

Good luck on relocating. Don’t know what to tell you about A and B.

Terry


#17
Wow, much more left dissolved in the tank than we ever knew. 

While it is true that just because the gauge is at zero doesn’t mean
the tank is necessarily empty, with acetylene, you can’t use all the
gas in the tank. When you get close to the “bottom”, you will be
burning both acetylene and acetone, which the acetylene is dissolved
in (at least, this is how it was explained to me).

In any case, the flame will not be as hot as the same size flame
when the tank is full, and you will think you’ve lost your touch, or
gone crazy. So, when it gets low, refill it.

By the way, this is not the case with propane-- seems to be “good to
the last drop”.

Noel


#18
By the way the exchange cost me about $42.00. It keep going up! 

Check every welding supply source, the largest companies in Denver
are at about $38 for a B tank of acetylene, but at one source it just
went up from $18 to $20.

Richard Hart


#19
With all respect to Leonid, I have always heard from myriad sources
that this valve should be released at the end of each day to avoid
wearing out the diaphragm by leaving it stretched. 

This is the suggested standard practice, to back off the regulator
adjustment handles till they move freely to relive the pressure on
the spring and diaphragm.

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550


#20

Leonid,

Your suggestion of leaving the regulator pressure adjusting screw
engaged is incorrect and a fire and explosion safety hazard. Just
because you have not had a accident from this practice does not make
it safe. It is up to you whether you want to do some research about
this and maybe change your practice. However for your safety and
that of the people around you but I would suggest you do so.

The best source for this safety info is ANSI Z49.1;2005 Safety in
Welding, Cutting, and Allied Processes you can download it here
http://www.aws.org/technical/facts/Z49.1-2005-all.pdf Sections 10.7
and 10.8 cover the correct procedures for attaching regulators to
cylinders and setting up torches.

This is the proper sequence for setting up, lighting and shutting
down an oxy-fuel torch. Always use the following sequence and
technique for lighting a torch:

(1) Open fuel gas cylinder valve (acetylene 1/4 to 1/2 turn.

(2) Open fuel gas torch valve 1/4 turn.

(3) Screw in fuel gas regulator adjusting valve handle to working
pressure.

(4) Turn off the fuel gas torch valve (this will purge the fuel gas
line).

(5) SLOWLY open oxygen cylinder valve all the way.

(6) Open oxygen torch valve 1/4 turn.

(7) Screw in oxygen regulator screw to working pressure.

(8) Turn off oxygen torch valve (this will purge the oxygen line).

(9) Open fuel gas torch valve 1/4 turn and light with lighter.

NOTE Use only friction type lighter or specially designed lighting
device. NEVER use a butane lighter.

(10) Open oxygen torch valve 1/4 turn.

(11) Adjust to desired flame.

Always use the following sequence and technique for shutting off a
torch:

(1) Close fuel gas torch valve first, then the oxygen valve.

(2) Close fuel gas cylinder valve, then oxygen cylinder valve.

(3) Open torch fuel gas and oxygen valves to release pressure in the
regulator and hose.

(4) Back off regulator adjusting valve handle until no spring
tension is left.

(5) Close torch valves.

The buffer maybe the most dangerous tool we use on a personal level
but there is no doubt that the torch is the most potentially
destructive on a large scale. Be safe.

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550