I had an acetylene and acetone leak last week that is puzzling and
disturbing.
For health reasons and inertia I haven’t used my shop in a long time and
used my torch for the first time in ages.
I did some annealing for just a minute using a moderate flame from a
Smith Silversmith with #2 tip. My MC tank is chained upright in a steel
cabinet outside and when I went out to shut it down there was a very
strong smell of acetone or similar solvent with a smell of acetylene
mixed in.
Some time ago I commented on the size of the flame a Silversmith torch
with #4 tip could produce and Sessin Durgham of Rio Grande Technical
support replied that Smith informed him drawing too much fuel too
quickly from an MC tank could lead to ‘instability’. So I stopped using
the #3 and #4 tips. Maybe the #2 is also too large and led to trouble?
Because the tank was outside, I have to wonder how much fuel and acetone
would have leaked without my knowing it had I done a lot of soldering.
‘Outside’ seems to have drawbacks.
Later testing with Safe-D-Tect solution on every connection revealed no
leaks. I did smell some acetylene and perhaps acetone. As I turned the
tank off, the tank pressure gauge went from a little over 50 psi to zero
in about 2 seconds, before I had a chance to go inside and bleed off the
hose. Gauge pressure at the hose stayed at 5 psi. Shouldn’t the tank
pressure have stayed at 50+ until I bled the hose? Is the tank side of
the regulator leaking? Did using too large a tip and ‘instability’ in
the tank damage the regulator?
That leak shook my sense of being in control and safe. I can’t have an
acetylene tank in my garage, no longer trust one outside, so I’m going
to try using a disposable propane tank indoors, where I can smell a leak
right away.
UPS just delivered a Meco Midget and Paige tips. The Meco looks puny
compared to the Silversmith. Can it solder and anneal larger silver
pieces like belt buckles and cuffs?
If the disposable tank isn’t good enough I’ll go to a 5 lb. tank in my
outside cabinet, but with a propane leak detector as well. Has anyone
had experience with those?
Given that you tested the connectors (and hopefully the hose) Sounds to me like your regulator has sprung an internal leak. Take it to your welding supply house and they can either repair or replace it for you.
Where does the acetone come into play?
I am not aware of it’s use in soldering.
Your gauge/ hose should not bleed down at all on shut off of they are working right. As long as all valves from the torch to the tank are snug, no leak should occur. Check gaskets, double check hoses and swedged fittings, and absolutely the regulator.
I have had regulators go bad( they can be rebuilt… Send them out so the liability is on the rebuilder).
I have had swedged fittings fail, with disastrous results , burn back being one.
When I say you should lose no pressure, I mean in the immediate sense, where you can watch it go down.
You can expect a normal pressure loss over hours.
Why are you at 50 lbs pressure? Torch tip/ volume?
Here’s the thing my friend. You can have a hose that is cracked a little
and it is frustrating. Turn on the gas and smell along the line. Somewhere
you have a leak. Doesn’t take much. A little gas smells a lot. All the
hardware is rigid. Lines are susceptible.
It is my understanding that acetylene must be dissolved in acetone or a
similar solvent, not just pressurized like oxygen or propane, so tanks
have acetone in them. It should also not leak out of an upright tank.
Your gauge/ hose should not bleed down at all on shut off of they are
working right.
That’s what I thought. Tank side dropped quickly while hose side kept
its pressure, so I guess the problem is in the regulator.
Why are you at 50 lbs pressure? Torch tip/ volume?
To the best of my knowledge torch / hose pressure should never go over
15 psi. I had it set at 5. The 50+ psi was tank pressure, closer to
empty than full.
Given that you tested the connectors (and hopefully the hose) Sounds to me like your regulator has sprung an internal leak.
I don’t think the problem was on the hose side. It held its pressure,
little that it was. The smell was all at the tank.
With the tank shut down there isn’t much gas on the tank side of the
regulator because of the short distance - maybe 2 inches of brass
tubing? So I can see a small leak bleeding off what little gas is there
quickly.
What really disturbed me was the stench of acetone. That should not be
coming out of a tank that has been upright for a very long time. I was
also spooked by this happening in just a few minutes without my knowing
about it. How much might have leaked out in half an hour? I don’t want
to think about what might happen with a half hour of leaked acetylene.
I will never use a tank outside again without some kind of alarm to warn
of a leak.
I’ll have the regulator checked as you say, and if there is a defect
I’ll get it fixed so there isn’t a bad regulator that looks perfectly
good out there. Or if the cost is not worth it to me I’ll just destroy it.
Do a web search on “plumber acetylene explosion” or view this
Given the shape of the regulating cavity in the regulator it is possible for a little acetone to accumulate there. If the diaphragm springs a leak near the bottom the small amount of acetone would be forced out, and has you know it does not take a lot to smell. The only other possibility I could think of is that most acetylene tanks have a fusible plug in the bottom that will melt out in a fire so that the acetone (with the acetylene) drains out and burns off (Which is better than an exploding tank). Doubtful but examine the tank itself for bad rusting or a leaking plug(in doubt take it to the welding gas supplier and let them examine it.)
Reference exploding tanks…. Look hard enough and you will find examples of every size and type of tank blowing up…… When you put a large amount of potential energy in a confined space, well the risk is always there. Probably the safest of all is a water torch because the potential energy held in it’s system is lowest of all, but it is expensive, especially if you are looking for one to melt wioth.
The Meco with a Paige rosebud gets plenty hot enough to anneal bigger pieces. I’m using a Mecco with Paige tips and a 5lb tank. You may find trying to use the 1lb oxygen tanks will hit your pocketbook hard … they empty a lot faster than the propane tank … been there, done that. Frankly, I find the Silversmith with acetylene more useful for sterling silver because its easier to set up and adjust on the fly. I use the Silversmith 90% of the time, and mostly only use the Mecco for making ingots, fabricating gold or fusing Agentium. I guess its what ever one gets used to … you certainly can use the Mecco with propane and oxygen as your only torch … just have to be a bit more careful with flame control as its a lot hotter than a Silversmith and acetylene … note hotter, not providing more heat. Just because a particular mix of fuel and oxygen get to a higher temp does not mean you are going to be able to put down enough heat to get a particular job done.
The Meco with a Paige rosebud gets plenty hot enough to anneal bigger
pieces.
The website said the rosebud tips should not be used with disposable
tanks. I called Paige. The person I talked with explained that the
smaller one could be used with a full disposable. The problem is that
with a less-full tank and resulting lower pressure the base of the flame
does not project away from the tip enough and heats the tip. She didn’t
say the problem was damage to the tip or just that the user might burn
her / his fingers changing tips. I tried the #5 tip with a fresh
disposable tank and the flame was way too small to anneal with. I tried
the smaller rosebud tip and that seemed really marginal to me. I’m sure
the flame is hot enough - it is just too small to cover a large area.
I’m using a Mecco with Paige tips and a 5lb tank.
I don’t see disposable tanks with fixed low pressure that declines with
use as working for me on larger items. I’m going to put a 5 lb. tank in
the cabinet outside my shop WITH a propane leak detector alarm.
I find the Silversmith with acetylene more useful for sterling silver
because its easier to set up and adjust on the fly. I use the
Silversmith 90% of the time
I used mine almost all the time too. I used an oxy/acetylene Little
Torch when I needed a small flame (I thought the Silversmith 00 tip was
useless). For larger pieces and for annealing I really liked the large
bushy flame of the Silversmith with #2 tip or larger when choked for air
a bit to get a reducing flame.
Right now the REAL problem I face is heating my garage enough (60* or
higher) for my oxygen generator. Warmer than 40* would be nice for me too!
I just took the acetylene regulator to my gas supplier for testing as
you suggested. Younger eyes than mine spotted a cracked nut on the
intake side, right at the regulator body. I must not have used
Safe-D-Tect at that spot.
They said acetone might have gotten to the diaphragm and may have
damaged it, so they are going to open the regulator and check that out.
Good call,
Gas / oxy equip is fundamentally a bomb and you’re always holding the trigger. I watched a oxy tank get dropped, knocked the valve off and went through 2 cinder block walls before it stopped… I also had the pleasure (sic) of blowing up the entire back of my shop in the early 70’s when an employee hooked up a oxy tank to a natural gas meter line that led into the shop for our casting, ( still don’t know how he managed that, lucky he was on the other side of the wall… My insurance co had a cow, but paid…
All scare stories aside, ( well, one more…) I had another employee have a micro torch acetylene line split while the torch was lit. The line had embrittleled ( age?) He had 3rd degree burns & lost the use of his hand for about 6 months while it healed.
If it smells, makes noise or the flame fluctuates… Shut it down, vent the room . You can also get the Gas co. To come out for free ( in California anyway) and check for multiple fuel leaks.
It’s always cheaper to be careful.
Best,
Jim
As far as not using acetylene in your garage, a lot of people have
welding equipment in their garages.
Our insurance guy said no problem.
Short reply, if nothing goes wrong, sure, why not have the tanks handy?
It is a pain to have a tank outside. Go out to turn it on, go in to
work, go out to shut off the gas, go in to bleed the hose, go out to
loosen the T bar.
Longer reply, 3 things.
I have driven for over 50 years. I have never had an accident.
Therefore, I have NEVER needed to wear a seat belt. That’s a fact!
Here’s my take on what happened last week. Preamble. Kids have been
dropping Mentos candy in 2 liter bottles of Coke to cause an almost
instantaneous geyser effect where the entire contents of the bottle
comes spouting out in a second. You can find videos of that online.
Explanation, the Mentos causes CO2 to be released, which drops the
pressure in the soda releasing more CO2, which drops the pressure even
more, in a self-feeding reaction that is almost explosive.
Now if the nut on my acetylene regulator was already cracked I’d have
smelled, and possibly seen and heard the leak of acetylene and acetone
before I was done turning the gas on, and even more likely by the time I
got the hose pressure set. But I didn’t. I don’t think the nut cracked
all by itself since the last time I used the MC tank. I believe that
using a #2 tip drew off too much gas from the small volume of acetone
that was at maybe 32* and it started a ‘Mentos’ reaction causing a drop
in pressure in the tank and a surge of gas coming out of solution, but
not having enough of an escape because the regulator would let only 5
psi out the hose, so pressure then built up enough to crack the nut.
Had the tank been inside my shop chained to my soldering bench pretty
much at my feet, and there was a nice fat flame coming out of the #2
tip, at that point I’d have really really needed to have that seat belt
on, so to speak. The ‘lots of people’ argument wouldn’t have worked for
me in this case.
I thought I was in complete control of my torch / tank setup. Not
quite. Since the tank was out of sight and smell I should have had a
leak detector with alarm in the cabinet with the tank. Also, having
been told one should not use a large tipped Silversmith with an MC tank,
I should have upgraded to a B tank right away, not just stopped using #3
and #4 tips. After reading what Jim said about a fuel hose cracking in
a jeweler’s hand while he was using a torch, I also think regular
maintenance is necessary, specifically replacing hoses after a certain
time, before they can crack and leak.
I have never, ever needed to wear a seat belt, but I always do. I had
an incident with my acetylene tank. Seat belt. Air bag. Careful driving.
Hi Neil,
Ted here in the UK,
Well ,a longish post from you, good too,
theres 3 things
seat belts,
ill comment as I likewise drove for 50 yrs without an accident and not wearing a seat belt, till I met up with the law who said you need to wear one, not because your a good and safe driver ,but to safeguard you from all the idiots on the roads now. Point taken, and now wear a belt for some 10 more yrs. And also use a dash cam. I have to trust my own judgment like you.
Acetylene,
In all the posts so far NO one has mentioned the tech details of cyls or tanks as you call them.
. theres is a max flow rate determined by the cyl size. Your gas supplier must give you the data sheet for the cyl size your using. Its very rare for the acetone to come out and into the regulator. your drawing too much gas per min. Get a bigger cyl.
The A is dissolved in acetone thats then saturated in fullers earth like a damp sponge inside the cyl.
what I dispair of on this forum, all the info you could possibly need to use your chosen technology is there. Just go and get it. you all collectively owe it to yourselves.
Theres no need to use A for just about any jewellers job. Propane and oxygen is a much safer bet .
Reason?
whats called flame rate. A has a very fast one. Thats why even with its low calorific value it will weld steel when propane will not, despite it having a very high calorific value. Mix propane with oxy and youve an ideal flame.
drilling holes, again i dispair of you jewellers, you need the right tool for the job. a normal twist drill is fine in a drill press but freehand? in 1/16thin and smaller, a waste of time. So how many holes do you drill in a day?
if its more than one get a drill press a cheapie from Harbour freight, Hold the work in a engineers drill press vice with cardboard over the steel jaws.
works a treat.
OK, heres a free tip from me to you all, have you heard of a center drill?
look it up . they come from .5mm upwards, the drill part is very short, like 2mm and then up sized to 3mm dia shank.
so easy to use freehand, and they dont skitter about if you center punch your drill register in the metal.
Try it. there cheap enough in HSS.
Happy and safe yule tide.
From
Dorset county
UK.
2 more cents…
And agreement.
I’m a welder by training (came with the jewelry, car, machining stuff).
So gas (multiple) MIG , TIG and Arc are all in my wheel house.
I Never use Acetylene unless it’s on steel (sometimes aluminum).
Map gas, Propane, will do everything, cleaner, better. no ash…
Also,
I have occasions where acetylene will embrittle platinum.
Now, I’m not sure if it was the gas or the alloy, I’ve tried so many… But over the last 10+ years with Map gas /oxy & 5% ru. Pt. no issues.
Probably some more sophisticated metallurgy at play here but That’s the end of these brain cells…
Thanks, Jim
Oh yea… yes to center drills, aircraft supplies have them too.
Hi Jim,
2 things,
Im a flight engineer by training, will explain a bit! ab out my work and tech ethos.
4 RR Griffon’s to care for.
Also have the best Hitatchi 3 phase inverter 300A tig welder, as well as the BOC micro plama unit for titanium.
Re cars, had a comission from the Science museum London to make a series of 5 plaques called the Great Age of Steam.
The Boulton& Watt beam engine, the Burrell Traction engine, the Waverley ship the Stevensons rail engine “rocket” and finally the 1911 Stanley steam car.
There 3in by 2in ovals. Just wondered if your car interests were in the Stanley? Do you have one?
Or maybe a Mercedes? The minting die for this design is another story!
Ted.
One thing that may have been overlooked is the the Smith Acetylene air torch should never be used on an “MC” tank for safety reasons. The smallest tank this torch can safely be used on is a “B” size 40 cubic foot tank. Smaller than that and it can and will draw the acetone up into the regulator and damage the regulator.
Phillip Scott
Technical Support Specialist
Rio Grande
One thing that may have been overlooked is the the Smith Acetylene air torch should never be used on an “MC” tank for safety reasons. The smallest tank this torch can safely be used on is a “B” size 40 cubic foot tank. Smaller than that and it can and will draw the acetone up into the regulator and damage the regulator.
Smith did not provide this information with my Silversmith torch. It
would have been the right thing for them to do.
I did learn of it from a post here on Orchid by Sessin Durgham of Rio
Grande, but assumed that foregoing the #3 and #4 tips would be good
enough. My mistake.
I just checked the Rio Grande web page for the Silversmith kit without
tank and didn’t notice any mention of avoiding the MC tank there. Rio
Grande is doing a very good job of providing information and instruction
on their website. This one piece of information seems to be missing.
Perhaps you could have that corrected. As it stands, those who know it
know it, and those who don’t, don’t.
It used to be that only professionals and those apprenticed to
professionals or taught at a school would buy and use professional
tools, and then only for making a living. These days all kinds of
professional tools are sold to the general public, and the general
public is getting into all kinds of activities they previously did not.
It isn’t a right or wrong issue, it is just the way things have
developed. Safety information such as you mentioned above needs to be
shared with buyers.