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Setting up an oxy-acetylene torch


#1

Hello. I have tried searching the archives because I’m sure this
topic has been covered before. But, I haven’t been able to find the
exact I need.

I have just set up my new Meco Midget torch with a 20 lb oxygen tank
and an acetylene B tank. I have a splitter on my acetylyne (one hose
for my Smith Silversmith torch and one for the Meco). I know I"m
supposed to open and light the acetylene first and then add oxy til
the flame is neutral. but, I have not been able to find information
on what pressure the gauges on the regulators should read. I know the
acetylene should be between 3-5 but what about the oxy? All the info
on line that I find seems to be referring to welding and cutting and
I don’t know if the info is the same for the jewelry application. Any
links or info you can supply would be greatly appreciated!! Thanks!
~Stacey


#2

I have here amongst my vast collection of lovely tools and equipment
a 1950’s varnished beech wood boxed set of the small BOC oxy/acet
torch and nozzell set.

In the lid is a label that says the following

  1. the nozzell sizes relate to the cub ft per hour of each gas used
    in average conditions from 1 to 25.

  2. the gas pressure for each nozzell size starts at 2psi up to 9 psi
    for the biggest…

  3. this is for welding steel from up to 20 g nozzell 1, to 5/16th in
    steel for nozzell 25.

Then they go on to say for the same thickness in copper use a bigger
tip and for aluminium a smaller one.

Also the tip size varies depending on the mass of the metal being
joined.

So, in your case as both oxy and acet gas are the same here as with
you, your regulator pressures are set to the same pressure. qed.

you will find that as acet has whats called a high flame rate as
opposed to propane or butane with very slow flame rates if your
pressures are to low for the nozzell it will back fire into the
torch. This is to be avoided. Your torch and gas suppiers are really
responsible for giving you the hazmat papers on your gases, torches
etc.

Chase them up.
Ted.


#3

Stacey. There should be a lot of on Orchid that is both
specific and general in nature to your question. Others may have
advice different from what I am about to give you. That is the neat
thing about Orchid. I too am a Meco Midget user and have been for
about five years. It is now my favorite torch. That being said, it
did not start out that way.

When I bought it, it came with generic one hole tips that were very
difficult to light. My first piece of advice is to buy a set of
Paige Tool tips. Talk to Richard, he is a lot of help and you won’t
regret the cost.

You might struggle with the original tips first to appreciate the
Paige tips. I too started on acetylene and O2. I set the regulators
to something around 5 PSI for both and then adjusted as needed for
what I was doing.

Having used single stage acetylene on a Presto-Lite torch for 35
years, I had several acetylene tanks, so I just need to buy an O2
tank. If you stay with this setup, don’t forget check valves and
flashback protectors. The mess that acetylene made in my shop drove
me to try propane. I did and never turned back. Make sure that your
tips are for propane. Again, Paige tips. So now I had a 20 lb propane
tank, medium size O2 tank, hoses, regulators, check valves, flash
back protectors all connected to my Meco.

With propane and Paige tips, I was finally in business and happy
with the torch. There was one problem. I work in my cellar and I had
two bombs sitting next to me. My insurance people were OK with this,
but I set out to see if I could reduce the potential for disaster. I
researched natural gas and air, propane and air, natural gas
accumulators, O2 concentrators, glass working torches, light weight
hoses, non-adjustable propane regulators, refilling 1 lb. propane
tanks and much more. My Meco has now evolved to the following. Meco
torch with an extended tube, Paige tips, light weight hose from TM
Technologies (you won’t regret it), 1 lb. camp stove propane tank
with a $60 non-adjustable regulator (these can be refilled from my 5
lb.

propane tank), O2 concentrator and that’s it. I now have a 5 lb and
20 lb propane tank, 2 O2 tanks, four regulators, hoses, check valves,
flashback protectors, a complete Presto-Lite torch and various
fittings all in storage. The Meco setup that I describe above allows
me to do everything that I need to do to include 2 oz. melts. You can
go to my website and click on More, then Shop Shots, then Pictures to
see what this setup looks like. You will note that I Y off with both
the Meco and a Little Torch sharing both propane and O2. I rarely use
the Little Torch, but appreciate it when I need it. You will also see
an EZ Torch on 1 lb. propane. I use this for annealing. I hope this
helps and good luck. Rob


#4

Hi Stacey,

When setting the regulators for your torch you usually use around the
same pressure for fuel and oxygen. I use a Smiths little torch and I
set both regulators to about 5 psi which suffices for all my tips.
Sometimes I crank the pressure up a touch when using the rosebud and
#7 tip. In my case I use propane for fuel but the principle is the
same with acetylene. Open the fuel first and light. You will get a
luminous, and in the case of acetylene, smoky flame. Slowly open the
oxygen to get the flame so that there is a slightly ragged edge to
the inner cone. You will probably have to tweak things a little to
get the flame stabilised. If when you open the oxygen valve and the
flame snuffs out then the oxygen pressure may be too high.

This can be a particular problem when using smaller tips. To
extinguish the torch turn off the fuel and then the oxygen. It is
vital that you have flashback arrestors fitted to both regulators.
Fairly soon you will develop a feel for your torch and adjustment
will become almost instinctive.

Make some lovely jewellery.
Jen


#5

Stacey,

I didn’t find a chart for the Meco tips, either, but the Smith Little
torchrecommends the same pressure for the acetylene and the oxygen
for all tip sizes except the rosebud tips, which take about 40% more
oxygen. So use about equal pressures and adjust for the type flame
you want (neutral, reducing) at the torch controls. If the torch
"pops" and the flame goes out, you have too much pressure. You will
get the hang of it quickly.

Roy


#6
I have just set up my new Meco Midget torch with a 20 lb oxygen
tank and an acetylene B tank. I have a splitter on my acetylyne
(one hose for my Smith Silversmith torch and one for the Meco). I
know I"m supposed to open and light the acetylene first and then
add oxy til the flame is neutral. but, I have not been able to find
on what pressure the gauges on the regulators should
read. I know the acetylene should be between 3-5 but what about the
oxy? All the info on line that I find seems to be referring to
welding and cutting and I don't know if the info is the same for
the jewelry application.

Stacey - Hopefully you have a flashback arrestor on your oxygen
bottle. Open the handle on the bottle all the way, so the arrestor
can be engaged. Set the delivery pressure initially to about 5psi.

The oxygen bottle regulator is always a two stage regulator. Your
acetylene regulator can be either a single or two stage regulator.
If this is confusing, get someone to help you the first couple of
times.

This is real stuff and your question means that you understand that
there are right and wrong ways to proceed.

Just crack the valve on the acetylene, and the valve on the oxygen
just a tiny bit. Use your electric torch lighter and you will get a
tiny flame. Adjust both to desired range. If you don’t have enough
pressure from either bottle, open delivery valve a bit more. Once
you figure out where you like your flame, it is repeatable. If you
don’t have an electric lighter, you need to just open the nasty
acetylene a fair bit and strike flint like you do with your Smith
torch, then add oxygen.

Judy Hoch


#7

I use a small torch like the Meco (not sure of the band) and use 5#
for Acetylene and about 11-12 # for Oxygen. Seems to work well for
me though the oxygen can blow out the flame if I open it too fast.

I use it mostly on Copper but also some silver (not enough shop time
available) Rockboy

Tim Kienzle
robbieflexibles.com


#8

Hi Stacey,

Short form: oxy should be twice whatever the acetylene is set to.

3lbs supply pressure acetylene=6 pounds on the O2.

With little torches like the Meco, there’s a lot of room for slop,
and the final adjustment is made at the torch itself anyway, so as
long as you’ve got “enough” (or more) pressure in your supply line,
you can dial it in from there. I wouldn’t go beyond 3x the
acetylene, just because there’s no point.

You’re probably not using anywhere close to 3 PSI on the torch end
of the acetylene anyway, but there’s no way to be sure what you’re
really using, so just set the O2 a little high, and dial it in from
there by looking at the flame. The more excess O2 pressure you’ve
got on the line, the more ‘twitchy’ the O2 knob on the torch is
going to be, in terms of getting from ‘notenough’ to ‘right’ to
"oops, I blew it out".

So 2x or a very little bit above that, and you’re good.

Regards,
Brian


#9

Thanks everyone!!

I’ve taken all your input and successfully lit my torch today! Wow.
That flame is so much hotter than my air/acetylene set up. As you can
tell from my question, I have a healthy respect for the gases and the
danger involved so I appreciate everyone taking the time to answer my
questions. :slight_smile: Stacey


#10

I gotta second Rob on the Paige tips - get 'em. Frankly, I use an
air/acetylene Smith torch with a selection of tips 90% of the time
on silver (even Argentium) and only switch to the Meco when I’m
casting ingots, have something bigger I need to get hot fast, doing
gold, or fusing Argentium and need a small, hot flame. I LOVE the
Paige tips with a rosebud casting ingots… but oxy/anything (I’m
using oxy/propane) gets hot so damn fast that you have to be
surgically precise with torch control when using Argentium. Damn
alloy. I hate it, no. I love it. no wait, I hateit :slight_smile:


#11

I gotta second Rob on the Paige tips - get 'em. Frankly, I use an
air/acetylene Smith torch with a selection of tips 90% of the time
on silver (even Argentium) and only switch to the Meco when I’m
casting ingots, have something bigger I need to get hot fast, doing
gold, or fusing Argentium and need a small, hot flame. I LOVE the
Paige tips with a rosebud casting ingots… but oxy/anything (I’m
using oxy/propane) gets hot so damn fast that you have to be
surgically precise with torch control when using Argentium. Damn
alloy. I hate it, no. I love it. no wait, I hateit :slight_smile: