Torch Problems

Jewelry Discussion
21

In a message dated 96-11-11 11:49:43 EST, you write:

<< NEVER, NEVER use oil on any fittings associated with oxygen.
This can cause an EXPLOSION!!! >>

Thanks for the info Something else I didn’t know.

Joan

22

Hi!

I’m not Joan, but will jump in again. I know a lot of people use Teflon
tape, but here’s what I’ve been told. The threads of a gas connection
are not designed to seal. They merely provide mechanical force to the
connection. The seal should be effective, even before it gets to the
threads. The mating surfaces of the connection should be providing the
seal.

FWIW,

Dave Sebaste

23

Seems as if ‘WE’ keep suggesting…‘REPLACE’ the regualator… I would hope
that we really are suggesting that the regulator should be re-built…???

Cost be $15.00 Per(or about!!!)

2 Months ago!

Jim

At 08:02 PM 11/11/96 -0700, you wrote:

24

Hi!

The threads of a gas connection are not designed to seal. They merely provide mechanical force to the connection. The seal should be effective, even before it gets to the threads. The mating surfaces of the connection should be providing the seal.

FWIW,
Dave Sebaste

Subject: Re: Torch Problems

Joan: What is wrong with using Teflon tape?

Gidday: Professional (registered) gasfitters in this country (NZ) use teflon tape for just about every threaded joint, except a few of the very latest type which seal perfectly every time and are quick to fix. I’ve used it for years. -

John Burgess, johnb@ts.co.nz

25

Previously this was said,

Hi Dave: The check valves you spoke of which according to
your supplier actually increase the danger of flashback,
these would not be one-way valves would they? I have always
identified one-way valves as “flashback arresters”. Wrong?

I agree with this. In fact, many of the valve packages call them, Anti
Flash or FlashBack valves.

FWIW

There are 2 different type devices available: a flashback arrestor, a check
valve.

The flashback arrestors generally have a check valve built in & also contain a
device (usually a series of very fine mesh screen or porus ceramic material)
that prevents a flame from passing through it.

The check valve is just that, a one way valve. Check valves prevent a fluid (gas
is a fluid) from flowing back in the direction from which it has come. This can
be important in oxy/gas torches due to the differences in pressures that may be
present in the 2 gases. The pressure differential could arise from: operator
error, a plugged tip, a defect in a regulator or torch. The higher pressure gas
could force its way back into the other source.

Both a properly operating flashback arrestor and check valve will prevent gases
from mixing behind the device. A flashback arrestor while also guarentee that no
flame proceeds back down a supply line if a failure exists in the system beyond
it.

The price of a flashback arrestor (mfgd by Victor) is generally $20 and up;
check valves are usually about $5 at welding suppliers.

Dave

26

Didn’t know what they were called(got them 4/5 years ago) cost $1.00
then(each) both… Master Welder and the Welding equiptment company… ‘same’

Jim

At 12:42 PM 11/15/96 EST, you wrote:

Previously this was said,

Hi Dave: The check valves you spoke of which according to
your supplier actually increase the danger of flashback,
these would not be one-way valves would they? I have always
identified one-way valves as “flashback arresters”. Wrong?

I agree with this. In fact, many of the valve packages call them, Anti
Flash or FlashBack valves.

FWIW

There are 2 different type devices available: a flashback arrestor, a check
valve.

The flashback arrestors generally have a check valve built in & also contain a
device (usually a series of very fine mesh screen or porus ceramic material)
that prevents a flame from passing through it.

The check valve is just that, a one way valve. Check valves prevent a fluid
(gas
is a fluid) from flowing back in the direction from which it has come. This can
be important in oxy/gas torches due to the differences in pressures that may be
present in the 2 gases. The pressure differential could arise from: operator
error, a plugged tip, a defect in a regulator or torch. The higher pressure gas
could force its way back into the other source.

Both a properly operating flashback arrestor and check valve will prevent gases
from mixing behind the device. A flashback arrestor while also guarentee
that no

27

Bruce Holmgrain wrote:

  1.  Get rid of the acetylene . . It's too hot for small jewelry

soldering… use propane and air… much cheaper… container for
propane cost.,… bout $10.00 on sale and $8.00 to fill… last for
ever!!!.

I was in a mall a few years ago and the fire marshall wouldn’t allow us to
use propane. He would allow acetylene. The only real problem with acetylene
was soot. We had soot everywhere. The stuff worked fine otherwise.

E-mail: manmountaindense@knight-hub.com
WWW: http://www.knight-hub.com/manmtndense/bhh3.htm
Snail: POB 7972, McLean, VA 22106

orchid@ganoksin.com

Odd that my cookstoves never blow up seems I have two that run on
propane and two porpane space heaters that are not considered
dangerous.My gas water heater yep it runs on propane never any
problem…G.Chando
and propane will evaporate upward in temps above about 67 degrees…In
very cold climates it just puddles on the floor as a liquid if a leak
occurs…Gavin