Flashback arrestors

[bluedog225]

I’d appreciate any opinions on flashback arrestors on an oxy acetylene setup. I pressed the sales guy pretty hard about any additional safety equipment needed and he didn’t bring them up. And the kit comes with backflow preventers but not flashback.

While watching a variety of safety videos, it looks like the flashback is a good/great idea.

I’m inclined to buy them unless there is some reason not to.

thanks

Tom

[Canoeyawl]

$20 the pair on amazon

[bluedog225]

Yeah. $50+ for the brand names. Seems like a place to spend the extra.

[Canoeyawl]

I have never had one "not work" as an arrestor, but I have had several that wouldn't pass enough volume. They were all Victor brand.
Those I'm using at the torch end are quick connects with back flow preventers.
It is considered good practice to install flash arrestors at the regulators, but again they mess with the gas volume. You may not ever notice it, but I have some big torches... straightening/bending 1"+ plate is not uncommon in my world.

[oznabrag]

And read up on the use of that machine.

Things like 'crack open the O2 valve SLOWLY.'

Sudden surge in pressure can turn any flammable speck of dust/grease into an explosion event.

Turn your face away from the valve while you crack it open SLOWLY.

Pretty dangerous in other ways, as well.

[bluedog225]

It’s interesting you mention that. I saw that advice in one of your other responses. So I asked the counter guy about any special instructions for the oxygen cylinder. Nope. Opening it part way versus all the way. Nope. Flashback arrestors. Not needed based on his 30 year experience. I had to dig around and find the Harris safety instructions to find the caution about opening the oxygen slowly.

So thanks for the tip. Made me realize I needed to go listen to some safety videos. All well worth while.

https://www.harrisproductsgroup.com/...Guidelines.pdf

[jpatrick]

There are many specific safety steps one must take when using an oxy-acetylene torch set. I urge bluedog and anyone else contemplating using one to get some competent instruction. This can be quite informal... like from a friend who is fully competent. Just be aware of some of the basics first: Stand completely to the side of the oxygen gage when opening the valve. If it's gonna blow, it will probably blow out the face of the gauge, not the side. And for crying out loud, the pressure adjustment knob has to be backed completely off before opening the high pressure valve. Never leave a unit that's unattended, under pressure. If your "teacher" doesn't insist on all these things, move on to someone else.

And don't ever move an oxygen bottle that's not secured in a proper cart, without it's safety cover/cap properly in place. That bottle is a rocket if it falls over and it's valve is damaged.

Jeff

[stromborg]

I concur with what Jeff said.

Some things you really don't want to learn the hard way.

[bluedog225]

By backed all the way off, do you mean opened all the way? And thanks. I agree on good instruction. The are lots of safety videos. It's interesting how they vary in quality.

[jpatrick]

By backed all the way off, do you mean opened all the way? And thanks. I agree on good instruction. The are lots of safety videos. It's interesting how they vary in quality.

Backed off means no gas going through the regulator. It's that big T-handle thing right in the middle. It has a regular right handed thread. Turn it counter clockwise as if to remove it. When it turns freely, that's it. One does not want high pressure hitting the regulator all at once. Bad things could happen.

Always, when you're done using the torch: Turn off the valve on the tank. Then bleed the pressure off by opening the valve on the torch handle. Then back off the regulator.

Jeff

[bluedog225]

Got it. Thanks!

[gypsie]

I thought this thread was going to be related to an over indulgence in LSD in yesteryear.

I was checking in for a .... friend.

[Andrew2]

Considered a 'must have' in UK. My old kit didn't have them, but now, they are cheap insurance.

[oznabrag]

Backed off means no gas going through the regulator. It's that big T-handle thing right in the middle. It has a regular right handed thread. Turn it counter clockwise as if to remove it. When it turns freely, that's it. One does not want high pressure hitting the regulator all at once. Bad things could happen.

Always, when you're done using the torch: Turn off the valve on the tank. Then bleed the pressure off by opening the valve on the torch handle. Then back off the regulator.

Jeff

Good.

Also, one should perform a leak test maybe a couple of times a year. Once the system is charged, you shut the valves on the torch, shut the bottle valve, and leave the regulator pressurized for several hours, noting the pressure at the beginning and end of the test.

There should be no change whatsoever in pressure on either gauge from beginning to end of the leak test.

Once your rig passes, shut down as above.

[Canoeyawl]

How to do it:
https://www.alce.vt.edu/content/dam/...es/oxyfuel.pdf
(See item "F" on pp. 4)

[bluedog225]

How to do it:
https://www.alce.vt.edu/content/dam/...es/oxyfuel.pdf
(See item "F" on pp. 4)

Nice. Thanks!