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Smith Air/Acetylene Handi-Heet Outfit NE835A should i use a flashback arrestor

I am about to purchase the Smith Air/Acetylene Handi-Heet Outfit NE835A need to know if I should get a flashback arrestor for the system. I am hearing yes and no.

Considering that a flash back can cause terrible damage, structure fire, serious injury including fatality… I’d suggest that it’s a reasonable expense for the added peace of mind. Just my 2 cents.

I suppose that you could install a flashback arrester, but you have no pressurized O2 to cause the flashback. My family used Presto-Lite torches for years and never installed one. Talk to the people who sell you the torch and use it (plumbers and HVAC people), and see what they say.

The other problem is many flashback arrestors require a minimum forward pressure to open and I don’t know if the oxygen generator would provide enough pressure to open them

A flashback arrestor doesn’t operate at residential pressure. Emily Benoit Ruffin in Taos runs her shop at street pressure. I choose to boost pressure with the G-tec so that I could use a flashback arrestor. It is the requirement of the NYFD that jewelers in the city use natural gas with a concentrator - i,e, the G-tec so that they can have a flashback arrestor. I erred on the side of caution. To the best of my knowledge, there are no torches that work with natural gas without added air. Mouth torches (blowpipes) maybe the exception.

I built 11 steel fishing boats and restructured others with typical Oxy/Acetylene gear with no arrestors in use. That said we had a recondition and replacement schedule on our regulators. And we took care of our torches.

Your comfort and assurance is reason enough to use them. I have no arrestors on my equipment. Either my Presto-lite equipment or my Propane / O2 gear. My son has one on his Presto torch. He hasn’t mentioned any negative to using it other that the expense.

Go with your gut. And maybe your Insurance man’s gut. If you will sleep better at night with flash back arrestors in place by all means do.


In Illinois we used flash back valves after they made us get rid of the much safer water system. (gas bubbled up through water and could not return down the pipe- problems arose when someone somewhere forgot to refill the water). There are different rules in different places. It is best to find someone in your area that has gone through it. I’ve found that asking people that don’t know what you are doing will have a tendency to get you a refusal.

The OP’s question had to do with the need for a flash back arrestor on a single stage acetylene and atmospheric air torch. There was no mention of natural gas or O2 generators in the original post. There is another thead that does include questions about natural gas and O2 generators. Do we have these threads mixed up or am I mixed up?

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I think it has morphed into a discussion of Flash Back Arrestors in general use. It seems they are perceived by some to be required or not for all applications.


If your torch is gas, regardless of the source, and O2 from a high pressure cylinder, you probably need flash backs and check valves or combinations. Again, check with the manufacturer of the torch. My torch system is non-adjustable propane from a 1 lb. cylinder and O2 from a generator. The propane pressure is fairly low and O2 pressure is very low. I know that neither would produce enough delta P to open a check valve or make it through a flashback leaving enough pressure to run the torch because I have tried it. I have run the torch on NG at street pressure and O2 from the generator…Rob

I was told by Cyberweld, from whom I purchased my Handi-Heet, that it was unnecessary to use a flashback arrestor.