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View Full Version : Re: flashback arrestors.



speedy
12-02-2008, 07:17 PM
Byron Bouchers' thread on flashback arrestors got me thinking.
It got me thinking that I should check the flow valves on my torch and also, that I should get around to fitting the resettable Witt arrestors that are sitting in my toolbox; the ones that look like small grenades, Witt super 78 I believe.
Well, it was just as well I did check 'cause the acetylene flow valve was buggered but the oxy one was Ok. That is not good is it?
So I gathered up the Witts and fitted them to the regulators but they are a damn nuisance in that they make for a messy arrangement and the total weight of the set up seems to concern me.
I am thinking that I could mount them seperate to the regs but attached (bracketed) to my weld trolley. Short hoses from the regs to the arrestors then the hoses attached to the Witt arrestors.
What is the opinion on this arrangement? Are there any drawbacks or dangers to this set up? Will it affect the function of the flashback arrestors??
Merry Christmas to you all.

torker
12-03-2008, 08:39 AM
Speedy.. I'm not familiar with the arrestors you spoke of.
Are they old ones?
all I can add...for that kind of stuff...the latest and greatest is a good thing.
I remember a few years ago having to go thru all the torch outfits at a big place I worked...we had to change out all the arrestors as the Workers Comp had deemed the old ones as unsafe. They were not that old either. There was a problem that came about as they aged.
I would only mount those as per manufacturers instructions.
The college I mentioned earlier...they have what they call the "Blast Chamber".
It's a clear "box" that the hoses couple to. Then they show you different failure modes of arrestors etc.
It's really a lot more violent than you would think.
I don't mess around anymore...I do buy the latest and make sure they are in good condition.
Russ

radkins
12-03-2008, 10:01 AM
Torker, I think one problem with getting people to take flash arresters seriously enough is that some just don't realize the potential hazards of Acetylene. Years ago when I was young and brave (stupid is a better description) a bunch of guys were horsing around in the shop and lighting acetylene under paper cups on a bench. Not too much was happening so I thought I would liven things up a bit when I spotted a small paper drink cup with a plastic lid and a straw sticking out. I adjusted the flame on a torch for a perfect gas/Oxygen mix and then snuffed out the torch on a piece of wood. I then filled that cup with this Oxygen Acetylene mix and when no one was looking I touched a flame to the tip of the straw, I certainly livened up things all right! That was nearly 40 years ago and I think I still have hearing damage from that incident to this day and had I not been wearing heavy insulated cover-alls at the time I could have been hurt even worse from the debris flying off of the table that cup was on. There was a guard shack at the parking lot gate about 500 yards from the shop and the guard on duty called the shop to find out what exploded! Needless to say I learned a lot from that little incident and if that small amount of gas mix could do that it does not take much imagination to think what could happen!

ahidley
12-03-2008, 11:56 AM
I know people that fill garbage bags with that and put a fuse on it. It will blow the windows out of a whole side of a house when its about 100 feet away.
Dont ask how I know...............

speedy
12-04-2008, 05:14 AM
Hi Russ. Yes they are old ones that I purchased, along with some other stuff, from an ex army welding instructor who was 'fleeing' to Aussie. They are still a current model and I have had them looked at by a weld supply/repair outfit in Onehunga . While they pronounced them fit for service,
I do appreciate what you are saying about the safety factor though.
These are the fellas here:
http://www.wittgas.com/proddb/007/e_st1.pdf
IIRC, at NZ$300ish a pop they aren't cheap. Then again, neither is workshop plant or human life(mostly)
Acetylene bombs are great fun aren't they. Well they were when I was a youngster.
They can almost guarantee a bowel movement especially when you're an unsuspecting 'victim' ;)