I have a Smith's cutting/welding torch set that came from an estate sale some years ago that recently suffered a near catastrophic failure. I've used it a bunch as it has the small bottles and I can take it places to where it's needed. Since I've owned it, it has always sort of pulsed when I go to cut something although it would still do the job. The other day, I was using it to heat and bend some small parts and when I shut it down, I noticed the cutting tip was glowing prompting me to take the tip off and clean it. I also took the cutting torch apart and cleaned it which had lots of carbon inside. Put it all back together and tried it but found the flame once adjusted would get slowly get smaller as if I was adding more oxygen. While attempting to to adjust the mix to get the desired cutting flame it started to pulse again and I could see the line pressure gauge jumping around which I had not seen before (and had looked before). The hose was also pulsing so I shut it all down. Then I noticed the hose was warm and kept getting warm. I closed the valves on the bottles and eventually it all cooled down. Oddly, the oxygen hose was the one getting warm. Disconnecting the hose from the torch mixer and the O2 hose was filled with carbon as was the torch mixer. I bought new hoses and have ordered a rebuild kit for the cutting torch. Took the mixer apart and ran it through the sonicator. I can't seem to comprehend what was happening here. Anybody have ideas?
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Cutting Torch Failure
- Thread starter Gazz
- Start date
- Replies 17
- Views 1,781
Big B
Diamond
- Joined
- Jun 26, 2009
- Location
- Michigan, USA
You said it is a small tank set. Maybe you are using too much acetylene for the tank size. I believe you can only use 1/7 of the tanks contents per hour.
I'm not an expert on torches but do know that this can be a problem.
DJ2
Aluminum
- Joined
- Feb 12, 2007
- Location
- Ontario, Canada
Do you use backflow and flashback devices?
Blazemaster
Hot Rolled
- Joined
- Oct 13, 2009
- Location
- Olympia, Wa
It's still a good idea to use flashbacks, since it sounds like you just had one. I don't have 51 years under my belt on the torch, but coming up on 20. I have had a few larger pre-mix torches do just what you described and it's always from not letting out enough fuel when you light the torch. Given your experience I'm not sure if this is what happened. If you clean it up, put it back together and it still does the same thing, I would just get rid of it and find another cutting torch. Pulsing sounds like regulator, torch valve, or torch tip. Hope you figure it out, faulty torch stuff is a pain in the ass.
Rob F.
Diamond
- Joined
- Aug 5, 2012
- Location
- California, Central Coast
Sound like it finally caught up to you.
Ries
Diamond
- Joined
- Mar 15, 2004
- Location
- Edison Washington USA
I had a Smith set I bought new in about 1980. Stopped using it awhile ago, and then dragged it out to try it- and flaming gas came out of all the connections. O rings dont last forever. Kinda like that low mileage 1940s car, where the tires and all the hoses are rotted out.
ebay and the big online welding supply stores have rebuild kits for some, but maybe not all, Smith torches.
also, regulators dont last forever either. some have diapraghms that decompose with time, some have springs that lose their sproing.
probably wouldnt hurt to rebuild them, too.
ebay and the big online welding supply stores have rebuild kits for some, but maybe not all, Smith torches.
also, regulators dont last forever either. some have diapraghms that decompose with time, some have springs that lose their sproing.
probably wouldnt hurt to rebuild them, too.
cyanidekid
Titanium
- Joined
- Jun 4, 2016
- Location
- Brooklyn NYC
flashback arrestors are cheap insurance, why wouldn't you use them? seems silly not to.
What happens during a so called "flashback"? Are you incinerated immediately? Does your shop burn or blow up? I have known about flashback arrestors for years but like I said, never used them and have never needed them. I don't know if they would have made a difference with my recent issue but I don't think so. I do not recall seeing them included with gauge/torch sets so I would guess they are not that critical for safe operation. I haven't looked at new ones recently though. Can someone provide examples of "flashback" incidents?. I can't say that I've ever heard of an incident but have heard you should buy them.
john.k
Diamond
- Joined
- Dec 21, 2012
- Location
- Brisbane Qld Australia
I have never had a pop,bang ,or a destructive flashback since I dumped acetylene for LP gas....barbecuse cylinder ,in fact........the reason for the flashbacks is that actylene is highly unstable at elevated temps......like you get cutting up scrap.....Note that a completely different technique is needed to cut with LP...When you know how to use it,the cut starts quicker than with acetylene.
mjr6550
Aluminum
- Joined
- Oct 7, 2012
- Location
- Lansdale, PA
According to that article, the hoses burst downstream of location of where flashback arrestors should be placed so how would they help? The other thing I noted was the operators methods, turning on both gases before igniting. I open the fuel gas first and light it, then open the O2 valve to adjust the flame. Also poor condition of the hoses seemed to be the primary cause.
john.k
Diamond
- Joined
- Dec 21, 2012
- Location
- Brisbane Qld Australia
The only flashbacks I had would destroy the small mixer tube inside the torch,melt the end of it.....first few times ,I got it repaired.....then I swapped over to LP gas ..problem solved ..no more flashbacks .. The LP cutting tips are two piece,and last ten times longer ,because I can clean them easily to dislodge oxide.
true temper
Stainless
- Joined
- Jun 19, 2006
- Location
- Kansas
30 years ago I had a torch pop flame went out and the handle got really hot quick burning my hand.
john.k
Diamond
- Joined
- Dec 21, 2012
- Location
- Brisbane Qld Australia
Ive noticed you have a lot more serious events with a torch halting work when you are paying wages than when you pay a flat rate of $20 ton to cut scrap.