Brodhead Pietenpol Association

Original Posted By: jmcnarry(at)techplus.com (John McNarry)
Subject: Pietenpol-List: fire ball>welding landing gear tube...>>putting a steel cap on top of a 2" hollow tube.>>Tube standing up right on shop table...>>Finished about 2 min. of spot welds...>>picked up tube, looked down hollow end....kind of like looking down wrong>end of a gun barrel....>>Ka-Boom ! Orange fire ball heads stright into face !>>By reflex, close eyes.>>Instant later feel symptoms of sun burn, smell burnt hair.>>Mustash burned back by 15 %>Eyebrows burned back by 15%>Eyelashes...almost gone, whats left are little pigtail stub ends...burnt>brown.>Hair on head singed back to ears.>>Smelled singe, and scorch all last night.>>Sat down and tried to figure how a hollow empty tube, hot at one end could>cause so much damage...>>Best I can tell, is the combustion process of actlyene, and oxy, leaves a>residue of combustable CO (carbon monoxide) in the tube. CO must beheavier>than air. So as I welded, the CO built up at the bottom of the tube, with>the red hot end at the top.>>When I picked up, and turned over the tube, the CO sank to the red hot end,>and ...POW ! I became the star attraction of an explosion.>>>I'm ok, but I sure do have a lot more respect for welding gas.>>BOB>>>________________________________________________________________________________

Original Posted By: jmcnarry(at)techplus.com (John McNarry)
welding landing gear tube...putting a steel cap on top of a 2" hollow tube.Tube standing up right on shop table...Finished about 2 min. of spot welds...picked up tube, looked down hollow end....kind of like looking down wrong end of a gun barrel....Ka-Boom ! Orange fire ball heads stright into face !By reflex, close eyes.Instant later feel symptoms of sun burn, smell burnt hair.Mustash burned back by 15 %Eyebrows burned back by 15%Eyelashes...almost gone, whats left are little pigtail stub ends...burnt brown.Hair on head singed back to ears.Smelled singe, and scorch all last night.Sat down and tried to figure how a hollow empty tube, hot at one end could cause so much damage...Best I can tell, is the combustion process of actlyene, and oxy, leaves a residue of combustable CO (carbon monoxide) in the tube. CO must be heavier than air. So as I welded, the CO built up at the bottom of the tube, with the red hot end at the top.When I picked up, and turned over the tube, the CO sank to the red hot end, and ...POW ! I became the star attraction of an explosion.I'm ok, but I sure do have a lot more respect for welding gas.BOB________________________________________________________________________________

Original Posted By: oil can
Boom? Bummer! The residual oil coating in the tube becomes vapourized by the heat ofwelding. The vapours are heavier than air so when the tube is inverted......well you know.It has happened to me. I even did it with ABS cement and a potatocannon..duh! Repaired a leaking joint after a misfire. Forgot the potatoewas still in the barrel and clicked the trigger. At least in that case Iwasn't looking down the barrel.-----Original Message-----

Original Posted By: Ed0248(at)aol.com
Only thing is, CO is noncombustible. It is acover gas for tig/mig, (I know there are others).Was there any oil present? sawdust? you know itcould have been just about anything (except CO).Consider yourself lucky, go out and buy some lottotickets before it wears off. Glad you are okay,sans hair.Bill________________________________________________________________________________

Original Posted By: Larry Ragan
Bob, sorry to hear of the mishap, but glad you're O.K. Another hard learned lesson for all of us to benefit from. Thanks for sharing another pitfall with us.Ed ________________________________________________________________________________

Original Posted By: Mike Bell
Dear Oilcan, Thanks for sharing that mishap with us. This is a hazard I willthankfully avoid all because of your experience. I will probably thinkof you for a long, long time when I am welding. I have had no formaltraining in welding and have often wondered about hidden dangers that Imight not be aware of. I'm glad that you are OK ......hair is cheap!________________________________________________________________________________

Original Posted By: Richard DeCosta
The tubing has an oil corrosion inhibitor in it. When you turned it over , theoil ran down onto the red hot metal and ignited.We had a similar experiance welding up the fuselage of a PA-18. We were workingon a cross tube in the cabin area. Tacked it in place then started finishwelding the far end. It flashed out the near end and caught my friend shirt onfire. One of the other guys grabbed a dry chemical fire ext and was about todischarge it when the first one said "NO". You can imagine the look of theperson holding a fire extinguisher about to discharge it and the person on firetelling him not to! We grabbed one of the buckets of water in the area anddoused the friend on fire. Minor burns on the chest but what a good story! Moralis, keep water handy any time you are welding. It comes in handy!oil can wrote:> welding landing gear tube...>> putting a steel cap on top of a 2" hollow tube.>> Tube standing up right on shop table...>> Finished about 2 min. of spot welds...>> picked up tube, looked down hollow end....kind of like looking down wrong> end of a gun barrel....>> Ka-Boom ! Orange fire ball heads stright into face !>> By reflex, close eyes.>> Instant later feel symptoms of sun burn, smell burnt hair.>> Mustash burned back by 15 %> Eyebrows burned back by 15%> Eyelashes...almost gone, whats left are little pigtail stub ends...burnt> brown.> Hair on head singed back to ears.>> Smelled singe, and scorch all last night.>> Sat down and tried to figure how a hollow empty tube, hot at one end could> cause so much damage...>> Best I can tell, is the combustion process of actlyene, and oxy, leaves a> residue of combustable CO (carbon monoxide) in the tube. CO must be heavier> than air. So as I welded, the CO built up at the bottom of the tube, with> the red hot end at the top.>> When I picked up, and turned over the tube, the CO sank to the red hot end,> and ...POW ! I became the star attraction of an explosion.>> I'm ok, but I sure do have a lot more respect for welding gas.>> BOB>--David B.Schober, CPEInstructor, Aviation MaintenanceFairmont State CollegeNational Aerospace Education Center1050 East Benedum Industrial DriveBridgeport, WV 26330-9503(304) 842-8300________________________________________________________________________________

Original Posted By: kyle ray
>welding landing gear tube...>(Snip)Bob,Thanks for sharing this with us. I am about to start welding my gear legs,and also have no formal training in welding. I will remember your storyevery time I light up the torch.Perhaps sharing your story in Experimenter might be in order? It may helpsomeone else avoid an injury.Thanks again.Al Swanson________________________________________________________________________________

Original Posted By: Michael D Cuy
Dannymac...Hair is cheap? You must have a full head of hair, or you wouldn't make a statement like that.Anyway, I save money on haircuts!Ed________________________________________________________________________________