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  • Safety Issue

    Now that everyone apparently is done beating up on Terry Sexton, there is one thing in the current issue of Home Shop Machinist that concerns me. Make that two things.
    These have to do with reusing old propane bottles.
    In the course of my career, a couple of things that have cost my mechanics their jobs immediately have been taking a torch to an empty drum or gas cylinder and leaving a key in a chuck. No questions, just go. They never came back, even with union grievance procedures.
    Using steam to purge the cylinder may be a good method of removing residual vapors, but using another cylinder as a steam generator, on an open flame with no protection for over pressure introduces another very dangerous situation.
    The photo showed a tank being heated with a burner attached to another propane tank. These burners have a pretty good output. The tank being used for the steam generator had a ball valve on the discharge. This affair has all the earmarks of a death trap in my opinion.
    Anybody else have thoughts on this?
    Jim H.

  • #2
    JCHannun,
    Quote:
    Now that everyone apparently is done beating up on Terry Sexton.

    It wasn't EVERYONE beating up Terry Sexton.
    It was you, and others.

    Guess you'd have fired me quick. No questions. Sure are sure of yourself.

    Leaving a key in is a little help when loading a part in a four jaw with four pieces of packing all at the same time.
    It's best to turn the power off or put in neutral.

    That other guy does sound like the fool in ohio last year. Didn't read the artical.

    mite

    Comment


    • #3
      OUCH !!!!!

      brent

      Comment


      • #4
        Mite; I was on Terry's side.

        Yes, when you are installing a part in a machine, and things are in control, things are a little different than when you are leaving a potential missile to injure or kill a fellow worker.

        Take a look at the article if you have the mag.

        The people in Ohio have learned their lesson. I don't want anyone else doing it.
        Jim H.

        Comment


        • #5
          JCHannun

          I agree with you completely on this. And so much risk for so little advantage . . . just for a splash guard! There must be so many other, safe approaches to do a splash guard.

          On chuck keys, I learned a very simple rule over forty years ago: "If the key is in the chuck, your hand is on the key" It's just that simple.

          Thanks for the important safety warning!



          ------------------
          Rich Kuzmack

          Pi = 355/113 . . . to
          <85 parts per billion
          Rich Kuzmack

          Pi = 355/113 . . . to less
          than 85 parts per billion!

          Comment


          • #6
            I was not impressed by the folly of cutting a propane cylinder either. Fill it with water first, dump the water out, then cut it. No propane. But, I would have just bought a nice stainless steel bowl at an auction to do the same thing. At least it is "shiney".

            BTW - if you tried to get any welding shop to do something like that for you here, the WCB would close them down and whack their pee-pees - with a 12lb. Sledge.


            Mite
            My lathe chuck key is a 14.4V 1/2" portable drill with a stub for the chuck. It is hard even for me to miss that monster.

            Comment


            • #7
              Saw a guy put the hurts to a lathe leaving a chuck key in. Thought when cutting a tank it was best to leave the water in while cutting.
              It's easy to die young ...... maybe the old guys in the shop aren't as dumb as some think.

              Comment


              • #8
                The old guys in the shop did not get old by accident.

                Comment


                • #9
                  Any time you're working on a fuel tank (on a car, specifically an old mustang with a rusty tank that forms the trunk floor), the first thing to do is drain the fuel, then fill it with water while you're welding it back together.
                  This also applies to a tank from a junk yard. Even less that a pint of gasoline would turn to fumes that can explode when sparked.
                  Basically, water is cheap. Hands are not.

                  Comment


                  • #10
                    CompositeEngr:

                    What some of the corvette crazies do up here is have a resin filled bag inflated in the gas tank. Leakproof repair, tougher, and cheaper than chevs $700 metal jobbies. They still look ugly on the outside - but that is what bondo was made for! I am told some guy that repairs sewer lines using the same method thought this up.

                    I remember soldering one gas tank with a heavy copper iron (heated on a stove) - we filled the tank with CO2. Scared the crap out of me.

                    Comment


                    • #11
                      the process of expelling fumes and gasess before welding is called " pressing" around here.
                      CO2 makes good press gas, as does h2o. I feel safe using dry ice in the container. Get dry ice by discharging a CO2 fire extnguisher if not thing else is available.

                      Thing to remember around explosive gases is that they have a upper and lower limit where they are "safe" (what ever safe means). Gas is pretty critical about exploding, Actylene will pop over a wide range, hydrogen over a even larger range. But they must all have something (usually Oxy) to pop.

                      In most cases, (hydrogen being an exception) the explosive concentration requires so much gas to be in the air that YOU will pass out from lack of oxy before the limits are reached. Remember the miners canary as a safety device?

                      The old National electric code allowed sparks and normal wiring above 48" (to best of my memory) and explosion proof below 48" when wiring a service station (gasoline).

                      Had an uncle, WWll merchant marine who saved his ship of coast of africa by going into compartment that was filled with fumes from crude oil and using a cutting torch. Had a big writeup in company newspaper. He told me it was safest risk choice available- other risk choices were to go down, drown or die of thirst. He figured the chances of explosion were minimal causethe cmopartment had not been purged of fumes. He donned a air supply mask, went in ,did his thing and came out.
                      "If the risks are acceptable, the job is safe"

                      Comment


                      • #12
                        [From docsteve] ...the explosive concentration requires so much gas to be in the air that YOU will pass out...
                        That's true if you are inside a room filled with fumes, but not if the fumes are in an enclosed space, like a propane tank. The O2/propane mixture can easily be combustible.
                        Obviously, it can be done successfully, or there wouldn't be pictures in a magazine; the original post is just pointing out that it isn't the safest way.
                        Probably the most dangerous is the high pressure involved in generating steam in a propane tank w/o a pressure relief system. Raise the temp too high, and you have a blow out. Most tanks are designed with a sacrificial weld that will blow out, instead of turning the whole tank into shrapnel. Still, that could get uncomfortable.
                        Besides, with 3 propane tanks sitting next to each other, what if you cut the wrong one?

                        Comment


                        • #13
                          COmposite:
                          I am under the impression that over heated propane cylinders rupture violantly, but don't explode. The difference is not just words. Any cylinder containing compressed gas and liquid, so far as I know, has a "critical tmeperature" and at that temp the liquid phase ceases to exist, it all turns to gas and is worse than a beer chile fart! Things get exciting about that time. I think even CO2 "explodes".
                          I guess best thing to do about gasess is know your gas and how it acts.

                          Used hydrogen in vac furnace for heat treating. I was disappointed that the operators were afraid, but I understood. But when I asked my engineers to issue an opinion they agreed with the operators. When we "Discussed " the problem rationaly, every one agreed that it was safe. The amount of H2 involved could not creat enough heat to be significant, the furnace was about 8 feet in diameter, the bottom was held up by the vaccumm and unlocked when heated. the amount of H2 involved was so small that the botttom would not drop. Yet men had lived in fear of this beast for years, but facts did not calm them. Even when we tried to drop the bottom by adding O2 to H2 it refused to drop. Some claimed the H2, O2 never ignited for some reason. When we tried to pop the gasses, every one, including me, agreed that one experiement would beat a thousand "expert opinions". When the results differed from what the "experts" expected they refused to believe.

                          Some times I think we prefer to live in fear with hand cuffs rather than be free

                          I am not advocating cutting propane tanks nor gasoline tanks. I do advocate using knowledge- not what is published in press, nor do I avocate believing me. I just say investigate and decide if its dangerous or safe for your self and just how imporatant is it to do something.

                          "can't vote on the laws of physics" & "it's what we know that ain't so, that gets us into trouble"
                          Steve

                          Comment


                          • #14
                            Doc:
                            Sounds like we mostly agree, but for different reasons.
                            Personally, I wouldn't hesitate to cut a propane tank apart, like in the article, but I'd make damn sure it didn't have any propane in it first. And I'm thinking the propane tank steam generator is actually a pretty good idea, it just needs one more part to make it something I would have in my shop. Even the little CO2 cartridges for pellet guns will split open when over heated. Otherwise, they'd tear apart and bits of metal would fly!

                            And yes, people are afraid of many things that they shouldn't be. Last year we evacuated one of our production facilities because we had a nitrogen leak... < 500 cu. ft of N2 per WEEK into a 450000 cu. ft building. The manager at the time (ostensibly a college graduate) didn't understand when I told him the air was 85% nitrogen anyway, and the amount of N2 released wasn't significant. He mumbled something about pollution and cleared the facility.

                            Comment


                            • #15
                              My 2 cents,

                              It only takes a minute for something to go wrong. I always argue with my guys about wearing their safety harness when working on the towers. Then one of them calls me to inform me he won't be coming in. He fell off the roof of his garage.

                              My point is that accidents are usually traced back to someone cutting corners. For example this propane tank article. I haven't read it, nor do i have the article but why don't you go and buy some new tanks to do the job with. All this to save 100.00 bucks. And that is Canadian too. Same thing with gas tanks. OK the water trick works well. But what if you don't do it right. A big if! All this to save 150.00 to fix a tank that will most like have another hole in 2 years or less.

                              I just don't see the safety versus cash advantage on these ones. That is me though. OH and everyone makes mistakes. I try to remember that before i yell at any member of my team .

                              Spkrman

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