Ask your WELDING questions here.

Discussion in 'The Garage' started by KTM640Dakar, Mar 5, 2007.

  1. clintnz

    clintnz Trans-Global Chook Chaser

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    From my dim memory of engineering class gas storage pressure vessels usually have a design temperature of 50C/120F, then on top of that there are all sorts of other safety factors. Ask your gas supplier.

    Cheers
    Clint
  2. P B G

    P B G Long timer

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    Or drive by your local gas supply in the middle of the day. Bet they don't have their tanks in air conditioned storage, no matter where you live.
  3. KTM640Dakar

    KTM640Dakar Motorsick

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    Your Oxy fuel bottles are fine in the hot sun. Just dont let them leak in a closed room or car and light them. Also dont let more than 14 psi out of an acetalylene bottle or it tends to self ignite. Keep an acetelyne bottle upright to keep the acetone inside from coming out of the bottle. If you do knock it over you should give the bottle time to settle the acetone to move back to the bottom of the bottle. The bottle has a menbrane that keeps the acetone and acetelene stable and safe. Sorry no spell check.
  4. ivantheterrible

    ivantheterrible Been here awhile

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    i hope this hasn't been asked already--i want to use some old tin roofing for a project, but don't want to get zinc poisoning. is there a (best) way of doing this? Cross wind from a fan? respirator? ( if so, a simple vapor one?)
    I've read about removing the zinc plating with acid, but this seems nearly as problematic as the zinc plating its self. i heard vinegar will work, but takes a long time.

    Anyone have any experience with this? Thanks
  5. Wadester

    Wadester Rides a dirty bike

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    Outdoors with a breeze works well with oxy/acetylene. Respirator with zinc fume cartridges would be safest.

    The one time I wanted to clean the zinc off and away, I used muriatic acid. Takes off zinc like washing off mud. Didn't attack the steel underneath, but I did wash/neutralize it after.
  6. ivantheterrible

    ivantheterrible Been here awhile

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    thanks wadester.

    How will I know when the zinc is gone, if I use the acid method? I know what the zinc plating looks like, will it just look like regular metal when the zinc is gone?

    if I wire brush it off, how far from the weld area do i need to take off to be safe? Also, again, if i use this method, how will i know when it's gone?

    Thanks again!
  7. ER70S-2

    ER70S-2 Long timer

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    I think muriatic acid fumes are as dangerous as the zinc, be careful with that crap. Outdoors during a tornado would be good. :D
  8. Wadester

    Wadester Rides a dirty bike

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    Muriatic fumes are irritating, nasty. Zinc fumes are poisonous and can cause permanent damage. Well ventilated spaces are always a good idea.

    You can easily tell when the acid has taken away the zinc. Obvious color difference, plus no more bubbly mess. Wire wheel will not remove all the zinc. Grinder, maybe.

    How far to clean? How big is the heat discolored area gonna be? A bit more than that. Clean a generous area. You'll need to paint/coat the area if you want rust protection anyways.
  9. ivantheterrible

    ivantheterrible Been here awhile

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    Can I get good results by brushing the acid on the areas to be welded? I think the size of the pieces to be welded might make finding a large enough container to soak them in difficult.

    thanks again!
  10. WormShanks

    WormShanks b00b

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    How much welding are you going to be doing on those things? If it's not going to be hours worth I would think doing the work in a well ventilated area and keeping your face out of the fumes would be sufficient.

    http://www.sperkoengineering.com/html/articles/WeldingGalvanized.pdf
  11. David R

    David R I been called a Nut Job..

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    Yeah, I had a bad experience with galvanized on a cell tower site. If you breathe too much of the white smoke, it gives me the shits and the shakes in the middle of the night. Only once.

    I grind the galv off but. If its on both sides, it will burn off the other side too.

    If you grind it, the metal will make sparks and the coating will not. A wheel made for aluminum will not load up like a wheel made for steel. There is a color difference between the coating and the steel, but its hard to see unless in good light.

    Just don't breathe the white smoke!

    David
  12. fxstbiluigi

    fxstbiluigi crash test dummy

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    And don't believe anyone that tells you to drink milk "It will take the poison out of your system" That's an old wives tale.
    Zinc, the coating known as galvanizing, is a heavy metal.
  13. Commanderkewl

    Commanderkewl Been here awhile

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    One thing about oxyfuel bottles is not overpressurizing the system.. Acetelyne will combust most easily, without a flame if the pressure is above the 10 (15 in the book, just dont run the pressure on the gauge in the red zone) psi mark.
    Having the guage open a 3/4 turn is all that is needed.

    Ive seen the truck with hoses over pressurized and 6 bottles go up in smoke..

    Ive also seen welders run it high and not get bit....your luck will run out sometime.

    Zinc- no laughing matter. Shortens your life.. Heavy metal, yes.

    www.aee.vt.edu/teacher-resources/lab-safety-resources/oxyfuel.pdf
  14. ivantheterrible

    ivantheterrible Been here awhile

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    thanks for all of the replies.

    The problem with grinding is that the metal is very thin, (old roofing tin) and I'm afraid I can easily take off more metal then I can afford.

    This is for a sculpture I'm working on. I'm planning on cutting out the shapes, shaping them on the english wheel, then attaching them together. I'd love to completely weld every seam, but it'll more likely be several tacks.

    if it matters, I'm using oxy / acet for the work.
  15. tbarstow

    tbarstow Two-wheelin' Fool

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    Use a respirator with zinc cartridges and use a wire wheel to remove the zinc. Since the material is thin, try tacking them to a backing plate.
  16. victor441

    victor441 Long timer

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    is proportional to the change in degrees kelvin, so the pressure increase for a gas bottle going say from 70F to 120F is not all that great... i.e. P1/T1 = P2/T2 or P2= (P1*T2)/T1 P2= P1 * (322/294) so P2 is about 10% higher
    http://en.wikipedia.org/wiki/Gas_laws

    on a unrelated welding topic just made a rack out of 1/2" tubing (not finished yet in the photo) and discovered a 12" round file is just the right size to notch the tubes and works quickly if the notch is started w/ an angle grinder...have a hole saw type notcher but AFAIK hole saws are only available as small as 3/4"

    [​IMG]
  17. JAFO

    JAFO displaced Jeep guy.....

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    Very nicely done. What process did you use, and and how did you make the bends? Also what kind of tubing?

    Sent from my MB886 using Xparent Green Tapatalk 2
  18. victor441

    victor441 Long timer

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    Thanks! I used MIG to weld and the tubing is 1/2" 16ga ERW, cheap and easy to find, Home Depot, Tractor Supply, etc carry short lengths that are overpriced....much cheaper to buy a 20' stick from a steel supplier. I packed the tube with sand (MUST be completely dry or a steam explosion is possible), heated sections with a MAP torch, then bent them around a big socket clamped in my vice...made a template out of coathanger wire first to get the bends right.
    FWIW there is a good article on sand bending at http://www.rorty-design.com/content/sand_bending.htm
    also at http://www.v-eight.com/tech_forum/viewtopic.php?t=203
  19. JAFO

    JAFO displaced Jeep guy.....

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    Damn! Great idea, will have to test this out sometime.

    I remember years ago going roundabout with one of the Senior 'engineers' the about why we were not getting good bends in our network equipment conduit, they were trying to use a pipe bender and wouldn't believe we needed to pack the tube with sand. They're out of business now, for some reason ;-)

    Sent from my MB886 using Xparent Green Tapatalk 2
  20. fxstbiluigi

    fxstbiluigi crash test dummy

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    HAHAhaaahaaha about a year or so ago someone was wondering how to bend pipe/tubing and I suggested packing it with sand, even went into some detail, about how to do that. I GOT crusified by all the self proclaimed experts that know everything about metal fabrication.