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  • Pricing a welding job...

    My brother has a friend who needs a timing cover (I think) from an old motorcycle welded up. It just has a crack and is leaking oil.

    Since the day he learned I MAY have the capability to weld aluminum he's been bugging me about it and has gone as far as bringing the part to the shop the same day I first welded with the machine

    I told him just to hang onto the part and not leave it with me and I'd think about it...

    Normally I'd just do it for free as a favor to my bro but I've met the guy...and he's payin for it...

    It'll just be a weld it up, grind it down and sand job.

    Anyway I was thinking about $50/min for firing up the machine and $25/hr with a minumum of 2 hours. The guy says he can't find anyone else that'll fool with it.

    I don't think that $100 for tig welding an aluminum housing is too steep. Some folks think that just because you work in a backyard shop you should do stuff for free but none of my tools were free...

    I also realize that castings can be porous and full of oil or be some mystery aluminum or even be magnesium... From the glance I had of it it looked to be pretty high quality stuff from a Japanese bike.
    Techno-Anarchist

  • #2
    I suggest you try to find a similar junk cover and practice on it first.
    Free software for calculating bolt circles and similar: Click Here

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    • #3
      BEWARE!

      magnesium!

      -Jacob

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      • #4
        I'd fix it for free. I'm always looking for welding projects. Sometimes I break stuff on purpose just so I can weld it back together

        -Adrian

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        • #5
          <font face="Verdana, Arial" size="2">Originally posted by 3 Phase Lightbulb:
          I'd fix it for free. I'm always looking for welding projects. Sometimes I break stuff on purpose just so I can weld it back together

          -Adrian
          </font>
          Sounds like you should live closer to ibewgypsie - I bet you'd get along great.

          -Mark
          The curse of having precise measuring tools is being able to actually see how imperfect everything is.

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          • #6
            <font face="Verdana, Arial" size="2">Originally posted by snowman:
            BEWARE!

            magnesium!

            -Jacob
            </font>

            Speaking of which... How could hoffman determine (safely) what material he's going to be dealing with here? I know of the "spark tests" for various steels (and the cautions about trusting them with "modern" steel), but is there such a thing to distinguish aluminum and magnesium, for example? Thanks.

            -M
            The curse of having precise measuring tools is being able to actually see how imperfect everything is.

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            • #7
              <font face="Verdana, Arial" size="2">Originally posted by Wirecutter:
              Sounds like you should live closer to ibewgypsie - I bet you'd get along great.

              -Mark
              </font>
              We would get along fine becuase there is no worm inside of my Gatorade bottle to fight over

              -Adrian

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              • #8
                You can TIG weld aluminum/magnesium without any problems. The key is a good pre-flow and post-flow.

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                • #9
                  It's easy to identify aluminum vs magnesium. Mix up a teaspoon of lye in a cup of water (Red Devil from the grocery store will do). Clean an area on an unimportant area of the part thoroughly. Put a few drops of the solution on the part. If it is aluminum it will react quickly forming bubbles of hydrogen, basically fizzing. If it is magnesium it will do nothing.

                  You can also identify using battery acid. Put a few drops on the part. Aluminum will do nothing and magnesium will fizz.

                  Wash the part with clean water and it will not leave a mark other than a slight dulling of a bright finish.

                  If it fizzes with both then you have an aluminum-magnesium alloy.

                  [This message has been edited by Evan (edited 10-18-2005).]
                  Free software for calculating bolt circles and similar: Click Here

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                  • #10
                    Thanks, Evan. Another one for the next tips book?

                    -Mark
                    The curse of having precise measuring tools is being able to actually see how imperfect everything is.

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                    • #11
                      I forgot to mention that you need to be sure that you are down to bare metal. Some of those cases are laquered and you want to get through any oxide layer too. A bit of stainless steel wool or emery should do.
                      Free software for calculating bolt circles and similar: Click Here

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                      • #12
                        I'm going to practice on some old castings I have around the shop. I don't really want to fool with it but $100 would make it worth it.

                        Good tip Evan!
                        Techno-Anarchist

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                        • #13
                          hoffman,
                          welcome to the club! i weld about a dozen of those things every day. from casings to covers to oil pans. speaking from my own experience, 90% of the time they'll be aluminum casting. the only magnesium i've ever come across is on chainsaws and (once) a lawn mower deck.

                          this probably isn't as rock solid as Evan's tests, but if it feels a LOT lighter than it should, its magnesium.

                          for aluminum castings you'll want to get your hands on some 4047 filler. its not the easiest thing to find, but its your safest bet for a good sound weld.

                          4043 leaves a nicer bead (shiny!) but may crack when the weld cools, depending on the casting alloys.

                          try to weld it when he's not around. if he sees it only takes you 5 minutes, you won't get $100 for it.

                          start cold with your amps.. the last thing you want is that casting to droop and leave a bigger hole than you're trying to fix.

                          if its just a crack (and not a patch job), grind the whole crack out with a thin cutoff disk.. down to about 1/2 depth. scrub the whole area clean.. and weld away.

                          some people recommend drilling a small hole in the end of the crack to keep it from propagating. i've rarely do this with alum, and only seems to be an issue with harder steels (like stainless) and cast iron.

                          for what its worth, i charge about $20 for a weld like that. granted i'm not looking at what youre holding.. but $20 in 10 minutes for a 3" bead is good money no matter how you look at it.

                          thats the kind of word of mouth that spreads fast, too. next thing you know, you'll have a whole pile of those covers behind your welding stool.

                          clean it REAL good. like you'd eat off of it. if its well cleaned (no dust), and its magnesium, it won't explode. in fact your weld bead might even look nice laying on top of it. but a gentle pry with a small screwdriver will pop the whole bead right up.

                          have fun
                          -tony

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                          • #14
                            Isn't it supposed to be a good idea to preheat aluminum castings before welding? I'm not a welder but just asking if it's necessary to prevent further cracking of the weldment?
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                            It is true, there is nothing free about freedom, don't be so quick to give it away.

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                            • #15
                              Thanks for the advise Knuck. Maybe I priced a little high but I didn't make out that great on my last job. It was nasty and everything went wrong. I did get a repeat job out of it though...

                              Welding aluminum is like voo-doo to some guys around here so there's NO WAY I'm doing anything with someone watching/waiting.

                              It's sort of moot at the moment because my welder isn't put together.

                              So do you ride a Knuckehead or are you one (or both)

                              I learned a lot working on a friends older brothers Knuck ('47 I think) when I was a kid.

                              [This message has been edited by hoffman (edited 10-18-2005).]
                              Techno-Anarchist

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