DIY Welder

Discussion in 'Motorized Bicycle General Discussion' started by ferball, Jan 4, 2011.

  1. ferball

    ferball New Member

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    First off I love this forum, and I know most of you guys that read this will laugh and/or call me insane. I posted a few months back about a DIY Welder made out of microwave transformers. Some of the response were helpful, most were to the effect "Go buy a cheap welder". So I want to start this post off acknowledging that: yes I could buy a cheap welder, and yes playing with wires and transformers might kill me. That being said you can laugh at me all you want, just don't be shy on advice/experience that may help.

    After melting the secondary coil for the second time on my MOT (Microwave Oven Transformer) Welder I decided a new approach was needed. So I had the brilliant idea of winding my own transformers and making my own welder from scratch. There is little or no info about this on the internet aside from the pictures below. I can find info about transformer theory and some of the math involved, but no decent how to nor the actual math to figure transformer output. Could I use a solid core for a simple welder, or does it need to be a laminate core? And could I use multiple taps off of the secondary to make the amps adjustable? And how hard is a shunt to calibrate and use for voltage adjustment?

    The other problem I found with the MOT welder is I can not find information regarding actual voltage requirements for welding electrodes. I can find more than enough info about the amps but nothing about voltage other than what an over voltage bead looks like. But how much is "over voltage" 30v or 50v or 20v? I know it depends on the electrode, so can some one give me a clue there as well?

    I chose this forum as opposed to a welding or electrical forum because the talent pool here is quite diverse and the information tends to be more practical than theory. So I figure there is enough know how here to make a functional DIY welder with minimal cost and readily available material, and yes I am dumb enough to try plugging it in after it is built.
     

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  2. Fulltimer

    Fulltimer New Member

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    I can't help any on how you want to do it but I know that you can weld with 3 car batteries hooked together. I can post up the info if you want.

    Terry
     
  3. ferball

    ferball New Member

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    I have heard about the car battery thing, but three car batteries would cost more than a cheap welder, though an old battery charger may offer something in the way of usable transformer...

    I would still like a decent reference how to for transformers from scratch, there is lots of uses aside from welding. Though most electricians consider winding transformers a "black art".
     
  4. Goat Herder

    Goat Herder Gutter Rider

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    That where the Mesa Boogie Guitar amps were born. They were cleaned up hot roded Marshall amps back in the day.:D
     
  5. ferball

    ferball New Member

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    So I am thinking of using garden wire as a core material, it is insulated steel wire. I figure I can wrap it around something to give it a form, then cut it an tape it back together. Add winding and shunt and away I go. My theory is that the insulated steel wire as a core would work like a laminate core reduce eddy currents, I realize it is not as efficient as laminates because of "hysteria" loss or something like that, but I think it may work. Any thoughts?
     
  6. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    Keep a good fire extinguisher handy. ;)
     
  7. ferball

    ferball New Member

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    I plan on testing it in a snow bank just in case.....
     
  8. kipharley

    kipharley New Member

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    Before you start welding with your flux capasitor dial 91 on your cell cause you might not be able to get 911 out qiuck enough before your muscles start convulsing!
    To bad Gilligan's Island wasn't still on you could put a call in to the Professor I bet he could hook you up!
    McGuiver could do it with a clothes pin a Juicey fruit wrapper and a dead 9 volt battery and a glass of salt water!
    Or you could buy a new welder reverse engineer it and take all the parts back and tell them it wouldn't work!Kip.
    [email protected]
     
  9. culvercityclassic

    culvercityclassic Well-Known Member

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    This is one idea I would never touch...electricity does not forgive...trust me I work around it and deal with it everyday. I have also seen the damage it can do to the human body.

    CCC
     
  10. KiM

    KiM New Member

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    Theres a huge thread on DIY Welder build already on this forum do a search... For 99 bucks you can buy a new arc welder for 50 bucks you can buy a decent secondhand welder why one would take the risks of playing with electronics that will kill you at the drop of a hat is a lil silly ... IMO.

    Thats said all the best...

    KiM
     
  11. Goat Herder

    Goat Herder Gutter Rider

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    Yeah I don't think some folks here understand primary and secondary voltages.
     
  12. ferball

    ferball New Member

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    The whole idea behind the DIY Welder is to do it, sure I could buy one, just like any of us here could buy a moped, but there is some satisfaction out of saying "I made this". I also recognize that the performance will not be "high end" again motor bike vs moped example, but I do believe it would be functional, and with a little knowledge and respect for electricity it will not be to hard to live to tell about it.

    Anybody have any pointers on shunt design? I understand this is the key to limit output current (to aviod breaker blowing.)
     
  13. ferball

    ferball New Member

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    I have no problem finding amp ratings for electrodes, but I was wondering what the minimum operating voltage is for welding and/or what is a decent voltage setting that would make a functional welder, I know that it requires higher voltage to start the arc, but little voltage is required for the actual welding, keep in mind that the material in question being welded is just scrap bikes and mild steel, my rod of choice is a e6011 3/32 because it is readily available and it seems feasible to make a welder operate with in the amp range of that rod.

    I could go down to a 1/16 rod, but will that work for frame construction? It would mean I could make a much less efficient transformer.
     
  14. Elmo

    Elmo New Member

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    You really need a laminated core for your transformer and you really need to use magnet wire. It is copper wire with a thin insulated coating. This book may be of some help Lindsay: Thordarson Transformer Manual . Transformer Design & Construction
    23853 is another book they have. Basically you use a ratio for your windings. if you input 120 volts into your primary and want 12 volts out use 10 times more windings on your primary than you do in the secondary also the wire is heavier on the secondary.
     
  15. ferball

    ferball New Member

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    I understanding the whole winding thing. But the core is the big mystery to me right now, because everyone says you need laminate "electric steel" but that is not readily available nor does it fit into my idea of available/low cost materials for this project. Why not a solid core? is it just a heat thing? Practical infoon the core is lacking as it has been decided that "laminate or nothing" and I find it hard to believe that primitive arc welders used laminate cores.
     
  16. ferball

    ferball New Member

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    Thank you Blank, that is some good info.

    Here is another thought I had today regarding my DIY welder and in light of Blank's voltage info may make more sense. What if I made like six small transformers then wired them to together, it would allow scalability and some adjustment, by adding or removing a transformer from the circuit. What is the math for combining transformers in series/paralell? And what about the secondary winding series/paralell? and can different transformer sizes be wired together, or do they all need to be fairly close in size? My understanding is that the primary coils need to be fairly equal, but secondaries can vary with no problem. Any electrical engineers wanna she some light?
     
  17. professor

    professor New Member

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    Really good advise from Blakenstien.
    I weld on the bikes with a Lincoln (tombstone style)
    that I have had for 40 years. I have actually used it with 1/16 rod wired plugged into a 110 outlet. My upgraded house has 220, but I still use 1/16 rod to weld bike stuff. Harbor Freight has it and I use it at 60 amps or 40 amps.
    You have to be real fast though with the light material we are dealing with. A MIG is so much easier for a nubie, I don't think I would reccomend stick to a biginner when your hide is on the line.
     
  18. KiM

    KiM New Member

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    +1 to that and .... Blakenstein's advice especially his last post. Only takes ~500mA to stop a human heart, you really wanna know what your doing when your playing with high AC currents.

    KiM
     
  19. ferball

    ferball New Member

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    Just ease anyones concern about my ignorance of electrical safety...My first welder was housed back in the microwave "case" and the case was grounded to the ground wire,(that is why that third prong is on the plug right?) just in case of stray currents and what not. When I test my death traps I use an isolated circuit and observe all safety precautions. I may have crazy ideas, but safety first and I would not recommend playing with line voltage without a proper respect for electricity and a understanding of the safety and fundamentals of electricity

    Just wanted to clear up any misunderstanding like I was an idiot trying to get myself electrocuted. I may be an idiot, but I am planning on avoiding the electrocution part.
     
  20. culvercityclassic

    culvercityclassic Well-Known Member

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    Thank you...we were all worried about your adventure...
     

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