How to use a highoutput alternator as an emergency welder DIY

Discussion in 'All Things Boats & Boating' started by yachtwork, Jan 1, 2010.

  1. yachtwork
    Joined: Jun 2008
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    Location: Vava 'u Tonga

    yachtwork Junior Member

    Not sure exactly where to post this. It's kind of across the spectrum of subjects. This article tells step by step instructions on how to turn most any large alternator into an emergency welder. Hope it helps.


    Emergency welding with a high output alternator


    How to turn most any alternator in an emergency welding machine

    For rest of article see -

    By: Scott Fratcher - Marine Engineer/Captain

    Scott Fratcher explains how to make an emergency welder with a high-output alternator

    It's possible to weld with nothing but an alternator driven by a small engine, and although it's not recommended as a day-to-day activity, it's useful in an emergency.
    What if you were out at a remote island and broke a chain plate or your windlass mount cracked? This type of thing happens all the time with cruising boats.
    Here's how it's done. Start with at least a 100amp alternator (120amp is perfect - Delco's CS144 alternator is great for this application).
    You also need:

    * A 110V 60W (or more) light bulb and socket;
    * A few cables you can weld through (No. 4 or larger);
    * A welding electrode (stinger);
    * A small supply of 2.5mm welding rod (6013);
    * A variable resister capable of passing four amps continuous. It should be a rugged variable resister, at least 50mm across.
    To use your alternator as a welder you have to attach the welding cables to the back of the alternator. The ground lead is attached to the negative pole of the alternator and the positive lead conne ...

    For rest of article see -

    Note- At bottom of article is a link back to this forum.
    1 person likes this.
  2. Fanie
    Joined: Oct 2007
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    Location: Colonial "Sick Africa"

    Fanie Fanie

    Hi Scott,

    As far as I know you can buy them here, aparently they work quite well.
  3. apex1

    apex1 Guest

    Its enough!

    IT IS ENOUGH !!!!

    Stop posting your crap please. Every average idiot boater has someone near with more knowledge!

    We do┬┤nt need your amateur crap.
  4. yachtwork
    Joined: Jun 2008
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    Location: Vava 'u Tonga

    yachtwork Junior Member


    Thank you for your comments. I don't see many links to plans that give the instructions on how to use an alternator as a welder. I see lot's of sites selling kits for upward of 1000 dollars. This is simply a post that describes how to make an emergency repair that someone may need sometime.

  5. marshmat
    Joined: Apr 2005
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    Location: Ontario

    marshmat Senior Member

    Useful to know, just in case.....
    Not for someone with limited electrical knowledge, of course, and certainly not for someone who doesn't already know how to weld.... done incorrectly, this technique looks like it could easily cook a lot of pricey equipment. But for a cruiser in a real bind with the knowledge to pull it off, it just might save the day....
  6. Frosty

    Frosty Previous Member

    I don't think that will do the Alt much good, blow that and you are in worse trouble stranded with no alternator. I would say look after stuff like that when you are on desert islands.

    However I have heard it is possible to stick stuff together with just the battery.

    I have not done this but ive heard it can.
  7. Frosty

    Frosty Previous Member

    Im hoping Pistonbroke would see this.
  8. pistnbroke
    Joined: Jan 2009
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    More Yachtmaster Crap

    Found it thanks to a really cool PM ....Well I think all Yachtwork is doing is trying to advertis his books ....1800 hits from one post ..some idiot must have purchased a book ....whatever you say he just comes back smilling as it keeps the thread going and gets more people to consider his books....All of which seem to be glossed over amateur simpleton ****. Whilst what he says can be made to work ( I always carry a 110v 60w bulb and a Vresitor in case I need it ...I keep it with the condom )
    Technically this will work can bypass the regulator with the resistor and leave the regulator in place energise the rotor via WL ,,,, and the 110v bulb is a crude way of keeping the open circuit voltage down... As the output current is self regulating then a 100 A alternator would run a 2.5mm rod fine..You do of course risk wrecking the alternator and you would need to get the speed up ..say run the engine at 3000 rpm ..Personally you would be better using 3 12v batteries and a bit of a shaking hand to manipulate the rod .there was a device sold to do this some years ago .

    But this is 2010 and not the place for this sort of technocrap put here to induce book sales on the pretense of informing the reader
    Why does the moderator not take this Yachtwork crap off
  9. yachtwork
    Joined: Jun 2008
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    yachtwork Junior Member

    Batteries vs alternator welder

    Thank you for your comment. If I understand correctly you say a better weld would be made in an emergency by linking batteries than by using an alternator welder.

    I disagree for three reasons.

    The alternator welder mimics the open and closed voltage of a stick welding machine very nicely. Open voltage is about 80v and welding voltage is about 18v. Both are pretty close the voltages of the old Lincoln transformer welders.

    The open voltage allows easy arc starting because the 80 volts wants to jump the gap and start an arc. A battery pack is inferior to an alternator welder as the arc starting voltage arc is lower.

    Second, with an alternator welder the current to the weld can be precisely controlled through the alternator field. I have set the field and welded with a steady 80 amps showing on an AC/DC clamp amp. I have welded this way for hours and the amperage remained steady. The stable amps flow allows the welder to lay a predictable and thus stronger weld.

    A battery is inferior to an alternator welder because a battery does not have an easy and accurate way to control amps.

    Third, In a direct short of the welding leads the current potential of the alternator is about 120 amps while a battery bank might be capable of 800 amps. It is simply safer to work with a smaller maximum potential as the possible ramifications are lessened.

    Flor example in the event of a direct short with an alternator welder the worst that may happen is the alternator overheats and is ruined. A direct short in a battery can cause the battery itself to explode with resultant blinding battery acid sprayed around the work zone.

    For these reasons, if faced with an emergency I'll try welding with an alternator before a stack of batteries.

    Thank you
  10. yachtwork
    Joined: Jun 2008
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    Location: Vava 'u Tonga

    yachtwork Junior Member

  11. jonr
    Joined: Sep 2008
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    Location: Great Lakes

    jonr Senior Member

    If you think you will need to weld, there is a "Ready Welder" that allows wire feed welding from batteries (2 or 3). Wire welding makes sense for a constant voltage source.
  12. Frosty

    Frosty Previous Member

    There is no way you should risk your alternator to weld with. This is silly advise.

  13. Frosty

    Frosty Previous Member

    I understand that I can post where I bloody like!!

    Who's going to buy his book when he come out with childish crap.

    Nobody here is going to buy his silly books.

    How much are they anyway.

    How much would post be to Noosa in Aus
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