Rectifier for AC stick welder..
RSS | Subscribe | Contact Us | Advertise | About Us
Page 1 of 2 12 LastLast
Results 1 to 25 of 32
  1. #1
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Rectifier for AC stick welder..

    Here are some photos of my home-made rectifier, I still have to add an inductor to smooth the ripple. I made this to add DC to my Sears Colormatic welder. I eventually plan on buying a real Tig welder, but this should help me out for the time-being.
    I know spend the money on a real machine...I need to pay for my daughters first year at college and I don't want any debt, accept my mortgage...Talk to you later...
    Attached Images Attached Images     

  2. #2
    Join Date
    Dec 2009
    Location
    Las Vegas, Nevada, USA
    Posts
    468

    Re: Rectifier for AC stick welder..

    I'm confused. I'm assuming you are taking an AC only transformer welder, passing the output thru a bridge rectifier to make pseudo DC output. I understand how you can further stabilize the output from the bridge with resistors and capacitors to create a true (flat) DC output, with resistors and large capacitors. I will note, my old Sears Craftsman / Century 1980's era transformer machine used the pseudo output for DC without further damping function. It worked okay for welding, but you could not use a DC clamping ammeter to read current flow.

    So what's the inductor for? Are you attempting to create some sort of chopped output at particular frequencies?

    -- Zip. (Admittedly with mediocre juice skills)

  3. #3
    Join Date
    May 2010
    Location
    Cali
    Posts
    1,495

    Re: Rectifier for AC stick welder..

    Fuel....... I'm guessing your also a ham radio guy too?????
    Lincoln Power Mig 216
    Lincoln AC/DC-225/125

    Miller 625 X-Treme Plasma
    Miller 211

    Forney 95FI-A
    Milwaukee
    Hilti

    Dayton
    Delta
    Makita
    Victor
    Ingersoll-Rand
    Baileigh

  4. #4
    Join Date
    May 2009
    Location
    Wyoming US
    Posts
    2,112

    Re: Rectifier for AC stick welder..

    A low voltage transformer primary will work as an inductor,if you can find one that will handle the amperage.
    Though saturability of the coring might be iffy,a simple straight Iron core may be the simplest
    There were also some inductor experiments on a welding with batteries thread, and this one was fairly detailed .http://weldingweb.com/showthread.php?t=8996
    Hobart T225
    HF 151/2 Cap mod
    HF 131/2 Cap mod
    Miller Cricket XL
    Century Portable Mig
    O/A

  5. #5
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    No not a real ham guy..kind of interested though...I understand most people don't mess around with stuff like this..I like to learn new things and to made due with what I have...I spent way to much money on things when I was younger...Now my wife and children come first. One day I will buy a true ac/dc power source that is constant current so I can have clean dc and ac high freq to weld aluminum, But for now scratch start tig for stainless and steel will due. I only screw around making things for around the house ,fixing my vehicles and art projects. I am not a coded welder, I work with code welders and anything that is serious I ask them to help.
    Sorry for the long reply, I saw other dc conversions here and wanted to show what I did after reading their posts.

  6. #6
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    The only way to get true dc is with a storage battery...When you convert ac to dc with a rectifier you get pulsing dc..to smooth the dc ripple you use a inductor capacitor filter ...or a large inductor..depends on how clean you want the dc. In this case just good enough...Later

  7. #7
    Join Date
    Jun 2010
    Location
    Niagara on the lake Canada
    Posts
    1,242

    Re: Rectifier for AC stick welder..

    Post pics etc. I thought about doing this conversion once for my ac only machine but .. So I am following the post. There has been quite a bit on this very topic on here. and a lot about diodes and iducters ( do a search). Good luck.
    Miller thunderbolt 250
    Decastar 135E
    Recovering tool-o-holic
    ESAB OA
    I have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.

  8. #8
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    Ok here we go...

    The welds do not look good at all...I haven't tig welded in a very long time. I have never scratch started a tig torch untill this evening. I was also nervous because this was the smoke test for my rectifier... It worked !
    Now I can start a lot of practicing !
    Oh yeah, There's a picture of my folding welding table that is to heavy with a 3/8" top...I was inspired to build it from the people on this forum...When the weather here in Buffalo NY warms up a little I'll paint it...Later ...
    Attached Images Attached Images      

  9. #9
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    Here are some pictures of the rig with a manual gas solenoid. I didn't want to wait for a torch with a valve. The welds are with e3 electrodes..not thoriated electrodes. I am going to make a platform to hold the power supply and the bottle of argon...There are pictures of the shelf that will hold the rectifier...the argon bottle will be behind the power unit...later..
    Attached Images Attached Images      

  10. #10
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    Here are some pictures of the the shelf I made to hold the rectifier....
    Attached Images Attached Images    
    Last edited by Fuelhead; 02-17-2013 at 05:42 PM.

  11. #11
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    Here is the reply...

  12. #12
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    Sorry for the disjointed post..

  13. #13
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    I painted the shelf and added a torch/ground hanger..I still want to build a cart to hold the machine and the bottle of argon..here is a picture of my latest weld..3/32 thoriated tungsten...I finally understant how clean metal means it is easier to start an arc....To many years using a mig welder on rusty western NY steel..Oh yeah...trying to add a post flow timer circuit too..
    Attached Images Attached Images    
    Last edited by Fuelhead; 02-23-2013 at 02:24 PM.

  14. #14
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    Here is the beginning of the welder cart and some more welding pictures.. .100" steel to .100" chinese steel, the square I welded around..3/32" tungsten 2% thoriated, 15cfh argon, the cart I welded with my lincoln 255 power mig...later
    Attached Images Attached Images     

  15. #15
    Join Date
    Jun 2010
    Location
    Niagara on the lake Canada
    Posts
    1,242

    Re: Rectifier for AC stick welder..

    For an inducter I suppose you could wrap ...like 6 awg single around a ...what do they call the short weight lifting bar? maybe that would be better and help you stablize. I don't know.
    Miller thunderbolt 250
    Decastar 135E
    Recovering tool-o-holic
    ESAB OA
    I have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.

  16. #16
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    I have a piece of laminated steel from an old transformer, I need to make some brackets to mount it in the bottom of the rectifier box. I also need to make some ends to keep the wire coils in place. I was excited the rectifier worked and I wanted to mess around with it,you know kid with a new toy. I'll fine tune it soon..I wanted to get better at scratch starting an arc too. Oh yeah, the arc, once started is stable. The only time I had issues was when I was in a hurry and didn't clean the base metal good enough. Bad habit from welding rusty vehicles back together with a mig. Without a sandblaster , a wire brush and grinder can only dig out so much rust.
    Last edited by Fuelhead; 02-25-2013 at 06:02 AM.

  17. #17
    Join Date
    Apr 2007
    Location
    Poco British Columbia
    Posts
    185

    Re: Rectifier for AC stick welder..


    So I should be able to do this for mine also.
    This is my 180 Amp from the 70's, belonged to my late uncle.

  18. #18
    Join Date
    Mar 2006
    Location
    Yuma, Arizona
    Posts
    2,586

    Re: Rectifier for AC stick welder..

    Do we have a few extra spacers? Either fender spacers or alignment spacers?
    Lincoln Power Mig 350MP Ready Pak
    Lincoln Precision TIG 275 Ready Pak
    Lincoln WeldPak 100
    CK TIG TORCH gas diffuser and pyrex cup
    Thermal Dynamics Cutmaster 101
    A stout 15 yr old son to help!!

  19. #19
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    Yes, The diodes I had were only rated to 150 amps,I only use it on the lower output. I am going to order new diodes with a higher rating..I used 2 stud anode and 2 stud cathode..look around for the schematics if you aren't familiar with electricity..It will hurt or kill you..!

  20. #20
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    They were left over drive motor line up shims..foot mounted electric motors...

  21. #21
    Join Date
    May 2009
    Location
    Wyoming US
    Posts
    2,112

    Re: Rectifier for AC stick welder..

    Quote Originally Posted by Fuelhead View Post
    Yes, The diodes I had were only rated to 150 amps,I only use it on the lower output. I am going to order new diodes with a higher rating..I used 2 stud anode and 2 stud cathode..look around for the schematics if you aren't familiar with electricity..It will hurt or kill you..!
    Actually,If they are properly heat sinking,each leg only runs half of the time.
    That would mean the 150a diodes should be good up to 300a.
    Hobart T225
    HF 151/2 Cap mod
    HF 131/2 Cap mod
    Miller Cricket XL
    Century Portable Mig
    O/A

  22. #22
    Join Date
    Sep 2012
    Location
    Knoxville, TN
    Posts
    880

    Re: Rectifier for AC stick welder..

    Quote Originally Posted by Bluewelders View Post
    Actually,If they are properly heat sinking,each leg only runs half of the time. That would mean the 150a diodes should be good up to 300a.
    That's consistent with the diodes that are in my welder. 140A max output (DC) welder, 70A diodes.

  23. #23
    Join Date
    Dec 2012
    Location
    Outside Buffalo N.Y.
    Posts
    76

    Re: Rectifier for AC stick welder..

    You know...I was thinking that, I read some other posts regarding this and that's what was stated. I never messed around with large stuff like this. I have made small power supplies to mess around with small electronic circuits, never anything of this current. When I made the copper buss bars/heat sinks I filed them flat with a vixen file and then used a whet stone to get them flat for the diodes to sit on. With this and the cooling fan I guess I can crank out the output and see how it goes! Thanks for the reminder!

  24. #24
    Join Date
    Sep 2012
    Location
    Knoxville, TN
    Posts
    880

    Re: Rectifier for AC stick welder..

    Quote Originally Posted by Fuelhead View Post
    You know...I was thinking that, I read some other posts regarding this and that's what was stated. I never messed around with large stuff like this. I have made small power supplies to mess around with small electronic circuits, never anything of this current. When I made the copper buss bars/heat sinks I filed them flat with a vixen file and then used a whet stone to get them flat for the diodes to sit on. With this and the cooling fan I guess I can crank out the output and see how it goes! Thanks for the reminder!
    Did you use thermal paste? It'll really help, if not.

  25. #25
    Join Date
    Jan 2012
    Location
    Leander, TX
    Posts
    177

    Re: Rectifier for AC stick welder..

    You can also make an air-core inductor, or even a sliding core. Put many turns around a pvc tube. You can find an iron bar or equivalent to go inside the pvc. Then you could run it full air core, or you could move the bar to adjust the inductance.

    Capacitors are not what you want. Yes, some resistance going into a capacitor forms a low-pass filter. However, a capacitor stores charge and can release it basically as fast as its internal resistance (and inductance) will allow. This means the capacitance would charge to the OCV during times you weren't using it, then would discharge in a huge surge current during arc start, potentially blowing away whatever you are trying to weld on. A capacitor would work perfectly for CV though, but that's not what you want.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
RSS | Home | Penton Media | Contact Us | Subscribe | For Advertisers | Terms of Use | Privacy Statement