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ac-dc lincoln tombstone conversion

Posted: Fri Jan 14, 2011 11:33 pm
by kermdawg
So a while back I ran up on this website that sells this unit and I can't find the darn site for the life of me. Anyone know what it is?

Secondly, I read somewhere that on the ac stick welders you should move the stinger to the ground cable. Any reasoning behind this?

Re: ac-dc lincoln tombstone conversion

Posted: Sat Jan 15, 2011 4:47 pm
by turbo388
This?

http://www.proto-power.com/dc_cheater.html

With an AC welder, there's no such thing as a 'ground', it's alternating current. ;)

Re: ac-dc lincoln tombstone conversion

Posted: Sat Jan 15, 2011 6:41 pm
by kermdawg
Hey I'm a plumber/wanna be welder, not an electrician :p But your right, I guess I mean to say the neutral. But why do they call it a ground clamp then? Because even with DC you only have positive and negative? They dont call it a neutral clamp :p

YES, that is the site I was looking for. Couldnt find it for the life of me. Wanting to make one of those myself, since 200 bucks is crap for a little box.

Thanks

Re: ac-dc lincoln tombstone conversion

Posted: Sat Jan 15, 2011 7:33 pm
by turbo388
Well, everybody calls it that because that's what it looks like. Technically, its proper name is work clamp.

There's nothing special in that conversion box at all, I think you can get the big diodes off ebay. And if you build it yourself, you don't need an external box, you can set it up inside the existing welder..

Re: ac-dc lincoln tombstone conversion

Posted: Mon Jan 17, 2011 5:47 pm
by kermdawg
yep, you read my mind. Thats exactly what I'm trying to do. Just havin trouble finding a supplier for the rectifiers. Ebay aint cuttin it.

Re: ac-dc lincoln tombstone conversion

Posted: Mon Jan 17, 2011 7:20 pm
by turbo388
Search ebay for these item numbers...
370474766469
290521971299
230478425019
etc.
Contact the sellers, almost a certainty they all have more units on hand than what they have listed.

Hell, if you don't mind being creative, you could even use the guts from a bunch of junkyard alternators.

Re: ac-dc lincoln tombstone conversion

Posted: Sat Jan 22, 2011 3:45 pm
by rickbreezy
I'll bet you could get a cheap deal on craigslist. dont worry about the quaility/age, becuase ussually those tombstones last forever.

I bought one once for 100 buck, with only a few hours on it.

Re: ac-dc lincoln tombstone conversion

Posted: Sun Feb 20, 2011 12:45 am
by kermdawg
Sorry for late reply but WOW TURBO thanks dude! Thats awesome I've been callin every electrical/electronic supply company around here and none of em carry anything for that high an amperage.

Re: ac-dc lincoln tombstone conversion

Posted: Sun Feb 20, 2011 12:48 am
by kermdawg
Hey again-I dont know if this would work for the application but what do you think-

http://www.centurytool.net/51_235_250_A ... 51-235.htm

My electrical/electronic knowledge is limited to ohms triangle and wiring up outlets :p so all this stuff goes over my head. But thats similar to the one I saw in the kit for 200 bucks, just not copper plated.

Re: ac-dc lincoln tombstone conversion

Posted: Tue Feb 22, 2011 3:34 am
by turbo388
I don't know, and I don't know how you would go about finding out exactly how to hack that piece to make it work without buying one and poking it with a multimeter. As it's a replacement part meant to go in something else, there probably isn't any published data on what its made of.

That $200 kit is just some custom parts to connect up the fat diodes. I would stick with something you can get actual specs on.

Re: ac-dc lincoln tombstone conversion

Posted: Wed Feb 23, 2011 8:14 pm
by kermdawg
That $200 kit is just some custom parts to connect up the fat diodes. I would stick with something you can get actual specs on.
I just think that 200 for the kit is a ripoff. I'm really just mad I didnt come up with the idea first :p that dude would make a killin if he would advertise in the right places.

Re: ac-dc lincoln tombstone conversion

Posted: Wed Sep 07, 2011 10:44 am
by marshal
If you are looking for diodes to make the rectifier box from the site in a previous post you can look at the online electronic suppliers Such as Newark Electronics, Mouser, etc. They will sell to an indivigual and don't have minimums on the amount of an item you must buy unless they come in a package. The cost from them is very low so I would goto them for the selection, quality, one stop shopping. If you can not find a Diode with enough amperage capacity then you can hook them up in paralell or series I can't be sure which and their capacities are added. The volage should be well above what you anticipate will be the max they see for reliability can't get to high a voltage except as voltage rating goes up so does the price. Also be sure to get and use the thermal paste or grease when mounting the diodes to the heat sink as it makes the heat sink much more efficent in dissipating the diodes heat for long life as the fan only cools the heat sink so it is vital to get as much heat out of the diode into the heat sink. These companies are alsoa good source for components to repair other eqipment such as a tig powersource. A "Miller" mosfet $100 exact same general componet from mouser $24. Nothing against the manufacturers but money is really tight right now so ever bit helps.

Re: ac-dc lincoln tombstone conversion

Posted: Tue Sep 27, 2011 10:32 pm
by kermdawg
Awesome! just what i was lookin for! i long gave up on this project but now i might just have a reason to start it up again. :) Ill look through the site and see if i can find what we need.

Re: ac-dc lincoln tombstone conversion

Posted: Tue Oct 04, 2011 10:02 am
by ogorir
these aren't super cheap, but they should work: http://www.mouser.com/ProductDetail/Vis ... Sfq3oes%3d

300a, 600v. $31