DC Cheater Experience?

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Hello all,I'm hoping someone has some experience with a specific device that is available to convert AC only stick welders to DCEN/EP. I tried a number of forum searches and found very little relevant information about these converters. I put this post in the General Welding Questions forum instead of the Electrical forum just to get a little more exposure. Hope that's ok.I have a very old but reliable Miller Thunderbolt 225 AC only welder and it works well. I use it almost daily practicing welding exercises from my welding classes. As a full time student, money is tight and these DC converters seem to be an inexpensive (relatively) way to expand the capabilities of this machine. Selling the Miller and buying a new stick welder is not an option as it has some sentimental value.The product I was looking at is found here:http://www.proto-power.com/dc_cheater.htmlA couple of questions come to mind and I'm emailing the manufacturer as well but would really appreciate any firsthand experience or comments from those who have tried converting an old buzzbox. Here's my concerns:Some of the schematics for AC to DC conversion I've seen on the web either have an inductor and/or capacitors in their design to eliminate the residual AC ripple that is left behind after full wave rectification. The device in the link appears to be just 12 high power diodes and a fan for cooling. Is arc stability affected significantly with a system like this or is it not that big a deal. I like the design of this device in that it does not require any serious modification to the welder. I don't have a problem doing the mods, I just wanted to leave the box in its original condition. I'm not a big fan of shortcuts so I understand that you get what you pay for. I'm just curious if this is a viable alternative to buying another welder.Thanks for your help.EricP.S. Yeah, I know its kind of weird to feel sentimental about a piece of equipment, especially a plain old Miller T-bolt. Its a long story but that's the way it is. I'm sure some of you can relate.
Reply:There is plenty of material on doing it, it's an alternative, but for what the cheater costs you can often score an AC/DC machine used off trade papers or Craigslist.Lurk using a Craigslist aggregator. For example, I just saw an Idealarc 250 for 175 bucks a few hours away. That's a MUCH better machine, cheaper than a cheater. The economy is driving down welder prices, so I wait for bargains.
Reply:Thanks Farmall,OT question though, what aggregator do you use? I'm a Mac guy (Snow Leopard) and neither Safari nor Chrome seem to work with these aggregators.E.
Reply:I use Search Tempest, works fine on my Mac with Firebox browser.  You type in your zip code, how far away you want to search, and what you want to search for.   It will show you what is available, city by city.   In my case, I want to look at Denver, Boulder, Fort Collins CO, and Colorado Springs, and it does that very well.   In most cases I don't want to drive 500 miles to pick up something, so I limit it to 200 miles or so.   http://www.searchtempest.com/In your case, I would suggest searching for "Welder" or "Stick welder" or maybe "AC/DC welder".    Of course, you don't know exactly how the poster is going to describe it, so you might miss something if you are too specific.I like the idea of buying an AC/DC welder, and then selling the AC welder, may not cost you that much money in terms of difference in price.RichardSculptures in copper and other metalshttp://www.fergusonsculpture.comSyncrowave 200 Millermatic 211Readywelder spoolgunHypertherm 600 plasma cutterThermal Arc GMS300 Victor OA torchHomemade Blacksmith propane forge
Reply:Thanks for the suggestions. I finally decided to add Firefox to my collection of browsers just so I could do the CL Agg. queries. Three things:7A749 - Good advice, I have a Howell address but am closer to Argentine and Linden if you know the area. I never know whether to say I'm Central Mi or SE Mi. Out in BFE where I like it. Saw some pics of your OA cart. Nice work. Seriously. If you ever get out this way we should get together for coffee some time.Farmall - I have a 49 Cub sitting under a lean-to shed next to my welding barn. She's not pretty but she runs very well. Just had it running a few days ago. Is your WW handle a reference to the tractors? Dumb question - I know. And Finally, raferguson - I just looked at the link to your website. Beautiful pieces. My faves are the Mobius strip and the ball cap. How's the ball cap in electrical storms? Thanks again everyone.E
Reply:Hi,I was given an AD Thunderbolt, a machine I had used extenstively years ago,  On this site I learned the advantages of DC.  I had a project that needed some serious welding.  I chose the Cheater after talking to the designer.  Assembling it was a one night project, and it gave me a sense of a quality build, and the ability to replace diodes easily in the future.  It has a fan which keeps everything cool.  I believe it provides up to 195 amps DC output, which is considerably more than the AD/DC Thunderbolt.   I was worried about the lack of capacitance, but the designer suggested it was not that significant in real use, but  looping a couple of rounds of welding cable over a vise, propane tank, anything steel would smooth the arc. I wound several loops around a grill size propane tank that was nearby.   I was welding 3/8 inch angle iron, which were braces on an outdoor deck and had to be inspected by the building inspector. I did this and found that the arc seemed to be smooth, easier to light, and appeared to penetrate well at my 180 amp setting. The job  passed inspection.  The inspector made me unbolt one of my brackets and cut it in half to see the penetration. I forget which rod but think I was using new 7018 rods.  It  was mostly vertical up.I found the the little box was inconvenient in that it required to be plugged into an receptacle where I run  my angle grinder.   You do have to cut  the  both welding cables, crimp or solder on four new lugs  and put the converter in the middle.  It is not as handy as switching to the DC side of a welder. I never have found a good place to this small box in the middle of my welding cables, and usually set it on the ground where I trip over it. But this is not the fault of the converter. I discovered that it is portable, can be moved from welder to welder and is often now borrowed and  used by a welding pro who has  a small portable AC welder (Miller?)  on his truck for small side jobs.Where are you from? If it is practical, you an borrow mine to try out.Hope this helpsLast edited by davehowell; 01-26-2011 at 10:52 PM.
Reply:Hi davehowell,Kind of sounds like a decent product. I had thought that seemed inconvenient having to plug the DC Cheater into another 110 outlet but awhile ago I had to replace the fan inside my Thunderbolt and realized that I could just pick one leg of 110 and the neutral inside the case to power the replacement fan. So, although I'm reluctant to make any serious mods to the welder, one could easily add a 110 receptacle to the back panel of the welder and just plug the cheater in to it. Maybe a custom shelf on the welding cart for the box to sit in?Never thought about making an inductor with the welding cable and an iron core like you mentioned. Not a very elegant solution but it sounds like it works. Still not sure which way to go on this. I successfully set up a Craigs search aggregator last night and found quite a few deals out in the rural areas. I usually lurk in the Detroit area CL and the market for welders/metal working tools is quite a bit higher than than in the boonies. Lots of AC only boxes for under $100.00. I certainly appreciate you adding your experience with the Cheater.I'm near Howell, Michigan. Are you? Your WW handle has me wondering.Eric
Reply:Another good CL / eBay search engine is www.statewidelist.com You can search craigslist statewide and it lists ebay results also.  Its very easy to use.
Reply:I built a dc converter several yeas ago. I didnt cut my cable, just bought a 24 foot length of  new and used a ground clamp and rod holder I had on hand.The reactor was wound on a lenght of tractor axle with 2 20 ft lengths of # 6  fiberglas insulated wire in pararell.That gave me a #3 wire in the reactor.The reacator has to be built right.The patch jobs described are not effeicent,I had some parts so the total cost was 100 bucks.I put a fan in to cool the rectifiers,Heat sinks were made with aluminum plates I had under the bench.Front panel is made with tempered masonite.Brass bolts were used for terminals.Converter works fine.I can switch polarity by moving cables.Capacitors do raise the open circuit voltage to 92 volts.A hi watt resistor can be used to pull down the voltage.I used 4 300 amp diodes.Box is 2 feet square.Easy to move around.Lets me use the 6010 rods ive collected over the years.I find DC alot easier to weld with.I can use the full 225 amps while a new lincoln is limited to 125 amps on DC
Reply:Just wanted to thank you all for the replies. Perhaps I'll just run AC only for now. I have plans to find a decent TIG machine in the not too distant future and since that machine would certainly be both AC/DC, it would be a pretty big waste of time and $$$ to either build a converter or purchase another SMAW only welder.But, as always, mucho gracias for the good information.EricP.S. farmer37, check your messages.
Reply:Does anyone have schematic and parts list to build one for the old AC225?  I'm gonna build one and I've only found bits and pieces of info. Really I know how to wire the full wave rectifier I just don't know what size cap to use.  I can get 4 250amp diodes for galco.com for a decent price, just not sure about the cap.
Reply:Originally Posted by mrnicksDoes anyone have schematic and parts list to build one for the old AC225?  I'm gonna build one and I've only found bits and pieces of info. Really I know how to wire the full wave rectifier I just don't know what size cap to use.  I can get 4 250amp diodes for galco.com for a decent price, just not sure about the cap.
Reply:I wanted to use Dc rods on my ac225 so I took the diodes from I junk welder. It didnt seam to work rite so I took it apart and wired it like some plans I had.It never seamed to weld very good. I went to a sale and got 2 airproduct Ac/Dc single ph. They work ok but I have never used a Dc single ph welder. Are they not as good as a 3ph or engine driven welder.
Reply:$210 for rectifier bank?  I don't see this as a viable way to go.First, you can get way more welding capability for less money by buying a used welder.That kind of $ has gotten me several AC/DC welders that I have resold for near double what I paid for em. *- $100 Linde 250 AC/DC - no cables- $175 Lincoln AC/DC 225/125- $225 Lincoln AC/DC 225/125- $150 CTC AC/DC 230/140That's the second thing; used this toy has marginal resale value - maybe $50 - 75?Third - and most important, you are missing the arc stabilizer, the big choke coil that is part of every transformer-based DC stick welder.  That device is vital to stabilizing the DC arc and maintaining a constant-current supply.  It's not enough to just have converted AC to DC.  Yes you have pulsing DC but... you have just isolated the electrode from the inductance of the transformer and thus lost almost all inductance working to produce a constant-current source.  You really have to add a sizeable arc stabilzer (choke, coil of wire) after the rectifier bank.  A couple of cable turns around an anvil is not going to do it!*Every AC/DC welder in my used list above was fitted with a sizeable arc stabilizer - usually of a size of 1/4 to 1/2 the size/mass of the main transformer.Anyway, that's my take on this... nice idea but too much $ for not enough performance.Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet