Re: Homebrew Welder, what is ya\'lls opinion?
Here's my opinion...
I have an On-Board Welder and it's the greatest thing since sliced bread. I have an old Link-Arc that a friend gave me - it has a 190-amp HD alternator that is the Ford external regulator style - but alot more meaty - the contacts are 3/8" bolts vs. the stock like 10-32 machine screw size. A link Arc is identical to a Premier Power Welder - they bought out Link Arc.
I of course have a manufactured unit because someone gave it to me - I did spend about $250 getting it up and running, but was told by the alternator shop that the alternator was worth about $550 - it has 12 diodes in it - whatever that means, but that's alot - I think most have one or two...
ANYWAY - throughout getting mine up and running, I had the control box all apart and also read all of the do-it-yourself articles, and here's my opinion: Aside from the fact that you really need a kick-ass alternator, there's really nothing to these things - just like in the articles attached above. The control box is just a nice neat little place to put the switches, plugs, and volt gauge. There's a solenoid in there just like a winch or starter solenoid - I never really psyched out EXACTLY what it does, but I'm sure it's the same as in the diagrams included in the articles above. From what I've been able to determine, welding and 110 power is accomplished by simply bypassing the vehicles voltage regulator, thereby allowing the alternator to go nuts and put out all kinds of volts - controlled by vehicle RPM. You weld from 35 to 55 (which with a 190-amper is just a little above idle), and run tools at 115.
The whole thing works awesome! It was a little tricky to get used to, but that's probably because I never arc welded before - only Mig.
If you're going to build one from scratch as described above, I see ABSOLUTELY NO PROBLEM with EXACTLY duplicating the factory units with readily available junkyard and Napa parts - there's nothing special about it. You've already got the instructions - DO IT!! :-)
Final Note - get a BIG alternator. This 190 amp unit is so great - especially for winching - forget dual batteries, this thing puts out 55 amps AT IDLE! You can winch all day and for the most part, the battery isn't even touched!
AND - THIS IS MY BEST ADVICE - Forget the GM internal regulator styles. In Jon's article on his site which you attached above (great write-up), he uses the GM style with internal reg, and explains how to bypass the regulator. Forget all of this, do yourself a favor and skip that whole mess and go right to an external reg Ford HD style - there's a 2 wire pigtail with field and stator connections, and then two posts, Ground, and Positive. This is what you're after, and you don't have to get in there and fudge factor it just to get back to this point. At least get an alternator LIKE this... These on-board welder companies used to sell a 135-amp job, but now only sell 160 and up, so I'm assuming that someone figured out you really need at least 160 to draw a good bead on anything substantial. Talk to your local alternator shop and see what they suggest - they can probably get you a very good price on something new, or at least tell you applications that have what you're looking for... Good Luck! - Enjoy! (You feel so invincible when you have air, welder, and 110 power. It's also a major ego-boost when you whip that stuff out... :-)
P.S. I just checked out that article above by Dave Goodale, and he did an EXCELLENT job - the difference between his and my Link-Arc is negligable really... (It makes me wish I COULD go build my own now... :-)