View Full Version : Porta-welder (Nice Name HUH!)

Shed Machinist
08-14-2003, 01:07 AM
OK, if i hooked up a "welder" from surplus center to a Briggs & Stratton engine. And i connected an alternator would i have a generator/welder that i could mount on a specially built bike trailer?

[This message has been edited by Shed Machinist (edited 08-14-2003).]

Shed Machinist
08-14-2003, 02:03 AM
So would it work Thrud?

[This message has been edited by Shed Machinist (edited 08-14-2003).]

Shed Machinist
08-14-2003, 02:39 AM

Dr. Rob
08-14-2003, 03:05 AM
I find it very hard to believe that you're thirteen years old. I know folks about twenty times your age that couldn't figure that out.

PS I don't know either.

Shed Machinist
08-14-2003, 03:06 AM
Do i take that as a compliment? If so thank you.

Dr. Rob
08-14-2003, 03:18 AM

What are you doing up at three in the morning? What do your neighbors say about running machinery at that time of night?

Shed Machinist
08-14-2003, 03:20 AM
Only 2 here, but i am just thinking of this idea. Would it work and if so where would i go to get a cheaper welder to hook up to my engine. And since you are bringing up the subject what are you doing up at 3?

08-14-2003, 07:01 AM

read your email.

Dr. Rob,

this is my kid. i tried to teach them all independence, free thinking, and initiave. looks like it worked at least once, but the others don't hang around machinist forums.

he got the hours from me too. i like to work at night. quiet. peaceful. nobody bothers you. also a lot cooler where i live in the summer.

however, i tend to go to bed earlier and get up real early. but then i am old too.

kid is something, isn't he? you should see him run machines. hard to tell where the kid leaves off and the machine starts. it is also a joy.

this kid has been this way from birth. sometimes he scares me with what he knows and can perceive. sometimes he scares me with what he does too, but hopefully he will learn a little more common sense before he hurts himself too badly. looking back, i was the same way. was building 'bombs' at about his age. upset my parents too, and they were a lot less than willing to encourage me to follow my interests than his father is. i would rather not be so with my children.

i do try to teach them safety. got lots of scars myself, and they can see the effects of screwing up. hopefully, they have paid close attention. otherwise, there comes a point when you have to 'let go' and allow them to try their own wings.

soometimes they fly. sometimes they fall. mostly they learn from it if they live.

i don't want to sound crass or unfeeling, but i have raised 4 children. all of them are smart and really cool little people. everyone should be so lucky. i do understand that they have to have the space and opportunity to develop their own interests and to learn for mistakes.

i have seen too many kids whose parents kind of kept them in a bubble and they are pretty useless human beings in my estimation. this kid's brother could do a brake job at 10. i should point out that he has little or no mechanical inclination. he is in the process of rebuilding a 79 ford truck at the moment. he does the work and consults me if he has a problem. his sister can change her own oil, and can do lots of other things. i tried to teach them what they needed to know for life. things they don't bother to cover in school.

didn't mean to be long winded. i am pretty proud of my kid[s]. he is gonna be ok. we would all be better if his mother would let him come live with me.

happy thursday.

G.A. Ewen
08-14-2003, 08:25 AM
Shed, if you are refering to an old army surplus aircraft generator then yes, they will weld after a fashion but you need at least 16 hp to run them. The old Mother Earth News magazine had an artical on welding with a automotive alternator mounted on a lawn mower. If you are interested in it I will try to dig it up tomorrow. (very busy today)

Shed Machinist
08-14-2003, 11:09 AM
G.A. Ewen, I would like that, i am looking for something portable.

08-14-2003, 11:14 AM
G.A. Ewen

If you could find that article I would love to read it. I'm wanting a welder but my financial situation doesn't permit the purchase of one right now.
However, I could get an old alternator for free. Then rebuild it myself, and build a welder with it. All of my welding is just household stuff. Mainly Dave and Vince Gingery type stuff.


You amaze me. I hope my son has your love of machinery when he's your age. I'm trying to foster it, but he's only 4.

G.A. Ewen
08-14-2003, 11:27 AM
Ok, I found the "Mother Earth News" artical, scaned it but again Photobucket won't accept it. I can try to e-mail it or photo copy and send in mail. It's only one page.

Shed Machinist
08-14-2003, 11:32 AM
That would be cool

08-14-2003, 11:50 AM

start him out now.

you have to understand though that sometimes your kids have different interests and think differently than you do. it may not be something that he is 'into'.

John's brother lives with me nad has completely different interests and abilities. same parents. same everything except that.

[Shed's dad]

08-14-2003, 12:00 PM

Yes, a rig like this can work and be made portable to boot. Like a Ranger 8 on a much smaller scale.

A buddy of mine uses an 8hp Briggs and a modified Delco alternator as a DC welding rig. I believe the limit of his setup is 125 amps. He's changed the wiring to a Y-connected layout (don't understand that) and added diodes on big heat sinks. The alternator is belted up at 3 times engine speed.

Overall, the whole rig is a little crude and there's more to it than what I've described, but it works quite well. What size welder did you get?


Shed Machinist
08-14-2003, 12:30 PM
I didn't get one of those welders yet, just in my head. But i did get a little 110 Campbell hausfeld welder.

G.A. Ewen
08-14-2003, 02:38 PM
s7hss, can you provide further info on the alternator modifications that your friend made?

08-14-2003, 03:53 PM
Bill, sounds like you are doing an exceptional job with your kids. If more parents did what you have done, this country would not be in the sad shape it is currently in.

Tom, if I remember correctly, some altenators have a 3 phase output, so the Y connection may be needed to rectafy the 3 phase into DC.

Shed, remember that you have to supply dc power to the field on the altentator to get any output from it. It does not have magnets like a generator. Also, do some calculations on the pully diameters of it and the main pully on the motor is is off of. You want to get the same rpm at the altenator when connected to the Briggs engine. By the way, Briggs engines ran at 3600 at full throttle. You can get some big diodes off of Ebay cheap a lot of times. I got 6 600 volt, 450 amp diodes for $20! Go for it! Experiment and learn all you can.


Shed Machinist
08-14-2003, 04:00 PM
Okay i am not sure what a diode is and what rectify means or what you mean by supplying dc power to the field on the alternator.
By the way G. A. Ewen i got the second email and i thing i undestan most of it once i find out what a diode is.

08-14-2003, 08:24 PM
A diode limits the flow of current to one direction. Think of it as a one-way valve. A rectifier converts alternating current to direct current. With AC, the current goes back and forth, with DC, it goes from negative to positive (B. Franklin got it backwards).

O.K. Shed, sounds like you might need a dictionary. I will give you one if you are without.
While there is no inherent knowledge contained within words or an extended vocabulary, the lack of appropriate terminology intrinsic to a particular field of endeavor precludes facilitative communication. And that ain't real convenient sometimes. (A good vocabulary allows you to annoy people in a new way) Might I suggest you find a half-price bookstore nearby and look for some books on electronics, or anything else you find interesting. Reading is a very fast way to learn.
But I'll bet you already knew that.

[This message has been edited by Joel (edited 08-15-2003).]

08-14-2003, 11:26 PM

Many off-oraders have welding rigs under the hood of their jeeps. This unit hooks up to a beefed-up alternater and allows for welding in the field. The welds may not be pefect, but it can get you out for the wilds alive...

To put out around 1000A like a Portable welder takes around 100HP to turn the alternator (a real big one). Some commercial units liek Millers "Mickey Mig" could stick weld, Mig or provide 5KW of power. They are nowhere nearly as good as a Lincoln portable (natch) but have their place.

If you want to pursue this then start reading electrical books (for the generation side) electronic books for the rectification and regulation/control circuits, and auto mechanics to get the motor humping.

08-15-2003, 09:18 AM
The alternator was a 60 amp model with an internal regulator. Regulator and diodes were removed. Diodes were replaced with much beefier ones mounted on heatsinks. The connection that ties all three phases together is undone and 2 ends of 2 phases are tied together. Welding output went through the diodes. I could be wrong because this is the result of a cursory inspection in the semi-dark.

Beyond this, it's tough for me to tell what else he did. He said he'd built this from an old magazine article about twenty years ago. This is definitely not my field of expertise. I have no idea how the power output was controlled or anything else about it.

Would one of you fellows with welding or electrical background care to add to this? Somebody educated in such matters can comment better than I can. I can't recommend this setup one way or the other because of my own lack of knowledge. I have no idea just how safe it is or isn't.

Man, I hate disclaimers.

08-15-2003, 03:31 PM
G.A. Ewen
My email address is fortj3@bellsouth.net
I'd be much obliged if you could email the article to me. I'm itching to start welding.
But I'm too broke to buy a welder. I seem to have a 100 amp Chrysler alternator lying around here somewhere. Wonder how many amps I could get out of it?
I can get a used 60 amp unit from my dad for free.

I know what you mean. I've been a lifelong wrench, yet my brother is a mechanical retard. My brother is into computer games and TV. I'm into the outdoors and machinery. And metalcasting. And building the largest tool collection I can. And woodworking(not very good yet, but I like it). And hunting, fishing, camping, hiking, shooting, etc.
I really enjoy spending time with my son, my brother pretty well ignores his. My brother would just love to be disabled, like I am. I'd much rather be able to work everyday and make a lot of money.
Sometimes I wonder how we could possibly be from the same gene pool.
But, he's better with some of the electrical and electronic things than I. So I guess he's useful for something after all.


125 amps? From an alternator? Sounds good to me. When you compare that to the prices on some of these 80-100 amp chicom welders of dubious quality and safety. Pretty good. For me, anyway. I don't need to weld huge I-beams, just small 5/16" or thinner, around the house and shop projects. Yet another reason it makes more sense for me to build my own, instead of throwing good money away on a cheap import welder. If I had the money, I'd probably buy one anyway, but I don't.

Thanks to all who reply.

G.A. Ewen
08-15-2003, 04:09 PM
Jaymo, I will send it as soon as my e-mail server goes back online.A result of the Ontario power outage.

08-15-2003, 04:09 PM
Found a couple of goodies on the net.

This one is for Shed.


08-15-2003, 04:16 PM

where do you live?

i cannot understand why anyone would want to be disabled. i am as well and it ain't no fun.

let that kid play with your tools. pick tools that are not sharp so he won't hurt himself. they can learn early if they have a chance.

i am following this welder thread with some interest. sounds like my kid is picking everybody's brain. good. sometimes he makes me think too much and gives me a headache. i could use a portable machine once in a while. maybe his lawnmower and alternator idea is the answer.


G.A. Ewen
08-15-2003, 07:12 PM
Jaymo, clik on Evans first link. That is the welder that I was referring to.

08-15-2003, 08:04 PM
Look at www.pirate4x4.com/tech/on-boardwelder/index.html (http://www.pirate4x4.com/tech/on-boardwelder/index.html) for alternator alterations.

[This message has been edited by Chester (edited 08-15-2003).]

08-17-2003, 10:41 AM
To All

Thanks for the replies


Because he is lazy.

Yes, being discombobulated does suck, in a huge way. That's why I keep hoping that if I keep at it, I can one day get my elbows to rehabilitate and I can go back to work. I've been a mechanic my entire adult life. While growing up, I was the one under the hood with my dad, fixing the family grocery getters, while my brother was in his room being the stereotypical computer/electronics nerd. He spent his spare money on electronics crap, I spent mine on tools and hunting/fishing/camping equipment. I knew from an early age that I would be a mechanic.
Now I want to get back to it. I miss it. I miss the money, too.

I live in GA.

My son absolutely loves to play with my ignition wrenches and my 1/4" drive ratchet and sockets. They're just his size. I try to drag him out to the shop(if you can call it a shop) as often as possible. I try to teach him shop and tool terminology and shop safety. Never too early for safety.

My dad has a couple of old riding mowers he no longer uses. I'd like to rebuild the engines, install 2 alternators(1 modified into a welder, and 1 connected to an inverter), and use it as a welder/generator that I could drive from the shop to the driveway, or even to my brother's house down the street. Portable, self-propelled, perfect lazy man's welder. If I'm half as smart as I think I am, I'd like to build it so I can retain the mowing deck(or maybe swap it out for extra alternator, nice modular design) and the electric starter. Riding mower/generator/welder. Mount my wife's big, loud, cd boombox on the hood and I can listen to hard rock/heavy metal(very LOUDLY) while cutting the grass or welding. Yippee!!!!!
And to think, I almost invented the racing lawnmower 20 something years ago. Problem was my dad wouldn't let me have the old riding mower with the rusted deck. Now he just wants to get rid of a couple of them.

HMMM, racing mower/riding mower/generator/welder. See what kind of projects you can think up when you have too much time on your hands??

[This message has been edited by Jaymo (edited 08-17-2003).]

Shed Machinist
08-17-2003, 10:47 AM
I remember when i was four i took my bike apart and put it back together by myself.

08-17-2003, 11:04 AM
Perhaps you're destined to be a mechanic. It's one of the few good "service" type jobs, for those who are a bit more blue collar.
Or at least you aren't destined to be one of these computer weenies who can program this and that but can't even find the dipstick on their own cars. That type offends me, as a man, but the girlie men did give me 5 good years of being an auto mechanic. As well as quite a few laughs during that time.

Anyway, I'm glad to hear you were born with a wrench in your hand, you little grease monkey. So many of your peers can't do anything to a car that can't be handled by plugging it up to a laptop.
Based on your posts, and thirst for mechanical knowledge, you're already much more of a man than many of my peers. Congratulations for not being a weenie. Now, if we could only download your brain and upload it into the skulls of the millions and millions of baggy pant, backwards hat, waste of DNA, oxygen theives that mindlessly roam the earth, we would be in a lot better shape.

08-17-2003, 12:23 PM
Excuse me. I can program the dipstick on my car! I am a Machinist AND a Computer weenie! The two are not mutally exclusive.

For an example: The fuel injection system on my 88 ford Ranger is electronically controlled by the engine computer. However, there is a stub on the vacuum system that controls the injector pressure. Take the cap off that stub and the pressure goes to full (45 psi) at all times giving a rich mix, perfect for hauling my trailer.

08-17-2003, 12:38 PM

You're coming down a little hard on those fellas that don't march by the same beat as most of us do, don't you think?

I have a little brother that is one heck of a fine auto mechanic and my older brother is an engineer, but neither is more "man" than the other nor are either one more "man" than the computer guys I have had the pleasure of working with for many years now. Some of these guys have really challenged me and been a real stimulation to the sleeping brain cells.

Bottom line: There is no shame in doing anything constructive as long as you enjoy it and pursue it with a passion to be your best at it.

I have some natural mechanical abilty, did a complete ground-up restoration on a 1949 Indian and am a hobby machinist and woodworker, did some backpacking, skiing, climbed Mt. Hood, Mt. Saint Hellens, Mt. Raineer, did some indoor pistol shooting, etc., etc., and yes I could change my own oil but I don't, I hire a mechanic to do it,but I am no more "man" than Yo Yo Ma ( One of greatest Celloists in the world ) and I would trade all of my mechanical ability to be able to play the cello or violin but I have no musical ability at all.

That,s what makes the world so wonderful, diversity.


08-17-2003, 01:09 PM
Am with you! If I could play the cello I would, 24 7. I love a string quartet.

INDIAN!! Jealousy rampant. I do have a Suzuki GN400. It is a weird Japanese bike (made for only two years)Some guy in a Japanese plant went off the deep end to design it. 400cc single cylinder four stroke. Not stealable, unless you know how to work the compression release. Front fork is raked out about eight inches from the engine frame. If I ground off the SUZ name on the side cover most people would think "Where did you get half a Harley?".

I tried it in a hard tail but the roads here are too rough. Just about killed my kidneys.

[This message has been edited by Evan (edited 08-17-2003).]

08-17-2003, 01:33 PM

Ah yes, a string quartet, maybe in another life.

"Half a Harley", that's good. Suzuki made some real thumpers, high compression large bore singles, back when I was working in a shop. That's when I did the restoration, 1973. One of the guys that hung around the shop had a 400cc 2 stroke moto cross bike, man what a dirt plowin machine that thing was, but you're right, if you didn't know where the compression release was there was no way you were going to kick it over.

My Indian was a 220cc single also hard tail. It was a baby by comparison to the Scout and Warrior of the time but it was my first bike. I restored it to show condition then entered it in a show in Portland Oregon in February 1974 and won 3rd in the class. I didn't keep it long after that, traded it off.


Shed Machinist
08-17-2003, 04:32 PM
Jaymo, i am sorry but i am one of the baggy pant people. And my mom corrected me by saying i was 3 not 4 when i took my bike apart and put it back together.

08-17-2003, 06:13 PM
I too am disabled - I used to be indestructable, but no more. I can't say I like it at all. I would rather be making stuff. I do what I can when I have the energy and can tolerate the pain. As I was in a wheelchair for 7 weeks I can also say the world is not built for wheelchair users. http://bbs.homeshopmachinist.net//frown.gif

Kick your brother in the balls and tell him he has no excuse to be a mendicant. That is what brothers are for - wake up calls. http://bbs.homeshopmachinist.net//biggrin.gif

[This message has been edited by Thrud (edited 08-17-2003).]

G.A. Ewen
08-18-2003, 12:00 AM
Shed, here is another link that you will find interesting.

J. Randall
08-18-2003, 02:03 AM
Shed you sound like a fine young man. Wear your pants anyway you want to. It does not change who you are. I wore my hair down to my shoulders when I was young, and it was not fashionable in the small Okla. town where i grew up. I think I grew stronger because of the flak that I took. Bilr Jaymo and Thrud, I too am disabled. I have been since 1989, and I would give anything to just be able to put in a hard days work and just come feeling tired. Jaymo, my first career was as an auto mechanic and I loved it just like you. I will get off my soapbox now, don't post much just had to respond to this one. James