On 4 Jan 2005 19:51:52 GMT, Ignoramus28225
wrote:

A post in the transformer thread made me think. I have a very large
transformer with many windings. At least a 200 pounds beast.

http://igor.chudov.com/tmp/capacitors/

I hope that I can find a way for it to reduce voltage to say 30-60
volts or something, on those windings. Maybe rewind it a little bit.

I am going to have a 60 AMP subpanel in my garage soon, I am working
on it anyway (compressor needs more juice etc).

Then, to have a rudimentary welding machine, all I need is to add a
onboard overcurrent protection device, a rectifier big enough, and
welding cables. Am I missing something important? I know next to
nothing about welding equipment and wanted to tap into your collective
knowledge.

Do welding machines need to be DC powered?

Thanks!

i

Nope you can weld with AC, I think DC is nicer though. Look around on
the web there are lots of great DIY welding plans out there and you
have a good start with your transformer core.

That transformer looks like it has pretty beefy secondaries already.
When you energize the primary and connect the secondary windings in
parallel, what do you get for an open circuit voltage?

Most guys who make welding transformers remove the secondary windings
and wind on a few turns of flat copper bar. If you want to convert
to DC you may have to spend some serious change to get a rectifier
beefy enough to handle the stress of striking an arc. Google for
the terms "welder" and "snubber circuit" or something.

And do NOT fall in love with your transformer. In my neighborhood
I see 225A AC welders for $50 several times a year, it would be a lot
easier for you to start with one of those.

GWE

Here is a link to some items I made a few years back
http://www.motherearthrecycling.net/welding/welding.htm

I would consider buying one, it might cost you less in the end and you can
just plug it in and not worry about cooking something you didn't want to.
"Grant Erwin" wrote in message
...
That transformer looks like it has pretty beefy secondaries already.
When you energize the primary and connect the secondary windings in
parallel, what do you get for an open circuit voltage?

Most guys who make welding transformers remove the secondary windings
and wind on a few turns of flat copper bar. If you want to convert
to DC you may have to spend some serious change to get a rectifier
beefy enough to handle the stress of striking an arc. Google for
the terms "welder" and "snubber circuit" or something.

And do NOT fall in love with your transformer. In my neighborhood
I see 225A AC welders for $50 several times a year, it would be a lot
easier for you to start with one of those.

GWE

Where do you live? Have you looked in your local newspaper's classified
ads, your local "nickel ads", your local craigslist? - GWE

Forget the welder...make a TIME MACHINE!!!



"Ignoramus28225" wrote in message
...
A post in the transformer thread made me think. I have a very large
transformer with many windings. At least a 200 pounds beast.

http://igor.chudov.com/tmp/capacitors/

I hope that I can find a way for it to reduce voltage to say 30-60
volts or something, on those windings. Maybe rewind it a little bit.

I am going to have a 60 AMP subpanel in my garage soon, I am working
on it anyway (compressor needs more juice etc).

Then, to have a rudimentary welding machine, all I need is to add a
onboard overcurrent protection device, a rectifier big enough, and
welding cables. Am I missing something important? I know next to
nothing about welding equipment and wanted to tap into your collective
knowledge.

Do welding machines need to be DC powered?

Thanks!

i

On 4 Jan 2005 19:51:52 GMT, Ignoramus28225
wrote:

A post in the transformer thread made me think. I have a very large
transformer with many windings. At least a 200 pounds beast.

http://igor.chudov.com/tmp/capacitors/

That looks like a constant-voltage or ferroresonant transformer. The
presence of the oilfilled caps in the background supports that notion.

If the middle leg (iron) is movable, it might indeed make a good
arcwelder with that being the current-control shunt.

On 4 Jan 2005 20:47:37 GMT, Ignoramus28225
wrote:


Thanks. I looked on ebay. Is something like this:

http://cgi.ebay.com/ws/eBayISAPI.dll...4256 919&rd=1

worth anything?

Not much.

You want something more along this line....

http://search.ebay.com/lincoln-225_W0QQfromZR40QQsojsZ1


I bought one of these locally for $20 a few years ago. Ive outgrown
it, but it was a fair machine. The Lincoln 225 is a decent machine as
well.

I have both for sale, but shipping would eat your lunch.

Gunner


It's not unwise to remember that Mother Nature is essentially a
murderous, sneakly, promiscuous bitch who has been trying to kill you
since your conception.

Eventually she will succeed, perhaps with the help of your fellow man.

Life consists in putting off the inevitable as long as possible and
taking what good and joy you can before her success.

Whether you attribute that situation to evolutionary forces, a fallen
nature after Adam and Eve screwed the pooch, or whatever, it's no less true.

Be friendly, pleasant, unaggressive, and honest toward all and be
prepared to ignore, avoid, or even kill anyone who is otherwise toward
you. Being ready doesn't mean eager, just ready. What true friends are
found in life will undestand and accept that fundamental rule of human
interaction." John Husvar

"Ignoramus28225" wrote in message
...
On Tue, 04 Jan 2005 23:51:50 GMT, Gunner wrote:
On 4 Jan 2005 20:47:37 GMT, Ignoramus28225
wrote:


Thanks. I looked on ebay. Is something like this:

http://cgi.ebay.com/ws/eBayISAPI.dll...4256 919&rd=1

worth anything?

Not much.

You want something more along this line....

http://search.ebay.com/lincoln-225_W0QQfromZR40QQsojsZ1


I bought one of these locally for $20 a few years ago. Ive outgrown
it, but it was a fair machine. The Lincoln 225 is a decent machine as
well.

I have both for sale, but shipping would eat your lunch.

Thanks, I will look for a cheap local one then.

i


i

It might be interesting and rewarding and even educational to build a
welder with the transformer you have. It probably boils down to deciding
what is more important to you, Building a welding device or Doing some
welding.
I own several Miller welders MIG, TIG and even one that does both. But, I
prefer to use the stick welder I made from scrap. I sure dont suggest the
junky-scrap welder I made is superior to the Millers, but, I sure like
useing the ugly thing.
The design considerations involved with making a decent stick welder are
kinda interesting.

Jerry

"Ignoramus28225" wrote: (clip) I thought that connecting different secondary
windings in parallel would be some sort of equivalent of a short.(clip)
^^^^^^^^^^^^^^
If the windings have the same number of turns, and you don't get the
polarity reversed, they don't act like a short.

A "stick" welder has to have inductance in addition to the transformer
itself, so that while you are welding, the current remains relatively
constant. Particularly, while you are striking the arc, you are shorting
the welder output. Without the extra inductance, the current would jump way
up, possibly sticking the rod and turning it red hot.

I think building a welder is an interesting challenge, but if you try to
weld with an unknown and imperfect setup, you won't know which part of the
problem is the machine, and which part is you. I agree with the others who
say you should start by buying an inexpensive unit.

Do you know about sci.engr.joining.welding?

And do NOT fall in love with your transformer. In my neighborhood I
see 225A AC welders for $50 several times a year, it would be a lot
easier for you to start with one of those.



Good point. I might just look for a used welder. Imust say though,
that Idid look for one and did not find anything cheap.


Home Depot sells the Lincoln ac225 arc welder for 279.00 bucks. Cheap for what
you can do with it. Of course, if sheet metal or aluminum is your fetish, your
screwed without a tig welder.....
MLM

About 80#.
Bugs

I have a Lincoln 225 [oldie but good] in Eastern TN. The first $50 gets
it. I'm having fun with my new Lincoln TIG/Stick.

Ignoramus28225 wrote:

I have been having urges to mess around with machinery lately. So, I
would not mind making a primitive welder. Any website suggestions?

i

www.google.com

Search home made welder, build a welder, building a welder,do it
yourself welder, microwave transformer welder, etc.

Lot's of stuff out there.

Cheers
Trevor Jones

Bugs wrote:

I have a Lincoln 225 [oldie but good] in Eastern TN. The first $50 gets
it. I'm having fun with my new Lincoln TIG/Stick.



Yup, I recently got a Lincoln Square Wave TIG 300, and am learning to
use it.
Steel was pretty easy, but the aluminum is a good deal trickier. But, I
have
made a couple test welds on aluminum that started to look pretty good!
Fascinating machine!

Jon

On Tue, 04 Jan 2005 23:29:35 GMT, "Tom Gardner"
calmly ranted:

Forget the welder...make a TIME MACHINE!!!

We know what YOU want it for, Tom. You want to go back to the point in
time just before the perps came out of your shop so you can kneecap
'em, don't you?

(Let me know how it works, Iggy!)


--
"Menja bé, caga fort!"

I got to get a bunch of new stuff! I doubt I could hurt anybody over stuff,
it's just stuff and it doesn't go on the score card.


"Larry Jaques" wrote in message
...
On Tue, 04 Jan 2005 23:29:35 GMT, "Tom Gardner"
calmly ranted:

Forget the welder...make a TIME MACHINE!!!

We know what YOU want it for, Tom. You want to go back to the point in
time just before the perps came out of your shop so you can kneecap
'em, don't you?

(Let me know how it works, Iggy!)


--
"Menja bé, caga fort!"

On Thu, 06 Jan 2005 04:33:18 GMT, "Tom Gardner"
wrote:

I got to get a bunch of new stuff! I doubt I could hurt anybody over stuff,
it's just stuff and it doesn't go on the score card.

Its just Stuff that represents your time, your labor, your blood
sweat and tears. That accounts for a lot. It does for me anyways.

Just my opinion of course.

Gunner



"Larry Jaques" wrote in message
.. .
On Tue, 04 Jan 2005 23:29:35 GMT, "Tom Gardner"
calmly ranted:

Forget the welder...make a TIME MACHINE!!!

We know what YOU want it for, Tom. You want to go back to the point in
time just before the perps came out of your shop so you can kneecap
'em, don't you?

(Let me know how it works, Iggy!)


--
"Menja bé, caga fort!"



"Gunner, you are the same ridiculous liberal f--k you ever where."
Scipio

I thought that welding transformers were built with a large leakage
inductance, so that the arc is struck with a higher voltage, which falls to
10-15volts as soon as the arc strikes.
I believe a power transformer would not behave like that - a transformer
with good regulation would burn out in seconds if it were used for welding,
unless there were some current-limiting in circuit.

Perhaps somebody who knows could enlighten me?

G.H.Ireland

--
igor
_____________________________________________
Acorn RISC OS4
_____________________________________________

On Tue, 11 Jan 2005 21:40:03 GMT, Mr G H Ireland wrote:

I thought that welding transformers were built with a large leakage
inductance, so that the arc is struck with a higher voltage, which falls to
10-15volts as soon as the arc strikes.
I believe a power transformer would not behave like that - a transformer
with good regulation would burn out in seconds if it were used for welding,
unless there were some current-limiting in circuit.

Perhaps somebody who knows could enlighten me?

G.H.Ireland

They are built like that. A separate variable inductor could be used for
current control in series with a normal power transformer to give the same
'nominally constant current' effect.


Mark Rand
RTFM

Ignoramus28225 wrote:

Then, to have a rudimentary welding machine, all I need is to add a
onboard overcurrent protection device, a rectifier big enough, and
welding cables. Am I missing something important? I know next to
nothing about welding equipment and wanted to tap into your collective
knowledge.

Lindsay Publications had a little book on making your own welder, I
didn't see it on the website but maybe it's in the catalog:

http://www.lindsaybks.com/

Ken Grunke

--
take da "ma" offa dot com fer eemayl


----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups
---= East/West-Coast Server Farms - Total Privacy via Encryption =---

Mr G H Ireland wrote:

I thought that welding transformers were built with a large leakage
inductance, so that the arc is struck with a higher voltage, which falls to
10-15volts as soon as the arc strikes.
I believe a power transformer would not behave like that - a transformer
with good regulation would burn out in seconds if it were used for welding,
unless there were some current-limiting in circuit.

Perhaps somebody who knows could enlighten me?

G.H.Ireland

I don't know about that. Welders do use wide flat 'wire' and complex
cores. I know for more years that I want to think power transformers
have been used as welding transformers. You are talking about open circuit
voltage vs. closed circuit. Regulation is the name and efficiency is it also.
Once HV OSC's were or'd into the main work lead, that need went out the door.

Pure stick likely needs it. Stick with a fancy HV OSC like TIG would be just fine.

That is my take -
Martin

--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

On Wed, 12 Jan 2005 01:39:03 +0000, Mark Rand
wrote:

On Tue, 11 Jan 2005 21:40:03 GMT, Mr G H Ireland wrote:

I thought that welding transformers were built with a large leakage
inductance, so that the arc is struck with a higher voltage, which falls to
10-15volts as soon as the arc strikes.
I believe a power transformer would not behave like that - a transformer
with good regulation would burn out in seconds if it were used for welding,
unless there were some current-limiting in circuit.

Perhaps somebody who knows could enlighten me?

G.H.Ireland

They are built like that. A separate variable inductor could be used for
current control in series with a normal power transformer to give the same
'nominally constant current' effect.

Yes, but a ferro-resonant transformer as shown does current-limit.
If the cross-leg were sawn and made adjustable, it might behave a lot
like an arc welder.

On Wed, 12 Jan 2005 09:50:13 -0600, "Tim Williams"
wrote:

Err, so TIG doesn't need a current-limited transformer?

Yes, it does. TIG and stick have essentially the same electrical
characteristics. They are called "constant current" or CC machines.
They are not necessarily electronic, e.g. Miller Dialarc HF.

A V vs I curve with varying resistive load would look like the first
quadrant of an ellipse. Voltage is fairly flat at the top (open
circuit, high load resistance) region, but the curve is nearly
vertical (constant current) near short cct condx. OCV is typically 60
to 80 volts, arc voltage is typically about 24 volts.

This sort of VI characteristic is also typical of oil ignition and
neon sign transformers. It is achieved with leakage inductance in the
xfmr (often just a magnetic shunt), though welders do sometimes have
additional inductance as well.