Welding application question

[[email protected]]

Someone recently gave me a 225 amp AC welder which was made by Lincoln
about 25 years ago. It has been sitting for about 20 years and was
previously hardly ever used. It has a switch on the front with
positions ranging from 40 - 225 amps. Admittedly I don't know much
about welding however I have heard that DC welders are much more
desirable. So I have some questions:
1. Where or when would it be more desirable to use an AC over a DC
welder?
2. Am I correct in assuming that the secondary on the unit's
transformer is tapped and then simply run through a switch on the
output?
3. If so can I construct on a suitable heatsink, say a 400 amp bridge
rectifier circuit and install it between the switch and before the
ground and electrode cables?
4. Are the outputs of welders normally protected in some fashion
against current overload. Would I need to do this?
5. The unit operates from 240VAC. What would the minimum breaker size
have to be to handle full load?
Thanks very much for any information on this. Lenny Stein, Barlen
Electronics

 

[jakdedert]

Someone recently gave me a 225 amp AC welder which was made by Lincoln
about 25 years ago. It has been sitting for about 20 years and was
previously hardly ever used. It has a switch on the front with
positions ranging from 40 - 225 amps. Admittedly I don't know much
about welding however I have heard that DC welders are much more
desirable. So I have some questions:
1. Where or when would it be more desirable to use an AC over a DC
welder?
2. Am I correct in assuming that the secondary on the unit's
transformer is tapped and then simply run through a switch on the
output?
3. If so can I construct on a suitable heatsink, say a 400 amp bridge
rectifier circuit and install it between the switch and before the
ground and electrode cables?
4. Are the outputs of welders normally protected in some fashion
against current overload. Would I need to do this?
5. The unit operates from 240VAC. What would the minimum breaker size
have to be to handle full load?
Thanks very much for any information on this. Lenny Stein, Barlen
Electronics

You probably need more help in this matter than you're going to get here
in an electronics forum...or any other for that matter.

Google is your friend. In any case, to answer #5, above, check the spec
plate on the welder itself.

CAUTION: Arc welding is an extremely hazardous occupation when done by
amateurs! Do some reading! Take a class! Examples of Bad Things which
could happen are: Electrocution, Blindness, Serious Burns, Fires and
Inhalation of Noxious Fumes....

jak

 

[GregS]

Are you suggesting making a DC welder? I did. You also need a LARGE
coil in series with the output. I took an extra large variac torroid, has
one winding on it. I scoped out the winding. I was going to cut
the winding into four parts, and run 4 sets in parallel. The thing that needs
to be done, is cut the core all the way through somewhere. A thin cut which keeps the core from
saturating. Well it worked.

greg

 

[[email protected]]

I just talked to the manufacturer today and found out about the coil.
Its 165.00 FOB. Does anyone have any idea as the the inductance of this
thing? It couldn't be anything too special. Lenny.

 

[James Sweet]

Someone recently gave me a 225 amp AC welder which was made by Lincoln
about 25 years ago. It has been sitting for about 20 years and was
previously hardly ever used. It has a switch on the front with
positions ranging from 40 - 225 amps. Admittedly I don't know much
about welding however I have heard that DC welders are much more
desirable. So I have some questions:
1. Where or when would it be more desirable to use an AC over a DC
welder?

Personally I wouldn't mess with it, AC is fine for welding, in my experience
it's easier to get a nice clean weld with DC but with practice you can do a
decent job with AC. You might want to take a class though before trying to
use it or you'll get frustrated quickly, either welding the rod to the thing
you're trying to weld or making puddles of molten metal on the floor. It
takes a lot of practice and you have to use the correct type of rods and the
right current for whatever you're welding and some rods require different
techniques than others.

 

[Rene]

Someone recently gave me a 225 amp AC welder which was made by Lincoln
about 25 years ago. It has been sitting for about 20 years and was
previously hardly ever used. It has a switch on the front with
positions ranging from 40 - 225 amps. Admittedly I don't know much
about welding however I have heard that DC welders are much more
desirable. So I have some questions:
1. Where or when would it be more desirable to use an AC over a DC
welder?
2. Am I correct in assuming that the secondary on the unit's
transformer is tapped and then simply run through a switch on the
output?
3. If so can I construct on a suitable heatsink, say a 400 amp bridge
rectifier circuit and install it between the switch and before the
ground and electrode cables?
4. Are the outputs of welders normally protected in some fashion
against current overload. Would I need to do this?
5. The unit operates from 240VAC. What would the minimum breaker size
have to be to handle full load?
Thanks very much for any information on this. Lenny Stein, Barlen
Electronics

Why don't you sell it and buy a DC model if that's your choice.

 

[Bennett Price]

I concur. Welding is a lot harder than soldering or brazing. A
community college introductory course would be ideal. It will also
give you a chance to compare DC to AC welding.

 

[Dave Plowman (News)]

I concur. Welding is a lot harder than soldering or brazing. A
community college introductory course would be ideal. It will also
give you a chance to compare DC to AC welding.

And MIG welding is the choice for amateur use. Doesn't take too much
practice to get decent results for many things.

 

[Homer J Simpson]

[email protected] wrote:

CAUTION: Arc welding is an extremely hazardous occupation when done by
amateurs! Do some reading! Take a class! Examples of Bad Things which
could happen are: Electrocution, Blindness, Serious Burns, Fires and
Inhalation of Noxious Fumes....

Also sun burn from the UV output from the arc - really!

 

[Porky]

If you're handy, you can learn to weld, without burning yourself or
your shop. Use general purpose rods, 611 and 613 come to mind. I
suggest use it as is, you can upgrade to DC some other time. Buy some
metal and build something. Cut it apart and build a better one. One of
my early projects was a garden cart with bicycle wheels. We still use
it, but the tires are starting to rot. AC welding is just fine if you
use the right rods with the right settings. Angle iron is good to start
on. Too hot on thin metal like a muffler will just burn a big hole. You
learn to fill the holes by letting the weld cool a bit before going
back to it, keep adding a bit till the hole is filled. You can buy
expensive burning rods for cutting with, although it's better to use an
angle grinder with a cutting blade. Stand on a rubber mat when you weld
and put the stinger down before you reach for the ground clamp. Too low
of a setting and rusty metal, especially under the ground clamp -you
can't strike an arc, then it sticks, then it arcs while your mask is up
and you blind yourself. Then once you've burned the flux off the end of
your rod, it gets even harder to get an arc started. Sometimes you'll
be better off to grab a fresh rod, get a nice bead going, and you're
welding!

John K

 

[[email protected]]

This is more information than I had ever expected to receive. Thank you

to everyone for all your time and responses. I have actually been
posting this for my son who in fact is currently enrolled in a night
welding course at the local tech college. Someday I may be able to
find the time to go myself as well, but for now I thought that I would
try to experience the the hands on part vicariously. As for the
electronics part, that was what interested me. After reading all this I

may never attempt the modification, but we'll see. Before I do anything

though, as suggested I am going to let him try the rods that were
recommended here for AC and see what he thinks. Best regards, Lenny
Stein.

 

[Asimov]

"[email protected]" bravely wrote to "All" (19 Oct 05 10:13:06)
--- on the heady topic of "Re: Welding application question"

ca> From: "[email protected]" <[email protected]>
ca> Xref: core-easynews sci.electronics.repair:345714


ca> This is more information than I had ever expected to receive. Thank
ca> you
ca> to everyone for all your time and responses. I have actually been
ca> posting this for my son who in fact is currently enrolled in a night
ca> welding course at the local tech college. Someday I may be able to
ca> find the time to go myself as well, but for now I thought that I would
ca> try to experience the the hands on part vicariously. As for the
ca> electronics part, that was what interested me. After reading all this
ca> I
ca> may never attempt the modification, but we'll see. Before I do
ca> anything
ca> though, as suggested I am going to let him try the rods that were
ca> recommended here for AC and see what he thinks. Best regards, Lenny
ca> Stein.


Lenny, no one mentioned this but one thing about rods is that they
must be warm and dry before use. A cold wet rod will be difficult to
ignite and burn up the tip. It takes a lot of practice and experience
to make a decent weld. It doesn't help when one has a hard time with a
poor rod. Pro welders keep their rods in a closed wood box into which
an ordinary house lamp socket is installed. The lamp's heat keeps the
rods warm and dry. Thought I might add a couple of cents worth.

A*s*i*m*o*v

.... That was a fascinating period of time for electronics

 

[James Sweet]

Lenny, no one mentioned this but one thing about rods is that they
must be warm and dry before use. A cold wet rod will be difficult to
ignite and burn up the tip. It takes a lot of practice and experience
to make a decent weld. It doesn't help when one has a hard time with a
poor rod. Pro welders keep their rods in a closed wood box into which
an ordinary house lamp socket is installed. The lamp's heat keeps the
rods warm and dry. Thought I might add a couple of cents worth.

They don't need to be warm, but dry is very important, I suppose a warmed
box tends to keep them dry. We were told to put them in an oven and bake
them for a bit if they'd been sitting around for a while.

 

[Rene]

I saw several shops keep rods in an old air tight refrigerator with a small
bulb inside.
At home I keep mine on top of my hot water tank, as I don't do much welding.