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Welding application question

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
Reply to
captainvideo462002
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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

Reply to
jakdedert

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

Reply to
GregS

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.

Reply to
captainvideo462002

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.

Reply to
James Sweet

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

Reply to
Rene

Reply to
Bennett Price

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

--
*I started out with nothing...  and I still have most of it.

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.
Reply to
Dave Plowman (News)

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

Reply to
Homer J Simpson

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

Reply to
Porky

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.

Reply to
captainvideo462002

" snipped-for-privacy@yahoo.com" bravely wrote to "All" (19 Oct 05 10:13:06) --- on the heady topic of "Re: Welding application question"

ca> From: " snipped-for-privacy@yahoo.com" 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

Reply to
Asimov

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.

Reply to
James Sweet

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.

Reply to
Rene

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