Good day,

I recently purchased a Lincoln AC-225 welder for $40 (Minus leads of course). Before I plugged it in I decided to take it apart and clean it. I will show you how you can take your old welder and make it work like a new one.

These machines have been produced for many years, and chances are you own one, why not pass it on to your kids? 

I cannot state how easy this is to accomplish. Chances are if you own one of these welders you are more than proficient to dissemble its simple switch assembly and properly clean and lubricate it. In fact, the most difficult part in my opinion, is the tedium of removing the screws to access the internals. 

Please, do not be afraid to attempt this. 

You will need:

Tools to remove sheet metal screws, plus a phillips, and flat screwdrivers
5/16", 3/8", an 7/16" box end wrenches and sockets (One of each for each size)
Good quality grease. I used Mobile-1 Synthetic automotive grease
A Dremel tool with light abrasive polishing bit 

Step 1: Cut the breaker, unplug the welder, then start removing screws.

Picture of Cut the breaker, unplug the welder, then start removing screws.
Unplug your welder. This is a life and death step. 220VAC is very dangerous-it is dangerous because it is high current, and it GRABS you when you come into contact with it. Higher voltages such as 30kV low current are actually less dangerous, because they will REPEL you. 

So make sure your tombstone welder is unplugged, because it's too early to have your own. Tombstone, that is. 

There are lots of screws. Mine had an amalgamation of flathead, phillips, and hex-head screws. I am not sure if they come from the factory like this. 

I did not take pictures of every step as far as screw removal goes. All I can tell you is to keep all of the screws in a container. 

The front specification plate must be removed. To do this, there are 4 screws in the front, but you must also remove the selection switch handle (White arrow). To do this, simply remove the flathead screw that is in the fat portion of it. (See green arrow)
jonm1723 days ago

Thanks for taking the time to show all this!

walkerbert10 months ago

"Unplug your welder. This is a life and death step. 220VAC is very dangerous-it is dangerous because it is high current, and it GRABS you when you come into contact with it."


I grew up in Germany, where standard wall current is 220VAC. It bit me a couple times, mainly because of my own carelessness, but it didn't grab me like described here. Getting juiced by anything isn't probably good for you, and the advice to unplug and ground out any appliance or mechanism before working on it, is sound advice. Especially anything that might have a high-potential capacitor in the circuit, somewhere, those things can put a charge in you, if you're not careful. Also, start your inspection/rebuild process, with the cord itself. Get the whole thing under a nice bright light, are the pins clean, pitted, corroded, are they seated in the socket head properly, do they wiggle, how about the rest of the cord behind the plug head, any cracks, insulation peeling off, visible kinks or bends, bubbles, cuts, or burn spots, anything that looks like it might be broken under the outer casing, and, test for continuity. With a welder, you're dealing with slag spatter, and while these things are built a little on the heavy side, slag has just been at about 5,000 degrees or whatever the arc temperature is, and if it's an older machine that's seen a lot of service, cord replacement might not be a bad first step.

As for the insides of one of these things, I kind of want to lean toward handing that work off to a certified professional. I guess I could probably do some of it myself, but I'd want the rebuild book and a parts kit and preferably some adult supervision there to help me along...this page is a good intro, though, and thanks for posting it! I'm getting a Lincoln, today.

I was in Germany myself and got tickled with 220 volts, it is at 50 hertz there. Here it is at 60 hertz, and it will GRAB you! I can attest to that. That mere 10 hertz in frequency makes a BIG difference in how it acts.

sleisher2 months ago
great advice. Just to pass on some info, that's a cracker Jack or cracker box welder. I'm including a picture of a tombstone welder. I drove 3 hours once to buy a welder that the guy swore was a tombstone......it wasn't. The difference is like having a s-10 and a Cummins one ton dually.
sleisher sleisher2 months ago
Buzz box welder. auto complete put cracker.....
yanggers3 months ago

I have a question about greasing the copper contacts. This must have worked out fine for you, so I'm asking just for my understanding. Wouldn't the coat of grease insulate flow of electricity between the copper contact plates?

allyour80211b5 months ago

quick question before I start, does the front face separate from the sides? I see the seam where they meet but am unsure if indeed to remove screws from the sides at all or is it just front face screws that come out and the face cover (not the instructions plate) comes off leaving the sides and back in place.

AlW18 months ago

Quick tip: After the contacts are all burnished and dusted off, a light coating of OX-GARD (anti-oxidation compound) on the contacts and selector will keep it fresh. A small tube is cheap.

Geordi1 year ago

I would like to give my thanks too. I was given a fairly old welder and wanted to put it to use. Its a bit different than yours (small flat steel connectors to the selector instead of wires) but enough to help me on the way.

Thanks again

tundrawolf (author)  Geordi1 year ago

You are welcome! It makes me glad to know that people are helped by this. Remember to polish those flat connectors where they are screwed down, both sides, for optimal conductivity.

whiterider2 years ago
Thank you so much for posting this. I acquired a welder that has not been used for years and has been stored in a place that was not the most waterproof. Your instructions just may get me up and running!
Bobdeham2 years ago
It a transformer based machine and as long as it unplugged from line AC mains there is no shock hazard.
Even though it is unplugged is there still a chance it could shock me? Anything inside that I could get shocked with?
stantique3 years ago
I just bought one of these with the leads for $100. This instructional works! I revamped mine with following this page and no cash. It now runs like brand new! Thanks alot!
tundrawolf (author)  stantique3 years ago
Thank you very much. It makes my day to see you helped. Thanks again.
ungubungu3 years ago
An excellent article on the tune up for Lincoln welders. Great pics and great script. I used dielectric grease meant for spark plug boots. Also it helps to pull out on the selector switch when making voltage changes.
tundrawolf (author)  ungubungu3 years ago
Thank you for the kind words.
bilray4 years ago
Very useful info and good job, Thanks.
tundrawolf (author)  bilray4 years ago
My pleasure. Happy to be a help.
My welder was stuck on the 75 amp setting, thanks to your instuctable I took it apart and refreshed every contact in it.Works like new.Thanks again.
tundrawolf (author)  bilray4 years ago
I was very blessed by this comment. Thank you.
rimar20004 years ago
You did a very good deal!
tundrawolf (author)  rimar20004 years ago
Thank you my friend! Muchos gracias mi Amigo!