Refurbishing two old Lincoln SP-250 MIG machines.

[strantor]

I've been looking for a decent 250+A MIG machine for a couple of years now. I have a 200A TIG that suits all my needs but it's a pain in the behind to always have to TIG things what don't need TIG'in. MIG is much faster and easier to get set up and and also weld. I got spoiled at my last job where we had a small fab area with a Millermatic 252. Been looking to buy something comparable ever since I left there. I check Craigslist and Facebook marketplace daily or weekly depending on how much money have in the pocket, waiting on a good deal. Actually what I've been looking for is a broken MIG machine that I can fix. I gots some electrical and electronical smarts. I don't know how the used welder market is across the country, but in my area people seem to think welders depreciate no more than 1% per year. People are trying to sell 10 y/o buzzboxes for $10-$20 less than brand new ones in the store. I thought for sure I'd be able to find a broken machine for scrap price. No such luck. Then two weeks ago I happened upon this listing:


Based on my familiarity with this market I considered this deal "too good to be true." I barely looked at it. Coming back to the marketplace and seeing them still listed for sale day by day eventually built up my curiosity. I figured they were probably flooded in Harvey but regardless I did a little research on them and found that (according anonymous & uncited sources on other forums) they were from the early 1990's and weren't very popular in their day. They were ahead of their time. Synergic welders with a panel chock full of buttons and electronic boards. I get the impression they weren't marketed to the right demographic. They were full-featured welders that belonged in commercial shops, being marketed to weekend warriors who were used to having two knobs. They didn't sell well, and production was stopped after just a short time. Spare parts are hard to find, and expensive. So maybe that's why they're so cheap. They're busted and the parts to fix them don't exist. Interesting.... So I went to look at them.


One of them looked pretty rough and the seller didn't seem to know much about them. He said one works but doesn't maintain constant wire speed and the other one doesn't work at all. He didn't know which was which. That was the description he received from the guy he got them from years ago, and he never plugged them in. He wasn't sure if the spoolgun worked. He didn't have anywhere to plug them in for me to verify tbey even powered on, but I decided to take a chance since I didn't see any flood damage and buy them in hopes that with the parts from two complete welders I could at least get one working one, and maybe sell any remaining working spares for at least the $500 I bought them for.



I let them sit for a few days until yesterday I decided to tackle one of them. I chose the one without the spoolgun. The one with the crusty white face and red primer splashed all over it. I chose that one because it had no spool in it, so I assumed it was the one that didn't work at all. I figured it probably had a simpler problem, like a blown fuse or 'sploded capacitors. Powered it up, it came on, but wouldn't weld. Found corrosion where the gun plugs in, on both sides of the from fascia. Cleaned that up and it worked just fine. I tested it with Argo from my TIG and it sucked as expected but it didn't seem to have any speed issues. So I think I "fixed" the one that "didn't work at all."


Since it apparently works just fine, I decided to make it pretty. Chipped off all 26 years worth of dribbled epoxy and splashed paint, peeling finish and petrified stickers, and gave it new coat of paint. The front fascia was white and crusty with paint overspray or peeling finish, not sure, but it scraped off easily with a credit card and a pocket knife. The protective layer over the LCD was petrified, yellow, and cracked. It was barely readable. I very carefully scraped/chipped it away and painted over it with my wife's clear fingernail polish. It's much better now.


The MIG gun itself after being cleaned, seems brand new. Probably worth as much as the welders.

So one down, one to go. I hope to get both of these functional and have one setup for mild steel and one setup for stainless & aluminum. I will update the thread with pictures from the 2nd machine when I get around to fixing it up.

 

[strantor]

I got into welder #2 today, the one with the spoolgun. I'm thinking this is the one described as having spool speed issues. The plastic spool holder (main spool, not the spoolgun) is past the end of its life and does not freely spool anymore. The drive roller is pulling but the wire coming off the spool just digs in a few layers deep until it finally lets go and then it spools freely for 90, 180, maybe 270 degrees and binds up again. I think I will fabricate a new (metal) spooling system as well as a metal replacement for the old plastic feed idler hold-down. All the plastic parts are nearly garbage or already there.

The spoolgun feeds and arcs so electrically it might be OK, but mechanically, all the plastic parts are severely degraded. The handle portion was badly cracked all over. I removed it gingerly and managed not to crack it any worse. My plan was to superglue it back together, so prior to that I needed to get the dirt out of the cracks. I sprayed electrical contact cleaner into it, which instantly made the plastic so soft that it started falling apart in my hands. With every attempt to get the stuff off, I was breaking off more and more pieces. So I put it down and came back later when it all had dried up, and the plastic was back to its previous (poor) structural integrity. I superglued the 3D puzzle back together and I now realize it's just too far gone. Instead of trying to reuse the superglued handle I'm going to use it as a mold form and cast a new plastic handle. It occurred to me to just buy a new handle and I got the part number from some document on the internet but can't find it for sale anywhere. I guess as old as this machine is (1992), the parts are way past obsolete.

 

[yomax4]

I've sold many and owned 2= SP250's. It was a great machine and a little ahead of it's time. Everyone was afraid of the touch screens back then and they were easily damaged. The drop in spool core was a great idea that didn't work all that well without continuous lube. The welder would show parameters in several different languages too. Euro connect was fairly new then and I think L-Tec was the only one using it. Solid machine all things considered.

The spool gun is still used today and parts are available. I might even have a drive roll or two in a box in my shop. Everyone I know that still has an SP250 is on the constant lookout for junk machines to salvage the front panels in the event that one fails. So far most are still in operation.

The Gun you have with it is only $125.00 aftermarket Tweco lookalike. The gun that came with the welders Looked like a Lincoln Magnum gun but it had a slide switch on the handle to toggle between different saved programs. It's also a gun that the SP guys keep an eye out for. Not really needed but some like the option to do that. There are other dual scedual guns out there that can be made to work the same way. Good Luck with the project !!

 

[robstaples]

Nice job cleaning up the unit! Now looks like mine! I have this unit and the wire gun. Bought it new. Mine will shut down when I weld outdoors in the sun. Dealer says it has a sensitive mother board. In doors, unit is fine. Just a hobby welder. Have mine setup with two gas feeds, steel- mig gun and AL — spool gun . Not sure how I could help.

 

[strantor]

I've sold many and owned 2= SP250's. It was a great machine and a little ahead of it's time. Everyone was afraid of the touch screens back then and they were easily damaged. The drop in spool core was a great idea that didn't work all that well without continuous lube. The welder would show parameters in several different languages too. Euro connect was fairly new then and I think L-Tec was the only one using it. Solid machine all things considered.

The spool gun is still used today and parts are available. I might even have a drive roll or two in a box in my shop. Everyone I know that still has an SP250 is on the constant lookout for junk machines to salvage the front panels in the event that one fails. So far most are still in operation.

The Gun you have with it is only $125.00 aftermarket Tweco lookalike. The gun that came with the welders Looked like a Lincoln Magnum gun but it had a slide switch on the handle to toggle between different saved programs. It's also a gun that the SP guys keep an eye out for. Not really needed but some like the option to do that. There are other dual scedual guns out there that can be made to work the same way. Good Luck with the project !!

You're right about the gun on the first unit. I looked it up. The gun on the second unit however, it has the thumb switch and is branded magnum SP.

How do I get parts for the spoolgun? Does Lincoln sell direct?

Edit: also, what do you use to lubricate the spool? I might try that first. There is some sticky/gummy grey residue there where I assume someone tried lubricating it with dry moly, which may have reacted with the plastic. If I cleaned that crap off and lubed it properly, maybe the remaining plastic would work well enough if lubed.

 

[yomax4]

The spool gun is just the Lincoln Magnum and either still used or very recently. They don't make it. ESAB also uses ( used ) the same gun in black called the SG250 if memory serves. The spool gun parts can also be bought direct from another company but I'd have to try to remember the place. Anyway you can print a manual with breakdown on the net I would think and order parts from your welding supply or find a junk one on e-bay.

 

[yomax4]

You're right about the gun on the first unit. I looked it up. The gun on the second unit however, it has the thumb switch and is branded magnum SP.

How do I get parts for the spoolgun? Does Lincoln sell direct?

Edit: also, what do you use to lubricate the spool? I might try that first. There is some sticky/gummy grey residue there where I assume someone tried lubricating it with dry moly, which may have reacted with the plastic. If I cleaned that crap off and lubed it properly, maybe the remaining plastic would work well enough if lubed.

In the old days Lincoln had people use food grade grease. Now most use synthetic. Either one will work and not mess with the plastic. Others modified the side panel to lift up and then installed a regular wire spindle.

 

[strantor]

The spool gun is just the Lincoln Magnum and either still used or very recently. They don't make it. ESAB also uses ( used ) the same gun in black called the SG250 if memory serves. The spool gun parts can also be bought direct from another company but I'd have to try to remember the place. Anyway you can print a manual with breakdown on the net I would think and order parts from your welding supply or find a junk one on e-bay.

Thanks. I found the esab equivalent. They call it a MT-250SG. I found the Esab p/n for the handle and found it for sale. Only $72. I've already ordered the casting compound but I'm going to order the handle too. If the casting compound shows up first I'll try casting it "just because"
WeldingSupply 36455

 

[strantor]

The spool gun is just the Lincoln Magnum and either still used or very recently. They don't make it. ESAB also uses ( used ) the same gun in black called the SG250 if memory serves. The spool gun parts can also be bought direct from another company but I'd have to try to remember the place. Anyway you can print a manual with breakdown on the net I would think and order parts from your welding supply or find a junk one on e-bay.

Thanks for the tips. I was going to order the Esab handle but one last search I did find the Lincoln part. I ordered several new parts to rebuild both MIG guns and the spoolgun. The first machine is now working flawlessly with new liner, idle roller arm, all new o-rings, new trigger switch, diffuser, contact tip, etc., and I've purchased a bottle of C25 gas dedicated to that machine now.



The spoolgun also now has in addition to the new handle, a kevlar zipper sleeve, new diffuser, feed tube, contact tip, trigger switch, et. al. and seems to be working as best I can tell. I've never held a spoolgun in my hand before this so I have no clue if it's behaving as it should, or if I have my settings correct. But it is definitely spitting out metal and melting it. I have it connected to the Argon bottle that I was using for TIG.



I also replaced the plastic feed drive idle roll arm which I suspect was part of the feeding speed problem, but I have not yet tested the repair.

 

[yomax4]

Looking good !!! Yeah, Spoolguns are ok and work ok. They start cold and finish hot but you can work through that a little by starting in the middle. Wht does the other max=chine need to get it going?