View Full Version : antique welder

10-07-2007, 11:16 AM
I have just acquired an antique Fansteel DC welder. It had been sitting in a barn for many years but ran when plugged in. I did not have any way to test it before I brought it home but when I did it appears to have been rewired for AC output. Doesnt work worth a darn and I have no idea how to rewire for dc output or if it would work anyway. Is this worth any effort at all or just scrap. It is a Fansteel dc welder with lugs on the front to change from 26V to 13V output rated 115amps. Selenium rectifier on front label. Probably prewar as Fansteel Metalurgical came into being in 1935 or there abouts and changed name again in 68. Weighs about 200lbs. Thanks, Steve

10-12-2007, 06:34 PM
You might want to post a pic as some of these (cough, cough) older guys might recognize it and be able to give some insight.


10-14-2007, 02:58 AM
Since you say that the basic transformer works, you can probably make a useful (albeit probably not ideal) welder out of it. Does it have any rating plate on it? Does the transformer have any parts (coils or magnetic shunts) that can be moved with cranks or levers? Does ithe transformer have taps that can be selected by plugs or by a switch?

At 200 pounds, it probably has enough oomph to do some useful work on relatively light steel, but without any photos or a circuit diagram, it's hard to say how to make it useful. Lots of light-duty home/farm welders weigh less than 100 pounds.

However, considering the relatively low cost of basic welders on the used market or from big box stores, this may be more of a project for someone who wants to restore an antique than for someone who merely wants to have a good welder.

Assuming that the transformer is OK, you can test the rectifier to see if it is still useable. Connect the two transformer output leads to the rectifier AC terminals (often painted yellow), put a resistive load like a heating element or large light bulb across the DC terminals (usually painted red and black or stamped with "+" and "-"), and see if you get power to the load. If all four diodes in the rectifier are working you should get the same heat or brightness with the load connected across the AC terminals or the DC terminals. Be aware that you will get only a dim glow or low heat from the load on the transformer outlet, either AC or DC, due to the low voltage, but you should still be able to determine whether the rectifier is working or not.

If the rectifier is shot, you will have to accept that you will only have an AC welder (which is still quite useful - I've been using an AC only stick machine for decades) because the basic machine is not worth the cost of replacement rectifiers - even from surplus - unless you pick them up for a song. Rectifiers, selenium or silicon, are not repairable.

Post some pictures and try to draw up a wiring diagram and we may be able to help you.


10-18-2007, 10:54 AM
Sorry so lame in keeping up here. Ended up selling the leads to a friend and cutting it for scrap. 2.50 a pound for the copper and 25 or so for the rest. Ended up with 103 bucks for scrap and made out ok. It had been rewired internally for ac only perhaps because it had burned out dc section.

10-26-2007, 11:37 AM
What are you going to replace it with. John

10-27-2007, 11:52 AM
No replacement, I have a Powcon for stick and innershield and picked up a 300 Airco Squarewave for learning tig. Just cant pass up what could have been a useable machine for cheap. Steve