Hand held spot welder - Cooked Electrodes ??

I was given an old hand held spot welder that I would like to use. I took it to a welding repair/supplies shop and was told that the the basic unit was ok but the electrodes (the 8" long copper fingers) were cooked and should be replaced. What is cooked ?? Does the coppers structure somehow change if overheated ? He quoted some Alloy name and claimed it was $140+/Kg. Is there some trick to cleaning the electrodes ?? They don't look that bad although the very contact tips are extremely large (about 5/16") I thought they should be about 1/8" at the point.
Any insight would be appreciated.

Danny

I have a Dorman 1.5kVA hand held (I've also heard them called tong welders) and the electrodes were also buggered but I just bought some 1/2" copper rod and made up new ones. The 8" long copper arms that the electrodes mount in I wouldn't have thought needed replacing.
Tips can be dressed with a file - as you suggest they should probably be a maximum of around 1/8".
Plan A would be to dress the tips with a file (nice conical shape, flat tips need properly, smaller than 1/8" diameter) and then try it. Make sure your contact force is not too light if you have dressed the tips. Plan B would be to head to the local copper merchant and buy a small length of 'electrode copper' in the right diameter and make up some new tips. Plan C is to pay the repairer's seemingly high prices.

Michael

i think for non stop industrial use the repair guys right, has come up before and there is a specific copper bassed allloy for the trodes. Coppers the every day make do option but wont hold the shape as long. Over here you can get a ratcheting reamer you clamp bettwen the tips and it recuts them to the right profile. The profile makes a big diffrence to the strength and also what thickness you can weld upto.

Here is some info about electrode alloys: WELDING DATA