Copper To Iron Ratio in Transformers/Electric Motors

This has been discussed before, but I can't seem to find the link in the search function. I have approximately 400 pounds in transformers and 100 pounds in Electric Motors. As is, my payout is as follows

Transformers: 400@ .32 =$128
EM: 100@ .25 = $25



As a general rule of thumb, what percentage of a 10 pound transformer would be copper? What percentage of a 10 pound electric motor would be copper?

even if you had the weight to weight ratio, would it mean one way was better than another? I'm seeing some are worth working with, and some are just too much trouble. At what point would you decide whether to tear it down?

It works out profitable for fridge motors as they only give you 'light iron' price for it because they don't know whats inside it.

Fridge motor is 9-10Kg, say after scrapping I get 8Kg Heavy Iron & 1Kg Copper.

ie, before I got $1 for it, after scrapping I get $2 for the Iron & $8 for the Copper.

Maybe I should call this "How to make $9 from $1......"

Small electric motors On the .5 thru 2 horsepower on the average will yield 10 percent.Again I repeat on average,some up to 12 percent have experienced 14 percent but rarely.Like someone post above make sure they do have copper winding by cutting a piece of the windings and check.If you go by color you can be fooled.The yield is based on starting weight without pumps,pulleys etc...

The few I've weighed and tested the ratio yeilded around 18% copper recovery. This will obviously vary. Unless you are super efficient, have a lot of time, or need to squeeze every dollar. I wouldn't, then again I only have so many hours during the week. Tear a few apart post results.