Last night I spent sometime evaluating our different categories of scrap. We have accumulated several 5 gallon buckets of the little transformers. Also had a full bucket of solenoids, a mix of hard and soft body ones. Almost all of the hard body ones come from my landscape company. The soft body solenoids come from recycling of dumpster waste at the commercial business parks we manage. Have never sold scrap items in the category "copper bearing". Going to start though, as I don't see busting up the little transformers as productive and cost effective. What I'm going to do is evaluate the various copper bearing items, scraping methods, time, ease of recovery and percentage of copper return to actual weight.
I did several soft body solenoids (coils) last night and thought I would share what I found. We get about 10 to 15 of these a week, from a company that does appliance repair. I'm going to give only three types, the most common are from gas dryers and some gas stoves. They are mounted in pairs. The two connector coil weighed 1.10 ounces and the three connector coil was 1.59 ounces. The other type of solenoid is also very common, as it comes from refrigerator/freezer that have automatic ice makers. This coil weighed 1.31 ounces before copper removal. I'm giving just the actual coil weights and not the whole solenoid assembly that coil is part of.
Earlier in this thread I recommended setting them out in the sun for a couple of hours to soften. Well last night I didn't do that (no sun). What I found was the PVC cutters cut the soft bodied coils just as easy, so forget sun step! I do highly recommend the use of the PVC cutters and the dental tool. I didn't time myself, but I cut the bottom off each coil and removed the copper (about 1 minute per coil). I don't even try to recover every bit of the fine "angel hair" copper. A little copper is always stuck to the plastic body and that gets tossed into city recycle bin. The two connector (gas) coil copper weighed .83 ounces, the three connector (gas) was 1.26 ounces and ice maker coil was also .83 ounces of copper. I used the same formula for figuring copper percentage return on insulated wire. The percentage of copper return for each coil was: 75.4%, 79.2% and 63.3%. There is also a little bit of brass (the connectors) on each coil. The gas coil connectors are very small, weighing only .2 grams, so on the two connector gas coil you have .4 grams of brass. The ice maker coil connectors weigh .85 grams (1.7 grams per coil).
I will continue to process these coils for the copper. We get a lot of them (10 to 15 per week) for free, they are easy to process and copper return percentage is above 70%. I have read the past threads about these soft bodied coils. Most have said they are hard to work and use various techniques/tools. Some use hammer, hatchet, screw driver, chisel and suggest freezing. I'm not sure how/why we started setting them in the sun. Last night I learned that is a waste of time, also learned I need to review methods. The PVC cutter and dental tool is the way to process these coils. For me these little coils equal 25 to 35 pounds of #2 copper per year. More important they were going out with the trash and into a landfill.
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