It's been a miserable year for casting here, if it wasn't raining it was in the 90's, and the business was keeping me busy. The rain still won't go away so I decided to clean out my stash of motors that have been stored under the house. They are die cast bodies, 3/4hp 3 phase face mounts. First thing was to strip them down to the stator body, then run them across the table saw and score the alloy deep enough that a good whack with a three pound sledge split them open. I removed the stator core and then smashed the shell into four pieces. Each motor contained 3.8 lbs of alloy and 1.6 lbs of copper. Ended up with 105 lbs of alloy.
Yes, I cut the copper out and recycle. I'm down to 8 left to do, started with 31 motors and there are probably a couple more buried in my garage. I looked up die casting and it seems the most common alloy is 380, 383, some 419, high silicon content 9%-12%. I'm hoping this will work well for my plaques and thin castings. Another option is mixing Al wire in with it to lower the Si content. I've been recycling the wire and would sure love to use it. Another rainy day project, went through my brass scrap and took apart all the valves and separated the yellow from the red. One day I'll do my first brass melt.
You've got me curious about the source of those seemingly identical scrap motors! I have a few laying around, but 31?! If you'd rather not say I understand. When you remove the wire do you saw one end off and then work them out the other end of the rotor? Ive accumulated quite a bit of copper from insulated wire and cable (Romex, etc) and have a pretty fair amount of enameled magnet wire from motors and transformers as well but wondered whether the poly/varnish on the mag wire would make it unsuitable for melting in a crucible. It seems like it would make for a lot of extra crap in the melt unless it was cooked and cleaned beforehand. Pete
That's quite the hall Bonz. 380 series and most likely die cast alloys in those motors are scrap based and will have higher impurity levels than some of the other 3xx series casting alloys but should be decent casting stock. The Si should make for good fluidity (also wear) which should be helpful for plaques and ornamentals. In general they will be more brittle and have lesser mechanical properties without the use of modifiers and refiners, so if you need to bend/form or machine the castings be so advised. In my experience with the very hi Si alloys, I didn't seem to gain a lot in fluidity compared to my other casting stock and produced duller casting color. If there was any salvageable Al in the motor rotors, that stuff is usually 1xx series and fairly pure aluminum too. Best, Kelly
Thanks for the info Kelly. Sounds like adding the wire is going to be the thing to do. Pete, the motors were used takeoffs from my previous place of employment. We scrapped four 80 foot machines that had about a dozen motors each on them. I made a deal with the boss, if I disassembled the machines to separate the metals (the decks were 1/2" x 55" x 25" Aluminum plate), I could have the motors. I was turning the rotors down to add neo magnets to them to make wind turbines. Perfect motors for that, Al bodies, 5/8" shafts, stainless bearings, six wire points so you could run them series, parallel or individually rectified. I did about 5 of them and the rotors were beating my little lathe to death with the sandwich of Si steel and Al. As far as getting the copper out, I use a wood chisel to cut one end off and then hammer the rest out with a piece of flat steel with a V notch in the end. The 3 lb sledge is getting a workout. The copper will go to the scrapyard at some point.
Seems to me the last time I scrapped motors, I got ~90cents a pound. Not shabby when ya roll in with 8 monster AC compressors totaling over 500lbs. The guy that took them didn't ask if I drained the oil and I didn't say a word. Draining and cutting these open is just not going to happen on my watch. I cut one open one time and that metal was just not worth the risk of losing a finger or dealing with the inevitable fire you get slicing into them with an angle grinder. Ya pick your battles wisely.
You're in for a rude awakening if you scrap one now, you'll get the same price as scrap steel, about 8 cents a pound. I took a couple small motors and xformers in last year and got that rate. The #2 copper is around $1.98/lb.
More rainy day work. Finished with the motor breakdowns, have two buckets of copper windings. Stripped the wire scraps I have at the house. It's large four aught and two aught feeder wire cut in four foot sections and coiled around a pipe so I can plunge it into a molten heel in the crucible. About 20 lbs here.
