Chinobi Posted March 21, 2013 Share Posted March 21, 2013 Hey all, I dont have anything specific projects in mind at this time, but i wanted to bounce this off the collective to see if it was worthwhile to maintain as a raw material, or if it is not worth the effort. i have a sack of Chinese 5 Fen coins, probably about 250-300 of them, that according to my world coinage book and several sources online are struck from aluminum. I have not see any specific alloy information listed anywhere, just 'aluminum'. For the most part they are fairly clean and in good condition, not real heavily corroded or covered in mystery muck. They strike me as having potential to be a good raw material for casting due to being a homogenous material, and already in prefabricated bits of more or less identical size (1.55 grams each), which makes for a more accurate system of measurement for volume purposes. Does anyone know anything more specific about Chinese coinage that can share some insights on the alloy? Many thanks. Quote Link to comment Share on other sites More sharing options...
Nobody Special Posted March 22, 2013 Share Posted March 22, 2013 One's from the 40s were pure Al, or around .5% Cu. Can't read the date on yours. Later one's don't know specific alloys, but some of the later ones were aluminum bronze alloy, and I noticed yours look yellow, although that may be the light. So readeth the coin collectors sites. Quote Link to comment Share on other sites More sharing options...
Chinobi Posted March 22, 2013 Author Share Posted March 22, 2013 thanks, yea the yellow cast is definitely from the lighting. in person they all look like plain aluminum. i didnt exhaustively check but i saw a lot of 1980's and 1990's dates when i was fanning through them. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 26, 2013 Share Posted March 26, 2013 In general items that were cast were cast from alloys suitable for casting. Items that were extruded were made from alloys suitable for extrusion, etc. As the coins were plancheted and then struck I would *guess* that they were an alloy suitable for that and so not the best casting alloy. Quote Link to comment Share on other sites More sharing options...
Chinobi Posted March 27, 2013 Author Share Posted March 27, 2013 Thanks Tom, that makes sense. I wonder if its close 'nuff to be workable though. i gotta get a few more crucibles and check it out. Quote Link to comment Share on other sites More sharing options...
Nobody Special Posted March 27, 2013 Share Posted March 27, 2013 Depends on your intent too. If you're planning to cast something small and decorative, you could probably use what you've got. If you're planning to build something like a lathe, or drill press, that depends on strong structural integrity, maybe not with an unknown alloy. I wouldn't necessarily try to get more of the same without knowing. If you're looking for scrap aluminum to cast, I've had good luck with breaking up cast parts from cars, such as aluminum pistons, trannie cases, alternator cases, intake manifolds, etc. Also note that a straight, single casting without heat treating may change the composition and structure of the alloys. Quote Link to comment Share on other sites More sharing options...
Chinobi Posted March 27, 2013 Author Share Posted March 27, 2013 not to worry, anything i cast will be pretty small, and would not be a strucutral part of something meaningful. the most demanding application might be structure for some kind of spring powered device (hand held) or just as little fob-y kind of things, or chess pieces. things of that nature. not looking around for more either. we had a tennant that used to use the 5 Fen coins in our coin-op washing machines (insert child friendly explitives here), so i have a bag of them that we accumulated over 2 or 3 years. they are almost identical in dimension to a US quarter :( so seeing as i have a pile of this largely useless material i figured i could press it into service as a raw material. Quote Link to comment Share on other sites More sharing options...
Gromgor Posted March 28, 2013 Share Posted March 28, 2013 funny story: the reason most US coins have ridges on them was originally because they were crafted with the value of gold vs. their weight in mind. Industrious individuals would file bits of the coins down and make extra coins. The ridges were a counterfeiting measure. Now they remain to help the blind be able to tell which kind of coin they're touching. So it's not unprecedented to use the metal in coins for things not intended. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 28, 2013 Share Posted March 28, 2013 In earlier times the difference between coins and bullion was not large. A coin was worth it's bullion content and you could take your coins to a silver smith and have items made from them. I have seen this done in the 19th century as ornamentation for a american frontier rifle and in fact a friend of mine cast a coin silver trigger guard for a reproduction he was doing. Quote Link to comment Share on other sites More sharing options...
oof Posted March 29, 2013 Share Posted March 29, 2013 you could use it to make zamak. mark Quote Link to comment Share on other sites More sharing options...
Chinobi Posted March 29, 2013 Author Share Posted March 29, 2013 not really, i posess a sack of spare aluminum coinage, i do not have another 50 sacks of zinc to get up to the 96% zinc 4% al levels =/ plus no way im alloying and casting zinc in a residential setting. thanks though. Quote Link to comment Share on other sites More sharing options...
Nobody Special Posted March 30, 2013 Share Posted March 30, 2013 Pennies past 1987 are 98% zinc, however I agree with you about melting it at home. Especially since aluminum melts around 600 degrees or so hotter than zinc. Better safe than in the hospital drinking lots of milk and wondering what happened. (I've melted it from time to time, but then, I'm occaisionally stupid, and got zinc poisoning this way on one occaision when I tried it without proper ventilation.) In earlier times I have seen this done in the 19th century as ornamentation for a american frontier rifle Thomas, how old ARE you??? Quote Link to comment Share on other sites More sharing options...
Chinobi Posted April 3, 2013 Author Share Posted April 3, 2013 yea i avoid melting pennies past 1981 (mid 1982 is listed as the switching point from 95% copper to copper plated zinc) so that makes it simpler than trying to weigh the '82 wildcards and figure out which is which. Quote Link to comment Share on other sites More sharing options...
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