sundog
12-10-2006, 09:54 PM
Felix, finally got around to casting with some of the #5 alloy today. Here's some observations. I needed to get ahead on next year's mil bolt boolits, so I cleaned up the 311291 and preheated on the wood stove. I had about 2 pounds of recycle scrap in the pot and put in enough WW to top it off with 3#s of #5 Copper Babbit Alloy. #5 is the stuff back in my shop and the other is the stuff that you couldn't use (too sheety) is on the barn floor (we'll dilute it later). So, I get started and first thing I notice is sheeting on the ladle coming out of the pot. Uh-oh, too much copper yet again, but I give it a chance and let everything get good and HOT, pot cranked all the way. Ladel is sheeting a little but turning a loss to a gain, I let the end of the sheet drizzle into the sprue hole. Keep going. Nice boolits, really nice boolts. Over 15 pounds worth it worked so well.
The sprue had at least a couple of VERY DISTINCT stages of setting up and frosting. Also, the puddle stood up high and even pulled away from the sprue plate at the edges of the puddle - lots of surface tension. At one point I accidently let a sprue run over the front of the blocks and it sheeted and froze and didn't drop off - just hung there like a drape. BUT, the boolits are very crisp, clean, and completely filled out. Occassionally I would open the sprue a little early and tear the base a little. Kinda fine granular, but no smearing.
I refilled the pot like before, took a break, and did a big batch of 30-180-SP. Same-o-same-o. Another really good looking BIG batch of boolits. I'm thinking these things are gonna be very brittle, but who cares if they only get used for drilling holes in paper and beer cans.
Both of these boolits do right tolerable in 2-groove 03 bbls for mil bolt matches.
I water quenched these boolits while casting and before coming in for dinner checked a few. Can't even drive a thumbnail into them!
If there had been even just a little more copper in this mix, it would not have poured. Now, to see how they'll shoost! sundog
oh, one more observation. While casting I had to several times stir as a bronze sheet would form on the surface anywhere I did not have any wood ash. I'd use the spoon to push the ash down into the melt and stir and do it again, fluxing. When finished the wood ash flux was like clumpy globs.
The sprue had at least a couple of VERY DISTINCT stages of setting up and frosting. Also, the puddle stood up high and even pulled away from the sprue plate at the edges of the puddle - lots of surface tension. At one point I accidently let a sprue run over the front of the blocks and it sheeted and froze and didn't drop off - just hung there like a drape. BUT, the boolits are very crisp, clean, and completely filled out. Occassionally I would open the sprue a little early and tear the base a little. Kinda fine granular, but no smearing.
I refilled the pot like before, took a break, and did a big batch of 30-180-SP. Same-o-same-o. Another really good looking BIG batch of boolits. I'm thinking these things are gonna be very brittle, but who cares if they only get used for drilling holes in paper and beer cans.
Both of these boolits do right tolerable in 2-groove 03 bbls for mil bolt matches.
I water quenched these boolits while casting and before coming in for dinner checked a few. Can't even drive a thumbnail into them!
If there had been even just a little more copper in this mix, it would not have poured. Now, to see how they'll shoost! sundog
oh, one more observation. While casting I had to several times stir as a bronze sheet would form on the surface anywhere I did not have any wood ash. I'd use the spoon to push the ash down into the melt and stir and do it again, fluxing. When finished the wood ash flux was like clumpy globs.