David2011
08-20-2017, 07:17 PM
I've been casting for a while, starting in 1982. I've probably used 3000 pounds of lead so far. My boolits have with a few minor exceptions consistent and of good quality and very consistent weight for the application, a little plinking, a little hunting and a lot of action pistol shooting. Apologies for the long post. I have a talent for making a short story long.
Last weekend I got tired of messing with a mold that didn't want to drop boolits so I (UGH!!!) sprayed aerosol bullet mold release in it. The boolits came out with a texture that offended my eyes but were perfectly serviceable for Cowboy Action where the targets are large and close. This weekend, on Saturday, I decided to pursue the issue further. I cleaned the mold, a Lee 358-158-RF with a solvent, scrubbed it with Dawn and hot water and gave it a final cleaning with lacquer thinner and Q-Tips. After that I went over the edges of the cavities that were reluctant to drop with an X-Acto knife looking for burrs and other rough spots. A few suspect spots were found and smoothed.
I fired up the furnace and prepared to make another batch of boolits. I know all of the basics except how to consistently get shiny boolits. They always started out shiny but I quickly got the mold too hot and they frosted. I could reliably pour and drop about every 25 seconds as long as I didn't mind frosted boolits. This cycle time was about the same regardless of the size or material of the mold. I was running the furnace at around 700 degrees by a thermometer.
So far this is pretty routine. What happened next made everything I knew about casting come together. My boolits were good and satisfied the need but were never as pretty and shiny as other peoples' boolits. I know frosted boolits are fine and understand what causes the frost. I was plugging along making my usual lightly frosted boolits and started slowing the pace to try to get a little more shine to them. I really slowed the pace but there was still that bit of frost. I started reducing the temperature of the furnace. Over the next 20 minutes or so the boolits started getting shiny. As the temperature dropped further I was able to increase the pace and the boolits were still shiny. I finally settled in at about 625 degrees and let the sprue cool for 15 seconds before opening. Every boolit had that nice shiny look. I finally got the look I wanted and found that by going slower the boolits seemed to shrink a little as they dropped much easier.
I was so thrilled with the way everything came together that I mixed another alloy and repeated the results with different molds and alloys. On Sunday I went to the shop, mixed up another favorite alloy and enjoyed the same results with two more molds. I even cast with two very different molds alternating between them and had great results. One was a 4 cavity 170 grain .401 Lyman TC and the other was a two cavity 125 grain 9mm TC. I had no rejects with the .401 mold and only 5 or 6 from the 9mm. The 9mm mold is a little harder to pour for than larger molds. It fills so fast even with the pour adjustment throttled down! Most of my casting is from 158 to 250 grains.
For Pete's sake, I had been putting up with frosted boolits for all those years just because the melt was a little too hot. I would have had to slow my pace to probably one pour per minute to get the same results at a 700 degree melt temp.
In the past I got shiny boolits from time to time but never connected all of the dots. I knew the frost was from the mold getting too hot but going a little slower didn't make any difference. It just didn't occur to me that I was running the melt that much too hot.
This may sound like a total noob oversight but I've been making the same mistake hoping for different results for a long time. (Insanity?) Time after time we have all including myself told new casters to control the mold temp with the pace and not the pot temperature but that only works if the pot temperature is within the range where it needs to be for the mold, alloy and pace. While my numbers may not be valid for the next caster the concept probably will be so I wanted to share my enlightening.
David
Last weekend I got tired of messing with a mold that didn't want to drop boolits so I (UGH!!!) sprayed aerosol bullet mold release in it. The boolits came out with a texture that offended my eyes but were perfectly serviceable for Cowboy Action where the targets are large and close. This weekend, on Saturday, I decided to pursue the issue further. I cleaned the mold, a Lee 358-158-RF with a solvent, scrubbed it with Dawn and hot water and gave it a final cleaning with lacquer thinner and Q-Tips. After that I went over the edges of the cavities that were reluctant to drop with an X-Acto knife looking for burrs and other rough spots. A few suspect spots were found and smoothed.
I fired up the furnace and prepared to make another batch of boolits. I know all of the basics except how to consistently get shiny boolits. They always started out shiny but I quickly got the mold too hot and they frosted. I could reliably pour and drop about every 25 seconds as long as I didn't mind frosted boolits. This cycle time was about the same regardless of the size or material of the mold. I was running the furnace at around 700 degrees by a thermometer.
So far this is pretty routine. What happened next made everything I knew about casting come together. My boolits were good and satisfied the need but were never as pretty and shiny as other peoples' boolits. I know frosted boolits are fine and understand what causes the frost. I was plugging along making my usual lightly frosted boolits and started slowing the pace to try to get a little more shine to them. I really slowed the pace but there was still that bit of frost. I started reducing the temperature of the furnace. Over the next 20 minutes or so the boolits started getting shiny. As the temperature dropped further I was able to increase the pace and the boolits were still shiny. I finally settled in at about 625 degrees and let the sprue cool for 15 seconds before opening. Every boolit had that nice shiny look. I finally got the look I wanted and found that by going slower the boolits seemed to shrink a little as they dropped much easier.
I was so thrilled with the way everything came together that I mixed another alloy and repeated the results with different molds and alloys. On Sunday I went to the shop, mixed up another favorite alloy and enjoyed the same results with two more molds. I even cast with two very different molds alternating between them and had great results. One was a 4 cavity 170 grain .401 Lyman TC and the other was a two cavity 125 grain 9mm TC. I had no rejects with the .401 mold and only 5 or 6 from the 9mm. The 9mm mold is a little harder to pour for than larger molds. It fills so fast even with the pour adjustment throttled down! Most of my casting is from 158 to 250 grains.
For Pete's sake, I had been putting up with frosted boolits for all those years just because the melt was a little too hot. I would have had to slow my pace to probably one pour per minute to get the same results at a 700 degree melt temp.
In the past I got shiny boolits from time to time but never connected all of the dots. I knew the frost was from the mold getting too hot but going a little slower didn't make any difference. It just didn't occur to me that I was running the melt that much too hot.
This may sound like a total noob oversight but I've been making the same mistake hoping for different results for a long time. (Insanity?) Time after time we have all including myself told new casters to control the mold temp with the pace and not the pot temperature but that only works if the pot temperature is within the range where it needs to be for the mold, alloy and pace. While my numbers may not be valid for the next caster the concept probably will be so I wanted to share my enlightening.
David