Bob58
03-26-2007, 07:47 AM
Thanks to all who have responded to my initial post on bullet casting.
I have a couple more questions to ask, along with a few observations.
1. Is it OK to leave the Lee Pro 4-20 pot filled with metal at the end of a casting session? I have been "draining" it down to about 1/2" depth, but this seems like wasted effort. Won't the metal heat up faster for the next casting session if it's in to pot as a solid block, rather than in the form of rejects and sprue cutoffs from the last casting session?
2. How often should I be fluxing the metal? All I have used for fluxing so far is some fine cedar mulch (purchased originally for pet bedding), and that seems to work well. After fluxing, the metal looks clean and bright on top. What I have been doing is waiting until the cedar all appears charred, then mixing the pot well (using either the RCBS thermometer that I use to measure the metal's temperature) or a length of hardwood dowel rod. After mixing, I have been removing the charred cedar, and replacing it with fresh cedar mulch.
3. What is a reasonable range of casting temperatures to try? My Lee pot doesn't want to pour unless the temp is at least 650 degrees. I have been trying to stay close to 700 degrees, but have tried casting as high as 800 degrees, for better fillout (didn't work.)
4. At one casting session, I did get a few of the very narrow driving bands to fill out on the 255 grain Lyman GC .45 caliber bullets. I saved these bullets, and found that the weight from each of the two individual cavities on this mold were very consistent (less than about 0.3 grains for each cavity.) The problem is that the two cavities are casting bullets with slightly over 1 grain difference in weight. Is this likely to create accuracy problems, if I load with bullets from both cavities?
5. One of the two cavities had quite a burr at the top of the cavity, which I didn't realize until I was looking at the "good" bullets with a 7X magnifying lens. I have since removed that burr with very careful stoning, but I wondered if, since these are GC bullets, would the slight heel imperfection result in accuracy problems (the defect is entirely hidden by the gas check.)
6. I just finished my fourth casting session, and had the poorest bullets from any of the sessions. The front driving band, on many of the bullets, doesn't appear as anything other than a slight rounding on the surface of the bullet. I suspect that I didn't get the mold sufficiently degreased (I had sprayed it with Rust Prevent after the previous casting session.) Thanks for all the comments on mold storage - I will see about getting an airtight container for the mold, and storing it in this container with desiccant when the mold is not in use.
7. I tried Midway's spray Mold Release during one casting session, but didn't think that worked as well as smoking the cavities with a match. (Match smoked cavities produced the few only completely filled out bullets I have seen so far.) I plan to buy a butane lighter for future mold smoking purposes, unless someone has a better suggestion. How close should the flame be to the mold surface when smoking the cavity? How long should it be held there, so that a sufficient "smoke barrier" (?) will form on the cavity surface?
I have a couple more questions to ask, along with a few observations.
1. Is it OK to leave the Lee Pro 4-20 pot filled with metal at the end of a casting session? I have been "draining" it down to about 1/2" depth, but this seems like wasted effort. Won't the metal heat up faster for the next casting session if it's in to pot as a solid block, rather than in the form of rejects and sprue cutoffs from the last casting session?
2. How often should I be fluxing the metal? All I have used for fluxing so far is some fine cedar mulch (purchased originally for pet bedding), and that seems to work well. After fluxing, the metal looks clean and bright on top. What I have been doing is waiting until the cedar all appears charred, then mixing the pot well (using either the RCBS thermometer that I use to measure the metal's temperature) or a length of hardwood dowel rod. After mixing, I have been removing the charred cedar, and replacing it with fresh cedar mulch.
3. What is a reasonable range of casting temperatures to try? My Lee pot doesn't want to pour unless the temp is at least 650 degrees. I have been trying to stay close to 700 degrees, but have tried casting as high as 800 degrees, for better fillout (didn't work.)
4. At one casting session, I did get a few of the very narrow driving bands to fill out on the 255 grain Lyman GC .45 caliber bullets. I saved these bullets, and found that the weight from each of the two individual cavities on this mold were very consistent (less than about 0.3 grains for each cavity.) The problem is that the two cavities are casting bullets with slightly over 1 grain difference in weight. Is this likely to create accuracy problems, if I load with bullets from both cavities?
5. One of the two cavities had quite a burr at the top of the cavity, which I didn't realize until I was looking at the "good" bullets with a 7X magnifying lens. I have since removed that burr with very careful stoning, but I wondered if, since these are GC bullets, would the slight heel imperfection result in accuracy problems (the defect is entirely hidden by the gas check.)
6. I just finished my fourth casting session, and had the poorest bullets from any of the sessions. The front driving band, on many of the bullets, doesn't appear as anything other than a slight rounding on the surface of the bullet. I suspect that I didn't get the mold sufficiently degreased (I had sprayed it with Rust Prevent after the previous casting session.) Thanks for all the comments on mold storage - I will see about getting an airtight container for the mold, and storing it in this container with desiccant when the mold is not in use.
7. I tried Midway's spray Mold Release during one casting session, but didn't think that worked as well as smoking the cavities with a match. (Match smoked cavities produced the few only completely filled out bullets I have seen so far.) I plan to buy a butane lighter for future mold smoking purposes, unless someone has a better suggestion. How close should the flame be to the mold surface when smoking the cavity? How long should it be held there, so that a sufficient "smoke barrier" (?) will form on the cavity surface?