This isn't intended to be a grand "how to" into ladle casting. I just wanted to share a few observations hoping that someone could recommend how I can improve from where I am right now.
By now you know I'm new to cast accuracy and although I've been casting for decades its only in the past year that I focused on shooting small cast groups with a long gun. Prior to that all of my casting has been with #2 Lyman's and various bottom pour Lyman furnaces. Two inch groups from a lever gun at 50 yards was fine by me.
When I started to focus on accuracy I knew the day would come when I would have to start ladle casting with Linotype. From the git go I was happy with how things went. But when I switched to longer casting sessions and my molds started to include multiple cavity molds and molds of different material things got complicated.
Properly ladle casting bullets that are good enough to compete in CBA competition seems to have as many nuances as any other aspect of cast accuracy. So I though I would ask for input from others about some of the methods I'm fell into using to see if I'm on the right track. Again, no expert here. Just a rookie learning as he goes. And some of this is probably so basic that its a waste of your time to read but I guess I had to verbalize it to those more knowledgeable than I hoping for feedback.
Accuracy work has been done with a .308 bolt gun in the bullet weights between 200 and 220 grains. Everything is with off the shelf Linotype from RotoMetal. Equipment was a Lyman 10lb dipper and a standard Lyman dipper. I tried the RotoMetal smaller 2 1/4" casting ladle but it was a little big for the 10lb pot, however the concept of the RotoMetal ladle seems solid. Since I was only dealing with a single cavity 220 grain mold I just stuck with the old Lyman ladle I had sitting around for nearly 30 years.
The following describes the method that I used on a single cavity brass 220 grain mold from Accurate. Alloy temp was kept at 750 degrees and the mold was kept as close to 345 as possible. I know 750 is way hot but I had just read Mr Barber's article in the last FS and I was quite taken by it. Cadence for the alloy to set up was 20 seconds. So here is my method and I was hoping you could comment on.
First tap the ladle clean (bowl and spout) before each dip. Before dipping, clear the alloy surface by pawing the alloy with the tip of the ladle spout below the alloy surface. That seemed to keep the spout hot and clean for the pour. Then without raising the ladle snout from the melt push it under the surface and come up horizontal with the ladle level full. I held the mold canted to allow runoff and pour the alloy through the sprue plate hole slightly offset. With the mold canted I continued the slow pour allowing the runoff to continue until the alloy formed a flat puddle over the sprue hole. I continued to pour above the sprue hole so that excess alloy was available for heat shrinkage so as to suck into the cavity for proper base fill.
I'm sure cadence is determined by the quality of the sprue cut and adjustments will have to be made on a mold by mold basis. In this case it was 20 seconds if the mold was kept at 345 degrees. I got a step higher on the learning curve when I sorted out how critical maintaining the mold temperature was. Keeping a consistent mold temperature is dependent upon alloy temp, mold temp, mold material, # of cavities but it seems to me that its real important to manage the mold temperature in order to keep a constant cadence for for a quality sprue cut.
To date most of my casting seemed to work best with the mold at 345 degrees. And keeping the mold at that temperature was pretty hard when you have alloy cascading over the mold. With any overflow on a two cavity iron mold the temperature could quickly climb over 400 degrees. That produces smearing or a super long extended cadence for it to set up. Using a wet sponge didn't seem to work for me. If the mold was overheated the sponge could cool down the mold so the outside would be back in the 345 range but the internal cavity temperature was still super heated and smearing would continue.
But like everything else about casting If you know what you are doing I am sure that controlling the mold temperature can be done that way. And now I understand why some folks run two molds at the same time. But that would be too complicated for me. Keeping an eye on the second hand of my clock for cadence takes all of the brain power I have available.
The only way I could keep things copacetic was to rest the mold on a wooden block with the cavities empty and the mold open. I'm sure the time needed for the cool down in order to keep the mold at 345 will vary based on mold material, number of cavities and how much overflow has to occur to keep the bullet base filled out. For the brass single cavity brass mold I was using 23 seconds worked.
Today's session was short and I only dropped about 85 bullets from the single cavity mold. I'm thinking that's not a bad quantity to shoot for if you're looking for high end accuracy with cast bullets. I'm a little under gunned if I were feeding a 9mm or a 7.62 x 39 with the 10 lb pot and the anal approach to casting I just described. On a positive not of the 85 that were dropped I culled 5 and the rest were all +/- .2 grains.
About cascading alloy over the mold and back into the pot. Leaving the mold level and leaving a tall puddle like bottom pouring just didn't fill out my bases. When I cascaded the alloy by keeping a flat hot puddle on top of the cavity it kept the bases filled out.
About mold temperature soaring. As an example my two cavity Lyman 311299 iron mold would soar from 345 to over 400 degrees in just two or three drops. But with a cool down period of 18 seconds the mold temperature would stabilize and the sprue cut was consistent. I want to give a big thanks to Loren Barber for the article he wrote in the last FS. I had just retired by best shooting mold which was a nearly 30 year old two cavity Lyman because I couldn't control the heat. When I read now he just used it as a single cavity I gave it another try and the mold became very manageable with nicely filled out bases. I recently dropped another 80 bullets out of that the they were all +/- .3 grains.
About tapping a mold to help fill out the base; I may be an exception but the weight of the bullets with the mold tapped and not tapped swung almost 3 grains and the nose diameter grew .0008". Nice to know you can effect bullet size but with all of the other variables I have to juggle to cast accurate bullets it was more than I wanted to take on. But again, good to know. If I have a situation where I need another .0003 on the bullet diameter I'll have to see if I can control that variable.
Thanks for listening to my whining. Hope I didn't offend anyone. Bill
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