Yesterday I was casting in tandem with a Saeco 25-100 and an RCBS 25-120 and Lyman #2 alloy at 700 deff. The Saeco fill out was great but the bases on the RCBS 25-120 had about a 50% rejection rate. The rest of the bullet filled out well, just the bases didn't always.
What's the possible remedy?
I should add that when used as a single double cavity mould,(instead of casting in tandem,) during previous sessions months ago, I never had this problem.
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Sounds like your mould isn't getting hot enough at the slower pace you get from tandem casting. You might benefit from higher alloy temp but, if you have had good results before, maybe just go back to what works for you.
John Carlson. CBA Director of Military Competition.
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Sometimes a hot plate will help keep the mold up to temp. You might also compare the size of the sprue hole. I had a Saeco mold for 22 cal with a very small hole that gave fits on base fill out. Drilled slightly larger and took care of that. I suspect the Saeco is smaller than the Lyman so temp of melt, mold and ambient temp all could be working against you with trying to tandem casting and a slower pace.
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Loosen sprue plate so that it swings open easier (better venting).Keep loosening until bases fill out without finning. Usually my sprue plate swings freely and I open and cut sprue with gloved hand after pouring.
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You don't mention alloy. If using wheelweights or range scrap of unknown composition even a small addition of tin in the order of 1% can make a big difference in fluidity and fill-out. In a new aluminum.mold light smoking is helpful for the first several casting sessions, but is not needed afterward.
73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia
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I can cast perfect bullets with pure lead without problem. Maybe just turn up heat little more. And maybe preheat mould hotter by dipping corner in pot before casting.
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I can cast perfect bullets with pure lead without problem. Maybe just turn up heat little more.
Are you tandem casting or casting with one set of molds? Ooops, makes my post look like the quoted portion, not the reply to the previous post.
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You don't mention alloy. If using wheelweights or range scrap of unknown composition even a small addition of tin in the order of 1% can make a big difference in fluidity and fill-out. In a new aluminum.mold light Two is helpful for the first several casting sessions, but is not needed afterward.
The alloy, as stated earlier, is Lyman #2. Actually the alloy prolly has enuf tin since an ingot of Lino inadvertently fell into the pot when I was using It to weigh down the RCBS mould at the rim of the furnace when I started casting with the Saeco mould before I tried the tandem bit.😂
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I'm gonna try OI812's suggestion of loosening the sprue plate.
Thanks for all the replies!🤗
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I loosened up the sprue plate and bullet bases filled out nicely. 😃
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Also try using a gloved hand to open sprue plate and cut sprue. I purchased cheap Lincoln welding gloves from Walmart. I'm right handed and wear glove only on right hand to open sprue plate.
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I loosened up the sprue plate and bullet bases filled out nicely. 😃
This would indicate that venting was an issue. A more permanent solution to improve venting at the base of the bullet would be to file or stone the top edge of the mold blocks where they come together when closed. Very little need be removed, just break the corner.
This trick is from Ben Hayes from Alabama.
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I rarely get good fillout when trying to run 2 moulds. For me it's about focus. I get great results when I focus on just one because I get the sprue puddles the same, and the cadence consistence.
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RicinYakima
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Tom Acheson
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