Making a Lead Sinker Mold???

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TomS

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I have zero experience with casting metal but that hasn't deterred me from attempting to make a lead sinker mold. And I must say it's not going well. The finished sinker/weight shape is 1/8" half round about 9/16" to 5/8" long. The grooves in the mold are about 6-1/2" long, width is 1/8" and depth is 1/16". The mold is preheated to 300 deg. F then the molten lead is poured. The attached pictures show what's happening, or not, during the pour process. I'm thinking I need to add a vent to the closed end of each groove but what do I know.

This started out as a request from a friend for what I thought was a few dozen weights. He's now telling me a relative of the inventor of the "No Name Lure" wants to relaunch the lure business and make thousands of these and sell them commercially. Maybe a mold is not the way to go. Possibly injection molding or extruding would be better. I'm interested/anxious to hear what you all have to say.

Thanks

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Definitely not an expert, but have poured lots of jigs , sinkers and round balls for muzzleloader. Looks like mold is still too cold. Just my two cents.
Dave
 
I'm no expert either, but that mold looks like it need vents. The air inside has no place to go, particularly with the long
skinny shape of your part. If your finished parts are cut from the parts you're trying to pour, you might also consider making them shorter to start with.
 
Try dusting it with talcum powder and preheating the mold.

Most mass produced lead castings are made in limited life heat vulcanized silicone spin cast molds.

Vents may help, but try the first tip above first.
 
Have poured a few lead sinkers, Disk, balls, and various others, Looks like mold to cold, and by the end the lead had cooled to much. With something that long and skinny you will have to keep the lead up to temp all the way down to the bottom of it. If it starts getting cold before it gets to the bottom or to the last one you pour it will start looking like that. Or at least that is my 2 cents on it.
 
Bob La Londe said:
Try dusting it with talcum powder and preheating the mold. Most mass produced lead castings are made in limited life heat vulcanized silicone spin cast molds. Vents may help, but try the first tip above first.
Click to expand...

Bob's tip probably comes from experience and knowledge but I'll add this.
I make lead molds for a friend who makes bass jigs (or plugs or whatever). He coats both halves with soot from a burning candle. I'm not even sure why he does this. I have had to remake some molds when the channels were too narrow to allow the lead to flow quickly enough not to cool.
 
Adding the soot is the same that they do when pouring Babbitt bearings on shafts to keep it from sticking.

David
 
Soot (candle smoke in particular) has a loyal following almost like the worship of alchemy or something. It works better than nothing. Graphite spray works better. Somebody will no doubt mention DropOut, but the graphite spray lock lubricant from your local box store works just as well. There are limits to how narrow a lead stream you can pour down a narrow passage, but often talcum powder works when graphite or candle smoke does not.

Narrow lead clearances, and fine details are my nemesis in custom molds. Talcum powder is usually my first fix. Once in a while I find one that graphite spray works better.
 
It seems like you are trying to cast wire, not how I would do it. Why not cast a shorter fatter slug then roll it to finished size? Check out bullet holding stuff from Lee Precision for ideas.
 
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