I poured my first sinkers yesterday and used a mold I made, based on a mod of a method I read about on here.
I saw a post or 2 about drilling into a 2x4 etc, pouring and then splitting the lumber, well I tweaked that idea just a little and it worked real well. Instead of splitting the board, I used to pieces, like 2 halves of a mold.
I took 2 lengths of 2x4 approximately 12" long, lined them up and then clamped together. I used a 3/4 spade bit and drilled right at the seam of the 2 boards so that I was drill the same amount into each. I drill a few holes about 1 1/2" deep, another about 3" and then used a 5/8 bit and made another. I used a regular drill bit and drilled the bottom so I could insert a nail to make a hole in the center of the sinker. I sprayed the nails with WD40 and poured. I only let the lead set for a few seconds then could easily pull the nail out. Few more seconds and I remove the clamps and out came the sinkers. I got 1 1/2 oz to 4 oz depending on the size and depth of hole and pour. The first holes did develop gaps after several pours, but if you can make 4 or more molds out 1 8' 2x4 I think I'll get my moneys worth and I can make multiple sizes.
One thing I did to keep the 2 boards aligned the same each time was to drill from the side on each end and slip in a nail through both boards. I made the whole big enough I could insert and remove the nails by hand. I also used heavy spring clamps so I could work quicker. The mold seemed to hold up better if I got the lead out quicker. I'll probably pour more by next weekend and will try to get some pics.
Still haven't taken any pics, but have done this a few times now. Have also used a 1/2" bit to make some smaller ones. I am using these basically like egg singers. I think I'm going to make some and insert swivels or small twisted wires so I can take them on and off or change sizes.