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homemade 'cannonball' mold
13 replies to this topic
Posted 13 June 2007 - 10:30 AM
Now it doesn't have to be in the shape of a cannonball since they tend to occilate. I would like a thinner shape. I have 2 fish shape weights to use off the riggers, but would like to make some spares. Molds are priced out of this world. I have the lead and a hotpot. Just need some ideas for a thinner shape. Wood has burned for me in the past, just making thin weights with a screw eye in the top. I would like to make two, with fins off the back. I would like them to be around 9 lbs. Would a coffee can stand up to the heat??? Pack sand around it. I would like to have a pancake shape, thinner to cut thru the water easier. Any ideas would be appreciated. Thanks. da Finn
Posted 13 June 2007 - 04:48 PM
You can use plaster for a mold if you are only making a few. The main thing is that it must be thoroughly dry or it will explode when you pour your first one.
Posted 13 June 2007 - 10:06 PM
Why not try using two small shallow pie plates clamped together to make a thin weight to cut through the water. bill
Posted 14 June 2007 - 10:00 AM
Thanks. Hadn't thought of that one. I have a Lee's hotpot with a spigot (?) so the mold has to be shallow. Not much room to put a mold under there. Pie pans would have to lay on the side. Hole would have to be drilled for the lead to go thru. Somewhere else a man said he poured one 8 inches across. Coffee cans, at least the one i have, is 6 inches. I have melted all the extra lead I have. Almost filled the hotpot up. Dont know how many pounds that equals. Will try tonight. Thanks again!
Posted 14 June 2007 - 11:47 PM
You may be able to unscrew the base and turn it around then clamp it on the edge of your work bench then you will have lots of room to put a mold under the spout. You probably have about 10 lbs of lead in the pot.
Posted 20 June 2007 - 10:01 PM
I have poured Dels plastic into plaster molds and lead into wood, but it makes me nervous pouring hot lead into plaster. What is the temp of liquid lead??
Posted 20 June 2007 - 11:25 PM
I believe it is around 700-800 degrees maybe a liitle bit less.
Posted 20 June 2007 - 11:49 PM
Have seen several sites have the number, but they all vary somewhat, but the melting point of "pure" lead is between 600-630 degrees. I have my RCBS pot set at 800-850. Don't know if thats what the lead really is, but that's where it's set lol.
Posted 21 June 2007 - 12:17 AM
My thoughts are to cook the plaster mold in the oven for 20 mins before use, to eliminate any moisture. Keeping the mold in an airing cupboard or on a radiator when not in use would probably do the trick. This subject has been through my mind a lot recently, as I plan to mold the lead onto the hangar wire, for consistancy of manufacture.
Posted 21 June 2007 - 10:32 AM
I will try to form the plaster around a fish shape cannonball I own now. I dont remember when I tried this before with a lure. If I fill a container with plaster, and put the weight half way in, I would have to support the weight somehow. Otherwise it would settle. Do I coat the weight with something, a release agent?? Also. I have an old plaster mold that I am not going to use anymore. Can I break it up and use it so I wont have to mix up as much of the new plaster?? Should I bury the mold in sand when I am ready to pour the hot lead??? Thanks again, da Finn.
Posted 21 June 2007 - 06:58 PM
A method that I have been playing with recently, is to cut the shape out of a balsa sheet (type of wood not important). I then jam the pattern into the hole half way. The cutout does not need to be a perfect fit, just tight in two or three places.
This then forms the bottom of the mold box. When the Plaster of Paris is poured, with a little agitation, the bubbles rise away from the pattern, leaving a perfect mold, no bubble craters and a flat surface. There is a little flash where the pattern did not fit the balsa perfectly, but once the mold has been fully dried, this sands off very easily, leaving good edges to the mold.
Is anyone else doing similar? If not, I think it is worth an experiment. Another advantage is that you can control precicely, how much of the pattern is molded.
Posted 29 June 2007 - 08:20 PM
Finally got that lead melted to find it weighs almost 8 lbs. Vodkaman- not sure what you meant with using the wood. Can u explain it again. I'm blonde...you say "jam the pattern into the hole halfway...What Hole?" Thanks.
Posted 30 June 2007 - 08:07 AM
build the Master in wood build mold around it pour Plaster of Paris around it up to ½ of the downrigger weight your eyelets should mark center.I´d suggest you to build master similar to an splittingaxe &add a sheet of SS in the tail 3x5" atleast . With this you´ll get cutting edge & a fin for stability