Quick tutorial on the actual cast?

[joelpete]

I've been reading and learning a LOT on this forum. IT IS GREAT, thanks to all you who contribute.

My question is, how long after pouring the alloy do you wait to dump the boolits from the mold? I've read that it should take 5~6 seconds for the sprue to solidify before you cut them, as to avoid a dimple caused by shrinkage, but I haven't been able to find any info on how to know when the boolits are solid enough to open the mold?

I haven't actually started casting yet, but I do have plenty of WW (around 320#) and a couple of molds (Lee TL452-200-SWC and a C312-155-2R). These are aluminum 2-cavity molds.

Thanks for any advice you may offer.

[fishhawk]

if the sprue is solid dump the boolits. steve k

[onondaga]

When I started casting (1957 !) I had the same question. I knew that if I tapped the sprue plate too soon that the cut would chunk out a piece of the boolit and that the longer I waited the harder I would have to hit the sprue plate to cut the sprue. I was very inventive then at 7 years old. I put a clock on the casting table and tried different amounts of time in seconds after the sprue puddle hardened. I settled on 11 seconds for the mold I was using and got clean cuts by watching the clock. Later in life I noticed that different molds and different pot temperatures and different alloys required different amounts of time.

You are just starting out, try the clock method. You will develop a cadence with experience as you continue in the hobby. Try to get a clean cut instead of a chunked out hole, that is all. When the boolit is cooled enough to get a clean sprue cut the bullet is cool enough to dump out of the mold. I dump onto a well wrung out damp towel in a brownie pan.

Gary

[gray wolf]

Very good answer--
Let me think---what can I add ?
Nothing

[gnoahhh]

I wait for the sprue to frost over, then I count to 3 and bump. That way, I feel, I'm automatically allowing for the different molds/alloys/temps/sizes of sprues I work with.

[canyon-ghost]

I use three different brands of molds. I do it by eyesight. When you pour the lead the sprue will be liquid so, I pour a little extra. Then I wait for it to frost over and watch it draw down (that dimple where it shrinks in), that completes the bullet. Then I drop them out - unless, I'm heating the mold by waiting extra time for the mold to absorb heat from the lead.

After the mold is up to temp, it's liquid sprue, frosted sprue, dimple, and cut. But I usually pause and let the bullet harden before I cut the sprue. When you start this, you'll see that staring at the sprue tells you what is happening in the cavity, or cavities. A guy learns.
Ron

[Moonie]

joelpete, you really just have to start. It is ok to be off a bit, you can always cull the bad ones back. The most important thing is to do it, just start casting. You will learn lots of things from your first few sessions.

We will always be here for the tons of questions you will have after.

[montana_charlie]

If you don't need a thousand bullets per session, there is no need to hurry when cutting the sprue. The longer the bullet stays in the mould, the more it shrinks...allowing it to fall out easier.
http://www.youtube.com/watch?v=OiJikigdIow

CM

[white eagle]

yep,yep

[docone31]

And, you want that dimple in the sprue.
It goes into the mold, rather than the material pulling away from it.
That is why you have a sprue button. That is the material to keep the fill. Should be the last to solidify.
In other words, when the sprue frosts up, you can cut. The casting has pulled from the sprue at that time.

[1Shirt]

All good responses. Trial and error will always produce in the end results that satisfy you (or you will say "to hell with it, and take up stamp collecting").
1Shirt!