Proper way to fill a Mold?

[Sharp Shooter]

Is there any certain way you are suppose to fill a mold? Specifically with bottom pour if it makes a difference. I figure there are ways to prevent voids and stuff in your balls so what are they?

Thanks a lot for all your help with getting me going on casting!!!

Kirk

 

[R.M.]

You're going to get many, and I mean many methods suggested to you. We all have differing ways to do it, and each mold has it's preferences.
Mostly, I lift the rod and let the stream run directly into the hole. Once a small puddle is formed around the hole, I quickly slide the mold over to fill the next cavity, leaving the same puddle. You might get some lead spilling over the sides, and that's OK. Better to have too much than too little. You need that extra on top of the sprue plate so it can suck lead down into the cavity as it cools. This helps fill any voids.
After a couple of seconds, you'll notice the puddle turn a more greyish color. This is when to cut the sprue. If it cuts real easy, you probably haven't let it cool quite enough. This happens mostly when the sprue-plate has gotten a bit too hot.Just wait a bit longer to cut it. When the plate gets too hot, you can get lead smearing, and this is a bad thing.

 

[BrownBear]

Good points from RM, and I'll add a little. When I cast balls larger than about 58 caliber it helps to put the sprue plate right up against the pour spout for a few moments so the "weight" of the lead in the pot helps fill, then lower it slightly with the valve still open to form the sprue puddle. This is even truer for conicals.

Lots of other things add up to a good clean ball or conical, ranging from lead temp to mold temp to smoking the inside of the cavity. Some folks even go so far as drilling a larger hole in their sprue plates for a quicker pour.

 

[paulvallandigham]

A Couple of basics to remember: If the lead reaching the mold, or the mold is not hot enough, you will get wrinkled casts; If the mold or lead or both are too hot, you get frosted casts.

Other than that, I do as BrownBear does. I want that mold in contact with the pouring spout on a bottom pour mold, so that the lead doesn't have a chance to cool before it enters the mold. As the mold fills, I drop the mold and sprue plate away from that spout, to allow lead to pool in the beveled hole in the plate, and on top of the plate. If I am using a multi-cavity( gang ) mold, I form that puddle on top of the sprue cut off plate, and then move on to the next cavity, again putting the mold tight against the pouring spout, to keep the lead very hot as it goes into the mold.

On large caliber casts, particularly bullets with flat bases, the hardest thing to get "right " in the cast is to fill the entire corners of the base of the bullet. This is directly under the Sprue cut-off plate, so that the lead has to move sideways from the entry hole in the plate to fill those corners. I found that leaving the mold up against the spout keeps that plate HOT from the flow of heat from the bottom of the pot through the spout to the plate. If I dropped the mold down even a 1/4", the plate would cool enough to NOT fill those corners, and all those casts had to be thrown back into the pot. On really large caliber casts, I have had to open the hole in the plate a bit to allow molten lead to flow into the mold faster to fill those corners adequately.

Use a mallet, or stick to knock open the sprue cut-off plate. Don't use a steel hammer head or you will mar and ding up the plate arm. It takes a quick firm blow to cut the sprues, and open the plate, but it does not take a lot of power.

I know some people use gloves and simply open the plate with their fingers, but I can't figure out for the life of me how they avoid getting burned fingers and thumbs doing that. They must be casting very small caliber balls with very small sprues with pure lead ONLY to get this done. I cast alloy lead bullets for years before I got around to casting pure lead anything, so I developed some of my casting " habits" that may not be necessary for casting pure lead balls. :hmm: :thumbsup:

 

[jtmattison]

I hold the mould very close, but not touching the bottom spout. I hold the mould at a slight angle so the lead sort of swirls into it as it pours. When it's full I hold the mould level and top off the sprue with a blob of lead to ensure the mould is full as it cools and shrinks.

HD

 

[twotoescharlie]

in over 50 years of casting balls and bullets I have found there are different ways to cast, it varies with the mould. a lot like loads in muzzlwloaders just about all have different methods that suits a particular mould.

TTC

 

[paulvallandigham]

Yep, Charlie, you are right. I just didn't want to try to list all the ways I have tried casting, to get good bullets over the years. I probably have forgotten more than I remember.

I have a good friend who was a professional caster for many years, and who still casts a lot. When I am visiting him during " Casting " time, we often remind each other of some technique we forgot we knew, and used, many years ago. Its a good laugh for both of us, as it reminds us to not take Life very seriously. :rotf: :grin: :hatsoff:

 

[cmdrted]

In the same lines, for hand pouring, is there a method or a reason that alot of my casts on the side of the sprue plate up by the sprue get a little wrinkle? I'm using Lee molds and it doesn't matter which size ball I'm casting there is usually this little swirl wrinkle. I tried polishing it out of my .490 but there is still a hint in the cast. I also messed with the heat up down doesn't matter. This is on the side of the sprue plate, never the other side. Any ideas?

 

[paulvallandigham]

Yes. The Dipper is NOT HOT enough, and both the dipper, and the time it takes you to move from the lead pot, to pouring the lead in the mold allows the lead to begin to cool. By the time you get the bottom of the mold poured, the lead has cooled enough to leave a wrinkle up near the sprue cut-off plate. Tilting the mold may only result in a "crooked " wrinkle, in the ball.

You have to leave the dipper on top of, or, in the molten lead to bring it up to sufficient heat. Because it adds a certain amount of mass to the mix, you may have to allow the pot to heat back up to its full temperature before beginning your pours.

And, even with this effort, you may need to drill open the hole in the sprue cut-off plate, to allow lead to enter the mold faster.

For instance, if you are casting balls in .58, or .62 caliber, those are huge balls compared to the standard size sprue hole in most molds. Opening up that hole a few drill sizes( use a drill gauge- see charts under Member resources at the top of the index page to this forum), and then beveling the hole again using a countersink bit for metal work, followed by polishing the bevel very smooth with extra fine emery cloth, will help.

As long as you are drilling the hole in the sprue plate, you might also check the hole in the dipper. It probably will work better if its opened up a bit, too. It certain can stand being polished, if its anything like the dippers I have seen and used.

 

[longcruise]

I hold the mould at a slight angle so the lead sort of swirls into it as it pours. When it's full I hold the mould level and top off the sprue with a blob of lead to ensure the mould is full as it cools and shrinks.

That's what I do. That same method was recommended to me by Veral Smith at Lead Bullet Technology. I use a hand dipper though.

 

[hanshi]

I've tried & still do every way I can think of to cast. With the bottom pour I keep coming back to the method of putting the sprue plate in contact with the spout. It seems I need the pressure even on small balls & bullets to avoid gaps and voids. I cast with the pot turned all the way up. Some pots stream too fast and can't always be filled with contact unless the mold is large. I cull the balls but don't worry much over a little wrinkling as long as it is minor. The ones with minor wrinkles seem to shoot at least as well as bought swaged ones.