Sharp edged bases...how to get them?

[webradbury]

What's the key to getting a good sharp edges at the base of the bullet? I've been trying different temperatures for the lead and also trying to vary my pouring technique and still, sometimes I get sharp bases and sometimes I don't. I'm using a bottom poor mold and a ladle. any suggestions? Will

[ku4hx]

If your pot has a spout try that with varying stream diameters/pore rates; don't know what the correct term for that is. Or maybe try pressure molding by mating the mold with the spout. Or maybe a larger sprue puddle when you pour from your ladle. A larger puddle allows for more alloy to be drawn into the cavity.

I stopped ladle pouring many years ago because of problems like this. Others have differing experiences but using the pot's bottom spout works for me.

[RickinTN]

Two things. Make sure you leave a large enough sprue puddle as mentioned above. Too much is better than not enough. Second....Fine tune your sprue plate tension. You must have it loose enough for trapped air to escape the cavity when the lead is introduced. Most folks recommend it to be loose enough that it will swing out of the way on it's own weight. This adjustment will be different with the mold hot than when it is cold. I adjust mine with the mold hot for this reason.
Good Luck,
Rick

[Doc_Stihl]

A larger sprue puddle would be the first thing I'd suggest.

[Larry Gibson]

What "lead"?

What "techniques"?

Let us know what you are doing specifically and we can be more specific in our answers w/o guessing so much.

Larry Gibson

[John Boy]

webradbury, Sharp edged bases are easy to obtain ... with a bottom pour or ladle, put the spouts firmly in the sprue hole and pour for 5 seconds. If the bases are rounded, you did not allow sufficient time for the melt to fully fill the cavity! Then create a sprue puddle that covers a goodly part of the plate, not just a button in one spot. Spreading the puddle across the plate keeps the plate hot. Then when the puddle frosts in 5 - 10 seconds depending on the bullet weight - it's time to cut the sprue. Glove handing the plate gives the bases the best edges, not whacking the plate with your stick. When cutting the sprue, apply downward pressure on the plate - you want to keep the plate as tight as possible to the top of the mold halves. If the melt is smeared on the bottom of the plate and top of the mold - you are castiing with too high a pot temperature. Your bases will be very sharp.

Of note: before you cast insure the plate cannot be wiggled up and down (too loose) - flip the handles with your wrist. The plate should swing open. With the plate that does this you will not scour the tops of the mold halves and allow the air to escape under the plate when making the pour. If the plate is too loose, this allows melt to rise above the top of the cavity during the pour and smear on the the top of the mold

[Spokerider]

Excellent reply.
Yep, a puddle of the sprue plate to keep it hot.
I hold the dipper firmly into the sprue hole for 3 seconds or so [ after the cavity is full ] so while the melt is leaking out onto the sprue plate.



webradbury, Sharp edged bases are easy to obtain ... with a bottom pour or ladle, put the spouts firmly in the sprue hole and pour for 5 seconds. If the bases are rounded, you did not allow sufficient time for the melt to fully fill the cavity! Then create a sprue puddle that covers a goodly part of the plate, not just a button in one spot. Spreading the puddle across the plate keeps the plate hot. Then when the puddle frosts in 5 - 10 seconds depending on the bullet weight - it's time to cut the sprue. Glove handing the plate gives the bases the best edges, not whacking the plate with your stick. When cutting the sprue, apply downward pressure on the plate - you want to keep the plate as tight as possible to the top of the mold halves. If the melt is smeared on the bottom of the plate and top of the mold - you are castiing with too high a pot temperature. Your bases will be very sharp.

Of note: before you cast insure the plate cannot be wiggled up and down (too loose) - flip the handles with your wrist. The plate should swing open. With the plate that does this you will not scour the tops of the mold halves and allow the air to escape under the plate when making the pour. If the plate is too loose, this allows melt to rise above the top of the cavity during the pour and smear on the the top of the mold

[detox]

Fine tune your sprue plate tension. You must have it loose enough for trapped air to escape the cavity when the lead is introduced. Most folks recommend it to be loose enough that it will swing out of the way on it's own weight. This adjustment will be different with the mold hot than when it is cold. I adjust mine with the mold hot for this reason.
Good Luck,
Rick

Bingo! Sprue plat tension and fill pressure are very important. You must know how to fine tune. This comes with time...

[GLL]

What alloy are you using? Adding a small amount of tin may help ( along with the previously mentioned suggestions !).

Jerry

[detox]

Using a ladle and loosening sprue plate tension, i can get square bases with any common alloy. From pure lead to linotype

[mookiie]

Interesting I would have thought a tighter spur plate would have been better for sharp bases. I too have been having trouble getting sharp bases.

[detox]

Interesting I would have thought a tighter spur plate would have been better for sharp bases. I too have been having trouble getting sharp bases.

Tighter traps air.

[.22-10-45]

For years I have been stoning top edge of blocs to a TINY 45 deg. angle using a hard arkansas stone..light touch is needed here..go too far and you'll have fins!...this gives trapped air an escape route under plate.

[MtGun44]

More tin and higher temps.
Loosen the sprue plate a bit.
Also use pressure casting with ladle or pot.

Bill

[Tatume]

Veral Smith says to continue to pour until your ladle is empty, and it works. Hold the mold over the pot, tip it slightly so the metal runs off one side, and just keep pouring. This keeps the base of the bullet molten longer, and keeps the sprue plate hot. It works.

[HeavyMetal]

try dipping the sprue plate itself into your alloy, I've been doing this for years when making HP's with the Lyman single pin system and always get a sharp base.

Needs to be done every 3 to 4 casts and ya need a pin heater to for HP's but that is not a problem for the OP.

Dip then put ladle to hole and roll mold and ladle as one to fill.

let us know if that cures the issue.

[Marlin Junky]

The following assumes you've already learned how to cast:

For problem molds (those that are not vented properly, which probably means every Lyman mold made after 1980 :bigsmyl2:) put a slight bevel at the top of the blocks where the two halves intersect by using a sheet of 500-600 grit sand paper (I use 1000-1500 grit for aluminum molds) placed on a clean, flat surface. Orient the mold block halves (do one at a time, obviously) so the intersection of their top and side that mates with the opposing block forms a 45 degree angle with the sand paper and drag the block half gently across the paper a couple times while maintaining the angle. You don't need to take off much metal, just enough to form a tiny, shinny, flat surface on the the edge indicated above.

MJ

OK, I just noticed that I've basically repeated the info in post #13 which gives the same result with a different technique.

[webradbury]

Thanks to all for the suggestions. The mold is a .441 500 gn pp mold from Accurate (brass). Nicest mold I have bought to date!! My alloy is 50/50 range lead/soft lead. The sprue plate is as it was shipped and judging from what was posted here in regards to looseness, it is just right. I'm gonna play with it some more soon and will let you all know. Will

[Moonie]

Thanks to all for the suggestions. The mold is a .441 500 gn pp mold from Accurate (brass). Nicest mold I have bought to date!! My alloy is 50/50 range lead/soft lead. The sprue plate is as it was shipped and judging from what was posted here in regards to looseness, it is just right. I'm gonna play with it some more soon and will let you all know. Will

I'd add a bit of tin to that mix, should help.

[WILCO]

and a ladle......

What type of ladle? Here's my experience and technique:

http://castboolits.gunloads.com/showthread.php?127865-Switched-ladles&highlight=switched+ladles


Did some Boolit casting Friday evening and was using a cast iron ladle with my LEE 110 volt melter furnace. This ladle was my first casting ladle and I’ve always used it. I like it. Never gave a thought about how it performed. Just used it every time. No train of thought from that point on. Casting boolits? Grab my only ladle. Done and done. Now, I’d like to say I’ve cast thousands and thousands and thousands of beautiful boolits, but that number is still in the hundreds and I’m learning as I go, so when I realized that my boolits weren’t filling out every time and I knew my temp was good, fluxing okay, the alloy is good, mold was hot enough, cavities were smoked, tin added, I’m stumped as to the problem. Then I suddenly remembered I had an old RCBS ladle set aside from a while ago. I grabbed it and was pleasantly surprised as to the ease with which I was able to cast! Boolit fill out was improved greatly. I believe this was due to the fact that the RCBS ladle has a large capacity which provides some pressure as the molten lead works it’s way through the spout when pouring. Couple that with pouring off to the side of the sprue plate hole, creating a swirl effect and pouring a big “button” whilst giving the mold a slight downward bump on the bench, I was very happy with the end results. Long story short, I’ve switched ladles. :happy dance:

[TrapperXX]

Great thread! I learned a lot.