Why do I occasionally get boolits with frosty voids

[44Blam]

Every once in a while I get a frostly void (indent in the boolit). It seems to tend to be toward the base of the boolit but in the side of the boolit.

What causes this?

I'm going to cast some tomorrow, if I get one I will post a pic instead of just throwing it back into the pot.

[clintsfolly]

With out seeing you yet to be taken pictures my suspicion is your using a sprue plate lube and getting it in the cavity. Use less.

[lar45]

Incomplete fill out of a driving band?
You can try adding a little tin to your mix to help the corners fill out better.
Another option would be to run your melt and mold hotter.

[labop]

I occasional get the same frosty non fill. Not usually a distinct void just an
area slightly undersize in diameter. My thought is for that alloy the hole in the sprue plate isn't big enough to fill before the bullet starts for harden. I ladle cast. The same mold will fill well with 16-1 alloy but not Magnum/hardball 92 lead, 6 antimony, 2 tin. labop

[GregLaROCHE]

Make sure the alloy is well fluxed.

[vagrantviking]

I know exactly what you are talking about and haven't figured it out yet either. Everything will be up to temperature and casting well then get a string with odd voids on the sides and not necessarily just the driving bands.

Interested if someone has a good answer.

[oley55]

Just throwing it out there, but I wonder if it is stratification in the pot (temperature and/or different alloys). Perhaps some routine stirring every so often. Not necessarily fluxing, but just a quick stir. (??)

[44MAG#1]

Unless you are getting an amount that is driving you crazy I would chalk it up to the "nothing is perfect" syndrome.
Every bullet you cast will not be "perfect " no matter what you do. No one casts perfect bullets no matter how much they would like for themselves and others to think they do.
Now if one is OCD I can understand the concern. BTW I know someone with that condition and am NOT making fun them. But living with the fact that one strives for perfection but will never reach it will help feret this out.
Give the bullets the "once over" and forget about it.

[Wayne Smith]

Another possible cause is too little of a sprue puddle left, the lead is drawn down into the mold as it cools and needs a nice puddle in the sprue to draw from as it is cooling.

[JonB_in_Glencoe]

Every once in a while I get a frostly void (indent in the boolit). It seems to tend to be toward the base of the boolit but in the side of the boolit.

What causes this?

I'm going to cast some tomorrow, if I get one I will post a pic instead of just throwing it back into the pot.


I know exactly what you are talking about and haven't figured it out yet either. Everything will be up to temperature and casting well then get a string with odd voids on the sides and not necessarily just the driving bands.

Interested if someone has a good answer.
I get this once in a while with only certain molds. The string of frosty voids are always in the same spot on the same cavities...not necessarily on all the cavities of a multicavity mold.

I have found when I get the string of frosty voids, I stop casting and put the mold on the heat plate and take a break for a while. When I comeback, the problem usually rectifies itself.

What I believe is happening, is that mold is getting hot spots or otherwise not a constant temperature throughout the mold. Probably caused by the mold not dissipating the heat consistently for some reason. If that is the case, that would cause that spot to freeze later than the rest of the boolit.

[lar45]

Frost is a result of the metal cooling slowly. If the rest of the bullet looks normal/shiney and the void is frosty, it is because the lead alloy that touched the mold cooled faster, so it is shiney. If the mold didn't fill out all the way, then the void didn't cool as quickly so it is frosty.
The problem is that the mold didn't fill out completely. The frosty part is just easier to spot on a shiney bullet.
So to rectify the problem we need to address the mold not filling out completely.
One option suggested is to make sure that you pour a large puddle on the sprue plate. If you are using a label, then pause longer after the cavity is filled. You should be able to see when the sprue pulls down in the middle. This is filling out the cavity. If it doesn't have a liquid puddle on the sprue plate to pull from, then the side of the bullet will pull in as the lead cools and contracts.
Tin helps the lead flow better to fill out completely. A hotter mold let's the lead flow in to fill out the corners before it cools. The same for hotter lead...
Hope this helps.

[bosterr]

This use to happen to me back when I used Lyman molds with very small vent lines and it was with a particular .357 mold I used. It ALWAYS happened to the second cavity poured. I merely slowed the pour and problem was gone. The lead needed a bit more time to push the air out because the vent lines weren't enough.

[Burnt Fingers]

I have this happen with NLG molds from time to time. It's really not enough to worry about.

[FLINTNFIRE]

If alloy and mold are both up to temp. and the flow of metal is sufficient and not dwindling right at the end then it is not enough sprue puddle on top , lube groove molds or no lube groove molds of mine are not having this happen , Lar45 is right , it is a fill out issue from mold or lead not being warm enough or not enough sprue puddle , a little tin will help the lead flow a big part of why it is alloyed in .

Vent lines may be part of the issue but if your mold needs a little more heat or a touch warmer on your alloy is cheaper then tin , try those first along with a larger sprue puddle .

[243winxb]

Drip from Lee pot enters mould. Cools. Then the hot alloy stream floats the colder drop towards the top. Some times there is enough heat to blend the drop in.
If running minimum heat, it forms a void.

Iron moulds dont seem to do it as much a Lee aluminum. Lees looses heat faster then iron.

More heat, higher temperatures fix it. Imo.

[44Blam]

I played with it today and just had a bad casting session. Tried lower heat and got wrinkled boolits - but no voids. Then more heat and no wrinkles but almost every one had voids. Tried higher heat more tin, etc.
I finally just dumped the pot into some ingot molds and gave up for the evening. I think I'll try again another day.

[gun toting monkeyboy]

I had one batch of lead that did that to me no matter what I tried. It would give me voids, wrinkles, all kinds of things. Even when it got hot enough that the bullets dropping out of the mold were still hot enough to be soft. I raised the heat, lowered the heat, nothing helped. I kept throwing the sprues and bad cats back in the pot, so the alloy stayed the same. I ended up adding some different lead to the mix, and it cured whatever the hell was wrong with that batch. You might try doing the same. Only use about half a pot of whatever you have been using. Mix in lead/scrap lead from a different source. See if that fixes the problem. When we are using unknown scrap lead, sometimes we just get an alloy that doesn't work. Change the alloy, and sometimes that will fix the problem.

-Mb

[44MAG#1]

The OP said. "Every once in a while I get a frostly void (indent in the boolit). It seems to tend to be toward the base of the boolit but in the side of the boolit."

How many is he getting percentage wise? 5 or 6 per hundred 50 or 60 per hundred?
To me that would make a difference in the type of response he maybe should receive. Just a few after rolling the around after casting, throw them into the next casting session and move on. No sweat. Many in a casting session do something to correct it.
How many on here casts with NO BAD BULLETS at all?

[vagrantviking]

Drip from Lee pot enters mould. Cools. Then the hot alloy stream floats the colder drop towards the top. Some times there is enough heat to blend the drop in.
If running minimum heat, it forms a void.

Iron moulds dont seem to do it as much a Lee aluminum. Lees looses heat faster then iron.

More heat, higher temperatures fix it. Imo.

A cold drip looks different, more like a wrinkle around the two different temperature components.

Thinking about it, it's mostly in Lee molds and the possibility of hot spots in the thinner parts of the mold makes sense to me. There's less metal in a band where the channel for the handles is cut which might line up with the spot the voids appear. Have to do some careful looking next time it happens.

[243winxb]

44Blam, have you tried pressure casting? The bottom pour spout in full contact with the mold.

Careful, hot lead may spray out.

My as cast weights are not as good when pressure casting.

Maximum heat solves many problems. Frosted bullets are ok, but may produce smaller diameters.
I always check as cast diameter as soon as a few bullets cool.

[gwpercle]

Another possible cause is too little of a sprue puddle left, the lead is drawn down into the mold as it cools and needs a nice puddle in the sprue to draw from as it is cooling.

What Wayne describes ... be sure to leave a generous sprue puddle even if pressure casting .
Gary

[Conditor22]

PC'd, this is the only one that did this.

https://i.imgur.com/MjVk9Kc.jpg[/img

[img]https://i.imgur.com/exQHBZj.jpg

https://i.imgur.com/0viqTrk.jpg

[35remington]

Look between cavities along the mould part lines. The mould stays hotter between cavities and in my experience this is where the sunken spots occur.

Solution is to bleed more heat or let the mould cool by staying open longer between casts.

[onelight]

Conditor the bullets in those pics look extremely rough to me , I have never had any drop from a mold that look like that .
I look forward to other responses.

[44Blam]

The OP said. "Every once in a while I get a frostly void (indent in the boolit). It seems to tend to be toward the base of the boolit but in the side of the boolit."

How many is he getting percentage wise? 5 or 6 per hundred 50 or 60 per hundred?
To me that would make a difference in the type of response he maybe should receive. Just a few after rolling the around after casting, throw them into the next casting session and move on. No sweat. Many in a casting session do something to correct it.
How many on here casts with NO BAD BULLETS at all?

Oh it was like 50 or 60 in 100. I was getting 1 or 2 good ones out of a 5 cavity mold.

I don't think I've ever seen one with a lube grove mold but in the groveless molds (HTC style) I tend to see a couple in a session. I always thought it was due to heat and opening the mold tended to fix the problem. This mold is a 225 grain 30 caliber mold with no groves. I think I might mix up the alloy a bit with some different alloy and I also notice that I am holding the mold a little to one side. I think I'll try to figure out something that keeps the mold level to avoid a hot spot.

[44Blam]

Well, this mold apparently needs to be run hot. I kept playing around with temp/cadence/etc and it turns out, when the melt is around 800 degrees and the mold is good and hot -- I get PERFECT frosty boolits.
My mold is a 5 cavity mold, so once it started working it sure drains a pot fast.

The mold is the NOE HTC 310-225 RN (TACO). This boolit is for 300 blackout plinking in the subsonic range and is a whole lot of fun to shoot.

280010

I told a buddy of mine that at sub sonic speeds, this boolit is big enough that if you made it bright orange or a similar color you aught to be able to see the thing. He looked at me and said "You *would* do something like that." I told him I certainly would and we'll have to see if you can actually see the boolit go down range. I've got some neon yellow PC and some Traffic Orange PC. I'm thinking a blend of those should make it easy to see...

[243winxb]

Maximum heat works for me at start up. Can fix a lot of problems. When i see frosted, back the heat down a little.

Seeing bullets fly, needs the sun at your back, on a good angle. Seen 45 acp cast at 700 fps go, naked eye.

22 lr can be seen with 12x scope. Just a blur.

Then there is the vapor trail shooting long range high power rifles. All fun.

[rockshooter]

I also find this more of an issue with the NLG boolets so I went back to buying regular molds. Thought about checking on the availability of for sale lube grooves.
Loren

[Four-Sixty]

I wonder if, and I am totally speculating here, if there could be some issue with the way the mold's body was formed, prior to the cavities being cut. I am asking what if the grain structure of the mold's metal, and in turn the metal's pores were 'opened up' a lot more in one particular spot just because of how the metal of the mold happened to be oriented, combined with the way it was machined? So there are really "wide open pores" in one spot that either retain more oils, wick moisture out of the atmosphere, or react with the melt in some weird way to cause a defect repeatedly. It is just a peculiarity of a given mold that can be remedied by more heat.

[Burnt Fingers]

I also find this more of an issue with the NLG boolets so I went back to buying regular molds. Thought about checking on the availability of for sale lube grooves.
Loren

Yes on this.

For me it's almost always on a NLG mold.