New problems

[kbstenberg]

I had a new problem pop up yesterday
I was using a new (to me) mold for the Lee 90483 which I have worked the bugs out of. I leemented it, I cleaned up the top of the mold from scratches made by the sprue plate, Put in a set screw on the bolt that holds the sprue plate. I cleaned the mold with dish soap an a toothbrush,
My alloy was 50%COWW/50%SOWW plus 1%Sn. I started casting at 715 deg till the mold was hot enough an showed signs of frosting. I turned the hear down to 700, an started using a wet rag to cool the molds every other cycle. Everything seemed OK with a quick glance at the bullets in the mold about every 10 th cycle. Everyone of the bullets were at the low end of the frosted stage. with good cavity fill out.
I was both WC and AC.
But over half of the bullets were rejects. Because they would have wrinkles. I am going to try shooting some of the wrinkled ones just to see how they shoot.
Earlier I had used the same alloy to make some 7mm hunter bullets an I had very few rejects at that time an none of those were due to wrinkles. The only difference was the heat that I had used 735 deg. on the rifle bullets.
So I'm wondering what I have to change to decrease my rejects.
Kevin

[canyon-ghost]

If you got wrinkles, the mold was too cold for what you were doing. Let me suggest that adding Stick-on wheelweights in the pot is a source of some problems. Your alloy should be already mixed before casting- I tried it with liontype once, got an amazing amount of rejects.

The rifle bullets you mentioned, I doubt you mixed pure lead into them. The pure will take more heat and weigh more. The amount of air you stir in fluxing and pouring effects the bullets, you get air bubbles.
I'm just surmising these are a few of the troubles,
Ron

[btroj]

What bullet is a Lee 90483?
I think you had a mould too cool. Wrinkles are usually from a cold mould or oil in the mould.

My suggestion is to ditch the damp rag every other cast. Cooling the mould too much for your rhythm and casting temp. I don't cool a mould until the sprue takes noticeably longer to harden.

Notice that when you cast the previous bullets at a higher temp you had no issues? That is because the hotter melt got the mould warmer and helped keep it there.

Every mould is different. Big bullets heat the mould really fast, small one hardly at all. Tailor you rhythm to each mould and what it was.

Brad

[JonB_in_Glencoe]

How did you leement the mold ?

I have used a modified version of leementing using a flitz coated paper type shop towel
wrapped around a tap (10=32) that grips the towel real well, but you have to be sure
to watch closely so the tap doesn't wear through the towel...the Paper shop towels that are blue are quite tuff....ANYWAY, there must be some oil in flitz...or something else that makes wrinkly boolits...It takes 50 to 100 cycles before I get unwrinkled boolits from a freshly leemneted mold.
Jon

PS, also, I run the melt HOT (around 775º to 800º) the first time I cast with a freshly Leemented mold and try to keep the mold as hot as possible, where as it takes about 10 seconds for the sprue to freeze...that helps cook out the oil or whatever. normally I try to run the melt at 675º with most Lee molds, once the mold is up to temp.

[kbstenberg]

Information to add to my opening statements.
The alloy was premaid days before. And nothing was added between casting the rifle bullets an the pistol bullets. Except more alloy. All being from the same batch.
How could the mold not be hot enough if the bullets were all coming out frosted?
The lee mold is a 44 cal 6 cavity non TL design, 240 gr. The 7 mm mold was a NOE 6cavity, that has to be extra warm otherwise all the bullets are wrinkled.
All of the Leementing was done with 2 grades of valve lapping compound, an then toothpaste. I spun all the bullets by hand rather than using a drill.
The wrinkling wasn't the kind that travels around the bullet. It was usually in a U shape an usually the open end of the U was pointed to the nose of the bullet.
Kevin

[plainsman456]

You might try offsetting the lead to one side of the opening when pouring,kinda makes the lead swirl around in the cavity a bit.
It has worked for me on a few that have had that same kind of problem.

[btroj]

It could be a cool mould. That would be my guess. Try keeping the mould just a bit warmer by not cooling the mould so often. If this doesn't fix it try holding the mould at a slight angle so the lead swirls in the cavity.
You are close it sounds, now to just find what the mould wants.

[canyon-ghost]

When I get that, it's usually something in the cavity. You get that every cast? If so, I'd be cleaning the mold, especially the cavities. If a mold pours wierd when the heat is up and the alloy hasn't changed, it's impurities. Skim often, don't let dross into the ladle or mold, that can do it too.

Try acetone to dry the mold after cleaning. It's the dryest solvent I've come across.

Ron

[a.squibload]

I had the same type wrinkle as you describe, in several new molds.:?
The molds were definitely clean (boiled, etc.).
Next session I pre-heated each mold on a hotplate,
then dipped the corners in the melt 'til the lead would fall off.
Concentrated on casting rythm to keep the molds up to temp.
Worked like a charm, wrinkles no more, good fillout (a little added tin helps there).

I read somewhere (CastBoolits!) that each mold has it's own requirements,
steel cools slower than aluminum,
big boolits put more heat into the mold than small boolits, etc.
If your molds are clean they're probably just running a little cool.

[kbstenberg]

It looks like I am going to keep the mold warmer, an clean it again before i cast with it next time.
Yesterday I was reading From Ingot To Target. An just by accident read about the same problem. The correction to it was to increase the sprue plate temperature. Supposedly the cooler SP cooled the lead to cause the wrinkles even though the mold was hot enough to cast with.
Kevin

[a.squibload]

Dangit! I knew I forgot something.
Someone here mentioned sticking the sprue plate tab in the melt to heat it up.
I was doing that too, seems to work.