Help with bullet casting!

[Darth-Vang]

Hi everyone. I am having a hard time casting with a .310” roundball. Mold is iron made by lyman, single cavity, lead is pure. I am having difficulty casting without wrinkles. I was told that small cavity molds are prone to having more wrinkles than bigger cavity molds. What are your tips to casting wrinkle free balls for small cavity molds?

 

[41 Mag]

Usually of it is a new mold it needs to be scrubbed really well using an old toothbrush and good decreasing dish washing soap and as hot of water as you can stand.

This is usually followed up with several heat cycles which will help season and release any residual oils in the pores. Throw in a last scrubbing for good measure.

Make sure your alloy is up around 700-725 to start with and cast fast to get your mold good and hot. It might take a few more seconds to cool before cutting the sprue.

Lastly you might have to add a few inches of tin solder to a full pot to aid in fill out. Start with 2" and try a full pour, add another inch as needed.

The best thing is everything you pour can be repoured as needed.

 

[LaneP]

Pure lead needs to run hotter, and the small cavity size in an iron mold means if you don't preheat you'll be casting a long while waiting for it to reach good running temp. I preheat mine by dipping a small corner in the lead until lead no longer sticks to it when withdrawn (about half minute guestimate). Leave the largest sprue puddle possible. Finally, if they still won't fill out you may need to look at your mold venting to be sure it's good.

 

[edwardware]

Wrinkling is usually a sign of the mold not hot enough.

Tin might help fill-out, but I think that's more about filling sharp corners, and less about wrinkles.

 

[Hooda Thunkit]

Generally speaking, wrinkles mean a cold mould. Pure lead needs to be hotter, crank up the pot a bit.
Preheat the mould; I use a cheap electric hotplate with an inverted coffee can over it. I cut a window out of the can to make a sort of oven. I set the moulds on the hotplate - set the plate on medium - and leave them while I get everything else ready.

Sounds to me like more heat will do you good.

 

[WeekendReloader]

Like others have said, it sounds like a cold mold and/or cool lead. I run my casting pot around 750 degrees to get better fill and less wrinkles.

 

[dgod]

I ALWAYS place my molds on top of the pot when I turn it on. The heating of the pot this way causes the mold to heat up as well as the lead reaching the desired 725 degrees.
This way the mold is hot and ready for lead. Then it is rock and roll until I have all the casting I need at the time.

IF I need to add lead to the pot at anytime, I place the lead in the pot to be melted, and place the mold on top of the pot to maintain temp for the mold.

Dan

 

[Docendo Discimus]

Casting at a faster pace can help with this. Iron molds are great but it can take some effort to get them up to temp. Cast 10 or 12 balls as fast as you can, don't look at them just keep casting. This will get the mold up to temp. Once you hit the sweet spot you can slow down some.

 

[AJC1]

So all the major points are hit So here might be something useful. I cut the sprues with a gloved hand. You will know the mold is hot when the sprue is very easy to cut. The second good indicator is if your sprue takes a few seconds to go solid. If the sprue takes 2-4 seconds to go solid you know your hot.

 

[WeekendReloader]

^^^ Yep

I usually cast 5 - 10 times and just dump them into the scrap pile to get the mold up to temperature. Sometimes it takes longer.

I'll fill the mold and leave a puddle on top of the sprue plate. When the mold is at temperature, it usually takes a few seconds for the sprue puddle to solidify.
You then need to keep casting at a regular rhythm to keep the mold hot and at the right temperature. If the sprue cools too fast, cast faster. If the sprue is taking a long time to solidify, cast slower.

Each mold will be a little different. Over the weekend, I used 5 different molds and cast a bunch of bullets. When I switched molds, it took me a few minutes to learn the mold and get a rhythm going.

 

[jmorris]

Wrinkles are caused by the liquid becoming a solid before you want it to. It happens every time I start, I recycle them back into the pot until the mold warms up and wrinkle free bullets start dropping.

At some point things can get so hot, they will start looking “frosted” or a “flat”appearance vs shiny, that’s when the mold is too hot.

The temperature the lead is heated to obviously if a factor in both situations too. You can adjust that and note the effect of that variable as well.

 

[BWS]

As mentioned above,mould oven.

Just too durn easy/cheap to make vs all the cast rejects it takes to get the mould in the sweet spot. Mine is a little over "medium" on the single burner/coffee can oven. Get the numbers right on your pot,and oven..... got some moulds here that will drop perfect bullets on the first cast.

 

[.38 Special]

I am another one who preheats a mold by dipping it into the molten lead. I normally keep the front edge submerged for a couple of minutes, which burns off any residual oils and ensures the mold is hot enough. Once the mold is up to temperature, lead falls off the outside of the mold blocks and you know you are ready to go. I have been told that the process will warp the blocks, but I have been doing it for decades without issue - and it is nice when the very first pour produces a perfect bullet!

 

[brewer12345]

With a big hunk of iron and a tiny, single round ball cavity, you need to preheat your mold. I use a cheap hot plate. Turn it on with the mold on the burner and then heat up your pot of lead. You will need to cast fast and possibly periodically reheat the mold. I usually run pure at 800F for better fill out.

 

[Bazoo]

I would use a hot plate if i could, but the generator I use for electricity won’t handle the extra. Barring that, I rubberband my mould handles together and let the mould rest in the lead, usually across my dipper so the mould isn’t submerged too far, just half way or so. Give it 3-5 minutes and it’ll be hot enough.

 

[mdi]

When I started casting I only had a pot, ladle and a Coleman stove. I didn't have any way to measure temps so I "adjusted" temps by visual inspection of the bullets as they dropped from the mold. Most basic indicators were; wrinkles and poor fill out, too cold mold/melt. Frosty bullets, too hot. I cast a bunch of balls for my wrist rocket, 432" balls. Good ammo!