Lead skirt around bullet base.

Boolit Mold Join DateMay 2013Posts4

I'm a newbie caster and have a 356-125r mold from Eric at hollowpointmolds.com. Very nice thus far, but I am getting a little skirt/overflow at the base of the boolit. Not terrible, but enough that I have to snip a little lead around the base on about 1/3 of the boolits before running them through the sizer. I've made sure my sprue plate is tight. I'm using a Lee bottom pour pot set on 6.5, casting straight wheel weights. I'm lazy by nature, so I leave my mold on top of the pot for plenty of time before casting, and after casting 30 or so, the problem is the same. I have thought of removing the plate, light sanding the base side flat, doing the same with the sprue plate, then putting it back on, but I don't want to screw up a mold because of a newb mistake. I've done my searches on here, but can't find anything. Any help?

Any advice? Thanks,
MattD.

Is it possible to post a photo of the boolits with the skirt/overflow?

Post photos of mould with sprue plate open and closed, top side of blocks, and bottom of sprue plate. That kind of behavior is usually caused by a too loose sprue plate with too much head pressure, something under the sprue plate causing it to lift, or a warped sprue plate.

Believe it or not, an overly tight sprue plate can cause the gap which allows for lead to flow between the mold and the plate. I have my sprue plates to where they can swing on their own with gravity. When I pour, I direct the stream onto the sprue plate and let the alloy flow into the cavities. This downward pressure of the stream is enough for the plate to seal against the mold blocks.

I use two cavity molds and fill both cavities at once and leave a decent sized sprue. As the alloy cools there is enough sprue to be drawn into the mold as it cools and shrinks. When things are running at temp the sprue generally solidifies within 3 to 5 seconds. The boolits are still firming up for a short while after that, depending on the caliber and size I'm casting.

Most of the time I cast with two molds at the same time so as I'm emptying and filling one mold, the other has that amount of time to cool sufficiently. When using a hollow point mold I cast that one by itself as this keeps the pin good and hot. I also cast the 225-415 mold by itself as 2, 55 grains boolits don't transfer as much heat.

The other day I was casting with an old single cavity mold I got in a trade. In order to get it going well, and to avoid the same skirting you have experienced, I had to carefully control the flow as pouring directly into the cavity didn't push the sprue plate down and the alloy pushed it up. The resulting gap caused skirting. I slowed down the stream, poured onto the sprue plate, and got great fill-out and no skirting. Try adjusting your sprue plate screw and the way you fill your mold.

"Silence in the face of tyranny implies consent, and I do not consent." Mike Vanderbough, April 20, 2013

Boolit Mold Join DateMay 2013Posts4

Thanks. All I have right now have been trimmed up and sized. I'll try to cast some more tonight and post a few pics and try loosening the plate also.

hold the mold and plate up to a light.
if it is too tight you will see daylight at the end away from the sprue bolt.
just loosen it a tick at a time until you see it lay flat on the mold.
no more and no less needed.

the other thing you'll need to look at is if it is on one side of the mold.
sometimes the lee plates are a little warped.
and sometimes one side of the mold rides just a tick lower because of the alignment.

it's all an educated guess,,,, till the trigger is pulled.

the more i find out about shootin boolits, the more it contradicts everything i ever learned about shooting jaxketed.

I don't think it is a Lee mould. Are you holding the sprue plate against the spout of the pot? If so, try holding the mould away from the spout a little to lowere the pressure on the cavity

Post photos of mould with sprue plate open and closed, top side of blocks, and bottom of sprue plate. That kind of behavior is usually caused by a too loose sprue plate with too much head pressure, something under the sprue plate causing it to lift, or a warped sprue plate.That's about it in a " nutshell".

The answer most likely lies in the above remarks.

Ben

I have had a small piece of lead get under the sprue plate by the pivot bolt to cause this. Also the pivot bolt too tight can cause this. A loose plate and alot of 'head pressure" on the lead pour can also do it.
As noted hold the mold up to the light and see if there is a gap.

I had one Lyman mold I bought used that had the pivot bolt threaded into the block on a small angle. I opened the plate and gave it a whack until it closed flush.

Boolit Mold Join DateMay 2013Posts4

Loosen the screw holding the sprue plate until it will allow the sprue plate to swing freely, then direct the flow onto the rim of the hole when filling the mold. Unless the mold blocks are uneven, or the sprue plate is warped, that should solve your problem. Rather than snip the offending flange off, just run the skirted boolits base first into the sizer. It will "Iron" the skirts onto the body of the boolits and won't bother anything.

_________________________________________________It's not that I can't spell: it is that I can't type.

Boolit Master Join DateNov 2006Posts970

Are you using Bullplate lube or something else on those molds, they look pretty roughed up on top...

Boolit Mold Join DateMay 2013Posts4

Just soothed, and lead smeared on top. I cleaned em up with a bronze brush and water an loosened the sprue. Seems to be working some better now.
Thanks.

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Pointed Soft Point "Core Lokt"

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