cracked boolits....

[CGT80]

I needed to feed this beast:

http://i1112.photobucket.com/albums/k484/CGT80/460270SAA.jpg

I fired up the pot and made these in a couple hours:

http://i1112.photobucket.com/albums/k484/CGT80/MP45270SAA.jpg

The problem is that they look like this:

http://i1112.photobucket.com/albums/k484/CGT80/crackedbullets.jpg

I cast some of these bullets earlier this year and they worked very well. I ran the mold hot and the pot at 7.8-8 on the control (lee 10lb dripomatic). I don't have a thermometer yet. I made a little steel oven for my mold. The oven sits on a hot plate, mold goes inside, and lead ingots sit on top to preheat. The mold is an MP 45 270 SAA with round pins. I got nice frosty bullets that dropped easily and would polish with a light rub of a cloth.

Tonight I used more of the same supply of lead. It should be ww, but I can't verify it. The bullets seemed a little more frosted, but they tend to crack a lot. Sometimes I didn't pour fast enough and the nose would solidify before the mold was full. When dropped, the bullets would break in half. That part was my fault. Other bullets split longwise at the nose.

I don't know if the alloy could be bad, or if the mold could have lube inside it, or if my temps are off.

The bullet on the left was from before the mold was fully warmed up. It looks great, but I have to tap the pins over and tap the handles to drop the bullets. When I get the mold hotter, I can work the mold completely by hand. The boolits drop right out, but are frosty (fine with me).

I was dropping onto a towel, just like last time. I don't remember this happening last time either. The bullets look a bit smashed on the nose.

Any suggestions?

[MDC]

Dropping them too soon. I have Mihec's 41-200HP and had the same thing happen. Once the sprue froze I cut it then waited about another two seconds then dropped them and fixed the problem. Mine is a bit tricky. I have to keep it hot enough so they drop off the pins but have to wait that extra couple seconds to make sure they cool enough not to break.

[btroj]

Mould is getting too hot and you are dropping them too soon. Sometimes you need to slow down the rhythm just a bit. A small fan blowing oer the mould can help too. I was casting some last night with a mold that overheats fast. Held it in front of a fan for a 5 count after each fill and it stayed right where I wanted it.

[chambers]

You have frosty boolits( lead too hot) and you are not letting the let cool down enough in mold before you open( slow down just a little bit and before opening the mold). Just experiment a little bit, you are close.

[madsenshooter]

Brass doesn't give up heat as quickly as aluminum does.

[Dennis Eugene]

or you could try water dropping them and you'll find they'll be just fine. Dennis

[CGT80]

Thanks guys.

Last time I made these bullets, the weather was cooler. I also used a wet rag to cool the bottom of the mold once in a while. I just wanted to crank out bullets last night and I didn't take the time to cool the mold or experiment.

I also had some smearing of lead under the sprue plate. Maybe it was because I opened the plate as soon as the sprue solidified and the bullet hadn't fully solidified.

Is there a preferred way to clean the molds? Metal polish, brass brush, oil, cleaner, etc. I didn't do anything to the mold, other than to oil the pins after I used it last. I want to keep this mold in great shape. It is the best one I have and is very well made. I read the forum last night, but didn't find much info on this.

[btroj]

Dropping them too soon will still be an issue even with water dropping.

The bullets are breaking on release from the mould, not when they hit the dropping surface.

Been there, done that.

[runfiverun]

just another 5 count in your cadence could have prevented it.
mold temp is critical whether it's with h-points or flat nose.
you just stepped over the line and never come back.
back it down to 3 pours a minute instead of 4.

[btroj]

And it isn't melt temp that causes this, it is mould temp.

[lwknight]

But higher melt temp does heat up molds faster and slow cadence.
That is why I like to find the low sweet spot that casts well and improves production.

[CGT80]

I just sorted all the bullets from last night. I pulled all the bullets that had any sign of cracks. I ended up with an akro bin (from my dillon 550) full of bullets that I think I will keep, and 4 handfuls of bullets with defects or cracks.

I was a bit worried about the cracks that run horizontal on the bullet. On the bad ones, the nose broke off the base when I dropped them from the mold. Is this also due to mold temp, or is it just a matter of not getting a fast, consistent pour into each cavity? On some, I splashed a little lead in a cavity, and then half a second later finished pouring it. These seemed to be the worst. I would hate to stick a bullet base in the barrel, but I started thinking that my loads should push both halves out of the barrel. I have heard of people shooting two balls from a shell at one time, with success.

I think I will try to gently clean the mold. I read here that some people use aerokroil to help prevent sticking. I think my dad has some of that out in his garage. I use wd-40 or pb blaster.

This batch of bullets didn't look as nice as the last. Looks like I need to take my time.

I have a line on 300+ pounds of Linotype for a great price. I think I will try to snatch that up. It appears that it would cost me $200 per thousand to buy a bullet that is as nice as the MP 270 SAA and I can cast those for $43 per K if I was paying $1 per pound for lead. Right now I have a few hundred pounds from my dad and grandfather and should be able to get the lino for less than market value. It looks like I could save a ton of money, but in exchange spend time on a hobby. I was quite pleased with the performance of this bullet at 40 yards when I was shooting 6" steel plates. I know I haven't even scratched the surface of what the gun is capable of, but I was doing great for my abilities and experience. I usually compete with a 9mm (124 j-word at 970fps) XD at shorter distances, but I was able to do pretty well at that range with the XD too. The 460 is more consistent.

Needless to say, I am more sold on cast bullets than I was in the past.

[runfiverun]

the worst thing that happens is you can remelt them and do it over.
cheap experience.
lino is good for bumping an alloy and mixing soft lead up to something else.
kinda expensive for just making holes in paper with or tipping over steel plates.
funny is lino is available to me usually too but everything else is hard to find.
i just don't wanna pay the price for it.

[Dennis Eugene]

Quote from Btroj
Dropping them too soon will still be an issue even with water dropping.

The bullets are breaking on release from the mould, not when they hit the dropping surface.

Been there, done that. Well I never thought of that. Thanks for the info , while I have had trouble with cracked alloy from droping while still hot it was mostly/always? while makeing ingots. I am glad to still be learning. Dennis

[CGT80]

I picked up that lead tonight. 147 pounds of lino mixed with soft lead and poured into 1lb ingots and some misc. lead all in trade for 2,000 cleaned/tumbled 45 acp cases. I think I did pretty well. I didn't scratch test the lead. The buddy I got it from said it is still pretty hard stuff. The guy that had it before him used it for large rifle bullets. I will mix it with some roof jack and sheet lead that I have. I would hate to waste sweet lead.

I managed to lube and size a few bullets and I sprayed my MP mold with some aerokroil and scrubbed it with a nylon brush. Tomorrow I will clean up he mold some more. I may have to use a toothpick to get some of the little bits of the lead off. I found proper lube directions on the forum tonight. I will be sure to lube all the right areas next time and then I will watch my temps a little better.

Looking at all the purdy pics of boolits on this forum makes me hungry. They just look so tasty. I could almost eat them. I must have a bit of lead poisoning or something. It is a good thing I can't eat them, otherwise I would weigh a ton :mrgreen:

[swheeler]

CGT80; Your mold is too hot, slow down your casting cadence, maybe do a search of doing the Bruce B, it works. Remelt your cracked bullets and try again, don't worry-be happy!!!!:)

[CGT80]

Thanks for the tip.

The first time I used this mold, I used the Bruce B method, but I cooled the bottom of the mold. Those bullet turned out pretty good. I will try cooling the sprue plate this time to see if it helps the smearing.

I cleaned up my mold. I soaked it in AeroKroil over night, but it didn't do that much for the lead. I used some very fine steel wool and kroil to polish the lead off the bottom of the sprue plate. On the inside of the mold I used a nylon brush and some toothpicks to clean up a few spots of lead that were in the vent lines. It isn't perfect but it helped. It might be better to heat the mold and then use a toothpick. I didn't wan to damage the mold.

On the outside, I used metal polish, by hand with a terry cloth towel, to clean the mold. I also did the top of the mold blocks. The polish cleaned up the smeared lead and made the surface slick. I am thinking this might help to keep it clean in the future. Boy, that brass MP mold is sure pretty when polished up. It almost looks too nice to use.

I also ran some 320 grit sandpaper over the penta pins. They didn't drop too well before and I read that others did a little sanding/polishing on the pins to help them drop. They feel smoother.

I will try that mold again. This time with better regard to the temp of the mold and starting out with a clean mold that I will not forget to lube properly as I use it.

Happy Casting!

[garrisonjoe]

Thanks guys.

I also had some smearing of lead under the sprue plate. Maybe it was because I opened the plate as soon as the sprue solidified and the bullet hadn't fully solidified.


Yep, another symptom of running your mold so hot that the bullets and sprues won't cool quickly. You can run faster if you rub just a little synthetic 2-stroke oil over the top of mold block and bottom of sprue plate, as a "sprue plate lube". Bullshop used to sell a great sprue plate lube, but 2-cycle oil works almost as well. Just keep the lube out of the cavities or you will have to clean (or cast a dozen bad bullets to get the cavity clean again).

Casting with lead smears on the sprue plate and mold top will eventually damage the mold (quickly on some aluminum blocks!)

Spray brake cleaner helps get any residual oil and grease off the mold quickly. Apply when mold is cool.