Heat shrinks?

[fatelk]

Rather than add on to the other thread about this mold, I thought it might be best to start from here.

I'm still having trouble with this Lee six-cavity .452 mold. All I get is undersize bullets. I have two other new Lee six-cavity molds; one in 9mm and one in .40. The 9mm throws perfect bulllets and the .40 mold throws them .004" over, with the same WW alloy and technique as I'm using with the .45 mold.

I've always cast with fairly hot lead, and everyone's been telling me to run the mold hot, so I usually have frosted bullets, and it's never been a problem. With this mold, though, I've tried everything I can to try to get good bullets. I have a hard time getting them to fill out well until they start to frost. Once they start to frost, even slightly, they are too small, .451 or less.

When they're on the edge of frosting, they sometimes get these odd frosty shrunken spots. They don't all look this way; these are just the worst. I have been completely unable, though, to get consistent unfrosted bullets that measure good.

Please don't tell me it's my alloy. I've tried several different batches of WW ingots, and it's all worked great in my other molds. If this particular mold won't work with WW lead, I'll replace the mold, not my alloy.

I know a lot of you guys have had some good ideas and suggestions on this mold in the other thread. Maybe cooler lead and a hot mold? Yes, I've cleaned the heck out of the mold, several times. I guess I'll try again, with a couple more things. I already sent the first one back to Lee. They said it WAS undersized and this is it's replacement.

[lwknight]

One of my molds did that. It was only one certain cavity so I reasoned that it had to be contamination. Finally I sprayed some frankfort arsonal mold release and rubbed out the excess after it dried and the weired little shrunked frosty spot went away.

I know that sometimes you get that from hot spots in the molds and they quit when the molds are a bit cooler.

I thought that it was the alloy for awhile and did everything under the sun to narrow it down. Turns out that the only thing alloy had to do with it was that higher tin content was more proned to act that way.

[243winxb]

replace the mold

[docone31]

Soak the mold in Mineral Spirits for a couple of days.
Gets the crud out.
If it still drops light, more WW, less pure lead.

[HeavyMetal]

I'm gonna second re cleaning the mold as well as suggest that you examine the mold cavities under a strong light with a good magnifiying glass.

I would think theres something in the mold? This "hot spot" seems to be to local for anything else.

[Bloodman14]

Do you ladle, or bottom pour? If you ladle, you may be tilting the mold, and the shrunk, frosty part is the last part cooling and taking up the 'shrink' in that spot. If you pour, do what Doc said and soak the mold for a week.

[BABore]

I used to get that alot, especially on bigger boolits. It's caused by a hot spot in the mold. I use a cooling fan to keep the mold temperature consistent. The flow rate of your pouring method will have a direct influence on your problem as well. Getting lead into the cavity faster will cure the problem. I test new molds almost every weekend. Being a ladle caster, I start off with a Rowell ladle to see if the flow rate is adequate for the particular mold. With a Rowell, you can't always pour a stream directly through the SP hole unless you use a thin stream. A thin stream equals a low flow rate. Some molds will tolerate that and produce well filled out boolits. Boolit length, diameter, and how intriquent the features are all dictate the flow required. A short 38 boolit with only a couple of wide grooves can usually be poured by just flooding the SP hole until it burps a good sprue and move on. Bigger boolits like your 45 TL design can be more difficult and will produce results like yours. In this case I switch to a RCBS ladle that has bee drilled out to at least 0.160 or 0.180 diameter. The mold is tipped and the ladle nipple held tight to the SP hole as it's rotated upright, then a final lift to produce a big sprue.

Lee molds do like to be run hot. This doesn't mean you have to run your alloy at top end to do it. Dip the mold corner into the pot for 20-30 seconds and go. I don't agree that you need to clean your mold to get rid of this problem. If it's dirty, why does the defect come and go or move around? Up your fill rate and keep a consistent mold temperature once you find your sweet spot.

[Bass Ackward]

Sometimes you just get a smaller cavity mold. It can be just that simple. You can get a mold too hot too. But because heat rises, you should see that on more of the bullets and around the bases first unless you have a venting problem that is causing this at lower temps than it otherwise would. Looking at your picture I see the possibility of one cavity venting into other cavities. This is most pronounced if you are you ladling. since air can't vent out the top.

Bottom line is that you can take a file and lightly bevel the blocks. How light is light? You should have a hard time seeing it with good eyes. Or losen the sprue plate some to test. Then maybe you CAN go on up in temp and get bigger.

One more trick is to cheat. Try pouring every other one and then switch. That ought to tell ya if it even worth putting the effort in.

If not or you simply DON'T want to bother, try trading with someone that needs smaller slugs.

[fatelk]

Thanks for the replies. I use an old Lee 10 pound bottom pour pot. It absolutely won't hold temperature unless I watch it close with a thermometer. I also think It's been running a little hotter than I thought. I tested my old thermometer in boiling water and it looks like it reads about 50 degrees low.

My problem hasn't been so much with the spots, more with the fact that the whole bullet diameter shrinks when they start to frost, and I can't seem to make a boolit that doesn't frost. The Lee guy told me also to clean the mold again and give it another try. I've already tried paint thinner, IPA, and dish soap, but I'll try again.

They already replaced this mold once, for being undersized, and assured me that this one should be big enough. I'll try a few more things when I get time. I have to do some homework now. Back to school after this long stinks, but after no work for over a year I have to do something. Hopefully Glorious Leader can solve all our problems soon and I can get back to work.:rolleyes:

[fatelk]

Well, I took a little time and tried again. I very carefully cleaned each cavity thoroughly, smoked them with wooden match sticks, kept the lead temp as low as possible, and tried the mold from cool to hot.

It does seem to help, but the diameter of the base is just barely .452, and the small middle bands measure .450-.451 at best, but at least they are more consistent.

How do you get non-frosted but filled out boolits in a mold like this? For me, once the mold starts to get hot enough to make good bullets, they start coming out dull, then frosted. The frosting from the hot mold doesn't seem to affect the diameter nearly like too-hot lead, so maybe it's no big deal. I think I'll lube and load up a few of these barely big enough boolits, clean my bore shiny clean, and see how they work.

[Bass Ackward]

Well, I took a little time and tried again. I very carefully cleaned each cavity thoroughly, smoked them with wooden match sticks, kept the lead temp as low as possible, and tried the mold from cool to hot.

It does seem to help, but the diameter of the base is just barely .452, and the small middle bands measure .450-.451 at best, but at least they are more consistent.

How do you get non-frosted but filled out boolits in a mold like this? For me, once the mold starts to get hot enough to make good bullets, they start coming out dull, then frosted. The frosting from the hot mold doesn't seem to affect the diameter nearly like too-hot lead, so maybe it's no big deal. I think I'll lube and load up a few of these barely big enough boolits, clean my bore shiny clean, and see how they work.


Well, as you said, if you get good diameter from other molds, then ...................

Diameter is over rated. I got a 45, 200 RF that is .4515 even with extra tin added. Dang thing is outta round on everyday but Sunday. But goose'em and they seal. If they seal, the gun makes me look like I know what I am doing. Same as it does with everything else to date, bless it's maker.

[mooman76]

If the base is coming out 452, that's what the mould is. If you wait and measure them again in a week you should find that they are about.001 bigger. You'll drive youself nuts tring to get good bullets without the frost especially with a 6x mould and a 10# pot. By the way I think a 10# pot isn't big enough for your 6x moulds and that's one reason you are getting the fluctuations. You should have at least a 20. You will probubly find also if you get the heat up a little and get some frost, you will end up with bigger bullets.

[bigboredad]

frosted boolits are OK and if you read the lee directions it says its preferred because the lla sticks to it better also smoking your molds can be the reason your bullets are coming out small

[AZ-Stew]

I'm guessing that your sprues cooled solid before the metal in the mould froze. As the boolit in the cavity then cooled, it shrank and pulled away from the mould wall, causing the depression and "frosted" appearance.

Try again, pouring a GENEROUS sprue puddle to keep the sprue hot and liquid while the boolit cools and solidifies within the mould cavity. You should see the sprue suck down and cause a dimple right above the sprue opening into the mould. When the sprue completely solidifies, cut the sprue and drop the boolit. I'm guessing this will eliminate your frosted depressions.

Regards,

Stew

[leftiye]

As Stew said, Boolit shrinking from mold walls. It isn't just about the sprue cooling before the boolit solidifies, though it does happen that way too. A too hot mold will fail to solidify the boolit on the outside, and as the whole boolit cools slowly, the whole thang shrinks. It can be because the outside of the boolit isn't frozen enough to resist the shrinkage and therefore doesn't cause metal to be drawn from the sprue puddle. Largest boolits come from moderately hot molds using moderately hot lead. Mold temp (measured with infra red thermo on outside top of side of mold) 250 -325 and lead about 700 degrees.

[fatelk]

Largest boolits come from moderately hot molds using moderately hot lead. Mold temp (measured with infra red thermo on outside top of side of mold) 250 -325 and lead about 700 degrees.
I will try this.

My frustration has been that whenever they start frosting, they start to shrink. I try to leave enough sprue, but I will try more. I wish I could afford a good 20 pound pot right now, but I'll have to make do with the old Lee pot someone gave me over a decade ago. That six cavity mold sure does drain it fast!

I have 60 or 70 bullets ready to go. I measured the batch carefully, throwing out a few, and the rest are all at about .4515" at the base, and .450" at the mini middle bands. We'll see how they work.

[Faret]

I have run my 50 bmg mould with a 10# pot 3 banger. That is about 3000 grains of lead at a crack including the sprue. Set about 7-8 on the dial (lee pot) and preheating the lead on a warming plate (700 watts) I can keep up with the mold. Mold runs about 350* and the sprues are put in too as I go along. The biggest thing I noticed is that the sprue has to be big and hot to get the back of the bullets to fill out.

[Wayne Smith]

One possible solution is to get a heat source, a pot, and a ladle and try ladle pouring the thing. I still use a Coleman 2 burner propane stove, and old SS 1qt kitchen pot, and a Lyman ladle. This setup is better for big boolits and for multiple cavity molds.

You should be able to set this up rather cheaply - you can use a hotplate for a heat source too. The ladle is the only thing that you are not likely to find at your local thrift store.

[fatelk]

You all are great! Thank you for all the help with this frustrating mold.

I just made another batch of 100 or so, that is consistently over .452, by cleaning the mold again carefully, setting the heat at 700 and watching it closely, warming the mold over the pot upside down to heat the sprue plate, and pouring a very generous sprue. This produced a much more consistent and acceptable diameter boolit.

Problem solved! Thanks again for all the great info.:)


Added: I do have a couple larger cast iron pots, a couple of old ladles, and a huge old Coleman burner I was going to try to use, but I doubt the thing will work for me. It's dang near an antique, and I should probably just sell it and save up for a bigger electric pot.
http://castboolits.gunloads.com/showthread.php?t=73452

[DLCTEX]

I'm glad you made it work. I was going to suggest heating the sprue plate by holding it in the melt for a short while. I preheat my moulds by dunking the corner in the melt until it's warm enough that the lead doesn't stick to it.

[fatelk]

One last thing: Lee customer service was great. They replaced the first one (which they said was too small), then helped me (with you all) trouble shoot the problem via email.

Pat at Lee was very helpful.:)

[mpmarty]

my six bangers all make beautiful boolits. I run the temp up over 700* and cast as fast as I can until frosting happens then I back the temp down below 700 to 675 or so and slow down the casting a bit cooling the mold on a damp rag in a shallow pan of water while the boolits are still in the mold after cutting the sprue with gloved hand. I seldom cool the sprue, just the mold blocks.

[HangFireW8]

I've seen that frosty side flat spot before! I had the exact same problem in a double .458 mold. It has to do with how close the cavities are together, and venting, and is more of a problem with multiple 45 molds than smaller calibers.

You see, if you pour the second boolit before the first one is solid, the air has to go somewhere, so the superheated air vents next door and creates a flat, frosty spot on its still molten neighbor.

Let each boolit cool until hard a few more seconds before pouring the next. In a 6 gang mold, you could probably alternate holes and keep your rhythm and speed going better than a 2-banger.

Gently chasing out the vent lines on the outside of the cavities will help. Let the vent lines between cavities clog up.

-HF

[HangFireW8]

Here is a pic. Notice the similarities- 45 caliber, frosty flat spot.
-HF

http://castboolits.gunloads.com/picture.php?albumid=274&pictureid=1830

[Clark]

You mean that one mold breathing on another causes the frosties?

I thought it was from the lead being too hot.

[fatelk]

Interesting. I have noticed on any of my out-of-round boolits, that the smaller diameter measurement coincides with the line on the boolit from the mold halves.


In a 6 gang mold, you could probably alternate holes and keep your rhythm and speed going better than a 2-banger.

Out of curiosity if nothing else I'll give this a try and see what happens.

[HangFireW8]

You mean that one mold breathing on another causes the frosties?

I thought it was from the lead being too hot.

I think the stippled appearance of the breathed-on side looks just like a frosty, too-hot boolit, but this is coincidence.

I figured out what was going one when I had some sticky boolits that did not drop in the second cavity, and the flat, frosty side was towards the first poured cavity. If you look at the rest of the boolit, the mold is running too cool, if anything.

-HF