Pure Pb Casting Temps

[PbHurler]

This last weekend I spent some time casting with pure lead, casted RB's out of a Lee mold, and a new NOE 510-380-HB (Great Plains) mold.

I noticed I needed to really crank the heat up to get acceptable (non-wrinkled) drops from both molds. The temps needed to be between 800 to 820 degrees (pot temp) to get good drops. Bottom pour furnace, Tel-Tru thermometer, lead was Rotometals pure.

I did increase my cadence to see if the increased mold temp could be the culprit but not so. It wasn't until I kept increasing the pot temp up to the 800 - 820 degree mark, that I began to get keepers.

Most, ok, ALL of my casting over the last 35 years has been with alloyed mixtures. Now with the ownership of a muzzle loader I'm venturing into pure Pb which is new to me. Since pure is listed to melt at 621 degrees, am I experiencing a normal characteristic of casting with pure?

What are your experiences with pure?

Thanks in advance

[Mike W1]

Not that I've anything too valuable to add but mostly to bump the thread in hopes of others chiming in. I don't have any pure lead but some that's close. Couple things come to mind. The calibration of your Tel-Tru for one? Mine was off quite a long ways till I calibrated it.

800+ ° seems pretty high to me for one other thing. Lead likely needs more than an alloy would - but that's pretty high.

Noticed your moulds are aluminum. Only have 1 myself but it would NOT get up to temperature by casting. I would strongly suggest a hot plate! Once I did that it was like a whole new ball game, wouldn't have thought it was the same mould.

[dubber123]

I always ended up casting at a higher temp to get good castings from pure lead. I am going to try adding just a little tin next time, and I expect it will help measurably.

[bigjake]

Like Mike said, put the alum mold on the stove burner. pre-heat the mold to about 400 degrees or so. it will cast great

[LAGS]

I run my Pure lead around 700 and use a HOT mold.
I get about ten casts, then the will start to frost a bit, then have to cool the mold slightly .
But adding a small amount of Tin will help, say about a 1/2 percent.

[PbHurler]

Years back, Bill Ferguson sent me instructions on calibrating my thermometer, by plotting the cooling curve of linotype. I did this a couple of times, & feel "reasonably" comfortable with it's accuracy. As a side note, I have placed the thermometer in with a PID controlled melt(s) & the differential between the two only varied + or -5 degrees. IMO, thats acceptable to me; I mean I'm only casting boolits.

I did preheat my molds on a hotplate, but I have to admit I'm not sure of the temps of the molds (hell the NOE is drilled for a probe!). I dont have the NOE digital thermometer as of yet, but I could've inserted my Tel-Tru, and didn't.

The LEE mold has that small footprint, The NOE has the protrusions of the internal pins which makes it tricky to get a good contact with the hotplate's surface.

I thought increasing my cadence would eventually bring the molds up to adequate temp, I was knocking the sprues immediately upon solidification, heck a few times when I tilted the mold(s) the sprues were still molten (my mistake). I still needed to keep raising the pot's temp to begin getting keepers.

Next time, I'll try to make SURE I've gotten an adequate pre-heat, it appears this may be the reason for all of the rejects.


I may try the addition of some tin to see what effects that may have. I've got some 20:1 alloy to give a try, & play around with just to see if I can drop the pot temp(s).


Thanks for your responses,

[iraiam]

I usually cast pure at 720 - 730 degrees, I use a hot plate to preheat the mold, I keep the mold hot, particularly when casting pure lead. About the only pure I cast anymore is a 370 grain maxi ball and .498 round ball, both are steel molds.

[newrib]

I have done my most successful minie ball casting with a pot temp of 830F, roto metals pure pb with a mold (alum or steel) heated on the hot plate set on med.. The hot plate with the mold on the coil and lead pot turned on at the same time. With the first 10 pours being scraped the finished bullets look and usually weigh great. That is ladle casting with minies and bottom pouring round balls.

[garrisonjoe]

Yep, casting soft lead takes a hot pot. Alloyed lead melts hundred or so degrees F less than soft lead. So, turn up the pot some and preheat molds.

[JonB_in_Glencoe]

This last weekend I spent some time casting with pure lead, casted RB's out of a Lee mold, and a new NOE 510-380-HB (Great Plains) mold.

I noticed I needed to really crank the heat up to get acceptable (non-wrinkled) drops from both molds. The temps needed to be between 800 to 820 degrees (pot temp) to get good drops. Bottom pour furnace, Tel-Tru thermometer, lead was Rotometals pure.

I did increase my cadence to see if the increased mold temp could be the culprit but not so. It wasn't until I kept increasing the pot temp up to the 800 - 820 degree mark, that I began to get keepers.

Most, ok, ALL of my casting over the last 35 years has been with alloyed mixtures. Now with the ownership of a muzzle loader I'm venturing into pure Pb which is new to me. Since pure is listed to melt at 621 degrees, am I experiencing a normal characteristic of casting with pure?

What are your experiences with pure?

Thanks in advance
The rule of thumb is to cast with your lead or lead alloy at about 100º above the melt temp.
As you stated pure lead melts at 621º
so a good pot temperature is 720º

Myself, I add about 1/2% of Tin to my pure when casting BP conicals and RB. The small percentage of Tin doesn't change the hardness, yet is enough to keep them from tarnishing and/or oxidizing for much longer time than pure lead. Also, that will provide better fillout and lower the melt temp of the alloy, allowing you to lower your pot temp.

[Nose Dive]

Yea...I agree with all above... 700 to 750 or so temp... and..be brave!!! go ahead! add some pewter and/or tin to the smelt.. it helps!!

Hot moulds and some tin or pewter really works well for me... As I never,,,ever,,,'know' i have pure lead because i never buy any...all my 'pure' stuff is grud and corrpution I smelt.... I get smelt stuff from anywhere and my 'go to' solution in pewter and tin....solder too...

I cast for a buddy of mine who owns a '$5,000.00" black powder rifle. Yes boys and girls...$5K for this beautiful rifle...weighs a ton and is ...jezzz...just gorgeous.... 50 calibre.... and he shoots 500 and 1000 meter shoots.... so....he gets my boolits...i get some beer...all are happy fellas.... He picks and buys molds.... i smelt, ally and cast and drink and provide.....He takes his molds with him when he leaves.... "special" molds you see....

I do BRH to 15....water drop...size,,lube,,(my lube)...and he lets them sit for 3 months before loading and shooting.....

really... I think my casting is all BS as the rifle is the key... think he could stuff thimbles stuffed with shot in that thing and win. I do also make his 'black powder' ....

and...sorry....no questions answered about all this or...or....the free beer with dry up.

Nose Dive

Cheap, Fast, Good. Kindly pick two.