High temp cast

[nueces5]

I started making some 9mm boolits, and I had the PID configured with 750F
I dipped one corner of the mold (aluminum) into the alloy
The mold heated up faster, actually cutting the sprue plate was very easy all the time, the boolits fell on their own with a slight tap.
A little frosties, but nothing that can't be solved with PC (it's an NLG mold)
I was making flux every 20 minutes or so and added a little tin to the mixture.
Is there a problem that you are not seeing with increasing the temperature?

[fredj338]

I do my casting between 730-750. I have no issues. Just stir the pot more. No need to flux, I only use clean alloy & just stir with a wooden stick each time & add alloy. All my fluxing is done turning scrap into ingots.

[Walter Laich]

If you're not smearing lead across the top of the mold or under the sprue plate you're good to go

I cast a bit cooler so I don't have to wait as long for the lead to harden but that's my choice

sounds like you have a good technique going--have fun

[charlie b]

My pot is around the same temp. Molds are preheated on a hotplate to around 350F.

[nueces5]

Thanks for the comments, I'm sure I'm slowly lowering the temperature
Just as they say, it hardens faster that way

[Oldfeller]

I keep reading about people laboring at fluxing their pot continuously as they empty the pot.

Here is some knowledge from past iterations of this list that has apparently been lost due to time.

First, you use vegetable oil based flux when you melt your wheel weights. Crisco is what I used by the table spoon full when I was melting / separated the WW steel from the lead in an old roaster pan heated up in a unused gas grill. There was a small pool of smoking oil and road dirt on top of the melt and very little oxidized crap. I skimmed with a big slotted spoon to get all the crap out of the lead.

Then I took skimmed lead directly into the ingot mold by dipping it out with an old stainless punch ladle into the muffin tin ingot mold. The cooled ingots were slightly greasy feeling and they dropped free when the lead cooled with no issues.

Then into the Lee Production Pot which got a quarter inch of standard commercial "steam expanded" clay based kitty litter on top of the melted lead. This stuff gets dirty over time but once your pot cools you can just pour off the ugly stuff and replace it with fresh litter. I do this every few months as I can catch the pot cold and the litter dirty.

Did you know Bentonite organic clay is an organic flux for lead? A quarter inch of kitty litter will flux replacement ingots and sprues as you rest them on top of the litter. The lead melts and trickles past the kitty litter getting cleaned and fluxed as it goes. The litter layer floats impurities (like the occasional zinc WW or steel clip) up on top where you can see it.

I never mess with fluxing my pot as I do it automatically as I add lead to the pot. Because I melt continuously, I never wait for the pot nor do I ever have dirty metal.

My pot stays clean, never building up the crap that others have to deal with.

[charlie b]

Just wondering. Why are you adding tin and how much? I've never felt the need to do that.

[45DUDE]

I heat my molds over the pot about 850 degrees, then turn down to 700-750 -800 <depends on outside temperature> and cast. I don't dip my aluminum molds in hot lead for fear of warpage. If frosty boolits let the mold cool 30 seconds or so. I like mine to look like Long Ranger boolits.

[country gent]

If its working for you and your happy with the results thats all that matters. I ladle cast with a bigger pot (100 lbs) and run in the 730-750 range normally. But my bullets are BPCR from 20-1 and bigger 365 grns up to 550 grns.

With the PID temp should be maintain as the level in the pot drops. Otherwise the temp will rise as the level drops more heat in a smaller mass.

[Txcowboy52]

I keep reading about people laboring at fluxing their pot continuously as they empty the pot.

Here is some knowledge from past iterations of this list that has apparently been lost due to time.

First, you use vegetable oil based flux when you melt your wheel weights. Crisco is what I used by the table spoon full when I was melting / separated the WW steel from the lead in an old roaster pan heated up in a unused gas grill. There was a small pool of smoking oil and road dirt on top of the melt and very little oxidized crap. I skimmed with a big slotted spoon to get all the crap out of the lead.

Then I took skimmed lead directly into the ingot mold by dipping it out with an old stainless punch ladle into the muffin tin ingot mold. The cooled ingots were slightly greasy feeling and they dropped free when the lead cooled with no issues.

Then into the Lee Production Pot which got a quarter inch of standard commercial "steam expanded" clay based kitty litter on top of the melted lead. This stuff gets dirty over time but once your pot cools you can just pour off the ugly stuff and replace it with fresh litter. I do this every few months as I can catch the pot cold and the litter dirty.

Did you know organic clay is an organic flux for lead? A quarter inch of kitty litter will flux replacement ingots and sprues as you rest them on top of the litter. The lead melts and trickles past the kitty litter getting cleaned and fluxed as it goes. The litter layer floats impurities (like the occasional zinc WW or steel clip) up on top where you can see it.

I never mess with fluxing my pot as I do it automatically as I add lead to the pot. Because I melt continuously, I never wait for the pot nor do I ever have dirty metal.

My pot stays clean, never building up the crap that others have to deal with.

Very interesting! Thanks for the info!

[kevin c]

I’ve never understood why some are obsessed with having shiny bullets. My aluminum molds cast best when the boolits have a slight matte frosting on them; I see that (running the PID at 730°, even more if it’s a cool or breezy day) I know I’ll have virtually no culls.

True that I HiTek coat everything, but I think I’d still be happier with flawless matte boolits than with shiny defective ones if I kept them in the raw.

[waksupi]

If my boolits aren't frosty, I figure something is wrong.

[gwpercle]

If my boolits aren't frosty, I figure something is wrong.

I don't have no PID or thermometer ... But
Get best boolits just at "frosty" ... I hear the frosty surface helps hold coatings !
Gary

[porthos]

i have a box enclosed with a computer fan on top. hold the mold under the fan for 3 or 4 seconds and the sprue hardens faster

[Dusty Bannister]

Porthos, while that will speed up the hardening of the sprue and cools the sprue plate, that does not allow the fluid melt to be drawn into the mold cavity as the casting cools and shrinks. With larger castings, that is not a good thing. That "starves" the casting and can create cavities and potentially a balance issue with the cast bullet.

[More_Slugs]

I have read the comments about fluxing, including a few that say they don't or there's no need. This is such a misinformed subject.

Fluxing is ABSOLUTELY necessary because it is the only way to return the separated metal oxides back into the melted alloy. And sawdust is the best material to flux with.

Read the attached article in the link, which was written by an avid caster with a degree in Chemistry. It's so important, flux is mentioned almost a dozen times.

http://www.lasc.us/castbulletalloy.htm#UNS

[243winxb]

Increasing the temperature , frosted = smaller diameter.


Don't dip aluminum molds in hot lead =warpage.

[Larry Gibson]

I add tin to COWWs to balance the amount of tin to that of the antimony. At a percentage of each not exceeding 5% each together they form a submetal of SbSn.

That submetal, SbSn, will then stay in solution in the lead, particularly as the alloy begins to harden. Excess antimony not in balance with the tin will simply be mixed in with the liquid lead and not in solution. Thus, since the antimony will harden before the lead it usually will appear as "frost" on the outside of the bullet. Antimony also shrinks more than lead and the frost can result in shallow depressions on the bullet. Sometimes easy to see and other times not easy. This all results in imbalances in the bullet and can cause antimonal smearing in the bore oft times confused with leading.

I cast at an alloy temp of 715 - 725 as measured with two thermometers; one measuring the temp of the top half of the alloy in the Mag 20 pot and the other measuring the temp of the bottom half of the alloy. As I cast while waiting for the sprue to harden I put the previously cut sprue into the pot. I only flux the alloy at the beginning of the casting session when the pot is filled, melted and brought to casting temp. The dross that forms on top of the alloy is not separated elements of the alloy but simply oxidized alloy. The tin and antimony ARE NOT separating out of the alloy. I also adjjust the alloy flow during casting , as the pot empties, to maintain an even flow pressure of alloy into the cavities [easily done with the Mag 20, not sure about the Lee production pot)?(]. When the pot gets low, if I'm going to continue casting, I'll add more ingots to refill the pot. When the alloy is to temp I will then flux that pot and continue casting. Thus I only flux the one time when using clean ingots to begin with. BTW; I flux with beeswax and a couple three wooden matches thrown in to ignite the fumes. Beeswax is also referred to as an excellent flux in the lasc.us writings.

Thus, if I have frosted bullets I consider something is wrong and I correct it. I haven't shot any frosted bullets of my own for 45 - 50 years.

[gwpercle]

Porthos, while that will speed up the hardening of the sprue and cools the sprue plate, that does not allow the fluid melt to be drawn into the mold cavity as the casting cools and shrinks. With larger castings, that is not a good thing. That "starves" the casting and can create cavities and potentially a balance issue with the cast bullet.

The Man is as Right as Rain !
Gary

[jdgabbard]

If my boolits aren't frosty, I figure something is wrong.

Diddo... If they're shinny, they're probably undersized... But I have a .356 mold that routinely drops close to .361 with the way I cast. So I guess that says something...

I have read the comments about fluxing, including a few that say they don't or there's no need. This is such a misinformed subject.

Fluxing is ABSOLUTELY necessary because it is the only way to return the separated metal oxides back into the melted alloy. And sawdust is the best material to flux with.

Read the attached article in the link, which was written by an avid caster with a degree in Chemistry. It's so important, flux is mentioned almost a dozen times.

http://www.lasc.us/castbulletalloy.htm#UNS

Nonsense. Many of us over the years have discovered that fluxing for that reason isn't necessary. Kitty litter over the melt helps to keep the O2 from the melt, reducing Oxides. Or just leaving the oxides on top keeps a barrier that does the same thing. It doesn't separate the alloy, it oxidizes it uniformly. I get no more oxide on my melt when using tin rich alloys than I do using Pb only. Believe what you want, but many of us stopped this practice many years ago - I haven't fluxed a pot of melt since probably 2009. And I have zero problems, and get groups that most people would be proud of.

Increasing the temperature , frosted = smaller diameter.

I and others have found the opposite to be true. If my bullets aren't frosty, the mold or the melt isn't hot enough. My bullets don't come out to the right size unless they're frosty.