Frosted Bullets Tempreatures Mold Heating And Alloys

[Keith 429421]

I have searched and cant come up with what temperature frosted bullets occur. I do know that mold heat has something to do with bullet frosting as well as what type of alloys are being cast

I just received a Roto Metals lead thermometer and at 780F using 20 to 1 lead tin alloy in my Master Pot with 34 pounds of lead I could not cast frosted bullets in my iron 4 cavity Lyman or aluminum 6 cavity moulds. I have casted them in my 20 pound Lee bottom pour pot with the temp up at 7 and the pot low on lead but have no idea what temp I was at I did create a lot of the oxidized "dirt" in the pot at that temp and the pot was glowing red at the bottom . I am having issues with my cast bullets coming out shiny and some wrinkling . I'm working on that issue and it may be because my mold shelve is too far from the spout I have recently had success with my Lyman mould that are taller

Additional I heated a 2 cavity Lee 200 grain .45 acp SWC mould in the lead one minute at probably 700F and immediately began casting some excellent bullets from the Master Pot but did not have the thermometer at that time

I'm starting this thread to get any opinions on frosted bullets as when they begin to frost I have had some excellent filling out of my moulds and then backing down a bit to unfrosted making good bullets with fill out and no wrinkling with the Lee pot. So let us all know what temp bullets frost with what alloys or any other knowledge you casters may have on the subject

[10mmShooter]

I prefer to cast at 725 to 750 tops, frosted bullets happen when you build too much heat in your mold, if you are cycling your mold or molds too fast you will start to see the bullets drop frosty. If you move slow enough you `might never' see frosting. Your pot temperature really is not the issue, it whether or not you keep too much heat in the mold. It's all about heat transfer. Frosty=mold too hot, its up to you to decide whether or not that's a good or bad thing

[Outpost75]

Binary Pb-Sn alloys less prone to frosting than ternary Pb-Sb-Sn.

I do not consider uniformly frosted bullets a defect. With ternary alloys the frosted appearance aids adhesion of tumble-film lubes to the bullet surface, when using 45-45-10, etc.

When preheating aluminum molds I use a Proctor-Silex hotplate with ceramic tile over the Calrod and a series of Tempilstik crayons in 10 degree increments from 350-400 degs. F, measuring the actual mold blocks, to determine the sweet spot when bullets start running well. A block temp of 350 degs. F provides good fill-out and sharp bands with no frosting using 1:30 tin-lead, and 400 degs. F is about right for good fill-out with no frosting using COWW with 1% tin. At 450 degs. F block temp bullets should drop uniformly frosted and well filled out from COWW + 1% tin.

Your mileage may vary.

[David2011]

I’m not a metallurgist but I do play one in my reloading room. As I understand it from those that know more than I do about it, the cooling rate is what allows boolits to frost. The frost is apparently the crystalline structure of the antimony which only develops if the mold is hot enough to make the alloy cool slowly. I usually get a few purty, shiny boolits and then they start frosting. I have trouble finding the balance of a pot hot enough to keep the spout from freezing and keeping the mold cool enough to make shiny boolits. Since I started to powder coat the frosted surface is better anyway. Yeah, that’s it, the powder sticks better. That’s my story and I’m sticking to it.

[Keith 429421]

So pot temp is not the reason but mould temp like when I got that Lee .45acp mould very hot. Can you use a infrared heat "gun" like what people who bake pizzas in wood burning ovens use to find out the temp of the moulds or the lead in the pot? I have one I bought to check my regular house oven with to calibrate it for Thanksgiving Turkey baking as it was too hot although it did say it wasn't really for that purpose . The turkey was great however! I do have some temp sticks but there for outboard engines and are too low temp for bullet casting. Ill check out those Tempilstick crayons that's a good idea thanks for the Temp F degrees too

Is there any agreement with the statement that the best bullets come out of moulds at temps just below frosting. It seems when my moulds are really hot they cast crisper definition bullets but I cant say yet what temp the lead in the pot is till I start useing that thermometer

Keep the ideas coming please

[Keith 429421]

One more question as most casters don't have ways of measuring mould temps. How many bullets do you cast to get moulds hot and what kind of moulds IE: Lee Lyman Saeco RCBS others 1 2 3 4 6 or other cavity moulds and bullet weights as I think that bullet weight will allow a mould to become hot sooner or later I usually cast about 30 bullets from my 4 cavity iron Lymans 162 200 245 and 250 grain and about 60 from my aluminum Lee 6 cavity 120 125 175 grain moulds to get them hot. Maybe I am backwards with this and should heat the Lymans longer and Lee shorter as iron heats slower then aluminum but the 6 cavity Lees cast more bullets faster then the 4 cavity Lymans and that s why I have been doing it

[Keith 429421]

My casting cadence is usually 3 casts per minute with these 4 and 6 cavity moulds

[Keith 429421]

Now I will have to time it as that's what it feels like

[kens]

antimony alloy will frost more so than a alloy without antimony

[Rcmaveric]

I preheat my molds on a hot plate set to high. After about 15 to 20 minutes or so i start using them. It takes a few cast for them to finnish heating. How easily the sprue is to cut and how well the mold fills is my que that i am good.

I take a small fan and point it my molds (aides in keeping me cool also). I cast 2 to three times then swipe the bottom of the mold across a damp sponge. How easy the sprue cuts and how sharp the sprue cut is my indicator.

If I use two molds at once then i dont need to swipe the mold across a sponge. Using two aluminum molds at once is really the best approach. For that i fill the mold and cut the sprue then set that mold aside. Dump the bullets from the other mold and refill and cut the sprue then set aside and repeat. If i dumped the bullets before setting aside then alluminum mold cooled too fast.

I mostly use Lee 2 cavities molds. I have a couple NOE molds that I use the same way. I have used iron molds as well. With iron it was much easier to slightly slow my casting speed and place the fan in my casting area to control heat.

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[RED BEAR]

I have no idea why but i have a lee 7.62155 gr sp mold for my 7.62x39 that the bullets always frost warmer pot cooler pot warmer mold cooler mold doesn't matter they frost some times more than others when things heat up . But the bullet that isn't frosted are a rarity. I am thinking its my alloy pure ww quenched but not really sure. They do shoot good so i guess thats all that matters.

[ShooterAZ]

My boolits usually come out of the mold fairly shiny, but as soon as they drop on the towel they turn sort of a "galvanized" color. Most of my molds have a sweet spot temperature wise, where the boolits will just drop out of the mold. It is generally in the 675-725 degree range. I make notes, so I can remember the mold/alloy combination so my results are repeatable. I can't seem to rely on memory so much any more :Fire:

[RED BEAR]

My boolits usually come out of the mold fairly shiny, but as soon as they drop on the towel they turn sort of a "galvanized" color. Most of my molds have a sweet spot temperature wise, where the boolits will just drop out of the mold. It is generally in the 675-725 degree range. I make notes, so I can remember the mold/alloy combination so my results are repeatable. I can't seem to rely on memory so much any more :Fire:

I usually cast between 700 and 750 but i have went to extremes with this mold and they just keep frosting. I smelt everything into two alloys one for hand guns the other for rifles. I can't remember anything anymore and if i write it down i usually lose what i wrote it on.

[GregLaROCHE]

I don’t have a thermometer. I adjust my temperature by the way my boolits look coming out of the moulds. Normally, I go up to when I start to see frosting, then back off the temperature or change the pace of pouring. I sometimes cool the moulds by touching the mould on a damp cloth.

An infrared thermometer should work for mould temperature, but doesn’t work for me for the temperature of the alloy. I always leave flux on top and I think that insulates the real temperature. If the pot is glowing red, I would think that it is too hot.

I get wrinkles on my boolits if there is any oil or grease left on the moulds from when they were stored.

[Tom W.]

I keep my drip-o-matic thermostat wide open. Sometimes I get frosted boolits, most of the time not, unless I am pouring with my Lee single cavity mold. Then I usually get a lot of frosted boolits if I don't slow down a bit. They don't worry me as I am using my cast boolits for killing paper or steel targets. When they get sized and lubed most of the visual frosted are gets turned into a shiny area anyway.

[mdi]

Lots of theories posted, all good, but all I know is if my aluminum mold is "too hot" it will drop frosty bullets. I cast for several years before I got a thermometer and I adjusted mold and melt temp by the bullet's appearance; frosty, slow down and/or turn down the flame. I use Lee push through sizing dies and noticed no difference sizing frosty vs. shiny, and all accuracy was the same...

[Bird]

All of the above posts supply good info.
My casting experience has been only with RCBS molds. Pot temp 720 deg, air temp 65 to 70 deg.
For my 2 cavity molds I pour the first 8 to 10 castings in rapid succession to get the mold up to temp. If the bullets start to stick in the molds, I know for sure they will come out frosty. This is using plain clip on wheel weights. Keep an eye out for smearing when cutting the sprues, which is not normally a problem as I always seem to add more metal to the sprues to keep the sprue plate hot to get good base fill out.
I then get the mold temp down a little by cooling the mold base on a damp rag for 1/2 a second or so, until the bullets fall from the mold easily. I dont like cooling the mold with a fan, as it also cools off the sprue plate.
I dont usually go for frosted bullets as they can end up slightly smaller in diameter, but not by much.
I recently started casting with a RCBS 45-405fn single cavity mold. That turned out to be a completely different experience. Using the above settings and alloy, I could not get a decent bullet out of 40 castings. I could not get enough heat into the mold, and ended up with poor fill out at the bands, and barely managed to get rid of wrinkles. The solution was to increase pot temp to 780 and use 14 fast initial pours to get the mold to temp. Once up to temp, I waited 12 seconds before cutting the sprue, and had perfect bullets falling from the mold. This mold, even though its iron, loses heat quickly, so no sticking bullets, and the need for cooling the base of the mold was not required. I could only get slight frosting of the bullet if I really tried.

[Bird]

Just a thought. Once you find out what your mold likes, make a note somewhere, or put it in with your molds.

[GregLaROCHE]

Maybe some day I will get a PID controller. It’s on my wish list, but hasn’t worked it’s way to the top yet. Too many other reloading and gun things keep getting in the way.

[midnight]

Swede Nelson at NOE used to sell a digital BBQ thermometer with a probe. He still will drill a hole for the probe with a set screw on the molds he sells. With the right size #drill you can drill other molds for the probe. That way you can the exact temp of the mold when it is producing the bullet you want, whether it be shiny or frosted or inbetween. You might be able to use the digital thermometer Lyman sells for $25.

Bob

[lightman]

I set the temp on my PID at 735º and cast with straight wheel weights. Mostly with 4 cavity iron molds but occasionally with a 2 cavity. If I cast too fast I get slightly frosted bullets. They don't bother me much but much cooler than 735º I get wrinkles and poor fill out. The larger the bullet the slower I have to cast.

[mdi]

Just a thought. Once you find out what your mold likes, make a note somewhere, or put it in with your molds.

Yep. Keep a casting log, just like you keep a reloading log...

[RED BEAR]

One more question as most casters don't have ways of measuring mould temps. How many bullets do you cast to get moulds hot and what kind of moulds IE: Lee Lyman Saeco RCBS others 1 2 3 4 6 or other cavity moulds and bullet weights as I think that bullet weight will allow a mould to become hot sooner or later I usually cast about 30 bullets from my 4 cavity iron Lymans 162 200 245 and 250 grain and about 60 from my aluminum Lee 6 cavity 120 125 175 grain moulds to get them hot. Maybe I am backwards with this and should heat the Lymans longer and Lee shorter as iron heats slower then aluminum but the 6 cavity Lees cast more bullets faster then the 4 cavity Lymans and that s why I have been doing it

My lee molds seem not to need as high heat as lyman or rcbs or mp. To cool my molds i use a aluminum plate that is curved so it stands off the table . To heat all my molds a $10 hot plate
Set at med works great for me. I may catch some flack on this one but i wouldn't waste my money on a pid. The temp just don't have to be that close. They are a neat toy but not necessary. I normally keep my pot between 700 and 750 and get very few rejects. I bought an rcds thermometer and use it to get an idea of pot temp but really don't use it to much anymore. You can get a feel from how bullets come out. Now if you have the extra money then they are a neat toy.

[kevin c]

I use aluminum eight cav MP molds, mostly 147 grains. The alloy is 95-3-2, kept around 720 degrees (higher when the casting in cold weather).

The mold starts on a hot plate with a glowing red element. The first couple pours are heavily frosted and undersized, after which the right cadence (one pour every twenty odd seconds), produces a light, even, matte silver color. This is what I shoot for, partly because I HiTek and I've read that frosted surfaces take the coating better, but mainly because I get the best fill out, the fewest rejects and the best productivity in a casting session when I'm in this zone.

The main issue I have is keeping the aluminum molds hot enough - they cool so fast. It's when I START to see shiny boolits that I know the molds are too cold, and that I need to speed up, or, if I'm tired and want a break, or if the pot needs more alloy (it goes fast with eight cavities), then the mold goes back on the hot plate. I haven't had much of the problem of the molds being too hot, but as I want to increase pours per minute while maintaining quality, I may start experimenting a bit more with mold cooling techniques.

[Rcmaveric]

I will also add that temperature of alloy is more of reference. Most people on here run around 700 +/- degrees. I use the Lyman dial thermometer and find i have to run around 850 +/- 50 degrees for mold fill out. If i am running straight range scraps i will have to run closer to 950 degrees for excellent bullets.

I dont think my thermometer is accurate either. But it is consistent and really cuts down the time it takes me to fiddle with temps to get great results.

High melt temps on heat molds faster.

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[RED BEAR]

I will also add that temperature of alloy is more of reference. Most people on here run around 700 +/- degrees. I use the Lyman dial thermometer and find i have to run around 850 +/- 50 degrees for mold fill out. If i am running straight range scraps i will have to run closer to 950 degrees for excellent bullets.

I dont think my thermometer is accurate either. But it is consistent and really cuts down the time it takes me to fiddle with temps to get great results.

High melt temps on heat molds faster.

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Yes i use the rcbs because it got better reviews but i seriously doubt its all that accurate i had the pot go well over 1000 degrees by it and i just don't think my lee pot is capable of that. So i mainly
Just use it for a reference.