Bullet Casting Temperature

[ryan richards]

Dear CBO's

Please comment about the following statement I found on internet:

"The ideal temperature for casting wheel-weight alloy bullets should be only
slightly higher than the melting point of lead (621° F). However, to get good
filling out of the mold most casters run about 625° to 675° F."

1) What's your advice to someone who doesn't want to reinvent the wheel?

2) Which thermometer (Lyman, RCBS, or other) would you advise me to buy to
monitor this temperature range?

Notes: I have learned that clip-on wheel-weight alloy reaches its "slushy" melting
point at about 463º F and its "molten" melting point at about 505º F.
Pure lead melts at 621.43º F.

Thank you again for your time and interest to help out someone new to the hobby.

Ryan

[JeffinNZ]

Hi

Re thermometers; there are lots of good digital ones available now if you have a surf around. I used mine for the first time a week ago and it works well.

Re temp; I found that I had to run my clip on wheel weight at 700F to get well formed bullets in my new CBE mould. 650F gave me some grief.

[cbrick]

Ryan, First don't confuse solidus and liquidus temps.

From this article: Cast Bullet Alloys (http://www.lasc.us/CastBulletAlloy.htm) and is a quote from "Alloys for Cast Bullets, by Jerry Gonicberg, The Art of Bullet Casting, Wolf Publishing, page 86".

One of the most critical yet least understood casting factors is temperature. When a bullet caster refers to the melting temperature of the alloy, what he means is the solidus or the temperature at which the alloy begins to melt. More important is the liquidus temperature of the alloy, the point at which the alloy is completely molten. An alloy may appear to be completely melted in the pot when in actuality it is not, since crystal formations of some of the important constituents of the alloy, such as tin and lead or lead and antimony, still exist.

I cast WW + tin at 700 degrees, any hotter can cause loss of tin and tin's benefit of reducing oxidation which occurs at about 750 degrees.

Hope this helps.

Rick

[trickg]

Dad always told me that "lead" - meaning wheel weight alloy - melted at "around 700 degrees." My bet is that he cast somewhere in the 690-710 range, but I don't recall that he ever used a thermometer. I think he casted based on the consistency of the melt - that or he just knew after doing it for so long how much flame he needed to use from his propane stove.

[cbrick]

Dad always told me that "lead" - meaning wheel weight alloy - melted at "around 700 degrees."

Nope, WW alloy solidus (melting temp) is around 570-580 degrees and liquidus around 50-70 degrees above that. Your dad's 700 degrees is a good temp for WW but it sounds like he based his temp on results and not temp. Nothing wrong with that except possibly repeatability, if it's working for you your doing it right.

Pure lead has a melting temp of 621 degrees but tin reduces leads melting point and the more tin the lower the melting temp. That's why 60/40 solder melts at 363 degrees, even the lead in it.

Rick

[DLCTEX]

Using aluminum molds I generally don't get good fillout until I am running considerably hotter than I do with steel molds, that temperature statement is a starting point , the individual mold will dictate the casting temp. IMHO. DALE

[leftiye]

Casting temp is not just about the temp of the lead, it is also about mold temp. For most casters this is moot because they must increase their lead temp to get the mold hot enough to cast.

If there is a separate mold heater one finds that mold temp is the important variable. The mold must be hot enough that the lead freezes at a MODERATE rate. That is, it doesn't freeze before it fills out the mold. Lead temperature does affect this, and how hot the mold gets, but adding an intermediate heat source makes possible casting with lead as cool as 600 degrees (as cool as what doesn't freeze in the nozzle in your bottom pour). With a mold heater, lead this cool can be made to cast shiny (even wrinkled) boolits - to boolits that are severely frosted and therefore deformed.

[Shiloh]

Dear CBO's

Please comment about the following statement I found on internet:

"The ideal temperature for casting wheel-weight alloy bullets should be only
slightly higher than the melting point of lead (621° F). However, to get good
filling out of the mold most casters run about 625° to 675° F."



1) What's your advice to someone who doesn't want to reinvent the wheel?

In a perfect world, yes. The lowest temp to get good bullets is where you want to be.
Your mold temperature will tell. If you get good boolits at 675 more power to you. I find around 750 is better for me. Different molds, different sweet spots. Same for alloys.

2) Which thermometer (Lyman, RCBS, or other) would you advise me to buy to
monitor this temperature range?

RCBS. Spend the extra $15. It is a better unit

Notes: I have learned that clip-on wheel-weight alloy reaches its "slushy" melting
point at about 463º F and its "molten" melting point at about 505º F.
Pure lead melts at 621.43º F.

Thank you again for your time and interest to help out someone new to the hobby.

Ryan
ryan richards is offline Report Post Reply With Quote

[cbrick]

leftiye, yep, your right, had to go back and re-read the original question. I cast WW at 700 degrees, pre-heat the mould on a hot plate AND pour at least 12 pours before I ever look for a keeper. Takes at least that long to get mould temp up high enough to cast consistent weights. The majority of weight variation (weights run light) in an entire casting run will be in those first pours even with pre-heating the mould.

Rick

[mooman76]

I think some people get too rapped up in casting temperatures. There are too many variables. the temperature you are working at ie ouside in the winter, summer or whatever, how fast you work, steel vs. aluminum moulds, alloy and so on. Casting thermometers can very in temp too. I've never used a casting thermometer and probubly never will.
Crank up the heat till you get good fillout. If it starts to take too long for the lead to harden start slowly turning the heat down til it's good. After awhile you get a feel to how the lead is working so you know when it's not hot enough or too hot.

[runfiverun]

my lee pot won't get over 630* and it does just fine.
of course i had to set it there, and add to it as i go to keep it there, and there are some
molds i have to run the temps higher.
for those i use 2 lyman mini mag 10 lb pots.
keeping the flow just right does require some tin though.
and if i want to hold it at 600 or lower i have to have near 2 lbs tin in the 20 lb pot.

[GP100man]

i warm the mold on the side of the pot ,run temp to 750f , fill the mold 10 times ,put those in the sprue can to remelt then pour keepers & start to turn pot down to around 700f or so as mold needs .


GP100man:cbpour:

[ryan richards]

Thanks guys,

From your experience, it seems that around 700º F is a good starting point for the melt and mold temperature for casting good bullets.

Ryan

[BruceB]

Just to toss one last worm into the salad, let it be known that my wheelweights are cast at 870 degrees with great success.

Start at 700 degrees, sure, but don't be afraid to REALLY crank up the heat to see what happens.

[trickg]

Bruce, I know my Dad used to cast pretty hot and his bullets were to my knowledge about as good as it gets for cast - they went back in the pot if they showed any kind of flaws.

[knordman]

Ha
s anyone ever used the infrared thermometer from Harbor freight?

[popper]

They don't work well on alloy. Remember, you are pouring heat, not alloy! Mould dissipates heat.

[lightman]

I cast wheel weight alloy at 735º. This works well with my RCBS 2 cavity steel molds, my 4 cavity H&G molds and my one aluminum Accurate mold. I use a PID on my casting pot but I have a Tel-Tru thermometer that I use on my smelting pot.

For whatever its worth, I cast and smelted for years without either a PID or a thermometer. I just started low and raised the temp until I got good fill out.

[kmw1954]

. Remember, you are pouring heat, not alloy! Mould dissipates heat.

Old adage from industrial refrigeration, "you are not generating cold. you are removing heat!" minus 40* is still warmer than minus 50*. Learned that from working with ammonia refrigeration.

[kevin c]

Ha
s anyone ever used the infrared thermometer from Harbor freight?I tried. As Popper said, they don't work well on molten lead alloys. Too reflective, apparently. I got a dial thermometer from Rotometals that seemed to work well, but eventually moved on to Hatch's PIDs.

Starting out, I'd read recommendations similar to what the OP found. Further advice found in the articles on the LASC site suggested a casting temp a bit above liquidus, as determined by monitoring the temp rise as the solid alloy melts (with heat applied, temp rises in solid metal until it reaches solidus, then pauses as the heat being absorbed is used to phase change the solid to liquid, then rises again; for an ingot added to the melt, the molten metal temp drops, rises, pauses and rises again). With my alloy, pot and thermometers, that temp was around 620 degrees.

But I usually cast at 720 to 730 degrees which gave me better fill out and consistency with fewer culls. I guess everyone's molds, alloy, technique, cadence and casting conditions vary enough that the advice in the articles may work well for some, but for others will only be a starting point.

[FLINTNFIRE]

I have one , I use it to check some things the chart it has to set settings changes readings and i do use it as a informational tool , but even the dial thermometers can be off also , had one read accurate and about a month ago it was way off , not sure what happened but I tend to set temp. setting and go cast by cast , yes I have pid that I use but casted for years without and still go by what bullets tell me , mould temp is important , start there adjust pot as needed , let the mould and the alloy guide you and when you find it the product will show you and and you will not worry about what temp. your device says.

[trixter]

I cast boolits from range lead ingots, I set my pot at 760° (built in PID) and put my mold on a platter type hot plate when I plug the melter in. I usually find something else to do for an hour and when I get started everything is up to operating temperature, I have also discovered that the lead stream from the pot needs to be quite slow and aimed at the beveled edge of the hole in the sprue plate. I am learning more and more as I experiment. I have no bad boolits, if I do not like one it just goes back into the melt. This is my formula for Lee 356-124-2R which I powdercoat for my 9mm.

[BC17A]

I cast boolits from range lead ingots, I set my pot at 760° (built in PID) and put my mold on a platter type hot plate when I plug the melter in. I usually find something else to do for an hour and when I get started everything is up to operating temperature, I have also discovered that the lead stream from the pot needs to be quite slow and aimed at the beveled edge of the hole in the sprue plate. I am learning more and more as I experiment. I have no bad boolits, if I do not like one it just goes back into the melt. This is my formula for Lee 356-124-2R which I powdercoat for my 9mm.

760° is right where I found the "sweet spot" with range recovered lead also. My Lyman Mag 25 heats 40 degrees low compared to set temp. Initially I was getting some very ugly casts until I cranked the temp setting to 800-810, and when I checked the actual temp with a calibrated digital thermometer it was reading 750-760 degrees. All my aluminum molds cast nicely at that temp with the exception of the 70 to 80 grainers which work best with a lead temp about 10 degrees higher.

[Martin Luber]

Someone mentioned mould temp...the difference between melt and mould temp is important hence the rate at which you cycle the mould. I have heard of going hot but that also affects the as cast diameter and in pure lead can give you smaller than desired castings. That changes with the addition of antimony and those expand on cooling. I suppose the answer is do what yoy like , just be consistent...

[Moonie]

Well at least the upgrade didn't break the ability to necropost lol. 11 years, wow...