Casting temp

[Long range plinker]

Not sure if I'm posting this in the right spot but here goes anyway. I'm new to casting and new to the forum. I jumped in with both feet as far as equipment goes. Pots moulds dippers alloys Brinell tester etc. got my alloy to the hardness I want then thought I was ready to start making boolits. Preheated the mould and got the lead up to about 750* Succesfully made a bunch of wrinkled boolits. From what I read I thought 750* would have been plenty of heat. (At this point I was casting from the bottom draw from my Lyman electric pot.) tried using the dipper ladle and they were better but still not up to par. I began playing around with the lead temp and after cringingly turning it up to 800*, eureka! Nice sharp cornered boolits. A little frosted but filled out and sharp. (At this point it didn't matter how I tapped the lead from the pot) I'm casting with a Lyman 44 mag mould with two cavities and gas check. Is this an acceptable temp or is their something I'm missing? I've read that at 800* you can start cooking the tin out of the lead. Didn't want to go through all the trouble of adding alloy and getting hardness just right only to ruin it in the casting process.
Thanks

[Calamity Jake]

I suspect that Lyman mold has some venting issues, check all the vent lines, make sure the vent lines aren't
closed up by small burrs at the cavity edges, go slow and use an Xacto knife to open the vents.
Using a knife sharping stone put a VERY small bevel at the top parting line of both halves of the mold.
Turn the pot back down to 700-725.
Also loosen the spru plate, you want it to swing of it's own weight but not be floppy.

[454PB]

You don't say what alloy you are using, but assuming WW alloy or equivalent, 700 to 750 degrees should work fine. If it doesn't, the mould is too cool or contaminated.

[RobS]

It sounds like you are using an alloy with tin in it since you are worried about oxidizing it out with too much heat????

[williamwaco]

Alloy is not the problem you can cast beautiful bullets at 600.

Your mold is too cold. Cast as fast as you can safely. (hurry slowly).

When the sprue takes 3 seconds to harden, the wrinkles will disappear.
This means that 2 seconds after you close the valve. If you tilt the mold, the sprue puddle should run off like water.

[HangFireW8]

Good advice above. Maintaining a steady rhythm is paramount. Stuck boolits destroy rhythm.

Beyond that, you might have the same problem I had, but only recently discovered- an inaccurate casting thermometer.

I only discovered it after buying a new PID controlled pot. So I got another dial thermometer... Which was even more inaccurate.

Use what works, think of the temp reading as a personal heat index.

[williamwaco]

Good advice above. Maintaining a steady rhythm is paramount. Stuck boolits destroy rhythm.

Beyond that, you might have the same problem I had, but only recently discovered- an inaccurate casting thermometer.

I only discovered it after buying a new PID controlled pot. So I got another dial thermometer... Which was even more inaccurate.

Use what works, think of the temp reading as a personal heat index.

I do not use a thermometer. Got by just fine for 60+ years.
Millions of shooters have cast billions of bullets for 150 years with no thermometer.

The correct temperature is the lowest pot setting that will produce good bullets.

The mold temperature is MUCH more important than the alloy temperature.
Read the postings about all the people who use hot plates to keep their molds hot.

[gwpercle]

The numbers on the dial are not an accurate indicator of the temperature. Set at 7.5 does not gurante the pot is heating to 750 degrees . Check the temperature with a Casting Thermometer, I would be willing to bet it's not getting to 750 . Notice how when the dial is on 8 , the bullets got better. You're not going to "cook out" the tin. My method is to cast , increase the temperature untill I start getting frosty boolits , then back the dial down so the boolits are just below or slightly frosty. You wont hurt a thing, your description of how they cast at 8.0 on the dial , sounds like the perfect temperature. If it bothers you get a thermometer and check actual temperature.
Gary

[44man]

I gave up the expensive pots. The lead is cooler at the pour spout because the are no elements in the bottom. I have seen Lyman and RCBS pots freeze lead before cycling again.
I like the Lee pots best. I just keep the dial at 750 and 800 for pure. I don't really care what it is exactly. All control is your cadence.
My friend has a Lyman and 2 RCBS pots and he has never cast a good boolit. He brings lead and I cast his.
It is an amazing experience to see a guy tip the mold when tipping a sprue to pour the boolit back into the pot, some don't know you can use both hands by themselves. I have to take over and show again but that doesn't work with some. No matter what, it does not register.
Helping on line is the most crazy ever. Old time casters know what I am saying. To us old goats it is so easy and each pour is seen and felt to be right. I don't time anything with a clock or counting seconds. It is right at what feels right. Go with the FORCE!

[dragon813gt]

To me it appears your mold wasn't up to temp. If you aren't preheating the mold in some fashion the mold is going to take a long time to come up to temp. The fact that it started working at 800 means you were able to put enough heat into the mold. Use a hot plate or dip a corner of the mold in the lead pot before casting.

People are going to tell you to do all types of things and what you do an don't need. At the end of the day use what works for you. I personally want to know the lead temperature. I cast in an unconditioned garage and have to change the temp based on ambient conditions. It's not uncommon to need 750 in the dead of winter while in the summer 700 works fine.

The more data points you have the easier it is to get repeatable results. It can be overwhelming for a new caster. And a lot of stuff isn't necessary. But it can and will speed up the learning curve.

It's easy for someone that's been casting for 40 years to say you don't need a thermometer because they have acquired the skills to cast by "feel". But when starting out you don't have these skills. If you are getting wrinkled bullets preheat the mold more, cast faster or turn up the pot temperature. All put more heat in the mold which is what you want. I use an alloy that's 2% tin. I don't worry about it oxidizing out even if I have to turn the pot temp above 700.

[44man]

Tin does not jump to the air if hot. It is an alloy on the molecular scale. it takes more then we can do to separate metals.
Like antimony that melts at 1166° but will alloy in at 600° with flux. Most 20 to 1 0r 30 to 1 lead tin alloys need cast at 800°. Show tin has been lost.
Had to get the numbers corrected and edit.
Sorry for that.

[runfiverun]

it's all about mold temp.
if you need to turn the pot temp up then turn it up.
I generally start out a bit high then turn the pot down as I go.
all I am doing is maintaining a consistent mold temperature.
I can do that by casting faster or by adding more hotness to the mold with each cast.

[williamwaco]

it's all about mold temp.
if you need to turn the pot temp up then turn it up.
I generally start out a bit high then turn the pot down as I go.
all I am doing is maintaining a consistent mold temperature.
I can do that by casting faster or by adding more hotness to the mold with each cast.

Also by pouring a larger or smaller sprue puddle. But if you get it too small your bases will not fill out.

[Shiloh]

750˚-800˚
If I go cooler and still get good bullets, that's where I stay. As cool as I can to get good boolits.
Range scrap, for me anyway, is at 800˚or a hair more to get good boolits.


SHiloh

[JeffG]

710-725 on the pot for me, which is plenty hot for the alloy. I will go to the low end if I'm casting bullets that are large and that are keeping a lot of heat in the mold, and as others have said, will turn down the temp if I feel like I need to. The mold needs to be very clean, I have settled on hot water, Comet and a toothbrush as of late and after that, put them on a hot plate till they get to about 375 degrees at least. I will start getting good bullets right away. Once casting, the NOE 314299 mold I used this past weekend, which I have a thermometer in, runs in the 430-450 degree range, which is pretty frosty but still very crisp clean lines. Bottom line, get that mold clean and hot. I use a hot plate with an old skilsaw blade on it to heat the molds and quit messing with dipping the corner in the melt, etc., a long time ago. Can you get by that way, sure. Is there a better more effective way, I think so, and hot plates are dirt cheap, also allowing you to preheat lead.

[Long range plinker]

Thanks for all the input. Sounds to me like an I.R. Thermometer will answer a lot of questions about temperature. Anyone use them?

[HangFireW8]

IR is useless against hot shiny metal. If you can shoot a dark part of the pot, you will get a better reading, but the melt at the bottom will be hotter.

[JeffG]

What HangFireW8 said, no good for the melt, I have one. I occasionally use it for mold on the hotplate, but not really necessary.

[high standard 40]

I cast more with the RCBS 7MM 145 than any other mold I have. I use only one cavity in this double cavity mold. My pot is the 20 lb RCBS running with a PID and alloy is 92-6-2. I run my PID at 710 and get near 100% keepers with great fillout. It's all about mold temp and cadence. I don't like to run above 725 for any mold. Oxidation on the melt surface becomes an issue that I don't want to have to deal with when you run higher melt temps.

[williamwaco]

Thanks for all the input. Sounds to me like an I.R. Thermometer will answer a lot of questions about temperature. Anyone use them?

Re-read the above advice. It is not necessary. The correct temperature is when the bullets are perfect. You can reach this by trial and error in 12 to 15 pours from a room temperature mold.