Something I learned last weekend, about temp

The timing on this post is way off as it looks like the last post was a couple of years ago. I'm going to ask anyway just in case someone is still looking this over. You certainly can get bad info from a lot of sources, but I was taught that frosting meant the boolit was too hot and that it would shatter on impact when shot. Now I'm seeing this post that the boolit should be frosted. Of course that causes me to ask....if the boolit is frosted will it maintain its integrity when it hits the target? I understand this also has to do with how much antimony is in the mix as I understand too much will also make the boolit fragment. Anyone still around that can set me straight on this?

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Originally Posted by jwlegal

The timing on this post is way off as it looks like the last post was a couple of years ago. I'm going to ask anyway just in case someone is still looking this over. You certainly can get bad info from a lot of sources, but I was taught that frosting meant the boolit was too hot and that it would shatter on impact when shot. Now I'm seeing this post that the boolit should be frosted. Of course that causes me to ask....if the boolit is frosted will it maintain its integrity when it hits the target? I understand this also has to do with how much antimony is in the mix as I understand too much will also make the boolit fragment. Anyone still around that can set me straight on this?

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Frosting happens when both your mold and alloy temp are fairly high when casting. It has nothing to do with hardness/brittleness. It will affect size/weight, though.
Hardness is a result of alloy and time and boolits really only become brittle when VERY hard - you might be able to get this with pure linotype? Maybe pure monotype?

https://uploads.tapatalk-cdn.com/202...ef0b0f9375.jpg

This was a good thread. Thank you. Beginner here. Same pot, same session, different temperatures. These are the extremes. Most were in between.

I spent my last two casting sessions experimenting with temperature, trying a variety of settings. I learned that turning down the pot temperature helps. Slightly frosted is better than very frosted looking bullets. Not above 6 on the Lee 20# pot dial. And slowing down the casting frequency. Casting with range lead.


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That boolit on the right is nigh on perfect. That very light matte frosting (or perhaps just a tiny bit more with my alloy, molds and technique) is what I want to see to get in the groove where it rains all perfect slugs. Congrats!

ETA: you may find that the alloy temp varies even at the same setting. One reason is that as the pot emptys, the coil heats up the remaining alloy more. Another is adding ingots or a bunch of sprues all at once which drops the temp significantly.

I intentionally ran the temp dial up and down the range. I also slowed down my casting speed to lower the temperature of the mold. I am trying to identify the target temperature. I’m just a beginner.


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You're learning fast!

Lot of beginners hope to be taught or read about optimal technique, but conditions vary so much, even from session to session for the same caster, finding what works well takes experimenting.

Carry on, and keep on having fun!

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Originally Posted by cbrick

From "Ingot to Target" by Glen E. Fryxell - chapter 4.

The benefits of sawdust are that it‘s a sacrificial reductant that can reduce any oxidized tin back to the metallic state, and it‘s cheap enough that the caster can use enough to form an effective barrier layer to protect the alloy from subsequent oxidation. What’s more, as the sawdust chars on top of the melt, it forms activated carbon, which is a high surface area, porous sorbent material that has a large number of binding sites capable of binding Lewis acid cations like Ca, Zn and Al. So it not only keeps the tin reduced and in solution, but it effectively scavenges those impurities that raise the surface tension and viscosity of the alloy (Al, Zn and Ca), keeping the alloy in top shape for making good bullets.


Rick

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Hi Rick, from another Rick:

Just browsing stickies this morning as it is raining hard enough out there that I'm not interested in going hunting. Always something new to learn (or at least think about) browsing stickies.

WAAAAYYYY back in the days of Fidonet prior to the WWW, Ken Mollohan helped me get beyond the stage of just dumping something molten into a mould and believing whatever resulted was kind of what you get with bullet casting.

Back then, Ken got me started fluxing with carnuba wax flakes. Along with a lot of other changes I made. I've been pretty happy with my bullets since Ken mentored me along until I was being thoughtful in my casting and expecting much more in what I got for results.

So... that said: how does carnuba wax stack up against sawdust for fluxing. I have a lifetime supply of carnuba wax here, but if there's a chance that sawdust instead will result in better results, there's a sawmill out where I do a lot of my elk and moose hunting where I can go for sawdust. Or alternately, my wife the aggressive carpenter makes LOTS of fine sawdust versus the sawmill sawdust.

And thanks for the informative posts on temperature that I've been scrolling through today.

Rick

Interesting comment on the effects of sawdust. Does the source of the sawdust make a difference, like pine versus other? On waxes, I have found stearic acid (a wax) to be a real good flux. When pine sawdust does nothing, stearic acid will release silver drops of metal. It also works as a solder flux. But the ability of sawdust to remove calcium zinc and aluminum is something I did not know about. On the other hand, stearic acid burns clean (but is not too cheap).

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Originally Posted by 303Guy

Interesting comment on the effects of sawdust. Does the source of the sawdust make a difference, like pine versus other? On waxes, I have found stearic acid (a wax) to be a real good flux.

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I don't know whether flake carnuba wax is a flux, or a reducer, or whatever. Reducer, I'm thinking. I'll guess Ken Mollohan, with his chemistry background, would have pointed me at stearic acid instead of carnuba wax if he would have thought it better.

But I did dive head first into that .pdf book written by Glen Frye. So I guess I've provided my own answer to the question I asked Rick - sawdust has the additional advantage of removing other metal contaminants that carnuba wax won't.

As my alloy supply is pretty clean stuff, I won't worry too much for now about not using something that will also clean the alloy in the pot of contaminating metals. Once I've gone through the carnuba, then I guess I'll go bug my wife for her cedar sawdust.

Carnauba wax is made up of acid and diesters of acid among other things so it makes sense that it would be a flux. I don't recall actually trying it in my melt pot or for soldering though. I'll give carnauba go when next I have an opportunity.

I just tried stearic because I had some and didn't think I had a use for it and since wax is used as a flux in melting pots, I threw some in to see what would happen and it separated metal from the dross very well. Then when I had no soldering flux I thought I would give it a try and found it makes a great soldering flux too.

I had a similar experience and wish I had seen Gear's post years ago. I stopped worrying about the thermometer and cast close to maximum on the rheostat. In both my pots. My RCBS thermometer reads high and so does my genuine Chineseum thermometer I bought 20 years ago. The important temperature for any heat is the one that consistently gives you good boolits as Gear states. Thanks for the posting.

Great information! Years of casting experience as I can tell. Thank you

Gears post is exactly the info I searched this site for and found it quickly as well! Thank you!!!

Welcome!

I usually get spots of frosting on my cast bullets. As far as I known their isn’t any antimony in my alloy just lead and tin. The small patches of frosting haven’t caused me any problems.
After lubri-sizing and loading in cartridges cases I wipe any lube that may have gotten oozed up out of the case. Wiping always restores a bright shiny appearance to the bullet.

I have a Lyman digital thermometer it works good. It just can’t be left in the melt for for more than 1 or 2 minutes because the heat travels up the metal probe and will start to soften the plastic fitting that connects the probe to the wire that plugs into the thermometer case.

My casting world changed when I bought a PID. My bullets are so consistent now. I can regulate my mold temperature as well as have a visual tossing spruces back in and cooling the mold off at times. If you don’t have a PID set up—it’s as paramount to good bullets as buying good molds

Incredibly simple. Still helping us newbies 8 years later. thanks to Gear for taking the time to write this up.

Resurrecting an old thread. All that I can say is Thank You to Gear!

Over the last 24 hours, allowing the pot and molds to cool I've come to the conclusion that he is spot on! I have my pot set to 720 (degrees. I set the mold on top of the pot to pre-heat. When the pot comes up to temp (120 degrees above liquidous) and I start casting, regardless of mold it's two casts and boolits start raining.

Thanks to all that have contributed. Gear, you've reinforced all that was taught to me (that I forgot) from my mentor Lester. May he rest in peace. A Korean War veteran that really never received the appreciation that these men deserve. I include the Viet Nam vets in this. We all owe a debt of gratitude to these veterans. Sadly, many are no longer with us.

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Originally Posted by Wooserco

Resurrecting an old thread. All that I can say is Thank You.....

Thanks to all that have contributed.

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I'm astounded that this thread is still going and that so many have learned so much (myself included). I've been away for a while but I just bought a new mould and going to start making some new boolits.

Cheers!

I just learned a couple of things from Gears long and very good post. Thanks Gear. I have been casting for about 55 years and have learned a lot by doing everything wrong until I stumble onto something that works.

I cast for around 40th years without a lead thermometer. I simply set the pot up to max and then started turning the temp down until the frosting just stopped. This worked fairly well for most molds. I now use a thermometer and set the pot at about 750 and preheat my molds. If I get frosting at that point, I use a small fan pointed toward where I'm holding the mold while cutting the sprue. Apparently mold temp is more important than I realized. I will also be checking the accuracy of my thermometer.