A white film on the bullets i cast???

[slamminsammy]

I am new to casting bullets so this could be a dumb question? There has been a couple times that when my cast bullets cooled off they would have a white film on them? It will come off them if i rub on them with a rag? Can anybody tell me what this is? I have searched on these threads and cant find nothing about this.:sad:

[geargnasher]

Do they look like these?

http://castboolits.gunloads.com/attachment.php?attachmentid=28348&d=1294465394

If it's a silvery, galvanized-looking surface "film" that wipes off with a twist of a dry rag and leaves a shiny, smooth surface underneath, it's what we call "frosting", and is a product of casting alloys containing some antimony in a mould hot enough to cause the effect.

Frosting hurts nothing unless the mould is hot enough to bring the "frost" to the point that the boolit surface becomes pitted or looks like it's been sandblasted. If that happens, try slowing your casting pace a bit to cool the mould, lower the alloy temp to reduce the amount of heat going into the mould blocks each pour, and soon you will be back in the "satin frost" range which is my favorite mould temperature range for casting. Some people prefer running their moulds cool enough for shiny boolits, but I find it too difficult to get consistently good fillout and sharp edges at those temps.

Lube 'em, load 'em, and go shoot!

Gear

[slamminsammy]

Yelp! that what it looks like! It had me worried i thought had some bad lead or something? LOL! Thanks Geargnasher!!!

[olafhardt]

I have a question? It seems to me that frosted boolits might lubricate better than unfrosted. Do they?

[Southern Son]

I have a question? It seems to me that frosted boolits might lubricate better than unfrosted. Do they?

I doubt it. The "frosting" is just a finish on the boolit caused by something being a bit hot (not neccessarily too hot, just a bit hot). Could be the mould or the melt. The "frosting" won't help the boolit hold a greater amount of lube (not enough to be measured, anyway), and if you are sizing and lubing, then the frosting will be wiped off in the sizing die.

If the frosted finish was bad enough that it could hold a significant quantity of lube, then I think that the boolit would have issues that the extra lube could not help.

Just my $0.01 worth (tax man got the other $0.01).[smilie=s:

[63 Shiloh]

Lee recommends a frosted boolit for their Tumble Lube designs, I can see a slightly 'rougher' surface enabling the Alox to cling better.

In conventional Grease Groove I cannot imagine it would be a plus or minus with grease in a lube sizer/

I have used non TL design boolits in .38 Special with Alox and a plastic snap lok bag. Squirt about half a teaspoon in a large snaplok bag with 150 .38 145gn SWC's, close the bag up and massage the lube and boolits ( sounding a little kinky really?), until you have a nice and even coat of Alox.

You do not need much at all, do not fall into the trap of trying to fill the grooves with Alox. You are just giving the boolits a light smear.

Pour boolits on a waxed paper tray to dry, add some mica before this step if you wish. The mica takes the tackiness off the Alox quickly and prevents seating plug build up.

Or, read up on Recluse's 45-45-10 mix and have at it mate.


Mike

[jameslovesjammie]

I seem to remember reading that the frosting is just the antimony crystalizing on the surface and doesn't really change the surface roughness...just a visual change. It has been a while since I read this.

[geargnasher]

I seem to remember reading that the frosting is just the antimony crystalizing on the surface and doesn't really change the surface roughness...just a visual change. It has been a while since I read this.

Oversimplified, but yes, that is essentially what's happening. If it makes a difference in the way they shoot, I can't tell it. Liquid Alox and the blend we call 45/45/10 will adhere to just about anything quite well, so I feel that the advantage of frosty boolits for tumble lubing is more perceived than real. The most important thing is good, sharp driving bands, sharp boolit bases, and complete fill of the mould, which to me is easier to achieve by casting faster and keeping the mould hotter than the guys casting shiny boolits. YMMV.

Gear

[williamwaco]

Well,

this is all good advice and all correct. BUT.

Don't get carried away with frosting. As the mold gets hotter and hotter, the frosting will get more and more severe and will eventually prevent the bullet from filling out fully and carried to extreme, can reduce the diameter by as much as .003 to .004 inch.

You can see this effect easily by continuing to cast fast as the bullets become frosted, The frosting will become heaver and heavier untill you start to get rounded driving bands. Slightly rounded driving bands will nearly always be improved by the sizing operation but eventually they will become so rounded that the tops of the driving bands do not fill the mold.

Testing this effect will do no harm to your mold and will teach beginners a lot about mold temprature control. When you satisfy your curiosity, set the mold aside with the blocks open for a few minutes. When I am casting fast, I set a small electric fan on the bench and after opening the mold, dump the bullets and set the open mold in the breeze of the fan while I inspect the previous dump. This timing can be adjusted to maintain any degree of frosting you desire.

For more information on severe frosting, see:

http://www.reloadingtips.com/how_to/frosted-bullets.htm

[geargnasher]

WW, that's a great link, thanks for posting! I seem to remember saying something along those lines :-D...

"Frosting hurts nothing unless the mould is hot enough to bring the "frost" to the point that the boolit surface becomes pitted or looks like it's been sandblasted. If that happens, try slowing your casting pace a bit to cool the mould, lower the alloy temp to reduce the amount of heat going into the mould blocks each pour, and soon you will be back in the "satin frost" range which is my favorite mould temperature range for casting."

Here's a pic of what I mean (sorry it's so big, I'm not extremely computer savvy and don't know much about editing for size), left is too frosty, middle is the way I usually cast them, and far right is from a mould too cool in some spots, like around the parting line where you can see wrinkles. In all cases the alloy temperature was the same, about 675 degrees. Note particularly the bases and band sharpness/lack thereof between the samples.

http://castboolits.gunloads.com/attachment.php?attachmentid=28007&d=1293562439

Gear

[williamwaco]

WW, that's a great link, thanks for posting! I seem to remember saying something along those lines


gear,

Yes you did say exactly the same thing and I agree with you completely. I just wanted to show a newbie how to test it for himself - and add some photos.

Your photo is an excellent visual representation of frosting that is just beginning to become too much as well as the same bullet with moderate and with no frosting. Excellent photo. ( I would be interested in knowing what camera you used. )

[geargnasher]

Thanks WW, I thought it was lousy light, blurry, and sized wrong, but I was in a hurry at the time I took it. Camera is a 7.1 MP Kodak Easy-share, set on portrait, absolutely nothing special. The point was that it illustrates an example, maybe I'll have to get my wife to take some more pics of frosty-to-wrinkled boolits with her EOS and edit them to fit our screen size.

I think it's a stellar idea for anyone new to casting or breaking in a new mould to set the alloy at the temp dictated by 100 degrees above the full-liquidus point of the alloy, then preheat the mould and/or cast as fast as reasonably possible until the point of severe frosting occurs, then slow down until the mould cools enough to get the results desired by the individual. Only way to know where the sweet spot is is to go to both extremes.

Gear

[olafhardt]

I don't know how to add all those stars but this thread deserves a bunch. This kind of learned answer by knowledgeable experts shows the true value of the internet!!

[geargnasher]

Olafhardt, I fixed it for ya! :drinks:

(look at the top of the thread, there's a drop-down menu for "rate thread").

Gear

[slamminsammy]

YELP! This place is very cool! About 6 months ago i noticed that there was not a very good selection of off the shelf .58 cal. conicals i could buy to play with my T.C. Big Boar. The Maxis i could find were very expensive! So i bought a pot,molds and lead. I thought how hard could it be? I cast iron everyday have been for about 20yrs. I will just jump right in there, whip a bunch of these bullets out piece of cake! WRONG!!!!! I couldnt make a good bullet to save my life!!! LOL! I checked the web and found this place. I read on these threads for weeks and finely figured out how to cast a good Boolit! And also how much fun it is! I am hooked!

[geargnasher]

I guess you already figured out that casting pure or near-pure lead is an art unto itself! Ignore the "100 degrees above full-liquidus" guideline for that stuff, sometimes it needs 800 degrees to cast well, and the moulds better be HOT to keep wrinkles and rounded edges away. A pinch of tin added (1% is plenty) helps, but lower the temps to 725 or so if you add tin because anything over 750 renders the oxide barrier that tin provides ineffective.

Gear

[TXGunNut]

Now I understand why the best boolits out of my new 6-banger Lee TL mould are all slightly frosted. I like shiny boolits but this mould seems to prefer slightly frosted. I'll put that in my notes, thanks!

[williamwaco]

Now I understand why the best boolits out of my new 6-banger Lee TL mould are all slightly frosted. I like shiny boolits but this mould seems to prefer slightly frosted. I'll put that in my notes, thanks!




I don't see this mentioned often and rarely think of it myself but it really needs to be repeated often.

Keep a page in your notebook or computer for each mold. Every one of them likes something different. Six months from now, when you pull it out again, you will not remember what it likes and can easily waste a couple of hours decoding it again.