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gunboat57
11-08-2012, 08:37 PM
I was given some old WW ingots and decided to use them to cast some boolits for my 45-70 Buffalo Classic. My mold is an old Lee 457-405, single cavity. After I had gotten the melt and the mold to good temperatures I cast about a dozen or so and they came out looking like this:

http://i127.photobucket.com/albums/p142/gunboat57/Cast%20Bullets/000_1077.jpg

The mold filled out OK but there are patches of surface roughness, not frosting. Is this just contamination, oxides, etc. in the melt? Should I just flux some more to try to get rid of it?

I use a bottom pour Lee furnace.

geargnasher
11-08-2012, 08:42 PM
Probably lots of aluminum and calcium in the WW metal. You might try remelting that batch of metal and flux it with pine sawdust or shavings, stir the melt a lot and use an cheapo Au Jus ladle from ChinaMart to bring the metal up from the bottom and pour through the smoldering layer of sawdust over and over to expose as much of the metal as possible to the flux. Skim the sawdust when it turns grey, and do it over at least once more, maybe twice more. When the sawdust becomes fine and "clean" looking as ash, you're done and they should cast a lot better.

Gear

I'll Make Mine
11-08-2012, 08:58 PM
Are those bullets significantly lighter than what you've gotten from that mold in the past? A well-stirred melt with too much zinc to fully dissolve might produce that patchy surface from segregation of the zinc (plus 1.8% lead) out of the lead (plus 2% zinc). A lot of zinc will also produce an "oatmeal" appearance in the melt at your usual alloy temperatures, requiring a higher temperature to fully melt the zinc.

Aluminum and calcium would lighten the bullets as well -- and muriatic acid, the usual test for zinc, will react even more vigorously with calcium (and almost as much with aluminum, once it eats through the surface oxide); I'd suggest following Gear's procedure first, and suspect zinc if that doesn't cure the problem.

geargnasher
11-08-2012, 09:14 PM
Sawdust will remove zinc, too, to a certain extent.

Gear

stubshaft
11-08-2012, 09:55 PM
Heat it up and flux it out again. Looks like contaminants to me.

KYCaster
11-08-2012, 10:18 PM
Try ladle pouring some. That seems to make a difference with heavy boolits.

Jerry

herbie
11-08-2012, 10:37 PM
I dont want to freak you out but you may have zinc in there. I am probably wrong but if you did melt WW at to high a temp you may have melted some zinc. They only reason i say that is because i noticed on the bottome of your boolits where the srue plate cuts off it looks "crystalized" also the edges around the lube grooves look rounded and not sharp which is what zinc does sometimes. If you try what the others have posted and that doesnt work then you should give this thread a look.

http://castboolits.gunloads.com/showthread.php?t=63082

Again im no expert and im probably just talking out my A#$ trying to sound smart.
what ever happens i wish you the best with your casting

44man
11-09-2012, 09:28 AM
Zinc for sure---rain gutter look.
Melt to 600* and scoop it off without fluxing. It will look like oatmeal. If you flux it will go back into the lead.

gunboat57
11-09-2012, 10:33 AM
Last night I tried some sawdust and beeswax with deep stiring to try to clean my melt. Every now and then I cast a .490 RB to see what the surface looked like. I think I'm seeing some improvement.

Then I turned down the temperature slowly to see if anything floated to the top that solidified. The melt solidified on the sides of the furnace first and left the center liquid until it all had solidified. If there is zinc in my melt, I should've seen it, right? I also looked at the free surface of my WW ingots and none had any wavy oatmealy appearance.

Today I'll try slowly heating the melt and see if there is anything that comes to the surface.

Just wanted to add, thanks for all the help. When I first began casting I had no one to learn from and few helpful resources. Here at castboolits I am among experts.

Gigs
11-09-2012, 10:44 AM
Keep in mind if you skim off your oatmeal top you are cleaning out your tin too. If you have some clean tin to re-add you should do that once you get it clean. Don't waste tin until you have nearly pure lead in the pot though.

popper
11-09-2012, 10:58 AM
Question - does all the junk from the pits on the CBs stay in your mould? Or are they shrink marks from lumpy alloy?

gunboat57
11-09-2012, 11:11 AM
Popper, the rough areas on my boolits form where the mold is clean and smooth. In fact, I have cleaned my mold because I wanted to make sure there was no crud causing roughness.

243winxb
11-09-2012, 11:47 AM
Use maximum heat in alloy & mould. Burn off the cleaning stuff. When you get frosting, drop the temp. a little.

44man
11-09-2012, 12:21 PM
Zinc must be removed. Don't worry about tin, it is still in the lead.
Start heating to 600* max and remove all on the surface that does not melt. DO NOT FLUX. You can add antimony at 600* with flux. Get flux out of your head until lead is clean.
Flux makes metals blend but you need to separate metals.

youngda9
11-09-2012, 02:43 PM
Send me all of your lead and I'll sort it out. :)

popper
11-09-2012, 03:43 PM
Just wondered as I see pits and bumps on them, maybe from the junk in alloy being transferred from cast to cast. When I get through, I see the junk left in the mould from the alloy. Yes, you have undesirable metals in your ally.

gunboat57
11-09-2012, 03:53 PM
44man, I heated up my melt at the lowest setting until it had all turned to liquid. Other than a thin film like what usually forms in air, nothing floated on top. I turned off the heat and let it cool down. It solidified around the edges first. Again, only a thin film on top until it all solidified.

I tried casting with a lead dipper, the kind that has a spout that engages the sprue plate hole. After a couple tries, I got bullets that had virtually no surface roughness. Could it be that my bottom pour furnace has got a lot of crud near the bottom that isn't getting cleaned out?

KYCaster
11-09-2012, 07:57 PM
44man, I heated up my melt at the lowest setting until it had all turned to liquid. Other than a thin film like what usually forms in air, nothing floated on top. I turned off the heat and let it cool down. It solidified around the edges first. Again, only a thin film on top until it all solidified.

I tried casting with a lead dipper, the kind that has a spout that engages the sprue plate hole. After a couple tries, I got bullets that had virtually no surface roughness. Could it be that my bottom pour furnace has got a lot of crud near the bottom that isn't getting cleaned out?




That's the same experience I've had. Kinda hard to see on smaller boolits, but really shows on the big ones.

Has to be the crud that clings to the bottom of the pot. I can't think of any other reason for it.

Jerry

runfiverun
11-09-2012, 08:44 PM
those look almost like a tin problem, i'd call it more of an inclusion from oxidized alloy thing though.
the edges where it is clinging looks like oxidized gunk once i zoomed in.
before that it looked like antimony dendrites forming unevenly and more tin was needed.
but the rough sunken edges say oxide inclusions to me.

try emptying the pot and looking at the gunk in there.

gunboat57
11-09-2012, 08:55 PM
Update: After dinner tonight I turned on the Lee furnace at its lowest setting and just walked away. About a half hour later I looked at the melt and saw maybe 5 little clumps of what looked like silver oatmeal. I scooped them out and did some casting using the spout dipper, with the spout held to the sprue then rotating mold and dipper to fill. Out dropped the best bullets I've ever cast. Bright, shiny, no roughness, and mostly sharp edged. Could probably use some lead free solder to boost the tin content.

Then for giggles I tried to do some bottom pour bullets but they were rough like before. Just too much crud down deep I think. I emptied the pot and will clean it out completely and plug the bottom pour hole. I think I'm gonna use a dipper to cast from now on.

44man
11-10-2012, 09:50 AM
Great, I still think there was some zinc. It takes very little.
It has a different galvanized look.

gunboat57
11-10-2012, 10:16 AM
Yeah, you were right about there being some zinc. Once I get the furnace all clean and refilled I'll let the melt sit at the lowest setting that keeps it liquid. I guess it takes a while for the lighter zinc to rise to the surface and form lumps. I'll probably do that for all my WW ingots just to make sure I've cleaned out the zinc.

Three44s
11-10-2012, 10:25 AM
I like to run and re-run my lead alloys in a plain pot first ......... bottom pours should be filled only with known metals as they are easy to gunk up and slow to clean out.

My big ones are heated with a weed burner torch on a stand I built out of a piece of well casing.

I keep tin on hand for adding as I feel I need it.


Three 44s

44man
11-10-2012, 03:13 PM
Yeah, you were right about there being some zinc. Once I get the furnace all clean and refilled I'll let the melt sit at the lowest setting that keeps it liquid. I guess it takes a while for the lighter zinc to rise to the surface and form lumps. I'll probably do that for all my WW ingots just to make sure I've cleaned out the zinc.
What happens is the zinc does not fully melt at 600*. It floats so you are correct about that. Just scoop it off.
When you melt batches of WW's, keep the temps low too and anything that does not melt, toss it. It is a small loss.

jdgabbard
11-10-2012, 03:14 PM
I dont want to freak you out but you may have zinc in there. I am probably wrong but if you did melt WW at to high a temp you may have melted some zinc. They only reason i say that is because i noticed on the bottome of your boolits where the srue plate cuts off it looks "crystalized" also the edges around the lube grooves look rounded and not sharp which is what zinc does sometimes. If you try what the others have posted and that doesnt work then you should give this thread a look.

http://castboolits.gunloads.com/showthread.php?t=63082

Again im no expert and im probably just talking out my A#$ trying to sound smart.
what ever happens i wish you the best with your casting

I dont agree with that statement. That could be from casting too hot. But I will say they do look like they've been galvanized. Possibly some zinc in there.