Ugly Frosted Sections on Bullets

[Colorado4wheel]

They bullets are not frosted from too much heat. In fact this happens as the mold is gettting up to temp even though I have the mold on a hot plate. If I start casting when the lead hits 700F+ I have wrinkled bullets for a period of about 10 cast (seems long but thats OK). Then I get these areas on the bullets that look dirty/frosted. It takes a lot longer for those to clear up. Nearly a 1/4 pot of my Lee 20lb. Even then I can kinda see them. I turn the pot up to 800F+ and the disappear a little faster. Seems to always be the same section of my Lyman 4 caviety mold. The mold looks fine. I clean it with a toothbrush and soap and then acetone. I heat the mold on the plate. I have started casting about a 1/4 pot of bad bullets then refilling the pot and fluxing to cast again after the mold is hot. If the mold cools at all I get the marks again. So this happens every time I refill the pot and have to wait for it to reheat even though I have the mold on the hotplate.

[BABore]

I'm not a pot dribbler and only use various ladles. When this happens to me, it's usually solved by filling the mold faster and sometimes using a pressure pour. I don't know if your Lee pot is adjustable for flow rate or not. If it is, open it up. If not, try pouring the mold differently. Some shoot the hole, others leave the flow swirl by hitting the edge of the hole. Distance is also something you can play with. What your seeing is an overheated area of the mold that needs to be filled faster.

[Colorado4wheel]

This is happening pretty quickly. I did not look closely at the wrinkled bullets but once the wrinkles start going away I get this frosted areas with black marks. Maybe my attempt to get heat in the mold is causing one area to get hot faster then the rest. Never thought about this as a issue.

[44man]

This can even happen with the ladle tip method I use. It creates a hot spot where the lead first hits the cavity. I have moved the mold around and cast from a different angle and the hot spot will follow.
The worst offenders are the TL Lee boolits. Only one other mold I have will do that.

[Colorado4wheel]

This is a lyman mold. So I need to pour onto different sections of the mold.

[DLCTEX]

Pressure pouring helps with that problem more than anything else I've tried, and yes, the Lee TL moulds are the worst at this. I think the narrow bands overheat easily. Yesterday I had good results by lowering temp. and pressure pouring some RD 460-350.

[Colorado4wheel]

I am only pouring at 750F when this is happening. Sometimes even lower then that. I rotate front to back on my mold when I pour so its leaning one way some of the times and the other way other times. How do you do the "pressure pouring"?

[HangFireW8]

They bullets are not frosted from too much heat.

Take a look at this picture (http://castboolits.gunloads.com/album.php?albumid=274&pictureid=1830) and see if the problem looks like one I had.

-HF

[runfiverun]

those are clearly hot spots.
pressure pouring is putting the mold up to the spout and filling it holding it there for about 2-3 seconds.
you could also build a little stand for the mold at a height of say 3/4" below the spout and hit the side of the sprue hole letting the alloy swirl in the cavity.
some molds like a straight shot to the bottom as quick as you can fill it. others like the swirl, letting the air from the mold.

[Lloyd Smale]

I have this happen with some of my big caliber molds. It usually appears where the mold is the thinnest between the two cavitys. Slowing down helps but with some alloys i have to just cast the mold as a single cav mold. Higher tin alloys tend to do it more so in this case more tin does not give your better fillout. I think it was felix that had the theroy on why this happens. Me, i just know it does.

[Colorado4wheel]

those are clearly hot spots.
pressure pouring is putting the mold up to the spout and filling it holding it there for about 2-3 seconds.
you could also build a little stand for the mold at a height of say 3/4" below the spout and hit the side of the sprue hole letting the alloy swirl in the cavity.
some molds like a straight shot to the bottom as quick as you can fill it. others like the swirl, letting the air from the mold.


So a quicker fill might help. I may be filling to slowly. Never thought about that.

[prs]

I have this happen with some of my big caliber molds. It usually appears where the mold is the thinnest between the two cavitys. Slowing down helps but with some alloys i have to just cast the mold as a single cav mold. Higher tin alloys tend to do it more so in this case more tin does not give your better fillout. I think it was felix that had the theroy on why this happens. Me, i just know it does.



This is prolly a case where the same problem figured-out by different independant solvers is approached differently. In running two 6 cavity Lee molds with .454 pills with WW alloy and about 1% added tin, my "solution" to the blotchy heat disfigurment was to go even hotter and faster. I pour hot and fast and the first cavity filled is still liquid after the last cavity is filled and the spru strip is one thick strip end to end. Even pre-heating by setting the heel of the mold into the molten lead for a few minutes, I discard the first several castings untill the temp is up to my target (that is, to where the first poured cavity is still molten when last pour is comleted). That way the boolits are pretty much all at the same temp and "freeze" at about the same time and there is not much disparity of temps between boolits or parts of boolits. BUT, my production is evenly frosty, but I see no problem with that, they are very uniform of diameter and weight and tumble lube clings to that frost like no body's business. Shoot well too.

prs

[Colorado4wheel]

http://i145.photobucket.com/albums/r215/98sr20ve/DSC_3313.jpg

Here is a picture of the bullets after the cool and sit for several days. The black area is gone, can see the frosty area and the shinny area above it. I did try pouring them all so they all frosted completely and the dark area (when fresh) went away and they frosted over nicely. I kinda though at the time that my bullet mold was dirty and the heat was cleaning it out. Guess that was wrong.

[abunaitoo]

Take a look at this picture (http://castboolits.gunloads.com/album.php?albumid=274&pictureid=1830) and see if the problem looks like one I had.

-HF

That's exactly what's happening to me.
Except mines is a .30 cal.
Is it pouring to slow or to fast?????

[runfiverun]

abuna: it's usually caused by a hot spot in the mold from either the alloy hitting the same spot over and over.
or between two mold holes close together.
slow down your casting speed and loaf along, let the sprue fully make the galvanized color before opening.
the above pictures look like a higher tin content which has pulled away from the antimonial content and has caused soft lead spots around them.
the other cause to them looking like that is dirty alloy.
but in this case i'd say it's a slightly dirty mold and the temp bouncing between just enough heat and going to the grey stage. letting the antimony bounce back and forth on the edge of the skin.
you have just enough tin in the alloy to keep breaking through the antimony at the heat range of part of the mold and not all of it.
clean the mold cav's.
and either up the tin a smidge or the heat about 15* and go with the grey/ galvanized color.
or heck just shoot em.

[Lloyd Smale]

that works with aluminum molds and ive done it myself but steal molds wont allow it.


This is prolly a case where the same problem figured-out by different independant solvers is approached differently. In running two 6 cavity Lee molds with .454 pills with WW alloy and about 1% added tin, my "solution" to the blotchy heat disfigurment was to go even hotter and faster. I pour hot and fast and the first cavity filled is still liquid after the last cavity is filled and the spru strip is one thick strip end to end. Even pre-heating by setting the heel of the mold into the molten lead for a few minutes, I discard the first several castings untill the temp is up to my target (that is, to where the first poured cavity is still molten when last pour is comleted). That way the boolits are pretty much all at the same temp and "freeze" at about the same time and there is not much disparity of temps between boolits or parts of boolits. BUT, my production is evenly frosty, but I see no problem with that, they are very uniform of diameter and weight and tumble lube clings to that frost like no body's business. Shoot well too.

prs

[abunaitoo]

Found, and fixed, the problem.
I tried casting again today. Same thing no matter what I did.
Only have problems with this mould, so I compared it to another mould.
The vent lines on this mould are not as deep as other moulds.
I smoke my moulds befor casting.
I started to thinking "maybe the soot is plugging up the vent lines".
Got a tooth brush and cleaned the soot off the surface without touching the boolet cavity.
First cast was almost purrrrrfect.
Forgot to blow the soot dust from the boolet cavity.
After I did that, all was right in my casting world.

Part Lee's fault. Vent lines not cut as deep as other moulds.
Part my fault To much soot applied to surface.
Learn something new everyday.

[prs]

Thanks Lloyd! I have not run into the problem with ferrous molds -- I only have a few of them and they are singles or doubles with plenty of bulk around the cavities.

abuniatoo, that's a good observation. I'll store that tip away.

prs

[docone31]

I smoke my Lee molds with a BIC lighter.
Back when I did it with a match, or candle, I got the results you did. Today, I heat soak the molds in the melt pot, then I cast. Rarely do I smoke the molds anymore
I also strip them before I cast. I soak them in mineral spirits for a couple of days. Probably longer than I need, but I have other things to do. I put them in a container, let em sit, then heat soak and cast.