Funky looking spot on my boolits.......

[John-n-va]

Been casting some Lyman .45 Postell boolits in 20-1 alloy. Using a Lee bottom pour melter that I bought 20 years ago for casting .58 minies for my front stuffers.

After getting my lead and mold up to temp. and the boolits are filling out nicely there is a "funky" (for lack of a better word) looking area on one side of every boolit. It almost looks like the lead trapped in the spout of the pot is hotter than the lead that follows. It looks kinda like some sort of contaminate but it never stops......if I cast 10 or 110 it is always there. Same thing with a 385 grain .45 boolit. When I cast some little 9mm slugs using straight WW's I don't see the "funky" spots.
Any ideas?

[NVcurmudgeon]

The "funky" spot may be localized shrinkage. I have disfunked my boolits by cleaning the blocks thoroughly and reducing temperature.

[grumble]

Curmudg, I'm ashamed of you. You should know better. You can't "disfunk" a mold. You can defunk a boolit, and anti-funk a mold, but you can't disfunk either. On the bright side, anything that is funkable can be unfunked with a little effort.

Well, almost anything. Never worked on my ex.

[Bullshop]

John-n-va
It sounds to me like what you are describing is oxidation from turbulance. This can happen from a bottom pour for several reasons. Two things that often combine are a large cavity and a high pressure pour. The alloy has time and room to splash inside the cavity which exposes more of the alloy to be oxidised. It will show up one one side just due to the way it is being held, at a slight angle so the oxidized lighter metal will go to the high side. Small cavities dont have this problem. This is why some feel ladle pouring makes better boolits because you dont have the turbulent pour and the oxidation is eliminated. Trueth is it only looks funky and causes no harm. Your boolits (if I am correct) can be wiped clean of the oxidized metals with a paper towel and a couple twists.

Steps to take to elininate the problem,
Adjust pour pressure to minimum.
Do not make the pour directly into the sprue hole. Hold the mold at a very slight angle and direct the streem to the plate beside the hole so it can run in without the pressure.
Adjust heat to the minimum that will keep the sprue puddle molten for about 2 seconds. This is plenty of time for air to escape. Longer is unnecessarily hot and more heat causes more oxidation.
With experiance you can learn to eliminate the problem and cast boolits with your bottom pour every bit as pretty as a ladle pour.
BIC/BS

[SharpsShooter]

Bullshop,

Reading your post was almost like you had been looking over my shoulder when I am casting 400gr and heavier boolits. Like you, I discovered that bottom pouring just a bit off center of the sprue hole gave me a cleaner cast that was both well filled out and consistant regarding weight. I'll readily testify that the oxidized metal wipes clean with a paper towel. Heck, that is exactly how I do it too. It was just kinda strange seeing it in print. Twilight zone

[Bret4207]

Freckles?