need to flux excessively?

[rogn]

I got Lees 0.378 250gr mold for the 38-55. I wanted to try it for reduced cast bullet loads in a Ruger 375. We have got a couple of hundred cast last week. I read up on mold tuning with the Lees and being lazy I thought Id try a bit of laziness in prepping the mold. I got an old toothbrush and some real toothpaste and went over the mold carefuly and gently. I just scrubbed the whole thing over , and tried to burnish or polish any of the areas that seemed to harbor any roughness or sharp edges. Thoro wash up followed. Then we did the Kroil treatment and started casting. I was using a mix of wheel wgts, range lead and solder. I warmed the mold in the lead pot and started out. The first bullet was wrinkled beyond belief and all the following bullets looked fine, some a bit frosted an if I let it cool off too much, i get a wrinkle or two. I was fluxing frequently with deer tallow and stiring full time. Pouring from the ladle and leaving a good puddle on the sprue worked quite well. BUT, after a while the pot seemed to want to separate out and required more frequent fluxing to keep "homogenized" I finally got tired or the smoke and need to stir and packed it in. Any ideas as to why I seemed to have all this separation ? I ran the heat up a bit and down a bit, with no changes. The great majority of the bullets looked good, not match grade , but shooters. ??

[HangFireW8]

What exactly was separating out?

[Cadillo]

Some folks have been satisfied with using Kroil in their cavities. For me it was a disaster. When my moulds are at rest, the cavities are lubed with Rem Oil or other to prevent rust, but when it's time to cast they are preheated and then flushed with brake part cleaner, the hinge and guide pins and recesses lubed, and then the whole thing reheated afterwhich I normally get great bullets from the first cast.

I suggest that you do a little research here on the forum and then try various methods you discover here. You find will something that yields your desired results. My moulds are all iron or brass, and as I have no experience with aluminum moulds, my method may not work at all for you.

[Cadillo]

Regarding the 'Separation", it sounds as though you are getting some oxide formation on the surface. After having used parafin and crayons for a long time, I finally came over to the other side and now flux with sawdust, which yields great results, especially with regard to reducing the oxides back into the melt without a lot of obnoxious smoke and flare up. My pot sides and bottom stay cleaner too.

If you are not running a thermometer to stay aware of your melt'ss temp, it would be a good thing to start. I find that the cooler I run my melt, the less oxide formation I experience.

[oneokie]

Sounds like you were running the pot heat too high and your casting cadence was varying too much.

[rogn]

Every 3-4 casts Id get a sludgy layer on the surface of the melt. If i fluxed it would disappear and the surface of the melt was smoother and shiny. The bullets seem acceptable. It appears as though the tin(?) may be separating.

[MikeS]

What temp is your pot? There's no reason to have the pot over 700F with an alloy containing tin, as the benefits of using tin in the alloy go away if the pot is much over that. I routinely cast at 650F and have no problem with any sludge forming. Also, forget about using deer tallow, and start using a wood based flux. The best is CFF a product from member PatMarlin, it's a mix of several kinds of trees that grow near him, then after that would be using hamster bedding available at any pet shop fairly cheaply, or using sawdust, which if you do any woodwork is free! If you're using a bottom pour pot, after you flux, just leave it sitting on top of the melt, it will protect the alloy from oxidation, and help keep the heat in the pot as well.

Also, while a good cleaning never hurt a mould, there's not really a reason to use the kroil in the mould, unless you're having a problem with the mould dropping it's boolits, and even then it just masks the problem, doesn't fix it. I don't use kroil, I don't smoke the moulds, heck, I barely clean them, and I rarely have problems with the mould releasing boolits. I would say for your next casting session, try doing it with the mould clean & dry, and see what happens. Also, preheat the mould either by using a hotplate, or by dipping a corner of the mould into the lead once it's up to temp for about 30 seconds or so, and you should be able to start casting keepers much quicker (if not with the first pour) than by using kroil.

[stubshaft]

If your using a bottom pour put some kitty litter on the alloy to reduce oxidation.

[runfiverun]

Sounds like you were running the pot heat too high and your casting cadence was varying too much.

as the pots go down they get hotter..
i flux when the gunk builds up and gets annoying to look at, otherwise it and the other stuff i got on top is keeping the oxides at bay.

[Bret4207]

Every 3-4 casts Id get a sludgy layer on the surface of the melt. If i fluxed it would disappear and the surface of the melt was smoother and shiny. The bullets seem acceptable. It appears as though the tin(?) may be separating.

That sounds like the oxides and dross coming to the top. Skim it off, save it and when you get enough try fluxing it alone. You'll get a lot of lead alloy back out of it, but it's a pain trying to get it reduced back into the melt while casting.

As I understand it tin will not separate out anyone than antimony will. They are bonded chemically when melted. The oxides will rise to the top as will all the dirt and garbage you are loosening.

[swheeler]

Rogn; you are just seeing the side effect of ladle casting. When you dip the ladle in the melt and bring it up to pour you are exposing more alloy to oxygen, creating oxides. I use the back of the ladle to push the oxides back, then push the ladle under the surface all in one motion. When you bring the ladle back up to pour you are'nt loading a bunch of oxides with the alloy, you come back up in the "clean" spot. When the oxides get too bad/thick you will have to flux again, but that is quite a few bullets later and what you remove after fluxing will be nothing but grey dust, maybe half a teaspoon full, continue casting.

[prs]

I have never treid Kroil, have not yet seen any need because just cleaning the moulds works great with Lee aluminum 6 bangers; so far. Then again, I am a bottom pour caster only.

prs

[rogn]

Well first, after the toothpaste and Kroil treatment I only had a couple of bad casts, and almost everything dropped from the mold immediately. At most a slight jiggle with my mold stick dropped the odd one, which mostly seemed to hang on the driving bands, not sticking. Im still not entirely sure whether the "sludge" is oxides or what, it has the appearance of a thicker, duller, clumpy metallic layer that disappears completely upon fluxing, but reappears rather rapidly. Ill try the next session at a lower temperature and see how that works. I did run the stove fairly hot due to a bit of breeze that came and went towards dusk. The good news however seems to be that the boolits will shoot well at least at the level Id started. They measure 0.379 and weigh about 252gr at rough ave. I tumble lubed and heavily chamfered fired unsized cases(375 Ruger). Im using these unsized at 0.379". 15 grains of an old batch of Alcan's AL-7 seems to give a subsonic velocity and accuracy in the limited shooting Ive done suggests 1 1 /2" groups at 100. It took 40 clicks to get on point of aim however. Loaded rounds function thru the magazine well. The goal was to get a milqe toast load that could be used for practice with low noise and recoil levels. So far Im happy.

[Boerrancher]

I don't mind a thin layer of Oxidation on the top of the melt. I noticed in the OP that the melt was stirred allot. It has been my experience the more of the melt that is exposed to the air the more oxidation occurs. I never stir the melt in my furnace. When I notice a build up of material on the top of the pot, always after adding material. I sprinkle a bit of sawdust or tobacco on the top of the melt, let it turn to ash, and start gently pushing all of the material to the edge of the pot and gently pushing it against the edge of the pot and a bit of the melt. As I do this the tin and antimony rapidly vanish back into the melt, leaving behind only the ash. No stirring is used because it exposes more of the melt to the air. You should only have to do this when you add material to the melt.

Best wishes,

Joe

[JeffinNZ]

You don't have some zinc wheel weights in that mix do you?

[oneokie]

Something to try-set your pot to about 550-600 degrees, starting with a cold pot. Do not flux or stir, when you get to a liquid state, skim all the cottage cheese looking stuff off and then turn the pot up to your normal casting temp and see if you boolits look any better.

[rogn]

Al the wheel weights are more than 20 yrs old and none melted slowly. Bullets are filled out well, bot are very varied in appearance. Best though is they shoot great at the low velocity Ive tried.

[leftiye]

Stirring with a stick? It's the only thang to stir with, nice hardwood dowell. I'd get a better flux too. The Buck Beaver stuff from eBay is the best I've found, and I've tried everythang. I usually use crushed charcoal (Kingsford, not forging charcoal), but I bottom pour. Get a Lyman ladle and set the spout down first, letting the ladle fill through the spout. I've added a quarter spherical piece to a Rowell ladle with a fill hole at the old rim opposite the pouring tube.