slag inclusions in boolits

[lylejb]

I'm getting slag / dross like inclusions in boolits, and it's getting worse every casting session. Most are not "chunks" in the boolits, but a fine, sand like spots on the outside.

I pour in a Lee 10lb bottom pour, and have fluxed with paraffin, sawdust, or both and stir with a wooden stick. Scrape the sides and bottom, nothing seems to help.

I've taken apart the pot, and wire brushed it with a cup type brush on a electric drill, and wire brushed the valve rod.

I've taken apart the mold, simmered the blocks in dawn and water after I lapped this mold with toothpaste and baking soda, to help sticking in the mold.

I don't smelt in this pot. I'm using 2/3 WW 1/3 pure +2% tin. All was smelted into ingots before going into the Lee pot.

I've tried temps from wrinkled to heavy frosted, no change.

There has to be a way to get this metal and pot clean, but no luck yet.

Tonight, I tried removing the valve rod, and spraying and wipeing out the pot, No help.

this pic is from tonights casting session. The mold wasn't up to full temp because I stopped when i saw how they were comming out. These are some of the worst, to make it easier to see.

How do you guys get rid of the crud?

[Buckshot]

..............It's a dirty pot or the crap is in the ingots. Er, you're not rendering down WW's or other scrap in your pot are you?

If you've done as you've described in cleaning the pot, unless your ingots are very dirty you shouldn't be seeing that. While lead will be heavier then anything likely to be run through your smelting pot or pouring pot, it is quite amazing what will find it's way to the bottom. When I first got my turkey fryer scrap rendering setup, it was an absolute amazement the crud that was on the bottom of the cast iron pot as I ladled the lead out.

Without proof the theory of entrapment between barriers and thermal convection movement seems most likely to me. As ingots are melted, part of any contaminants do end up on the surface but also some can end up against the wall of the pot. It is trapped between the wall of the pot and also the weight of the molten lead against it. Scraping up the walls of the pot pretty much just creates a momentary swirling eddy in the alloy rather then bringing up any contaminents, unless the side of the implement REALLY matches the curve of the pot wall.

Some dislodged bits will reach the surface, some will merely swirl around a bit and then end up back against the pot wall, or convection may carry some downward to the bottom or simply lower down on the pot wall. As the alloy level in the pot falls, all this simply takes place closer and closer to the bottom of the pot. These tiny particals ARE lighter then the lead, and are as particals, themselves very light. They aren't going to 'Head for the surface' like a balloon held under water. Convection currents may keep them suspended for some time.

The flow of the lead out of the spout would probably pull some particals downward. When the spout was shutoff they would take a moment to begin their natrural upward movement, but before then you pour another boolit and they're sucked down lower.

Anyway that's the theory. As I mentioned in my first paragraph, after dipping from and re-adding scrap to the cast iron rendering pot for some time (plus fluxing and skimming to a bright surface) there was a LOT of sandy black crud on the bottom of the pot. Tipping the pot up on one side this stuff collected in the bottom corner with the lead simply rolling back and forth over it like mercury. I poured out the small bit of lead into a bucket of water and then cleaned out all the black dust and began melting more scrap.

...............Buckshot

[runfiverun]

something in your alloy....
try an older batch of smelted stuff,or some new alloy.
grey gunk, it sounds like....oxide inclusions.

[Shiloh]

You said you are fluxing, are yo stirring the flux in so all the metal comes in contact with the flux?? I think it is something in the lead as you have cleaned you pot.

Shiloh

[Bret4207]

Do you have access to a batch of different alloy? Try that. You may have some weird stuff that resists fluxing. In the end fluxing is the answer. It may take some time.

[shotman]

I will bet you have a couple of Zincys in the mix. I had that from some "wheel weight ingots" that I didnt make . It dont take but one or 2. If that is the case run temp to max and they will all but go away. Then sell the rest on feebay.
One other thing guys You cant flux zinc in to lead at a low temp It will mix but not uniform. The boolits that he has there was cast at a low temp.

[243winxb]

Set pot on highest temperature, make sure alloy is at it maximum heat. Use Marvelux Flux. Mix like its a pot of soup. Then clean off what comes to the surface as it settles.

[lylejb]

Thanks for the replies,
As far as zinc, NO. I smelted all these ingots myself, and checked every weight with side cutters.

As far as crud in the pot, ingots, or both I think so. That's why I've been cleaning everything. This hasn't been helping much. What's the best way to clean the pot and ingots, what I've been doing must not be working.

Fluxing, I've tried paraffin and sawdust, sometimes both. Usually with paraffin, it melts and catches fire in a second or two, and once it burns out I stir with a paint stir stick. I really don't think that would do much for the bottom of the pot. With sawdust, I think you can stir it to the bottom, but appearently that's not doing much either.

As far as temperature, I don't have a thermometer, but higher temp doesn't help. Two nights ago I was up to the point the lead was faintly glowing orange, the boolits were very frosted, and starting to get a rough feeling from the frosting. While the frosted appearance somewhat hides the crud, it was still there.

How do you clean your pot? Ingots?

Thanks

[BABore]

I've ran into this problem when I put too much tin in an antimonial alloy. Try thinning out your alloy with WW's and see if it goes away.

[montana_charlie]

Do you own a dipper?
Try casting some without using the bottom spout...just so you can guarantee the alloy in the cavity was not in contact with the bottom or side of the pot.

If the bullets come out clean, you have a 'dirt' problem as you suspect.
If they still come out cruddy, it's something about the mould...or the metals in the alloy.

This article on fluxing might be informative in helping you cure your problem.
http://www.lasc.us/FryxellFluxing.htm

CM

[Bret4207]

Flux with your paint stick, don't bother with the sawdust. Just keep stirring and scraping and it'll eventually get as clean as it can.

[lylejb]

I think I should:
1: clean the pot again. Maybe a severe cleaning like a soak in kroil to soak out anything in the pores / texture of the metal. Or maybe a quick cleaning with wheel acid (industrial detergent + hydrochloric acid)

2: resmelt the ingots to try to get them cleaner.

Has anyone tried braizing flux while smelting? This should be a borax based flux, like marvelux.

[243winxb]

Usually with paraffin, it melts and catches fire in a second or two, and once it burns out I stir with a paint stir stick. Are you waiting to long to stir?
resmelt the ingots to try to get them cleaner This might help if not fluxed and cleaned well the first time. I use a 40lb pot, taking the alloy off the top after fluxing. There is stuff that does not come to the surface. I have always thought its sand from the indoor range where i get my alloy.

[runfiverun]

think back through your alloys steps.
where did your tin come from.
solder,babbit, pewter?
there are other things besides zinc that can cause these issues,copper for instance.

[lylejb]

The tin is new solder, 95 tin / 5 antimony , I bought about a month ago ($ouch$) as I couldn't come up with any scrap that i was sure of.

As a test, I took CM's suggestion a little bit further. I went to the local thrift store and got a 2qt stainless pot, a stainless coffee measure ( dipper/ ladle), and a long handle teaspoon.

Took the new pot, melted a few ingots ( same metal from yesterday. these are the muffins i made when i poured out the pot yesterday) Paraffin flux, and scraped the top clear. No stirring. My thought was if anything was going to stick to the bottom or sides, let it, just to keep it out of the molten pool. clamped vice grips to the coffee measure as a handle, and proceded to ladle cast some boolits.

About 99% clean.
about 50% rejects due to poor base fill out. Never had that problem before.

So, that tells me that it is crud in the pot, and being as i cleaned it a short time ago and it soon came back, must be in the ingots too.

So I guess I will have to re smelt the ingots, and be careful to only dip from the center of the melt. And clean that pot again.

What do you guys use to clean you pot?

[runfiverun]

when smelting
i use a rough pot and get what i can [flux,stir with a stick flux and scrape]and don't empty it. till the end of the session then just dump out the dust.
amazing what accumulates in there in just 2 pot fulls.
i use two pots ata time and do two melts and dump, then start again it looks like i dumped a brake drum out every time.
i lose some alloy to the bucket to be run again later, but i strive for the cleanest i can get when smelting.
and will flux a couple of times when ladeling out and use different fluxes as i go.
marvelux,sawdust, coaldust, different sticks, and old boolit lube.
i am a spaz about it and may go overboard a bit,but you have found out why.

[TAWILDCATT]

take another look he is not casting hot enuf.he has lines all thru.cant you see them??

[docone31]

You gotta crank up the heat in both your mold, and pot.
You will get better results.

[leftiye]

I believe it is lead oxides, and I think it is a bottom pour problem. I do everything I can and still get some of those nasties on my boolit surfaces. It doesn't happen with linotype Unless I'm wrrrr---. I also believe it is a wheelweight problem, my alloy is 50/50 WW/Pure, and it will not cast well unless frosted. I cast much hotter than you seem to be doing, fergit about shiny, melt them inclusions into your boolits, Cast lightly frosted.

Do sum studying on fluxes- wood stick (do stir!) -very good, stearic acid -vvery good, parraffins next in line, crushed charcoal -good to cover melt with to keep oxygen away, Marvelux -only if ye're brain dead (same with frankford arsenal borax - these stick all over the sides of your pot, and cause rusting - and they don't reduce oxides), and so on.

[runfiverun]

he did the heat thing already..
it's an alloy problem.

[462]

lylejb,

Do you flux as you smelt? I think the junk is in your ingots and then migrates to your casting pot. Just cleaning your casting pot will only work till the next time you cast. Re-smelt and flux your ingots, and I'll bet the problem goes away.

[docone31]

Ok, so the mold, and pot are up to heat.
Stir the melt. I use a wood dowel, and a long screw driver alternately. I also use a layer of Kitty litter on top of the pot.
I also soak the mold in mineral spirits for two days. Of course I use double cavity molds and a six banger is another issue.
I would crank up the heat, then heat soak the mold. Leave the castings in the mold after desprueing for a fashion. Let that heat really get there. You can always back off if it takes too long to cure.

[chevyiron420]

I know this isnt helpfull, but i have the same problem. I have fought with it for years now. I can dump the aloy right out of my bottom pour, into my other pot, and ladle perfect boolits with the same aloy. I have asked the same questions you have here but i cant put pictures up, however my bad boolits look like yours, just not as bad. When i bottom pour my reject rate is probably 50% or more, and when ladleing, only one or two out of a hundred. I realy wish i could make the bottom pour work cause its a bigger, better pot and much faster.
I have drained and cleaned my pot several times and it has never made any difference. I have also fluxed with, candles, boolit lube, NEI flux, and wood dowels and it makes no difference.[smilie=b:

[Bret4207]

The tin is new solder, 95 tin / 5 antimony , I bought about a month ago ($ouch$) as I couldn't come up with any scrap that i was sure of.

As a test, I took CM's suggestion a little bit further. I went to the local thrift store and got a 2qt stainless pot, a stainless coffee measure ( dipper/ ladle), and a long handle teaspoon.

Took the new pot, melted a few ingots ( same metal from yesterday. these are the muffins i made when i poured out the pot yesterday) Paraffin flux, and scraped the top clear. No stirring. My thought was if anything was going to stick to the bottom or sides, let it, just to keep it out of the molten pool. clamped vice grips to the coffee measure as a handle, and proceded to ladle cast some boolits.

About 99% clean.
about 50% rejects due to poor base fill out. Never had that problem before.

So, that tells me that it is crud in the pot, and being as i cleaned it a short time ago and it soon came back, must be in the ingots too.

So I guess I will have to re smelt the ingots, and be careful to only dip from the center of the melt. And clean that pot again.

What do you guys use to clean you pot?

Look, if you want to get the alloy clean you have to stir it around. Stir it with the paint stick,. As it chars the carbon will be down in the alloy, not on top as with sawdust or wax. Stir it through the mix and keep stirring. Of course the alloy has to be hot enough to stir, at least 650 or so. That's the only way to get it clean. It takes time if the ingots weren't clean to start with. Don't bother with wax and the flames and trying to stir with your hand in fire and all that crap. Just use the paint stick. Forget the borax, Marvelux, etc. Holds moisture, causes rust. Great stuff for brazing, not so hot for this. If you want to try cleaning the empty pot that's fine too, but be careful with acids and stuff.

When I went to a stainless 12 cup measuring cup my dross dropped to almost nothing from what it was with my iron/steel pots. I figured it's rust plus whatever is in a cheap cast iron pot. Using the SAECO BP I still don't get a lot of dirt because the ingots are clean and I stir it around good with a stick.

[Bret4207]

I know this isnt helpfull, but i have the same problem. I have fought with it for years now. I can dump the aloy right out of my bottom pour, into my other pot, and ladle perfect boolits with the same aloy. I have asked the same questions you have here but i cant put pictures up, however my bad boolits look like yours, just not as bad. When i bottom pour my reject rate is probably 50% or more, and when ladleing, only one or two out of a hundred. I realy wish i could make the bottom pour work cause its a bigger, better pot and much faster.
I have drained and cleaned my pot several times and it has never made any difference. I have also fluxed with, candles, boolit lube, NEI flux, and wood dowels and it makes no difference.[smilie=b:

Are your boolits wrinkled or do they have what appear to be slag or dirt inclusions? Rounded bases and poor fill out or pockmarks and little holes?

[armyrat1970]

The tin is new solder, 95 tin / 5 antimony , I bought about a month ago ($ouch$) as I couldn't come up with any scrap that i was sure of.

As a test, I took CM's suggestion a little bit further. I went to the local thrift store and got a 2qt stainless pot, a stainless coffee measure ( dipper/ ladle), and a long handle teaspoon.

Took the new pot, melted a few ingots ( same metal from yesterday. these are the muffins i made when i poured out the pot yesterday) Paraffin flux, and scraped the top clear. No stirring. My thought was if anything was going to stick to the bottom or sides, let it, just to keep it out of the molten pool. clamped vice grips to the coffee measure as a handle, and proceded to ladle cast some boolits.

About 99% clean.
about 50% rejects due to poor base fill out. Never had that problem before.

So, that tells me that it is crud in the pot, and being as i cleaned it a short time ago and it soon came back, must be in the ingots too.

So I guess I will have to re smelt the ingots, and be careful to only dip from the center of the melt. And clean that pot again.

What do you guys use to clean you pot?

Okay. I am by no means and expert when it comes to smelting or casting alloy for boolits but I will give you my advice. First. Get a thermometer to check your temps when smelting and casting. Lead melts at around 621Degrees and Zinc at around 787degrees. I know you feel you have no zinc contamination but it appears so. Resmelt your ingots keeping your temps below 700. Flux with whatever you use and remove the dross before you pour your ingots.
To clean your pot here is a trick I learned from another on a different forum. I used it for my Lee bottom pour that had heavy zinc contamination and it worked well for me. Go to the store and get a bag of Hardwood Charcoal. Not Briquets that you use to BBQ. Hardwood Charcoal that looks like pieces of burnt wood. Crush it down to around pea or bean size. It's going to be a little messy and I used a sock with a hammer. Fill your pot and crank it all the way up. Let the charcoal burn down to an ash. You may need to add a little more as it burns down to get the entire pot clean from top to bottom. Dump the pot and it should be clean.
Whenever you smelt keep your temps below or around 700 and flux and stir before pouring ingots. Never smelt in your casting pot. HTH's.

[243winxb]

How do you clean your pot? Ingots? I clean while fluxing. An old stainless steel straight edge table knife is used to scrape the sides of the 10lb pot. A table spoon is used on the rounded edge near the bottom of the pot. Scrape all surfaces so that the slag can float to the top. Getting some air into the alloy is good if you can do it with your ladle when making ingots. My ladle has a divider in the center, with holes on the bottom, this keeps any slag i scoop from the top of the 40lb pot from getting into the ingots. My ladle holds about 1lb of alloy. Always use maximum heat if your sure there are no zinc wheel weight in the scrap. http://i338.photobucket.com/albums/n420/joe1944usa/th_IMG_3864.jpg (http://i338.photobucket.com/albums/n420/joe1944usa/IMG_3864.jpg)

[armyrat1970]

I clean while fluxing. An old stainless steel straight edge table knife is used to scrape the sides of the 10lb pot. A table spoon is used on the rounded edge near the bottom of the pot. Scrape all surfaces so that the slag can float to the top. Getting some air into the alloy is good if you can do it with your ladle when making ingots. My ladle has a divider in the center, with holes on the bottom, this keeps any slag i scoop from the top of the 40lb pot from getting into the ingots. My ladle holds about 1lb of alloy. Always use maximum heat if your sure there are no zinc wheel weight in the scrap. http://i338.photobucket.com/albums/n420/joe1944usa/th_IMG_3864.jpg (http://i338.photobucket.com/albums/n420/joe1944usa/IMG_3864.jpg)

And you got this ladle from where? I don't ladle cast, but if I want to, I think that's a good ladle to start with.

[qajaq59]

Really fine sand is a bear to get out of your lead. The convection currents carry it to the sides of the pot and it's almost impossible to pick it up with a skimmer or even a spoon. Seems like it just wants to stay on the rough iron pot.

[243winxb]

And you got this ladle from where? Ladle about 45 years old, so don't remember. When i first started casting, i used the ladle to fill the mould. Now its used in the 40lb pot that i clean scrap alloy in to make ingots. I cast boolits from a Lee 10lb pot. The spoon and knife are uses in the Lee, not the ladle , its to big.

[leftiye]

Ladles can be made. How about a rowell style ladle (pours from a tube from the bottom of the ladle - that picks up nothing from surface of the ladle); with an extra 90 degree spherical hood added with a hole and short tube on the center of the old rim line where the hood was added - that allows you to fill the ladle from beneath the surface of the pot?

[Suo Gan]

I am sorry I did not read all the above posts.

But here is my take on your (our) problem. ALL SLAG DOES NOT FLOAT. When bottom pouring (esp.) some slag with certain boolit alloy will contain a lot of slag in the bottom layer in your pot even if you have properly fluxed the pot. The reason this seems to happen more in bottom pour pots is because they are stirred less (usually), and the bits of slag in question are heavier so they sink. I usually do not worry too much about some inclusions in my handgun or plinking boolits. If a pot is giving you this and you intend your boolits to be used for target work, use that alloy from the last 2/3rds of your pot. Perhaps you could cast some plinking boolits in the first third...or until you notice a marked decrease in the inclusions. If you keep having problems through an entire pot, I suggest letting your pot sit for a spell so that the entrained bits of slag can sink, and empty the remaining amount into your ingot mold and give the pot itself as well as the ingots a bit of cleaning before they are put back into service. The little buggers will be evident on the very bottom of the ingots, I use a wire brush over a trash can.

Also, when I smelt, I never take that alloy in the very bottom of the pot. It may sound anal, and perhaps it is, but I wait until the last of the alloy is being poured and mark it separately so that I can avoid some of these problems. I then use this particular alloy for plinking boolits.

Hope this helps and hope that this is not a repeat.

[geargnasher]

I see no one has mentioned the obvious, the OP said he stirred the pot with a wooden stick and scraped the sides and bottom. What happens when the end of the stick chars and you are scraping the bottom? Ash and carbon (which quickly turns to ash) is sloughed off UNDER the melt, trapped by the tremendous weight and surface tension of the bottom of the liquid mass. This ash migrates to the spout and voila!, little ashy craters in your boolits!

I have had this problem many times because I stir with a stick, the only answer has been to empty the pot, clean all the powdered junk out, melt a handfull of clean, lubed rejects to make a nice clean puddle on the bottom, and add ingots from there. The oxides on the ends of my ingots can also get trapped when starting a fresh pot, but usually I can coax them to the surface with a long, pointy teaspoon, then stir thoroughly with the stick without touching the bottom of the pot. The ash, however, comes out in the boolits just like in the pic in the op.

Gear

[gray wolf]

I wonder why no one has referred to my recent post with the same problem and almost the same pictures of bullets with inclusions. While I agree with all the comments it was not my problem.
I just cast with a loaner mold--a Lyman 77 grain for 32 ACP. I used the same problem alloy.
I had my heat up and my mold hot. I got the same crappy bullets right off the bat. The I started hitting the side of the mold and I let the metal swirl into the mold.
( thank you forum member ) the problem was gone at the first cast. I did many of the little 32 acp bullets and they were great looking bullets. Every once in a while I let it go right into the center of the hole and immediately got the inclusions.
MY ANSWER--gassing in the mold. I expect that when I try the brass mold again I will have the same results.
My thought is if it is Sand or dirt then how come we don't see it in the bullets as a positive ?
all we see is a negative as to show where something was. So where is the dirt/sand ?
I believe it is trapped air or as I said gassing.
Any way it stopped my problem. I don't say anyone else is wrong--just saying what worked for me.

[CeeHoo]

This probably is more or less academic question but...will slag inclusions accelerate wear of the bore? If caused by trapped sand particles rather than oxidized metals I would guess yes.