Critique these boolits! (56k death)

I posted a while ago about having trouble with my 314299. Well, I did some of your suggestions, and here is the result. I casted about double this, but had a 50% reject rate. It looks like there is either frosting on the boolits or dirt or something in my lead ... I don't think it's frosting because ones at lower temps (less than 700 degrees) look exactly the same.. Also.. some of these do have definite frosting (can see the grain patterns), and it is different. Any ideas why these look kind of crappy? Are these ok to use?

Every once in a while I nice shiny one will come out (but it always has some other defect).

What I basically did to the mold was clean with acetone and a brush. Then brake cleaner and a brush. Then I boiled it in soapy water followed by a rinse and a boil in clean water, blew it off and dried it, and finally I gently spun a phosphor-bronze bore brush in the cavities.

The most common defects were wrinkling and random voids on the surfaces.

These are 9 lbs of .22lr range lead mixed with plus metal and tin solder. I goofed and got the tin too high, so it should be something like 2-3% antimony and 5-6% tin. I cast in about 4 increments, increasing the temp by 50 degrees from 750 to 950 degrees... 950 actually had the lowest reject rate... a couple came out definitely frosted from 950, but most looked just like all the other non-rejects from lower temperatures. I do flux the pot (bottom pour), I use about a half pea sized piece of paraffin and mix with a wooden dowel. I do not skim the top unless it gets too much crap on it.

The range lead is collected from a .22lr only range by yours truly, and comes mixed with all sorts of dirt and rocks. To smelt I put it all in a dutch oven on an electric melter I made, and fluxed/stirred using a wooden stick. Cleaned off the crap and ladled it out from the top into muffin tins.

Never watched anyone else cast or smelt, and all I've learned has been from you guys... so any suggestions will be welcomed.

The pictures are huge so you can download and zoom if you need to get a better look. Thanks!


http://pic40.picturetrail.com/VOL361.../323547065.jpg


http://pic40.picturetrail.com/VOL361.../323547790.jpg


http://pic40.picturetrail.com/VOL361.../323547461.jpg

Edited to add:

The bases are also bad. There appear to be very large and definite grains on the inside of the boolits. I do not think it's tearing, because I noticed it while casting and the amount of time before cutting the sprue had little effect. This would mean the solidification time is too long, correct?

http://pic40.picturetrail.com/VOL361.../323557801.jpg

http://pic40.picturetrail.com/VOL361.../323557638.jpg

Like your rifle tell you how good they are. :-D

those are oxide inclusions..
and 22's usually only have 1.5% antimony in them.
not a problem though but the ton-o-tin is.
it wouldn't be but you got antimony in them. all is not lost as you have such a small amount of antimony.
the ones with the holes in the back [voids] means you will have a large variance in weight.

what i would do is go shoot them at about 1400 fps and have fun.
next time mix in 1.5% tin and water-drop them.
you will have to experiment in your pouring technique to get the voids down.
and the high heat is causing your oxide inclusins.

.................I don't see anything wrong with them. There are some surface blotches but those are not defects. You know, dropping fresh hot boolits (especially when cast at elevated temps) onto a towel will show stuff like that.

"The most common defects were wrinkling and random voids on the surfaces."

That would have been blocks too cool, alloy too cool. Voids and also wrinkling can also be caused by a poor stream of lead into the cavity. Too large a stream in poorly vented blocks will also cause fillout issues.

"I do flux the pot (bottom pour), I use about a half pea sized piece of paraffin and mix with a wooden dowel. I do not skim the top unless it gets too much crap on it."

Doesn't sound like enough fluxing material to me. Be sure to scrape up the insides of the pot, and across the bottom. Do you drain down the pot and clean it on occasion? Even with good clean looking ingots used in the casting pot, you'll still end up with some crap in there. Through heat convection, stirring, and flow through the valve a lot of these tiny bits (like tiny sand or dust) will collect on the bottom having worked their way down the sides (I assume as I don't see the stuff setteling mid-pot).

Though lighter then the lead, the theory is surface tension keeps them captive . These eventually find their way out through the valve and into the cavity. They usually appear as a small or tiny irregular foamy patch (for lack of a better description) in an otherwise smooth solid skin. Not frosty or sunken, but an anomaly on an otherwise perfect surface. Sometimes the inclusions (sandy dust) are visible as tiny groups on the surface. A fact of their lightness and the flow of alloy possibly.

Voids and/or poor fillout in the base normally means an insufficient sprue has been poured, or the sprueplate is swung too soon.

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

The pattern of the voids under your sprue holes has me a little spooked. It looks like you have some funny crystallization going on. I don’t like the sharp, straight edges that I see there.

As Buckshot said, try a little more flux. After you flux, the metal should have high surface tension as evidenced by a strong meniscus (sort of upward bubble like curve of the liquid lead in the pot). The surface of the lead should not go straight out to the sides of the pot. It should be shaped like a bead of water sitting on a freshly waxed car.

If better fluxing doesn’t do it, then try to think back if it might be possible that some other metal also got mixed in by accident.

Quote:

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Originally Posted by Buckshot;359526

[B

"I do flux the pot (bottom pour), I use about a half pea sized piece of paraffin and mix with a wooden dowel. I do not skim the top unless it gets too much crap on it."[/B]
Doesn't sound like enough fluxing material to me. Be sure to scrape up the insides of the pot, and across the bottom. Do you drain down the pot and clean it on occasion? Even with good clean looking ingots used in the casting pot, you'll still end up with some crap in there. Through heat convection, stirring, and flow through the valve a lot of these tiny bits (like tiny sand or dust) will collect on the bottom having worked their way down the sides (I assume as I don't see the stuff setteling mid-pot).


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

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Thanks for the replies everyone :) I have a question about fluxing. WHen I drop paraffin on the top it melts and then appears to pretty much just burn off before I can mix it in. How should I be doing this (and how much should I use)? What I currently do is drop a piece in, and then mix it with a wooden dowel (as much as I can but like I said it burns off so quick!). I try to get the sides and the bottom as best I can. Sometimes I'll do this 2 or 3 times in a row because I am using smaller chunks (bigger chunks = bursting into flames and I don't want to stick my hand in that). I don't really understand this whole process. Theoretically, the flux is supposed to reduce the oxides back into the mix, correct? Even when I flux frequently I still get this stuff, so I must be doing something wrong. I also notice that the "skin" on top doesn't really seem to go away with fluxing, it just gets pushed aside and then a new layer forms.


Before this session I drained the pot and hit it hard with a wire brush for a drill, and cleaned the spout out and everything... Before that it was brand new and I cleaned it before starting... so it can't be a dirty pot. I saw that someone else was having this problem. Is there a site that shows with pictures or video fluxing in detail so I can know if I am doing it right?

I hear this stuff about people putting parffin on top and leaving a layer about 1/8" thick to protect it... but when I put it on it burns off pretty much instantly. I also hear about leaving sawdust on top, I tried sprinkling some on a while back to see if it would help and it just released ridiculous amounts of smoke in a short amount of time.

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Originally Posted by JIMinPHX

As Buckshot said, try a little more flux. After you flux, the metal should have high surface tension as evidenced by a strong meniscus (sort of upward bubble like curve of the liquid lead in the pot). The surface of the lead should not go straight out to the sides of the pot. It should be shaped like a bead of water sitting on a freshly waxed car.

If better fluxing doesn’t do it, then try to think back if it might be possible that some other metal also got mixed in by accident.

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I've never heard that before. Thanks for the visual description I'll look for that next time.

The pattern of the voids under your sprue holes has me a little spooked. It looks like you have some funny crystallization going on. I don’t like the sharp, straight edges that I see there.


Those are in fact large crystals (grains) of lead. You can see them very clearly in person and that's undoubtedly what they are. I am guessing it's because I was running so hot at the end and the mold was blistering hot too. It wasn't tearing, I gave PLENTY of time on a few casts to see if that's what it was.

get rid of the flux. Flux your lead at the start of the casting session lightly and thats it. Run your mold and lead a tad hotter and back your tin content off to about 3 percent. You also might want to step up your pace a bit.

Tin content is higher than the antimony. Mold temp brings this out. You are not too hot, just too hot for too much tin. So you still get voids.

You are going to get soft spot formations in these areas. And your bullets will be outta balance as a result.

You also need to take a stone and just break the sharp edge on the top of the blocks to improve venting in that area if your plate is already lose. I would take a scribe to the vent lines too. Never hurts to have over venting as long as you don't walk into the cavities while you are doing it. Then pay attention to see if it's one cavity all the time.

Either that, or you are going to have to slow down your stream to allow venting through the top. But that don't work well for long, small diameter bullets. Don't be afraid to build a sprue puddle either. They remelt later.

I second the big sprue puddle motion . . . or is it third?

Find some wheel weights and add to the mix to cut your alloy. You don't need the wax to flux with, just use you wooden stick and stir, stir, stir and scrape as you do it. I hate to ask, but do you have a ladle you can try? Most the boolits look pretty fair, but some moulds respond to a ladle. You need a nice sprue puddle and as Bass said take a stone and just run it across the edge of the top once or twice to just break the edge. The scribe in the vent lines means just lightly follow the line ONCE, you're not digging them out, just touching them up to allow a bit more venting.

I think your alloy needs a little work and the mould, if new, needs casting. Some take a while to break in. If it's an older mould there still may be some gunk giving you that mottled surface on the boolits, but that isn't a big deal. The base voids are a big deal and that's what I'd worry about.

Lot of good words here. I would shoot them, and see.
The fluxing, I throw 20 Mule Team Borax from Wally World, onto the melt. It is an high heat flux, so it doesn't really melt. The crud clumps onto the borax, like sawdust, just not so smokey.
Those look like good paper patch candidates! Size them to .308, wrap away with Meade Tracing paper also from Wally World. (Thanks Beemer, it works!) No gas checks.
They will get better with time, I would use them now if nothing else but to just see and compare.

Minus the base craters they look fine to me. With gas check installed they probably won't be match grade bullets but will shoot surprisingly well, I'd wager.

But junk the ones with holes in the base! These voids will throw the bullet off - how far depends on the actual size of the void. That little hole that is visible may lead to a sizable cavity.
And +1,2, or 3 on the Too Much Tin comments. Cut it down to 2-3%, and have at it!

Quote:

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Originally Posted by MeestaSparkle

I do flux the pot (bottom pour), I use about a half pea sized piece of paraffin and mix with a wooden dowel. I do not skim the top unless it gets too much crap on it.

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Except for the 'scruffiness' added by the frosty-looking spots, your bullets don't look all that bad...outwardly. Yes, those little pinholes in the sprue craters might be 'windows' to huge caverns inside...and that is a problem to be corrected. But, in large part, your bullets are well filled, and the driving band and base corners are well-defined and fairly 'crisp'.

About your tin...
20:1 is a very popular alloy among BPCR shooters. That contains 5% tin. So, while you may have more tin in your alloy than you actually need...it is not so much that it will 'ruin' bullets.

But about your fluxing question...

Like you, I used to religiously drop in the pea-sized chunk of paraffin/beeswax/bullet lube/candle stub/ear wax/toilet ring/toe jam...tried to stir it before it disappeared...and skim the remaining crud from the surface. The 'crud' certainly didn't look like anything you would want in a bullet, but it was obviously made of metal. Since the only metal in the pot was metal that was supposed to be there, I always felt like I was doing wrong.

Then came stick fluxing...

Stir around, scraping the walls and bottom. If anything is there, it should come to the surface. Just stirring the surface crud layer has little effect, because the carbon in the stick is only able to 'touch' a small portion of the crud when you stir.

Instead, use the stick to gather it into a clump against one side of the pot. Mash the stick into one side of the clump to squeeze it against the pot wall...then slide the stick down into the melt...taking crud with it.
Rub it up and down a couple of times.
When you bring the stick up, it should be accompanied by some fine black 'dust'.

Gather the crud and do it again. Keep at it until the crud is gone, and only 'dust' remains.
Skim off the dust (if you want to) and feel good about the fact that your oxidized metal has been 'reduced', and recombined back into the alloy.

On your bottom pour pot, a thick layer of sawdust will keep the crud layer from forming so quickly...maybe prevent it entirely. But it has to burn down to 'dust' that is almost pure carbon.

CM

Guys, could this be zinc contamination? I have been running into the same surface blemish issues, but only with a certain alloy of "mystery metal" I have.

I had this problem last night. I was casting with a WW+2% tin mix, which worked beautifully, but then I added a couple pounds of my mystery metal, which I think might be high in tin (but maybe zinc as well?) and immediately started getting the same surface blotches as shown above. It's not a frosted look, it almost looks like dirt in the melt, but closer examination shows that it's not dirt, it's just a rough spot on the surface. Really weird looking.

I got less of these blotches as the temp increased, up to the point where they were really frosty and not filled out well on the edges. Lower casting temps showed more of these inclusions, which makes me wonder if it's zinc?

I'm fluxing with sawdust, and like I said, it's been working great with wheel weights.

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Originally Posted by yondering

Guys, could this be zinc contamination?

I got less of these blotches as the temp increased, up to the point where they were really frosty and not filled out well on the edges. Lower casting temps showed more of these inclusions, which makes me wonder if it's zinc?

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I'd say no. Fill out is too good. That plus the fact that the only defects, besides the oxidation of the tin, are at the base says no zinc to me.

A little better venting and this would not have been seen.

You get a touch of zinc and you start crying right from the first cast. You never get good bullets at reasonable temps. Reasonable defined as 800 degrees or less. You need 200 degrees over the melt temp for any mix and that is simply hard to get with zinc in commercial pots.

If I had to guess on your mix, sounds to me more like copper.

When you flux with wax & stir it back in, you still get some dross left on top. After fluxing the dross should be darker, dry & almost lite n fluffy. Before fluxing the dross was probably a goopy gray mess. spoon the dry dross powder off the top of the pot after fluxing & dispose of it properly. Then your pot should be ready to use.

You can not leave 1/4" of wax on top of the melt. As you have noticed, it will go up in flames. if you are using something like Marvelux on top, that can stay to prevent oxidation of the top layer & that will slow the degradation of the pot mix.

Also, make sure that anything you stick into the liquid lead is COMPLETELY DRY. Things like wooden sticks can sometimes pick up a little moisture & if you push moisture below the surface of liquid lead you will get a nasty little explosion of hot metal all around you. If you are in doubt about something being dry, let it sit on top of the melt for a little while & heat up. That will drive off any moisture.

I second that it's not zinc. I third that you need a little hotter mould and a bigger sprue puddle so that the puddle doesn't freeze for a goodly time so that any caverns inside the boolit can fill by drawing from the sprue puddle (puddles are liquid) before they freeze.

The ugly spots are inclusions of oxides. They form on the sides of the pot and work their way out as has been said here previously. Don't skim your pot. The crud keeps oxygen off of the metal. Add a layer of crushed charcoal to it to complete the sealing of the surface. The charcoal will donate carbon atoms which will reduce the oxides on the surface of the metal when you stir your melt WITH A STICK (I like dowels). It will also keep oxides from forming while you cast.

If you can abide being a little extreme, get a second pot that you can melt your alloy for replenishing your main pot, and also your sprues and dri/oppings in. Oxides form when metal is melted, and dropping lumps of lead into a melted pool is probly the most effective way to make oxides (so don't drop them in yer main pot?). It really helps if you can just pour this secondary pot into your main pot. This takes some planning to get the right setup, but it is worth the effrt.

My 2¢, the divots in the bases are the result of cutting the sprue too quickly. The alloy is still in a crystalline state.

Wait longer to cut the sprue or have a damp pad handy to touch the sprue plate to momentarily to speed up cooling.

Go here http://ktsammo.250x.com/castboolits/cst1.html Good info on how to use the damp pad for cooling the sprue and sprue plate.

IMO and experience, mould and alloy too cool, raise the heat, frosted bullets are not a detriment, OMMV.

MeestaSparkle,
This is a very informative thread you have going here.
I have been running into the same coloring as you the last few days.
Lots of good advice here.
Thanks,
Larry

Those voids in the base are caused by too much pressure from your bottom pour. When the pot is full, you have to reduce the flow, then when it's down about half way, increase it again. This is very typical of a Lee bottom pour, I see it all the time.

with my lee i put a piece of thick wire under the lift bracket to slow down the flow.
for the long skinnies, 7mm.
the same boolit design in 30 likes more speed right in the hole........go figure.
and the best way for vent lines i have found is a razor blade and a light hand.