Advice on troubleshooting Cast Boolits

[pdgoutdoors]

Hi all,

I’m an experienced reloader, but just started casting about a month ago. I have spent countless hours reading on this forum and the information has been invaluable. I have been able to troubleshoot most of the problems I have come across so far, but there are two Boolit imperfections that I just can’t figure out.

First, on the base of my Boolits where I cut the sprue, sometimes I get a nice smooth bottom and sometimes it sucks into the Boolits a little bit. I have tried changing sprue plate tightness, heat (I finally got temp control down), and pour height. The image below shows what I’m trying to explain. Is that a big deal or is it acceptable?

Second, I am sometimes getting rounded driving bands and crimp grooves. I am getting them from the same cavities that will cast a perfect boolit the pour before and pour after. This particular one is an MP 454640. The mould was cleaned correctly when I got it and heat cycled before use.

Thanks in advance for any knowledge bombs about to be dropped.

https://uploads.tapatalk-cdn.com/20231202/c4b5bd136cd915b2cbec3bfd4209e20b.jpg

[pdgoutdoors]

320507

[Dusty Bannister]

That is a shrinkage void. Sometimes resulting from a small sprue puddle, or sprue plate chilling the puddle right at the smallest point of the cone of the sprue hole. Knowing if you are casting in an unheated area, or an excessive draft might be a consideration. Bottom pour pots can lose heat as the stream falls from the nozzle to the sprue plate. Loss of heat during the pour can also result in fill out issues as well. Identifying your alloy and casting temperature are always a good idea.

[jsizemore]

Got any close pics of the mold block top and the upper mold faces? Could be a venting thing. Bullet base doesn't look round but your sprue cut looks good. Looks like the last air isn't making it out as the cavity fills.

You'll find the right alloy temp that fills out but isn't so high that it will start plugging the vent grooves cut into the face of the mold. Rate of pour also affects it. You have to find the balance of alloy temp, mold temp, rate of pour and venting. It isn't like everything has to be an exact amount but there is a band where everything works with minor variations. 2 seconds change from pour to cut can make all the difference in irregular fillout and just right. Experience will teach you as long as your paying attention.

[charlie b]

Since you are also getting some with rounding then I'd say the mold is a bit too cold and/or the pot temp is too low.

[pdgoutdoors]

Got any close pics of the mold block top and the upper mold faces? Could be a venting thing. Bullet base doesn't look round but your sprue cut looks good. Looks like the last air isn't making it out as the cavity fills.

You'll find the right alloy temp that fills out but isn't so high that it will start plugging the vent grooves cut into the face of the mold. Rate of pour also affects it. You have to find the balance of alloy temp, mold temp, rate of pour and venting. It isn't like everything has to be an exact amount but there is a band where everything works with minor variations. 2 seconds change from pour to cut can make all the difference in irregular fillout and just right. Experience will teach you as long as your paying attention.

I’ll snap a pic when I get home for you. Are the way the bases are now a big deal, or will they shoot just fine?


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[MostlyLeverGuns]

Mostly they shoot fine, depends on range and your accuracy requirements. Might start to notice accuracy issues past 100 yards.

[JonB_in_Glencoe]

Premature sprue puddle freezing.
Pour larger sprue puddle or keep sprue plate hotter.
When you are pouring alloy, think of it like pouring Heat.
Also, you want the sprue puddle molten as the boolit freezes ...as the boolit freezes it will shrink a bit, but if there is molten alloy in the sprue puddle, the boolit will pull that alloy into the cavity ...avoiding the shrinkage you are seeing.

[jsizemore]

Run them through the sizer and you can't tell the difference. You start shooting at the 200 yard line you'll need to hold the middle.

[WRideout]

That is a shrinkage void. Sometimes resulting from a small sprue puddle, or sprue plate chilling the puddle right at the smallest point of the cone of the sprue hole. Knowing if you are casting in an unheated area, or an excessive draft might be a consideration. Bottom pour pots can lose heat as the stream falls from the nozzle to the sprue plate. Loss of heat during the pour can also result in fill out issues as well. Identifying your alloy and casting temperature are always a good idea.

I agree. You didn't say how you are casting. It would help to know if you are casting with a spoon out of a dipper pot, or using a bottom pour pot of some description. Also, it would be good to know what your alloy is. A little tin added will often clear up the incomplete fill problems.

Also, which mold you are using. IME, aluminum molds like to run fairly hot, as compared to steel.

I was having a lot of trouble such as you mentioned, however I acquired a Lyman spout type dipper, and that cleared up most of my difficulties.

Wayne

[pdgoutdoors]

I agree. You didn't say how you are casting. It would help to know if you are casting with a spoon out of a dipper pot, or using a bottom pour pot of some description. Also, it would be good to know what your alloy is. A little tin added will often clear up the incomplete fill problems.

Also, which mold you are using. IME, aluminum molds like to run fairly hot, as compared to steel.

I was having a lot of trouble such as you mentioned, however I acquired a Lyman spout type dipper, and that cleared up most of my difficulties.

Wayne

I am using a MP brass mould poured out of a Lee 4-20 bottom pour. I’m just using straight up range scrap right now while I learn. I don’t have any access to tin and I collected about 50lbs of range lead before I started learning.


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[frkelly74]

My philosophy on range lead. " It worked once, it will probably work just fine again." Tin can be had from Pewter which may be found at thrift stores or yard sales, Sometimes also old rolls of solder. You really do not need much tin if you are using reclaimed boolits, there is probably tin in there already. If you render your lead from jacketed bullets you might get some benefit in better fill out with some small amount of tin/pewter/solder added. I think of casting more as an art than a science.

[Winger Ed.]

Welcome aboard.

Good advice above.
Range scrap is usually pretty good if a lot of it comes from a pistol range where folks are shooting
cast boolits. Especially if there is a lot of the harder commercially cast ones in the mix.
The Lead melted out of jackets is usually pure or real close to it.

To avoid rounded edges, I run the heat up until I get just a hint of frosting.
To improve the fill out if that doesn't quite work, I'll add just enough 94/5 solder until it flows better.
Any place that sells Pluming stuff will have it.
The down side is the price has gone up so much, it's higher than giraffe lips now days.

Another thing that may help is get a few ingots of the hard alloys from one of the seller/sponsors here.
For handguns, the alloy can be rather soft, with just enough 'goodies' in it to get a good flow/fill out.

There is a learning curve to casting, and you'll get it figured out pretty soon as to what temps. work,
and you establish a rhythm to your heat, mold fill, & drop timing.

[Shopdog]

Keep notes;

Dosen't need to be a "novel"... just a few lines on temps,alloys,pour rates,etc. Cpl reasons,there can be gaps in your time at the casting bench and,as you get more moulds it's just nice to look back at the notes.

Good luck with your project.

[Minerat]

I started having rounded edges on the base and found if I "break" the top edge of the mold with a small 45° angle on both sides it vents and gives me a flat base. I use a triangular stone for this before I break in the mold. I also found that when using a bottom pour pot that the wider I have it open, the larger the puddle and counting to 5 after it frosts helped stop the cavity in your photo. Also, at the ranges I shoot with my big bore pistols it did not affect my accuracy. On the other hand if the cavity really mattered why are there hollow based boolits or for that matter beveled bases.

For me if the handgun goes bang, that's the fun, I'm not good enough with one to worry about accuracy better than pie plate at 25 yards.

[wv109323]

My .0 2 cents. The sprue plate will cool quicker than the brass mold body. Cast as fast as you can to keep the sprue plate hot. Slow down when you start to get frosted boolits. I preheat the sprue plate as well as the mold on a separate hot plate.
Get the lead into the mold as quick as you can. Hold the mold where the stream of lead goes directly into the sprue plate hole. adjust the mold till there is minimal distance between pot and mold.
Pour a liberal sprue to allow for shrinkage.
Make sure the mold vent lines are open.
Insure your lead is back up to your casting temp. after lead is added to refill the pot. This was one of my pitfalls until I started using a PID. The recovery rime was much more than I realized.
Cast with a full pot of lead. Lead will get into the mold much quicker when the pot is full.
Weigh your best and worst boolits to see how much weight variation there is between the two. Plus or minuses 2 per cent will not hurt accuracy.
Bad boolits will look much better after sizing.
Your sprues look acceptable.

[Bazoo]

That pic is a pulled sprue. It's main cause us from cutting the sprue just a touch too soon. If you wait about 5 seconds longer it won't do that.

Getting the occasional rounded bands/base is likely from allowing the sprue puddle to flow into the adjacent cavity or off the side of the mould cavity. The metal that's flowing away from the cavity you're trying to fill keeps the weight of the molten lead from pushing downward into the cavity to fill out the bullet completely. A larger sprue puddle works better than a small one, in part, because the weight of the molten metal is pushing on the liquid metal in the cavity, causing better fill out. An alloy that this rich in tin has a lower surface tension, and doesn't do this as badly. Fluxing with beeswax also helps lower the surface tension for a short while, until the beeswax is burnt up.

[uscra112]

Premature sprue puddle freezing.
Pour larger sprue puddle or keep sprue plate hotter.
When you are pouring alloy, think of it like pouring Heat.
Also, you want the sprue puddle molten as the boolit freezes ...as the boolit freezes it will shrink a bit, but if there is molten alloy in the sprue puddle, the boolit will pull that alloy into the cavity ...avoiding the shrinkage you are seeing.
This ^^^^^

Charlie Dell taught me to forget the Harry Pope business about holding the spout to the sprue plate until you take it away. Let some molten lead run over the plate to keep it hot. Only way I can get good yield when casting my 60 grain .25 caliber bullets.

Second issue - my guess is that when you get rounded bases and lands you've delayed too long between pours, and the mould cooled off. Aluminum moulds are especially susceptible to this. Keep your rhythm going, and again, keep the sprue plate hot.

[waksupi]

The BruceB method of curing torn bases, is to have a wet sponge to touch the sprue to once it has started to frost. It increases production considerably. I use a can lid with the sponge, and water in the bottom of the lid. Add water as needed.

[rintinglen]

That pic is a pulled sprue. It's main cause us from cutting the sprue just a touch too soon. If you wait about 5 seconds longer it won't do that.

Getting the occasional rounded bands/base is likely from allowing the sprue puddle to flow into the adjacent cavity or off the side of the mould cavity. The metal that's flowing away from the cavity you're trying to fill keeps the weight of the molten lead from pushing downward into the cavity to fill out the bullet completely. A larger sprue puddle works better than a small one, in part, because the weight of the molten metal is pushing on the liquid metal in the cavity, causing better fill out. An alloy that this rich in tin has a lower surface tension, and doesn't do this as badly. Fluxing with beeswax also helps lower the surface tension for a short while, until the beeswax is burnt up.

+1. those pesky divots occur because you are cutting the sprue before it has fully frozen, so some of the granules of lead that are frozen, are ripped out from the ones that aren't quite there yet. Another second or two before cutting and you'll have a nice smooth base--that won't shoot very much, if any, better. A big sprue puddle and 1-2% tin will help prevent rounded corners.

[Forrest r]

Better too long (humps) than too short and tears like in your post.

Some time a mold just doesn't want to perform (heat/alloy/sprue cooling cadence). I always like to (any mold maker) leave the sprue loose and let the chips fall where they may when casting. I get the mold hot and let the sprue puddle harden (low shrinkage). Then I cut the sprue's and run the sprue plate back and forth cutting the base of the bullet even (no rise).

Molds with thick/heavy sprue plates don't have this problem when up to temp.

A picture of the bullet bases of a lee 6-cavity mold. I cast/run everything so that the bullet base has a extension that gets cut off with multiple passes of the sprue plate.
https://i.imgur.com/tM5PTMh.jpg

But this brings up when the basses are cut/flat correctly, other issues show up. Namely not enough fill out and off center holes/sprue cuts from the molds being cut and a generic sprue plate being attached to that mold. 1 out of 6 cavities hold true to the center of the mold/sprue hole alignment.

[dondiego]

When I cast with a 6 cavity LEE as above, my sprue is one long piece and my bases are filled out real well

[openbook]

That pic is a pulled sprue. It's main cause us from cutting the sprue just a touch too soon. If you wait about 5 seconds longer it won't do that.

+2. I get these when casting heavy 45-cal bullets in an aluminum mold. If I start working with a second mold, and let the large 45-cal bullets cool in the mold for a bit, I get bases that look like glass. For me it takes longer than 5 extra seconds.

[danmat]

Lots of good advice here.
I find when having most any mold problem,
Raise temp. to almost frosting or frosting
add a little solder
heavy sprue plate puddle
hot enough it takes 3 or 4 seconds for puddle to freeze
this usally solves most any problems.
Dan

[Soundguy]

to get rid of shrink voids.. overpour the sprue... to get sharp grooves.. make sure the mold is properly warmed.. the mix is above the minimum melt temperature.. and if those are good.. are you running any tin? adding tin helps with surface tension.. too much isn't needed and while tin will harden some.. it works best in a tin lead antimony alloy.. but sometimes clip on weights with little to no tin is helped by addition of .5-2.5% tin. add and re check.. etc. sometimes scrap linotype can be dropped into unsweetened pots to soup it up...

[justindad]

The BruceB method of curing torn bases, is to have a wet sponge to touch the sprue to once it has started to frost. It increases production considerably. I use a can lid with the sponge, and water in the bottom of the lid. Add water as needed.

I’m going to try this. What do you do so you’re not cooling the sprue plate too much? I usually cast in my shed at night, where it is cold and drafty. Cold sprue plates are my weakness right now.

[Kosh75287]

This probably isn't the most surgical response to your difficulties, but you'd be surprised at how many problems can be alleviated by a slightly elevated percentage of tin in the mix.
At one time, I had 25-30 pounds of 63:37 Sn/Pb solder, some of which I cast into bullets of various configurations (158 gr. or 230 gr.). When I had trouble with sprue cuts or (especially) fill-out, I'd add 5-10 of the solder bullets to the melt along with the bullets that didn't cast well, mix thoroughly and retry, usually with good results.
I suppose it's laziness, but I've got to the point that I don't cast anything without at least 2.5-3.0% tin in it, along with about 2.0% antimony. Waiting a few more seconds before moving the sprue plate should also help. Since I tend to water quench my cast bullets right out of the molds, I'm inclined to wonder if the bullets' cooler temperature when it hits the water might reduce the hardness I seek.

[pdgoutdoors]

Tons of great advice in here, I appreciate everyones responses. I haven't had a chance to cast any more since then, but next time I will wait longer on the sprue cut and try adding some tin in a hotter mould. Thanks again for all of the advice!

[405grain]

I second Kosh75287's recommendation regarding the tin content. An alloy that has is starved for tin will be brittle. Even a very small addition of tin will make the alloy more ductile, and less prone to tear outs. Also, the tin makes the mold fill out better, so no more rounded edges. All the other advise regarding mold/sprue plate temperatures and waiting to cut the sprue are very good. If those suggestions don't cure your problem, then try adding a small amount of additional tin into your mix.

[Land Owner]

Late to the Party, but not absent...

Welcome to the World of Cast Boolits. You are doing GREAT!! First and foremost, have Fun at the casting bench! This is NOT Rocket Science, although that rabbit and its hole are here for you to chase – as you wish.

Your alloy is an unknown - straight up range scrap
Your cast “looks” fine from a good brass mold - MP 454640

Shoot some to be certain! You may be well pleased! Even boolits of less than perfect fill-out are known to shoot to point of aim (at across-the-room distance) and you are currently casting for Learning Curve as well as plinking. Accuracy right out of the gate in a supply-poor economy will still require practice and patience as the whole process gets better. Have FUN!

Mold-line fill out will be aided at first by keeping the spru-plate HOT across every hole and the addition of Tin (by how much?). Scrounge for Tin (pewter) at Flea Markets, Thrift Stores, consignment shops, and garage sales. Enlist wives, church members, other casual shoppers to keep you in mind as they forage the world of thrift. Tin is a commodity at $10/pound. Keeping your “average cost” below that threshold, well below, is a fun factor of casting.

When your are ready, and that is probably now by the way you have researched and are asking, purchase (at below $1/lb), or scrounge from a tire shop, some lead stick-on wheel weights (SOWW), some clip-on wheel weights (COWW), segregate the zinc and steel WW and steel clips (won’t melt at lead melt temp), and with the Tin scrounged above, decide on a lead-alloy recipe.

EX: 49-49-2 percent Pb-WW-Sn (recommended for handgun velocity by Fryxell).

To components melted in quantities of (say) 100#’s (i.e. equal amounts of COWW’s plus SOWW or lead plus COWW’s), cast into molded 50-50 ingots at 2-3#’s each, add specific weights of Tin, cast as solid boolits or “thin ingots” to achieve your alloy percentages.

Don’t sweat the small stuff, and it is all small stuff. Have FUN! Good luck scrounging.

[Edward429451]

Late to the Party, but not absent...

Welcome to the World of Cast Boolits. You are doing GREAT!! First and foremost, have Fun at the casting bench! This is NOT Rocket Science, although that rabbit and its hole are here for you to chase – as you wish.

Your alloy is an unknown - straight up range scrap
Your cast “looks” fine from a good brass mold - MP 454640

Shoot some to be certain! You may be well pleased! Even boolits of less than perfect fill-out are known to shoot to point of aim (at across-the-room distance) and you are currently casting for Learning Curve as well as plinking. Accuracy right out of the gate in a supply-poor economy will still require practice and patience as the whole process gets better. Have FUN!

Mold-line fill out will be aided at first by keeping the spru-plate HOT across every hole and the addition of Tin (by how much?). Scrounge for Tin (pewter) at Flea Markets, Thrift Stores, consignment shops, and garage sales. Enlist wives, church members, other casual shoppers to keep you in mind as they forage the world of thrift. Tin is a commodity at $10/pound. Keeping your “average cost” below that threshold, well below, is a fun factor of casting.

When your are ready, and that is probably now by the way you have researched and are asking, purchase (at below $1/lb), or scrounge from a tire shop, some lead stick-on wheel weights (SOWW), some clip-on wheel weights (COWW), segregate the zinc and steel WW and steel clips (won’t melt at lead melt temp), and with the Tin scrounged above, decide on a lead-alloy recipe.

EX: 49-49-2 percent Pb-WW-Sn (recommended for handgun velocity by Fryxell).

To components melted in quantities of (say) 100#’s (i.e. equal amounts of COWW’s plus SOWW or lead plus COWW’s), cast into molded 50-50 ingots at 2-3#’s each, add specific weights of Tin, cast as solid boolits or “thin ingots” to achieve your alloy percentages.

Don’t sweat the small stuff, and it is all small stuff. Have FUN! Good luck scrounging.

I've been using one arm length of solder ike it used for soldering copper pipes. They fill out good and are not brittle.

[brokeasajoke]

When you guys say get the temperature up is there a range in which you cast in? My lee pot on setting 9 gets temp just over 700 on a cool day in the 40s.

[mehavey]

Lyman #2: 700 degrees
Pure Lead/30-1: 800 degrees

(All this presupposes preheated/up-to-temp mould as well.)
:drinks:

[brokeasajoke]

When you guys say get the temperature up is there a range in which you cast in? My lee pot on setting 9 gets temp just over 700 on a cool day in the 40s.

With advice from Dusty Bannister I may not be keeping my pot full enough and the lead is not fully contacting the portion of the pot with the heating element so maybe that's something other newbies can be aware of

[Dusty Bannister]

May want to test that theory first. Sometimes the melt actually can get too hot as you get below half full. Since it is colder weather, the heat transfer needs to be sufficient to keep the alloy at a working temp. You will know for sure the next time you top off the pot. That said, I also will suggest that you drain the pot to about half full when you shut down. The cold pot will melt from the heating element and the hot metal expands. If you have a full pot of lino, you will have a spurt of molten alloy once the pressure builds up enough, or it will lift the valve off the seat and drain the molten alloy from the pot. Use a sufficiently large catch pan and keep an eye on things as you bring the pot up to temp. If it can happen, it will, eventually. Stay safe.

[ACC]

Hi all,

I’m an experienced reloader, but just started casting about a month ago. I have spent countless hours reading on this forum and the information has been invaluable. I have been able to troubleshoot most of the problems I have come across so far, but there are two Boolit imperfections that I just can’t figure out.

First, on the base of my Boolits where I cut the sprue, sometimes I get a nice smooth bottom and sometimes it sucks into the Boolits a little bit. I have tried changing sprue plate tightness, heat (I finally got temp control down), and pour height. The image below shows what I’m trying to explain. Is that a big deal or is it acceptable?

Second, I am sometimes getting rounded driving bands and crimp grooves. I am getting them from the same cavities that will cast a perfect boolit the pour before and pour after. This particular one is an MP 454640. The mould was cleaned correctly when I got it and heat cycled before use.

Thanks in advance for any knowledge bombs about to be dropped.

https://uploads.tapatalk-cdn.com/20231202/c4b5bd136cd915b2cbec3bfd4209e20b.jpg

That is from not letting the lead cool before cutting the sprue. Either turn the heat down, not recommended, or slow your casting.

ACC

[vrod1023]

Better too long (humps) than too short and tears like in your post.

Some time a mold just doesn't want to perform (heat/alloy/sprue cooling cadence). I always like to (any mold maker) leave the sprue loose and let the chips fall where they may when casting. I get the mold hot and let the sprue puddle harden (low shrinkage). Then I cut the sprue's and run the sprue plate back and forth cutting the base of the bullet even (no rise).

Molds with thick/heavy sprue plates don't have this problem when up to temp.

A picture of the bullet bases of a lee 6-cavity mold. I cast/run everything so that the bullet base has a extension that gets cut off with multiple passes of the sprue plate.
https://i.imgur.com/tM5PTMh.jpg

But this brings up when the basses are cut/flat correctly, other issues show up. Namely not enough fill out and off center holes/sprue cuts from the molds being cut and a generic sprue plate being attached to that mold. 1 out of 6 cavities hold true to the center of the mold/sprue hole alignment.I read this with great interest since I've also experienced those divots in my bullets. I'm a new caster. As an aside I was wondering how you got such concentric sprue puddles. Said differently was there a big interval between pouring the first and 6th cavity?

Sent from my SM-A505F using Tapatalk

[Edward429451]

I read this with great interest since I've also experienced those divots in my bullets. I'm a new caster. As an aside I was wondering how you got such concentric sprue puddles. Said differently was there a big interval between pouring the first and 6th cavity?

Sent from my SM-A505F using Tapatalk

I've beeb casting quite awhile and from the looks of those rounded bases and sprues, I'd say, pour a more generous sprue because it cools down it draws more metal down from the sprue which helps it fill out better. If it's still having problems you might need to bump up the heat a little?

Good cast bullets are all about the pour temperature. I use a K-type thermocouple with a SS probe to keep carful track of the temp and plug it right into my multi-meter. . It gets hotter as the pot gets lower. You generally want to cast the boolits at the same temperature. One that barely is hot enough for the melt to flow good. It differs a bit with different alloys so keep track of what you cast and at what temp.

Dont be tossing sprues back into the pot willy nilly because that lowers the pot temp. When you cast at different temperatures then the as cast weight is all over the place!

[Dusty Bannister]

Looking at the illustration in post #37, I can see that the sprue puddle of each individual cavity is perhaps too small to remain fluid long enough to feed molten alloy into the cavity as the alloy cools and shrinks. You might find the divots to be less of an issue if you "connect the dots" to form one sprue that is hot and helps keep the plate hot enough to not cool the sprue as quickly.