Getting large molds to properly fill out. Tips?

[Hanzy4200]

Having a bit of trouble getting proper fill out on a 500 gr Accurate mold for my .500 Linebaugh. I know the issue is not the mold, as Accurate molds are superb. I have run it hot, and bumped tin content way up. No improvement. Bullets are shootable, but not what they should be. Lots of wrinkle around/between lube grooves. Mold way sprayed out with brake cleaner, had some wrinkles, then cooled and scrubbed with Dawn and a toothbrush. Still no change. I have never used a mold over 240 gr, so maybe I'm missing something. On another note, boy does this thing overheat fast!

[Winger Ed.]

Raise the heat. In the alloy and the mold itself both.
If you're casting something soft, add a little bump of tin the thin it out and improve the flow/fill out..

To speed things along, (with a old bottom pour RCBS) I start out too hot.
When I get solid frosting or 'fins', then I start easing back on the heat until they come out with just a small, little bit of frosting.

[cwlongshot]

Yup. Heat. Ya need more and blast it out with brake cleaner too.

[JonB_in_Glencoe]

Cast faster, mold needs more heat.

[lar45]

You might try smoking the cavities lightly.
When I pour big bullets, I like the mold and lead to be Hot, I also like to pour faster and put a big puddle on the sprue to get nice sharp corners.
If you're getting small wrinkles on the sides of the bullets, it could be that the lead is going in too slowly and it's starting to setup?
I've cast 700 gn 500 S&W bullets with this method without any trouble.
Once the mold gets up to temp, you might have to leave the bullets in the cavities for a few more seconds. I've had them bend from dropping too hot into a bucket of water.

[TNsailorman]

Someone on this site gave me a suggestion to try many years ago on the .43 Spanish Lyman die that I was having trouble getting the base to completely fill out. "Try drilling out the filler hole 1/16th size larger than it is now". I was frustrated as the devil so I decided to try it. I haven't had any problems since with that mold. I had already tried a higher temp on the lead and it did help but did not completely solve the problem. Worked for me, your mileage might vary. james

[Mk42gunner]

Ladle or bottom pour? I have had better luck filling large cavities with my bone stock RCBS lead ladle than I have with a bottom pour furnace.

Robert

[DonHowe]

Having a bit of trouble getting proper fill out on a 500 gr Accurate mold for my .500 Linebaugh. I know the issue is not the mold, as Accurate molds are superb. I have run it hot, and bumped tin content way up. No improvement. Bullets are shootable, but not what they should be. Lots of wrinkle around/between lube grooves. Mold way sprayed out with brake cleaner, had some wrinkles, then cooled and scrubbed with Dawn and a toothbrush. Still no change. I have never used a mold over 240 gr, so maybe I'm missing something. On another note, boy does this thing overheat fast!
You do not say how you are pouring, bottom pour, etc. When I shot .45-70 in BPCR Silhouette either 500 and 530 gr bullets I preferred ladle casting. The molds were custom iron single cavity. I had better results after enlarging the pour hole in the ladle I also pressure cast by holding the mold sideways, bringing the ladle to the sprue hole them rotating both vertically together. Alloy was 30-1 ant temp at 750°F +/- and mold temp controlled by cadence.
My partner/spotter got equal or better results with a bottom pour pot but I have not had a pot that I could control the speed of filling the mold as easily as with the drilled-out ladle.

[samari46]

Get one of the small electric hot plates and a piece of steel to cover the heating element. You'll find that when your mold is up to slightly less than casting temp the mold will respond better. And I have used the old trick of opening the sprue plate holes and casting ladle to work as well. Only do one thing at a time to lessen the variables. Frank

[guy_with_boolits]

as others have said, HEAT

but its all guessing until you can measure it..get a SMALL thermocouple or other temperature probe that will let you measure both the lead temperature and the mold temperature so you know whats what

[earlmck]

1) Wrinkles -- everybody else on castboolits can swoosh off their new mold with brake cleaner/wash with hot water 'n dawn and be throwing perfect boolits within 3 shakes. My molds get the same treatment and I still have to cast a couple hundred boolits before they quit giving me wrinkles. Maybe you are related to me instead of all the other casters out there.

2) Base fill-out -- until I have cast a few jillion boolits with the mold I gotta' give it full contact to get good fill-out of the big boolits (I'm a bottom-fill guy). That's after adjusting the flow so it isn't too ridiculous.

[Land Owner]

Aluminum, brass, or iron mold? Alloy? 1, 2, or 3 cavity? Individual spru holes or spru hole trough?

Go to this Sticky, "From Ingot to Target". Download the PDF, or on-line, open to page 67 - Heating the Sprue Plate. Part of your problem lies here.

https://castboolits.gunloads.com/showthread.php?110212-From-Ingot-to-Target-A-Cast-Bullet-Guide-for-Handgunners.

[Four-Sixty]

A trick that worked for me was to warm the mold up to casting temperature, then clean out the cavities with denatured alcohol on a q-tip. I would warm the mold for another couple of minutes then clean the cavities with denatured alcohol and a q-tip again. This solved the problem of persistent wrinkles on a 300+ grain 44 cal mold that was new and prepped with brake cleaner. Before the first and second cleaning I actually saw a slight white residue in the cavities. I suspect this was some component of the brake cleaner that was trapped in the pores. Each cleaning markedly reduce wrinkling. Many here swear by brake cleaner, I won't use it anymore. I suspect that perhaps grain structure, or orientation of the metal's pores just make brake cleaner less than ideal sometimes.

[farmerjim]

Try pressure casting. Several of my molds will not fill out unless I pressure cast them. Also make large puddles of lead on top of the sprue plate to add more heat.

[Cap'n Morgan]

Wrinkles are usually a sign of the mold or lead being too cold. Tiny dimples indicates the cavities are "contaminated" with stuff (often oil) which gasses off when heated. Partly filled grease grooves (rounded edges) can both be a temperature or a venting problem. A partly rounded base is almost every time a sign of trapped air, as this is where the air ends up when the mold is filled.

My pet theory is that venting the top of the mold is the most important part of casting large boolits. The suggestion of enlarging the sprue hole works well, not because the lead fills faster, but because the air has room beside the lead-flow to escape. Once I started cutting venting grooves on top of my molds they behaved much better - especially when pressure casting, where the nozzle blocks the sprue hole during most of the fill.

It's easy to overlook the physics of the invisible air in the mold cavities, but try squeezing bubble wrap, and suddenly the concept of air taking up space becomes tangible.

[GregLaROCHE]

As others have already mentioned, increase the temperature of alloy and make sure mold is hot too. It’s important to have the lead flowing as fast as you can keep up with it. I cast nice 500 grain, 45 cal. boolits in an aluminum mold from Lee. Bottom pour, no hot plate or thermometer. Some molds I find just need time to get broken in.

[Hanzy4200]

It's a aluminum 2 cavity and I am using a bottom pour. The pressure casting is a good idea, I've not tried that. The issue with adding heat is that the mold is already over heating within 4-5 casts at the current settings. At that point bullets are getting extremely frosted.

[GregLaROCHE]

If your Boolits are extremely frosted, the alloy is too hot. Lower the temperature of the alloy and your mold won’t heat up so fast either. Big boolits do heat up a mold faster than small ones. You can cool down a mold while casting by touching the the bottom onto a damp cloth.

[Targa]

As Mr. LaRoche pointed out above, a damp cloth or a sponge. When I cast 400 grain bullets I have my alloy around 800 degrees, every third cast or so the mold gets pressed into that wet sponge to cool it down.

[Larry Gibson]

It's a aluminum 2 cavity and I am using a bottom pour. The pressure casting is a good idea, I've not tried that. The issue with adding heat is that the mold is already over heating within 4-5 casts at the current settings. At that point bullets are getting extremely frosted.

Obviously more heat is not the real answer. The answer is to get the alloy into the mould faster before it cools and starts solidifying. Alloy cools much faster that we thin. As mentioned, using a ladle is probably the real answer. Long ago I discovered the ladle with large bullets [I usually go from the bottom pour to the ladle when the bullet is 325 to 350 gr or more] is the answer as I was casting excellent 400 and 500 gr bullets with the ladle but when I got the bottom pour the bullets came out just as you describe them. Switching back to the ladle and the bullets were excellent again. On the old original Lyman ladle I've even drilled the hole out larger to get the alloy into the cavity quicker. With the new style Lyman and RCBS ladles the hole is large enough. I use the ladle casting technique as described in older Lyman manuals up through CBH #3.

However, After my old Lyman 10 lb furnace gave up the ghost and I got a Mag20 I found with the spout adjustment opened up I can cast excellent 400 gr 45-70 bullets [16-1 alloy]. I keep the alloy temp at 710 - 725 degrees and have the sprue plate not more than 1/2" from the spout when pouring. I also pour so the alloy roils back up out of the cavity forming a goo large sprue , even if alloy runs off the srue plate. I have the ingot mould underneath to catch the run off.

[country gent]

Flow is the key to casting big long bullets. You need to get the alloy in the mold before it starts to solidify. I cast alot of long heavy bullets, in the 1.125- 1.300 range from 38 cal to 45 caliber. Watch our sprue puddle it should take 4-6 secs to "frost" over.

I cast these bullets with a ladle. Lyman or rcbs both have spouts opened to .205 dia from just under 3/16" much faster pour and better delivery. This modification greatly improved my results, with out raising temps or tin content.

I believe it is more a result of bullet length than weight causing this. As the longer bullets start to cool sooner in the pour than the shorter ones, and the heat is less localized in the blocks.

One difference in industry casting is those casting machines have a shot tube on them thats filled with the molten metal, then it pushes the material in under pressure filling the mould almost instantly, an option we dont have. The 'shot" goes in under several hundred psi and is held for a set time. This makes a mush better casting both in form and structure.

I would recommend opening the spout up some on the bottom pour to increase flow or a modified ladle a described above. Warm your mould up to temp and cast a fairly brisk pace adjusting pace as needed. Workin the 700*-725* range and adjust from there.

[DonHowe]

It's a aluminum 2 cavity and I am using a bottom pour. The pressure casting is a good idea, I've not tried that. The issue with adding heat is that the mold is already over heating within 4-5 casts at the current settings. At that point bullets are getting extremely frosted.

If the alloy temp is reasonable, 700 to 750 i don't the the exact temp is critical. In my experience you cannot speed cast large heavy bullets. You simply overheat the mold. It is about casting cade.nce; you simply have to give the mold tome between pours to cool enough for the next pour. I'm sure everyone has his own method, mine is to pour then do a mental count (like a digit per second) until the sprue solidifies then cut, open and drop the bullet.
I try to be as consistent as possible, cutting the sprue at the same count each cast. On a 530 grain bullet from an iron mold I might count 15 to sprue cut. If the mold seems s bit cool I'll decrease count to 14 or maybe 13. If at 15 the mold is showing signs of too much heat I increase the count until I find a happier medium. It just takes casting, being consistent and watching what the mold is doing ( what dropped bullets are like).
A 2 cavity aluminum mold for big heavy bullets can be overheated very quickly. A 2 cavity IRON mold can be overheated if casting too fast so aluminum is going to get their sooner. You need to fill the cavity fast, leave a good puddle on the sp t ue plate like Larry said then experiment with time between pours to find where happy is. It could feel like too long between pours but good bullets is the goal.

[popper]

Turn down the temp and make sure the vent lines are clean. My last mould from Tom had vent lines (IMHO) kinda in the wrong location - he uses a standard pattern. Had to smoke that one to get it to cast right. Break the top of the blocks, fine file or blade to just bevel the edge. 400F air expands >10x when heated to 750F and has to get out. If alloy cools on top of the air, you get wrinkles. If your venting is proper you want fast fill rate. Small sprue hole or nozzle will restrict flow. A problem ladle casting can solve, sometimes. 'Pressure pouring' is a misnomer. It can reduce 'heat' loss going into the mold but has nothing to do with pressure. Pressure is a function of height of a column of liquid and my pot is just as tall as your ladle.

[daloper]

When I cast for my Ruger 480, I have to pour with a larger stream to get them to fill out. Open up the valve to pour faster.

[beagle]

If it's wrinkles, pressure casting should cure that. If it'd improper band fill out, the mould's too hot. This is a common occurrence with moulds with high capacity cavities. The solution there is to slow down the casting tempo and let the bullet cool. I have one mould that I have to cast, watch the sprue and when I see the sprue frost, I know it's cool enough and will make good bullets. Slows down production but unless you're making good bullets, you don't have production.
The problem is that some moulds with big cavities have too much lead capacity and the blocks are too small in surface are to dissipate the heat between casts and run hot. This will cause incomplete fill out until you slow down the casting tempo.
I have a casting table I used for a while when making 400 grain plus bullets. Had a squirrel cage fan mounted under a screen and blew upward. After I cast, I set the mould on top of the screen and waited for the sprue to frost. Improved production and my casting speed. Once in a while, a hardened drop of lead got through the 1/4" mesh into the fan and things got exciting for a couple of seconds. "Were you there when the sprue droplet hit the fan?" Anyway, that worked pretty good and these 110V fans can be salvaged from old computer chassis for free normally./beagle

[Tazman1602]

Raise the heat. In the alloy and the mold itself both.
If you're casting something soft, add a little bump of tin the thin it out and improve the flow/fill out..

To speed things along, (with a old bottom pour RCBS) I start out too hot.
When I get solid frosting or 'fins', then I start easing back on the heat until they come out with just a small, little bit of frosting.

^^^^^^^ This! Get a $10 hotplate from Walgreens or somewhere and get the mold up to HOT, really helps on all my “monsters”

[Greg S]

Try pressure pouring with a ladle.

[popper]

Try pressure pouring with a ladle. Physics says there is NO SUCH thing as PRESSURE POURING!!

[charlie b]

It's just a term people use to describe the process of pouring from a 'side spout' ladle with the spout held tight to the sprue hole or holding the sprue plate up against the spout of a bottom pour pot.

[cwlongshot]

It's a aluminum 2 cavity and I am using a bottom pour. The pressure casting is a good idea, I've not tried that. The issue with adding heat is that the mold is already over heating within 4-5 casts at the current settings. At that point bullets are getting extremely frosted.. This STILL dosnet mean that the MOLD is hot enough! Your allow may be too hot and the mold cold.

Venting has been mentioned and it is an important part of casting a proper filled bullet. BUT its generally well done on current molds.

Wrinkles are caused by the allow cooling BEFORE it flows completely. That can really ONLY happen when something is too cold.

Someone else mentioned adding a bit of tin. This helps too as tin helps the lead flow. It usually dosent talk very much but usually isnt the case with COWW as these contain enough tin.

Has this mold been seasoned? That helps too. But is NOT REQUIRED as long as your patient. Because simply using, (heating and cooling mold) is accomplished with use.

If you mold is clean of any and all oils, made within the last ten or so years, (has proper venting) I STILL tell ya the problem is temperature.

Good luck

CW

[cwlongshot]

It's just a term people use to describe the process of pouring from a 'side spout' ladle with the spout held tight to the sprue hole or holding the sprue plate up against the spout of a bottom pour pot.

YES but the ladle dosent have the "HEAD" to creat pressure as a 20# pot will.

[jim147]

I have no advice. This is the game we play. Without having your pot and your mold in my hands it's just a guess.

Keep working on it, you'll figure it out.

[JonB_in_Glencoe]

It's a aluminum 2 cavity and I am using a bottom pour. The pressure casting is a good idea, I've not tried that. The issue with adding heat is that the mold is already over heating within 4-5 casts at the current settings. At that point bullets are getting extremely frosted.

Are you getting extremely frosted boolits that are wrinkly?

[popper]

Wrinkles are caused by the allow cooling BEFORE it flows completely. Sort of. If the alloy cools enough to trap air (and it doesn't take much 'air'), the increased air pressure will 'push' a wrinkle into the soft lead. Like a drop of water causing the tinsel fairy - high pressure/velocity gas takes some alloy with it when it vents. Tin reduces surface tension of the liquidus, antimony increases it and cools faster. OP didn't say what his alloy really is. Might need some As from shot (better surface tension). Impurities in the alloy can also cause wrinkles as they outgas when 'burned'. Tom must be using a flycut method for vents (economy) and they are not always in the right place. Lube grooves create a lip for trapping air as well as the alloy needing to flow 'under' the lip. I had a terrible time with one of his moulds, GC design and the last 'band' was terrible with fillout. I 'broke' the top edge and increased flow to solve the problem. Smoke the block faces and see if that helps. The tiny spacing between the halves might help venting.

[DonHowe]

Pressure pouring/ casting is a partial misnomer as compared to the industrial scenario mentioned by Country Gent but as the term is used in this discussion it is still pressure pouring/casting. Any filling of a mold cavity as we do is to a degree pressure. What makes this so is that any time you hVe a quantity of liquid (known as a "head") above your outlet the pull of gravity on that "head" of liquid creates pressure. This is why you have water pressure at your faucet when water comes to you from a town water tower/tank. Three: things affect the amount of pressure at the outlet:
1- the amount or weight of liquid,
2 - the height from which it drops,
3 - the size of the outlet.

This is physics, hydraulics, etc. A 2lb pot has more head than a ladle because of more weight of liquid above the outlet/spout and a 20lb pot has multiple times the pressure at the spout. This is why casting changes as the alloy level in your bottom pour pot decreases. Less head =lower pressure. This is true with a casting ladle and is why you get better results when you try to fill the ladle the same each time.
What is commonly referred to as pressure casting, as I have said, involves pressure but maybe is as much more direct fill and imitating the effects of sir in filling the cavity.

[Cap'n Morgan]

The pressure is determined by height and density (weight) of the fluid - volume doesn't matter as long as the height is the same. The amount of pressure is linear and doubles when the height doubles, meaning that a 5" lead-column in a bottom pour pot will deliver 5x the pressure compared to a ladle holding one inch of molten lead.

[Char-Gar]

Take a drill and enlarge the spru hole to get the hot metal in there fast. That will cure the problem.

[cwlongshot]

Take a drill and enlarge the spru hole to get the hot metal in there fast. That will cure the problem.


This is just not a real option for me. The larger the hole the harder it is to cut this effects wear and tear on the mold.

Use this as last resort or order new spure and drill away. I really feel collectively we have solved the probelm if you can apply our suggestions.

CW

[Multra]

Ladle cast, you get much nicer bullets. I used to do the bottom pour, but as you are discovering the large bullets don't turn out well, I switched to full time ladle casting.

[DonHowe]

Try pressure pouring with a ladle. Physics says there is NO SUCH thing as PRESSURE POURING!!

Believe or disbelieve what you will. Pouring melted alloy from a ladle does not create MUCH pressure not does a 20# pot but pressure is created. It is the force of gravity acting on the wdight of liquid alloy forcing it through the bottom orifice that creates the pressure. If the weight of alloy is known the pressure or force may be calculated.
I will agree that in this case the term "pressure casting" is at least partly misnomer as pressure is only part of what is in play. Speed of fill particularly with a drilled ladle spout but there is also the heat of the ladle or pot of alloy in contact with the mold. Then top it off with a fat puddle of metal onn top of the sprue plate and you're giving a big cavity the best chance at filling properly.

[robg]

run hot and fast,sometimes it helps to let the lead swirl into the mold rather than directly in.

[Char-Gar]

This is just not a real option for me. The larger the hole the harder it is to cut this effects wear and tear on the mold.

Use this as last resort or order new spure and drill away. I really feel collectively we have solved the probelm if you can apply our suggestions.

CW

I have opened up the spru hole on every 45 cal rifle mold I own (6 of them) with none of the effects you anticipate.

[Carrier]

So what size drill bit to enlarge the hole on a Lee mould plate? What size of hole would maximize bullet fill out?

[Hanzy4200]

Are you getting extremely frosted boolits that are wrinkly?

The extreme frosty bullets are not exhibiting the wrinkles. To those that assumed mold temp was the issue, I assure you it is not. From "warm" this thing is piping hot in 2 casts. After 5-6 I am in fear of leaving lead smears on the sprue plate as it is taking 8-9 seconds to solidify. I will fire it up again this weekend and experiment. My personal bets, after reading through your input, is likely flow speed or maybe alloy temp. My old Lee pot doesn't like being opened up on full, or she leaks like the dickens.

[Bird]

The extreme frosty bullets are not exhibiting the wrinkles. To those that assumed mold temp was the issue, I assure you it is not. From "warm" this thing is piping hot in 2 casts. After 5-6 I am in fear of leaving lead smears on the sprue plate as it is taking 8-9 seconds to solidify. I will fire it up again this weekend and experiment. My personal bets, after reading through your input, is likely flow speed or maybe alloy temp. My old Lee pot doesn't like being opened up on full, or she leaks like the dickens.

Your solution once you have reached the point of frosty bullets, is to wait a little longer between filling the mold. You should then get shiny bullets, if that is what you want. The sprue plate will run hotter than the mold, and may need a quick upside down tap on a damp rag.
My rcbs 405 grain mold does exactly the same as yours. The mold loses heat fast, a lot faster than smaller bullets, but the heat will remain in the sprue plate. Once up to temp, I time my pours, and don't have any problems except the occasional need to cool the sprue plate.

P.S set your pot temp to 780F. At lower usual temps of 720 you may never get the mold hot enough to cast decent bullets. Molds for the larger bullets don't have as much metal in them as smaller bullets, thus quicker heat loss becomes a problem, especially single cavity and aluminum molds. When you do finally get the correct mold temp, the sprue plate that gets sandwiched between lead will be too hot and cause the smearing you see.

[DonHowe]

Mold blocks with cavitiy/cavities for large bullets do hVe less mass than the same size block with cavities for small bullets but, and a very big BUT in my experience, a much larger mass of molten metal is being poured into that smaller mass. Smaller mass = quicker cooling but it also = quicker heating. Make that "less" mass of aluminum and it heat/cools even faster than iron blocks of the same physical size. I have cast with iron small cavity molds with which I struggled to cast fast enough to keep enough heat in the mold to get good bullets and 0 danger of the mold getting the mold too hot. On the other hand with those low-mass large-cavity single cavity molds which lose heat so rapidly it is no trouble at all to get them so hot as to smear molten alloy on both blocks and sprue plate. I have seen this with both iron and aluminum block molds. I have seen Lee .45-70 molds pretty quickly get so hot as to force the caster to take a break long enough for the blocks to cool.
My casting of large bullets, ie 400gr .40, .500/530gr .45, was all match quality bullets for BPCR silhouette so I was after the best bullets I could make. Production is slow enough with single cavity molds so any casting practice that forced me to stop and fix a mess or that resulted in a very high percentage of reject bullets was to be avoided. I know I am not the most proficient caster and my methods are not the only way to cast but I do know they work well.
It has been my observation that the primary consideration for many, maybe most, casters is how fast can I make them and how many in a given amount of time vs learn first to make good bullets then let speed come with practice.

[ddixie884]

Do you have a good puddle of metal on top of your sprue plate for your bullet to draw from as it cools? I had been using 4 cavity Lyman molds and bought some SAECO molds to round out my selection. I had trouble with fill and finally used a drill press and a countersink bit to open the fill holes evenly. I had a lot better performance. Charles is probably right............