The Los Angeles Handgun, Rifle, Air Pistol, Hunter/Field Pistol Silhouette Club

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A collection of comments and articles on the many aspects of bullet casting by various cast bullet shooters
Cast Bullets For Beginner And Expert
SECOND EDITION, 2007 - Joe Brennan
3.4 How To Cast Bullets

Safety

Melting lead and casting bullets can expose you and others to the lead, which is known to cause disease and physical damage. Minimizing the risk is easy. Provide proper ventilation of the casting area. Keep the area clean, sweep or vacuum often. Wash your hands thoroughly after contact with lead or bullets and before eating or smoking.

Molten alloy is dangerous. You will get burned casting bullets, what you want to avoid is getting burned badly. Wear glasses or goggles. Wear gloves. Wear shoes or boots when casting. Trust me on this one.

Clamp or bolt the pot down on the bench so it canít be tipped over. Trust me on this one too.

Never, ever, never have any liquid where it can get into the pot. Water in the pot makes an explosion. Everybody should see this happen once to make the point. Keep your Pepsi or your Evian away from the pot.

Understand that synthetic fiber clothing acts differently than natural fibers when lead splashes onto it. Cotton and wool provide some protection, synthetics get into the act by melting. When I was learning to wear shoes while casting I had on socks made of synthetic material, and the spill melted the cloth into my foot so that I got scab size and quality previously attainable only with involuntary motorcycle dismounts.

Here's reinforcement from Ken Mollohan:

Water In Molten Lead

Ken Mollohan

An advisory note of caution may be appropriate to warn CB casters of a very real, but not very obvious hazard of creating a substantial explosion in a pot of molten lead alloy.

I speak from experience, and perhaps a simple recapitulation of my story will serve the purpose.

I was a youngster living in Georgia at the time, and was casting Lyman 358429 slugs in a four-cavity mold (I still have it - and use it too!) on a hot, muggy Atlanta summer afternoon. It was pretty warm work, and I remember I was perspiring freely, and had paused several times to wipe my forehead to keep the sweat out of my eyes.

I noticed that the level of lead in the pot had dropped substantially (again), and picked up an ingot to add. Not wanting to get my finger tips burnt with a splash, I held it an inch or two above the molten surface and dropped it in, pulling my hand back quickly after releasing the ingot.

A substantial explosion then took place. I do not speak lightly about the force. The sound was not dissimilar to that of a cherry bomb. The explosion emptied the pot, as I later discovered, sprayed molten lead on the walls two rooms away!

However, that was later, because I was rather distracted at the time, since the explosion had also coated a substantial portion of my own person with molten lead. My face and MY OPEN EYES were almost entirely coated. The only saving grace was that a pinpoint of vision remained, and I was able to navigate to a nearby hospital where the attending physician literally peeled a mask of lead off of my face like you might peel the skin off of a banana. The sensation of having it peeled off of my eyeballs was ... highly memorable.

I can only surmise that whatever purpose God had for putting me on earth had not been fulfilled yet: I suffered absolutely NO permanent injuries. The doctor said that as far as he could see, the only thing that saved me was the extreme force of the explosion: It drove the lead melt at such a velocity that it spread into an ultra thin sheet when it hit my face. The sheet was SO thin that it was cooled almost instantly on contact by the perspiration on my skin and the natural tears of my eyes.

On returning home, I revisited the site of the accident to try to understand what had happened.

My first thoughts were quickly discounted. No primers or gunpowder were stored anywhere near the casting operation, nor were there any live rounds about to fall in and detonate.

Believe it or not, I'm sometimes dense enough that it actually took me a while to figure it out. I had apparently transferred several drops of perspiration to the lead ingot when I picked it up. When I dropped the ingot, it submerged far too quickly for the sweat to boil away, and was almost instantly encased in a pocket of chilled lead. However, chilled is a relative term: The temperature was still far above boiling, and the perspiration quickly became superheated steam under considerable pressure - which the lead sheath could not contain. The resulting explosion was essentially from a burst steam boiler.

This explanation was substantiated when I reflected on the bubbling that often occurred when a cold ingot was added to the pot: this is because of a phenomenon called 'adsorption', which is a fancy term to describe the tendency of a very thin film of water (only a few molecules thick) to adhere to most surfaces, including lead ingots.

     I also had noticed that ingots stored in a cool place tended to generate even more vigorous bubbles (due to more water adsorption from the warm humid summer air). But my sweat was considerably more than a few molecules, and the resulting 'bubble' was proportionally more than vigorous.

My enthusiasm for casting was considerably reduced by this experience, as you may imagine.

I almost quit, but once I understood what had happened, the remedies were obvious. I never again added a cold ingot to a melt: All ingots are preheated by being laid on the surface of the melting pot until too warm to handle without gloves. Then they are picked up with a pair of tongs and added slowly to the melt. They are NEVER dropped in the pot. Scrap wheel weights are never added to a hot pot under any circumstances, though I will sometimes START a casting session by filling a COLD pot with them. Any lead that goes into a hot pot has been melted and cast into ingot form first! This prevents water in a crack (not unusual if salvaged wheel weights) from raising a fuss.

I also wear a pair of inexpensive cotton gloves and long sleeved shirts to absorb perspiration, no matter how hot the day may be. Safety glasses and a sweatband across my forehead complete minimal safe equipage. To date (some 40 or so years later), I've never come close to a similar experience.

One other note: NEVER wear or use clothing or aprons made from synthetic fibers while casting. All garments should be of cotton or other natural fibers. If a lead splash contacts synthetic garments like polyester or acrylic slacks, it will melt the fabric, which will then become (in effect) a hot melt adhesive, holding the lead splash in intimate contact with your flesh. This will result in greatly increasing the severity and depth of any injuries. No joke!! If you have ANY doubt about the suitability of your clothing, remove a few fibers from inside a seam and drop them on the top of the molten lead in the pot. If they smolder, they are fine. If they melt, they are VERY hazardous.

     Hope this helps keep someone from a similar experience. The odds of the next guy being as lucky as I was must be millions to one. But it's simple to prevent. Don't let it happen.

Bullet Molds

Bullet molds are made of brass, aluminum, and iron. I have used one brass mold. I have owned a dozen or so aluminum molds, I own only one now. Some folks have good luck with aluminum molds. I have owned dozens of iron molds, and in my opinion iron or brass is the way to go. Much of what is included below pertains to iron bullet molds.

Bullet molds come in ďnose pourĒ and ďbase pourĒ. Most molds are base pour; the base of the bullet is on top of the mold. Some custom molds are nose pour, such that the metal is poured into the nose end of the bullet on top of the mold. The theory here is that the perfect base is more important than the perfect nose; that if the base is first to fill it will be perfect more often, thus the nose must fill last. I have had nose pour molds made by Richard Hoch and Dave Farmer, who took over Richardís business. The molds are great, but I think anyone would be hard pressed to prove that nose pour out-shoots base pour.

     Bullet molds come in single cavity and multiple cavity styles. Smaller-bullet Lyman molds are two cavity.

Iíve always-without exception-been able to distinguish between weight and dimensions of bullets cast in each of two cavities. I think I can detect accuracy differences between bullets cast in each cavity.

Some shooters mark bullet molds so that we can tell which cavity the bullet came from, and so that we can orient the bullet. I mark each cavity with a round-ended punch, like a de-capping pin. I mark one cavity toward the front of the bullet, and the other closer to the base of the bullet. A punch mark about .010" deep will do the job. Little is better! You just want to be able to see the mark on the bullet. Be aware that some mold manufacturers void the warrantee if the mold is marked.

Gang molds of three to ten or more cavities are generally used for pistol bullets. I have no experience with gang molds.

New Molds

New iron molds come with a coating of oil. Clean the oil off with hot soapy water and a toothbrush, immediately before casting. Use a dab of silicon grease (from the auto parts store) on the screws that hold the mold to the handles. This keeps the screws from rusting and freezing in the holes.

Casting

Sometimes I canít cast good bullets. I do everything the same as I always do, but after 30 minutes Iíve made few or no good bullets. I quit, and invariably get good results at the next casting session. Why? I donít know.

Some good shooters shoot bullets in the order they come from the mold. Bud Welsh, who makes barrels and other equipment for Schuetzen and modern bench rest shooters, recommended this as very important. I could never figure out why they do it or why I should do it, so I donít do it.

The way to learn how to cast bullets is to cast bullets. Itís not hard. There are a few tricks that will help you out, but the real secret is practice. The first trick is to keep a puddle of liquid lead at the sprue hole long enough to fill out the mold.

Preheat the pot and the mold. I turn the pot on and put the mold Iím going to use on the edge of the pot and the dipper in the center. I want the pot and the mold to have at least half an hour to heat up.

I put the pot on newspaper or cardboard, and drop the bullets on newspaper or cotton or wool cloths. Synthetic cloths melt when the lead hits them. So itís either cotton or wool or newspaper.

     The sprue plate must be slightly loose - must swing open or closed of its own weight. The sprue plate makes its seal with the top of the mold when it is loose enough to flop down on top of the mold. A tight sprue plate is ALWAYS cocked in some direction; making casting of bullets with good bases difficult-the base will have flash.

I use a single edge razor blade during casting to apply beeswax or Alox lube to the mold. The lube goes on the sprue plate screw; the sprue plate at the screw, and the alignment pins on the mold blocks. Use the tiniest bit of lube possible. When a piece of lead gets on the mold blocks, put a tiny bit of lube on it, keep casting, and the lead will go away. I donít scrape anything off the mold with the razor blade.

     I have used a #2 pencil to lubricate molds during casting, rubbing the graphite where needed on the mold. The pencil works but the razor blade and lube work better for me.

When the sprue starts to stick to the sprue plate, put a little lube on the edge of the sprue hole and the sprue will stop sticking.

Jim Borton suggested using a brass brush to brush unwanted lead off the mold. I got one the size and shape of a tooth brush at the hardware store, and it works great.

Get a rhythm or pace of casting, and keep that rhythm up. Donít stop for any long period of time.

Cooling the mold for faster casting

Dick Howes, one of the better offhand shooters at the Old Colony Sportsman's Association, was able to cast bullets fast by having a sponge in a shallow dish of water in the casting area, and pouring-cooling the base of the mold on the wet sponge-removing the bullet-pouring-cooling. He said that the problem in casting fast is keeping the mold cool so that the bullet hardens quickly.

(Ken Mollohan's Note: Iíve had good success using a damp cloth (actually, a clean but discarded bath towel) to rest gang molds on. The cooling is effective, the working area is generous, and there is no liquid water readily available to be a hazard. The damp towel approach also does a decent job of cooling the heavier bullets enough for handling in a reasonable length of time. It also has the advantage of provide the fast, cheap cooling of water without the hazard of explosions from liquid water: when it begins to dry out, just stop long enough to re-wet it at the sink and wring it out before resuming casting.)

A. C. Gould, in ďTHE MODERN AMERICAN RIFLEĒ, recommends cooling the bottom of the mold in a dish of water between pours. He talks about a person who could cast 12 perfect .45 caliber bullets in a minute, 505 in an hour. This is 30 pounds of 500-grain bullets. I wonder, could A. C. have told a fib? Maybe not.

Several shooters on the Internet cast bullet forums report cooling the sprue plate on a wet sponge or rag to cool the mold, and casting lots of bullets quick.

Bruce Bannister, on the "Cast Boolits" forum reports: "In one timed run at my normal rate with a SINGLE-cavity Lee .30 mould, I made 159 good bullets in thirty minutes. This translates to over three hundred per hour from a one-banger mould. It's not unusual to get well over 500 good 'uns in an hour from my Lyman or RCBS two-cav jobs, and 400 'bph' is easy. Lyman four-cavity moulds can give me over 1000 per hour on a good day. Casting heavier bullets takes a bit longer due to longer mould-filling-time than is required by lighter boolits."

Iíve tried the Howes/Gould/Bannister method, and it works for casting lots of bullets fast. But, water in the casting area is a danger. Just a drop of water in molten alloy makes an impressive explosion. The risk may not be worth the speed. A safe way to cool the mold between pours is to get a big piece of aluminum plate and put the mold on that. 

I've sometimes used a sponge on a small dish of water to cool the sprue plate of the mold. I find that I can cast faster when I cool the sprue plate, and that the bullets produced are almost as good as those I cast without speed casting. I'm not as fast as Bruce, probably because I'm left-handed and must switch hands on the mold and put down and pick up the mallet every bullet. I'm starting to like this speed casting. Be careful of the water!!

I don't do much speed casting.

I cast and inspect 100-175 good bullets of any caliber from .22 to .45 in a session that lasts just under two hours. I inspect every bullet and recycle any questionable bullet. Some people cast many more at a session, I canít.

Frosty bullets

Shiny bullets are nice. Contrary to popular opinion, frosty bullets are nice too. Shiny bullets with wrinkles come from a cold mold. Frosty bullets come from a hotter mold.

Donít believe that frosty bullets are bad; most of my bullets are frosty. (A. C. Gould said that bullets could be made shiny by putting half a silver dime in the pot. Barry Darr, famous barrel and mold maker, caused a stir at the Coors match iní83 when he claimed to add silver to his bullet alloy. Silver prices rose as gullible experimenters rushed to try it. I couldnít get the dime to melt.)

Casting bullets

Think of the alloy/mold system temperature as one variable that can be controlled by:

  • adjusting the thermostat on the pot, or

  • varying the time interval between pours, or

  • varying the time that the dipper nozzle is in contact with the sprue plate.

When bullets have hairs where the lead went into the vents on the mold, or when bases have flash even though the sprue plate is loose, the mold/alloy is too hot.

When the base of the bullet is rounded rather than at a clean sharp angle, the mold/alloy is too cool.

No hairs and a sharp base mean that the mold/alloy is at the right temperature.

(Ken's note: There are a host of other temperature indicators that were once used before thermometers were as available as they are today. Toss a live paper match on the surface of the melt. If the match ignites, the melt is hot Ďenoughí. If a dry splinter chars, but does not ignite, itís hot Ďenough. If it ignites, itís too hot. Ditto for a scrap of paper. If a bit of candle wax for fluxing makes billows of smoke but doesnít ignite spontaneously, itís hot enough. If the smoke does ignite, itís too hot. Granted, a thermometer is the scientific way to go, but these crude indicators enabled a lot of good bullets to be cast - and still do. The fact that waxes, greases and oils vary quite a bit in their melting and spontaneous ignition temperatures didnít seem to be a problem. Perhaps the real lesson is that as long as the bullets are casting well, you donít need to be too concerned about the actual temperature.)

I hold the mold at about a 30-degree angle and pour. I keep pouring, letting the lead dribble across the sprue plate and into the pot. I keep the dipper spout touching the sprue plate but not tight in the sprue hole.

One method of monitoring the heat and assuring good bases on bullets is to pay close attention to the bases of the bullets after opening the sprue plate. A cold mold/alloy will make bases with a shiny place and frequently a bump where the sprue plate cuts off the sprue. A hot mold/alloy will make bases with a grey hole. By adjusting the heat of the system to where the bases of the bullets have no grey sprue cuts with tiny holes or roughness will be the right temperature and the bullets will be close to perfect.

Cleaning the mold

New molds come from the factory with oil on them. This oil should be removed before casting. I wash new molds with dishwashing soap and a toothbrush. Then I put the mold on the side of the hot pot to dry off. Others recommend boiling molds in various cleaners, but I've never felt the need to do that.

Sometimes molds get some "stuff" in the cavity, I don't know what it is. When it affects how the bullets fill out, I scrub the (cold) mold with that dishwashing soap and toothbrush again, that seems to take out the "stuff".

Youíll make a mess of more than one mold; it will have lead stuck to the sprue plate and the inside and outside of the blocks.

I've been using a brass brush the size and shape of a tooth brush while casting, and find that this brush does a great job of keeping the mold clean; and brushing the cavities in the mold halves keeps bullets from sticking.

     If the mold is very messy, clean it up with a Bernz-O-Matic torch and a cotton or wool rag. Heat the mold all over until the lead melts and makes little balls. Wipe the lead balls off with the cotton or wool rag. Take the sprue plate off and heat it, wipe off the lead balls. Be careful, use as little heat as possible, donít heat the mold unevenly, let everything cool down slowly, and you wonít have any trouble.

The sprue plate screw is locked with a setscrew coming in from the side of the mold, and this setscrew can damage the threads on the sprue plate screw. Stuff some steel wool in the setscrew hole, then put in the setscrew, and the sprue plate screw won't be damaged.

Fluxing

We have been instructed to ďflux the potĒ for a hundred years, by a hundred authors. Fluxing the pot means dropping a thumb-sized piece of beeswax or bullet lube or wax into the pot from time to time, mixing the alloy with the dipper, scraping the side and bottom of the pot, and taking out the stuff which rises to the top of the pot and throwing it away. Ostensibly this will leave you with clean and shiny metal in the pot. We are told to light the smoke from the flux with a match, which minimizes the smoke.

I donít have to flux the pot, and cast many bullets without fluxing. Some gray sludgy stuff comes to the top of the pot; I take it out with the dipper and put it in a coffee can. I rap the dipper on the coffee can edge to knock the gray stuff off the dipper. (When I melt down wheel weights into ingots I put the grey sludgy stuff into the pot and it melts into the wheel weights as I flux.). Now and again I touch the hot nozzle of the dipper to some lube, and then put the dipper in the pot. This bit of lube at the nozzle makes the alloy flow freer. I donít flux the pot mostly because I never saw that it did anything.

I use Darr lubricant for many bullets, the lube gets old with stuff in it, and then I make a new batch and use the old batch for flux.

When I do flux the pot, the flux and flame makes the grey sludgy stuff go away, and leaves some grey/black powder on top of the lead. I take this powder off with the dipper-I think the powder is a metal oxide because it is quite dense. I've noticed that if I drop a piece of old Darr lube in the pot and the melted lube doesn't catch fire on its own, then the alloy is too cold to make good bullets. The alloy should be hot enough to ignite the lube-then you get good fluxing and can cast good bullets.

Here's the 4X magnifier light that I use to inspect each bullet. I got it at Office Depot for about $20.

Bullet inspection and weighing

There are pencil lines on the surface behind the pointer at .5 grain above and below the center marker. These pencil lines make it easy to select out those outliers.

Here's my setup for weighing bullets. These are Lyman/Pope 308403's cast 10/6/05 and weighed 10/7/05. Over on the left are 6 with visual defects. Then, left to right, 2 at 169.4 grains, none at 169.5, 14 at 169.6, 17 at 169.7, 92 at 169.8, 17 at 169.9 and 2 bullets at 170.0 grains. I'll put the ones with visual defects back in the pot, maybe the 2 at 169.4 grains also. This set of bullets is unusual in that there were no bullets more than .5 grain from the average. Generally there are a few of these outliers, they go back into the pot.

Bullet weight variation

For many years I have inspected and weighed every bullet I shot. I throw back a lot of bullets, every one with an obvious wrinkle or hole or Ö ?

In 2004/2005 I analyzed bullet weights of 10,008 bullets cast in 90 lots with average weights from 58.5 to 445.3 grains. The average standard deviation was .137 grains, with a minimum of .068 grains and a maximum of .294 grains. The standard deviation doesn't seem to vary with average bullet weight.

A good-running mold and pot will cast bullets weighing +/-.2 grains 80% to 90% of the time. It doesnít seem to matter whether itís a 150 grain 30 caliber or a 500 grain 45 caliber bullet. When I weigh bullets, I find a stranger here and there. Maybe one in one hundred will weigh substantially more or less than the rest. I believe that close inspection is mandatory, that weighing to eliminate the strangers is important for some shooting, but that weight variation of a few tenths of a grain is not important. Segregating bullets into tenth grain categories makes little difference in my shooting. Inspection of bullets without weighing is adequate for 90% of cast bullet shooting.

Mold coating

Some shooters smoke the inside of molds with a candle or a Bic lighter or some other flame. Other shooters coat the inside of molds with a patent liquid preparation. This coating business seems more popular with aluminum molds than iron molds. I donít coat any mold. Or didn't. In 2006 I started to get into Black Powder Muzzle Loaders, and in 2007 bought a Lee .490" round ball mold. This mold worked poorly with pure lead, many defective and wrinkled balls. After smoking the mold with one of those butane grill lighters, the mold got better and started to make perfect balls. I am going to try smoking some of my other stubborn molds.

Flat Bases

Sometimes the sprue plate leaves a small bump on the bottom of the bullet. We like flat bases because the gas checks go on the bullets more evenly, and because we're told that flat and precise bases contribute to accuracy. If you're plagued by these base bumps, here's how to fix the problem.

First, make sure that the sprue plate is loose and free to turn of its own weight. Then, after casting and opening the sprue plate, close the sprue plate such that the plate and not the hole is over the bump, and give the top of the sprue plate a good whack with the yellow plastic mallet. This will mash the bump down and make it go away.

Storing molds

I leave bullets and the sprue in the mold when Iím done casting, I just donít open the sprue plate the last time. Iíve never had a mold rust in the cavity with the bullets and sprue left in the mold. It is common for my molds to have light spots of rust on the outside. Some casters oil the mold for storage. Others put molds in a container with a desiccant or a "Vapor Phase Inhibitor" (= anti-rust chemical in a piece of paper). One shooter suggested putting a clean polished piece of steel with the molds, in a closed container. The idea was that the polished piece of steel would rust, absorbing the oxygen in the container, and keep the molds from rusting. I'm skeptical, but it can't hurt. If you're worried about it, why not just put the mold in a plastic zip lock bag?

Thermometers

Thermometers are available from Lyman and RCBS and others to measure the temperature of the alloy in the lead pot. I have never found the need for one of these, and I have read several comments about the inaccuracy of these thermometers. Perhaps they help some bullet casters, but Iím not planning on buying one soon.

Because I felt guilty, I did buy a lead thermometer in 2006. It's a nice instrument. I used it to measure the alloy temperature a few times, but I don't know why. I've put it away and haven't used it in a while.

How To Adjust And Maintain Bullet Molds

With help from Ken Mollohan

This has mostly to do with Lyman and other iron/steel molds with Lyman-style alignment pins. I know little about maintaining aluminum or brass molds.

Any trace of oil or grease on a mold will smoke and cause severe wrinkling of the bullets. Consequently, all molds must be clean and dry before use. Some casters never put any preservatives on their molds: they just leave the last bullet cast in its cavity as a sort of protection. I know one fellow who stores the dry molds in a box of heavily galvanized steel. It seems to work, but most of us are more comfortable with some sort of petroleum based rust inhibitor for safe storage. Which means it must be removed before the mold is used again.

Iíve used every solvent you can think of, and probably quite a few you never even heard of, trying to get the metal really clean. Some shooters clean their molds with soapy water and a brush and report good results. But the best way Iíve found was recommended in the American rifleman some years ago. They suggested bringing a sauce pan with 2 or 3 inches of water to a rolling boil, and adding Ďsomeí dish detergent - maybe half a teaspoon if you just HAVE to measure it. Then open the mold (on handles) and set the blocks in the pan. The water should cover the blocks. Then let the pan come back to a rolling boil. Youíd think this is going to boil over and make a mess, but it doesnít. Let it boil for about a minute. Then take it out and rinse it off briefly in scalding hot tap water, and sling it dry. Be very careful not to give it a long rinse with cold water: The metal will be so free from oils that if itís kept wet, it will rust in a hurry! But a hot mold will dry quickly, and will give you no trouble with rusting. This takes only a few minutes, and is the best method Iíve found.

Bullet molds need to be adjusted now and again because they wear and get damaged. Sometimes the mold doesn't close completely, sometimes the mold halves will move when the mold is closed, and sometimes the sprue plate isn't flat or has bumps.

There must be no lead on the face of either half of the mold. Get the lead off by heating the mold and touching the lead with the tiniest bit of bullet lube. The lead will go away as you cast.

Ken's method is to heat the mold so hot the lead specks melt. Then wipe the molten lead away with a slightly oily rag after youíre done casting, so it will be clean for your next session.

With the mold off the handles, check as follows:

Hold the closed mold up to the light, look through the bullet cavity, and see if there's light coming through a crack. Any visible light means that the mold isn't closing completely.

Hold the closed mold in two hands, one hand holding each half, and see if the halves move when you try to twist them. The slightest movement can be easily felt. If the mould fails either test it should be adjusted for the best results.

Remove the sprue plate and screw and washer from the mould half.

You'll need a small fine file. My file is eight inches long. A file with a "safe" edge, with no teeth on the edges, is preferred.

Here's a picture of the file and the mold that we'll use for an example. On the mold half with the alignment pin holes (the half without the pins sticking out), hold the file flat on the surface of the mould and lightly file off any metal that projects above the surface. We're not taking much metal off. We just want to take off the bumps and make the surface flat. You will be able to feel the file take off metal, and you'll feel it when the file is done taking off metal. The alignment pin holes on a used mold are almost always burred.

Here's a picture of that mold half after filing, the bottom alignment pin hole clearly shows the white ring left after the burr was filed off, the top hole looks the same but didn't photograph as clearly.

Now file the face of the other mold half-the half with the alignment pins sticking out-, being careful not to file any metal off of the alignment pins. Here's where having a file with a "safe" edge, with no teeth, is helpful. Just be careful not to remove metal from the alignment pins.

File off any bumps at the edges of the mold half. When it's flat, stop. Less filing is better.

To keep the alignment pin holes from burring again, get out your chamfering tool, or cricket, and chamfer the inside of the alignment pin holes-just a little bit!

Here's the mold half and the cricket:

(NEI and RCBS moulds come with the alignment pin holes chamfered, Lyman molds don't.)

Before you adjust the alignment pins, make sure that the mold half faces are flat and burr-free as explained above. These steps must be done in the proper order!

Adjusting the alignment pins

If you can feel movement when holding the mold halves closed in your hands-when twisting them-the alignment pins need to be adjusted. You will be able to feel which alignment pin is loose. Just fiddle with the mold for a while, twisting the halves in your hands. You can feel the slightest movement.

I use a punch, a hammer and a lead alloy ingot to adjust the alignment pins. Put the closed mold on the ingot and tap the punch on the alignment pin with the hammer. It may take several whacks, maybe a hard whack. Eventually the pin will move. If the pin has gone out too far, so that the mold halves stick together when closed, then just tap the pin back into the mold half with the hammer. The goal is to have no movement of the two mold halves and no sticking when the mold is closed.

(Some shooters adjust the alignment pins with an arrangement of ball bearings, shims, and a vise. I've never tried it.)

Filing the sprue plate flat

Sometimes the sprue plate gets bumps and uneven surfaces and lumps at the outside edges. The sprue plate must be flat. File the bottom of the sprue plate until all the bumps are gone, and it is flat.

Filing the mold top

The top of the mold sometimes gets burrs at the edges and around the sprue plate hole. ONLY after the mold half faces are filed flat and the alignment pins are adjusted, file off any burrs on the top of the mold.

Filing chamfers on mould edges

Some folks also file a chamfer on all four edges of the mating surfaces of both mould blocks; to make sure that no burrs will be raised to keep the blocks from closing completely.

Repairing mold handles

Mold handles are fairly expensive, and the wooden things tend to loosen over time and use; and fall off. I've fixed these by putting paper or cloth shims around the metal parts and forcing the wooden things back on, but those wooden things always loosen up.

To permanently attach the wooden things to the metal hinge part of the mold handles, I use GE Silicon Sealant Household Glue. This is what we used to call Room Temperature Vulcanizing, or RTV, rubber. On the back of my tube it says:" NOT FOR: surfaces that will exceed 400 degrees FĒ which I think means that it's good to 400 degrees F, or maybe a little more. Anyhow, I smear it on the metal gozinta parts and in the holes in the wooden things, put them together and the handles still work fine after many casting sessions. Paul Libby says that he uses JB Weld epoxy to hold the wooden things on, and that it is not affected by the heat.

Mold setup and lubrication

The mold is held on the handle with two machine screws. I dip the screw ends in silicon grease-available from NAPA auto parts stores before putting the mold on the handles. This keeps the screws from sticking. They frequently stuck on me before I used the grease

While casting, lubricate the alignment pins and around the sprue plate screw with a tiny bit of NRA ALOX lube. Using this lube, after a while, there's a coating of (maybe) beeswax that keeps everything moving freely. The smallest possible amount of lube does the trick. When a bit of lead gets onto the mold, a tiny bit of lube on the lead will make it go away. Also lube the handle hinge now and then. (Ken's note: This works if youíre really careful, but can cause wrinkling if the slightest bit of excess should occur. Graphite or Mica works fine, and canít cause problems.)

Adjust the sprue plate screw so that the sprue plate just closes by gravity. Keep it that loose, so it swings easily. A tight sprue plate is (almost) always a cocked sprue plate. As you cast, close the mold halves slowly, don't snap them shut.

When you're done casting, leave the mold cavities with bullets in them, and a big slab of lead on the sprue plate. I've never had rusting in the cavities when storing molds in this way.

The locking screw may have either a tiny slotted or Allen head. Get a longer Phillips or slotted head screw with a big head at the hardware store, it is much easier to adjust.

The locking screw sometimes buggers up the sprue plate screw. Stuff some steel wool in the locking screw hole, then put in the locking screw. This will keep everything tight without distorting either screw.

How to keep the bullet from "sticking" in the mold.

With some molds, the bullets stick in the mold after opening, and you have to whack the mold handle hinge to get the bullet to fall out. Mostly it's burrs at the mold half edges that hold the bullet in. Whacking the handle hinge takes a lot of time, it is far better if the bullets fall out when you open the mold handles.

The brass brush the size and shape of a tooth brush, that I got from the hardware store, is used to brush the cavities in the mold halves to remove those burrs and allow the bullets to fall out more easily. (Ken: Another trick is to flatten the mouth of a scrap case with a hammer, and use it to scrape the edges of the mold cavity. This will do a fine job of removing burrs, and at the very least, it will show you where any Ďroughnessí might be lurking.) When this doesn't work it's time to lap those burrs out. 

There's much info on mold lapping in this book. More experienced guys explain how to lap a mold using the best techniques. Here's how I fix the problem.

Make sure the mold is adjusted according to what's written above. Put the mold handles on, and make sure you have five or six bullets for each cavity. Put a bullet in the mold and close the handles tightly. Center punch a small hole in the middle of the bullet base, use a punch or a nail or anything sharp. If the hole isn't close to the center, discard the bullet and start again. Then drill a three-thirty-seconds inch hole in the bullet base with a cordless drill-you don't want the drill to get away from you. This hole is maybe one-eighth to three-sixteenths of an inch deep. Next screw a Phillips head sheet metal screw into the hole, not tight. Put a little bit of automotive valve grinding compound on the bullet-Permatex 34A water based works well-put the bullet in the mold, close the handles while turning the bullet-screw with a screwdriver. Now itís a matter of wiping the valve grinding compound off the face of the mold blocks, turning the bullet, and generally fiddling with the mold and bullet-screw until done. You can see where the valve grinding compound has worked on the mold surfaces. Now wash the mold off with hot water, and oil it if you're not going to cast right away. This whole thing takes less than half an hour, and works very well for me. Having those bullets drop out and not having to persuade them is a great time saver.

(Ken's note: My technique is to simply use a soft, fine brass wire rotary brush at low speed in a Dremel tool to polish the edges of troublesome cavities. The brass wears long before the steel, and doesnít harm the cavity, but removes any microscopic burrs quickly and easily.)

 

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Warning: All technical data mentioned, especially handloading and bullet casting, reflect the limited experience of individuals using specific tools, products, equipment and components under specific conditions and circumstances not necessarily reported in the article or on this web site and over which The Los Angeles Silhouette Club (LASC), this web site or the author has no control. The above has no control over the condition of your firearms or your methods, components, tools, techniques or circumstances and disclaims all and any responsibility for any person using any data mentioned.

Always consult recognized reloading manuals.

 

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