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
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.
reinforcement from Ken Mollohan:
Water In Molten Lead
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
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
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
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
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 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 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.
come in single cavity and multiple cavity styles. Smaller-bullet Lyman
molds are two cavity.
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
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.
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.
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
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.
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
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.
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.)
Think of the alloy/mold system
temperature as one variable that can be controlled by:
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
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.
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
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
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.
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.
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.
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.
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.
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 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
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
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!
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
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
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.
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
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
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
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.)