Casting Large Bullets?

[MLR]

I have been casting bullets for over 30 years so I do have some experience with it. All the moulds that I have used in the past were for .30 cal, .357, and 44's.
Never had much problem with any of those.
Now Ive started trying to cast for my 40-65's and my 45-90. I am not having good luck with these at all. I cant get the base to fill out properly.
I drilled out the spout on my dipper to 3/16 and set the alloy temp to 800.
BTW these are all iron moulds. The Lyman moulds are bad about sticking too but I recall that Lymans always were. I'm using 30-1 alloy.
Any ideas?

Michael

[Cimarron Red]

Mchael,

If you're not doing it already, try keeping the ladle in contact with the mold for a few seconds after you pour. I keep mine in contact for a count of six or eight, depending on the bullet and the temperature of the mold. For the .45-70, I cast 500 grain to 540 grain bullets tempered 25 to 1. Also, as you know, it's important to have a reasonably pure alloy.

[44man]

CR is right, you are depending on the sprue to fill the mold. Hold the ladle longer and just break the inner top edges of the blocks with a fine file. One little stroke on each side is enough for a good vent.

[MLR]

Thanks for the replys. I have tried both holding the ladle longer, and backing the ladle off and letting the lead pour over the mould. I also considered it was a venting problem. It looks as though there should have been one more vent cut at the top.
When I compare the Lyman to my other iron moulds the Lymans have half the vents the others do. I guess I should go to town and pick me up some jewlers files to cut a vent?
I just finished honing the sprue plate flat. Maybe that will help too.

Michael

[Cimarron Red]

Hi, Guys,

I have never vented any of my molds, although I have changed the angle of the sprue openings on some of my molds per Paul Matthews in one of his books. But the molds I use to cast my BPCR bullets -- an RCBS 500 BPS + for chickens and a Paul Jones Creedmoor 540 grain for the stick animals -- have had no modification at all. I will add that I no longer use Lyman molds for big bullets. My unscientific opinion is that the blocks are too small and therefore lose heat too rapidly. Whatever the reason, getting a near perfect large bullet from a Lyman mold was cause for celebration for me.

[leftiye]

If your sprue plate just lays flat on the surface, the upper part of the mold vents out under the plate, I think that's why lyman doesn't put in that last vent line.

You're already working in the direction I see as the best answer. To fill out well (not just the top edge) the metal has to fill the cavity with some authority, and it has to be hot enough,(likewise the mold) that it's still liquid when it tops out. A faster pour rate very close to the mold, and hot mold/ metal. Followed by making a large puddle on top of the sprue plate (will make the mold hotter, and allow the boolit to suck metal out of the puddle as the boolit cools). If you pour with the nozzle not in direct contact with the sprue plate, air can escape out the sprue hole also.

If you can't get the mold hot enough by casting speed alone, try placing it on a hot plate as part of your casting sequence. You could actually keep it there except when knocking the boolits out if you use a ladle. I suspect you already know all of this.

[jerrold]

I am a newbee my self so you may already be doing this!!!
Hold the mold at or near horizontal and make contact with the ladle, then turn both vertical to pour.? This made a great improvement on my 500+ 45 s for 45/90:drinks: ...
life is short
jerrold

[MLR]

thanks all,,,,im fixin to give it another try. Im raising the temp a bit this time.
Jerrlod what brand of mould are you using?

Michael

[MLR]

I cranked the temp up to 880 degrees and ive started getting some good bullets. They still stick in the mould like crazy but that normal for most Lymans in my experience.

Michael

[Cimarron Red]

Geez, Michael,

That's really hot. I've never cast at temps above 820-825 degrees. At your temp I bet the sprue takes a while to freeze.

[w30wcf]

MLR,
Good info from the pards. Glad to hear that you have made some progress.
You can vent the base of your mold by taking a very fine stone (important!)and holding it at about a 45 degree angle, stroke it a few times across the parting line.

You just want to just barely break the edge , just enough to vent so that your alloy doesn't whisker out. I've done that to some of my molds and it has worked well.


Cimarron Red,
WELCOME to the forum.[smilie=s:
Will you be shooting at Ridgway this year or have you moved west?

w30wcf

[powderburnerr]

I put my big moulds on a hot plate when I turn on the pot I turn on the hot plate this warms the mould up and should cast a good bullet the first or second bullet . .I set the temp on medium . then you have to cast about one a min to keep the blocks at the right temp , in my experiance..............Dean

[truckjohn]

I would also try a couple other things too.....

1. Clean the mold with Brake Cleaner spray --
soak it down good.
2. Follow up with Carb cleaner --
again a good soak and scrub.

Let it dry out good -- it will be *Dry*

Check out the vents with a scratch awl --
make sure the vents actually follow into
the cavity. (I've had molds that had plenty
of vent lines..... and all the vents were plugged
at the cavity by machining burrs.)

On pot temp -- My rule is I don't believe the thermostat...
I believe my thermometer. I have found that on the
thermostat runs colder on hot days, and warmer
on cold days (due to ambient air allowing faster heat transfer
on hot days.) 850 on a 35F, windy day runs like 1,000 actual.
850 on a 90F, still swampy day runs like 675F actual.

Typically, I cast extra-fast starting out.
I don't worry about bullets until the mold gets
good and hot..... really hot..... as in pour lead,
break sprue right as it sets, drop bullets....

Pour lots extra over the sprue plate.....
Seems like a good hot sprue plate will
help the mold fill much better.

On ladle casting.... I have found that a cheap $1.00
soup ladle casts many fine bullets. Easy to heat up,
aims pretty decent, and holds about 2lbs of lead.

I do have an RCBS ladle -- but the hole seems too small,
and it is nearly impossible to clean out once it gets fouled.

Once the mold is super hot and bullets are coming
out filled well, but with big holes pulled in the bases,
I slow down a little at a time till they cut right... then
cast at that pace.

On my Lee molds, I did find I needed to open up the
sprue hole. Turns out a 45degree countersink bit
is the perfect tool for this job. Once I did that, my
459-500-3R mold really filled out nice.

Best regards

John

[Cimarron Red]

Howdy, Jack,

Thanks for asking and thanks for remembering. We have not yet sold our house, so in the east we remain for a while longer. The silver lining to this particular cloud is that I'll get to a few more shoots at Ridgway, Shippensburg, McDonald and a few others. This will help ease the pain of not being in northern New Mexico yet. I hope our paths cross at Ridgway this year. Actually, an even more fervent hope is that ours paths cross at the Whittington Center!

Michael,

No intention of high-jacking your thread. As Jack said, you've received some good advice from the other posters here. One other thing I'll mention: from the time I began using my Paul Jones mold, I asked myself how I had cast without it -- and my silhouette scores improved significantly.

[Arnie]

Michael .I have been making these bullets for years now and a few things you need to do .Turn down your temp to about 750 .You dont need 800 or higher .If your using a Lyman mould ,do you have the newer thick sprue plate ?.Always use a ladle ,i prefer RCBS . Hold mould and ladle at 90 degrees and put spout of ladle onto the sprue hole and hold them together as you tip the combination to upright .Count to about 3 or 4 and then raise the ladle straight up about 1/2 inch and let the ladel empty right onto the sprue hole .This was told to me by Paul Jones and i can cast 100 ,550 grain 45 bullets with maybe 4 or 5 that are not with in 1/2 grian .Also if you tip the combination from 90 degrees to upright slowly your bullets will look really nice compared to if you turn it upright fast but they dont work any better .Arnie

[MLR]

Ive tried all the things posted so far. I'm not giving up on this mould yet.

CR
I plan on trying one of Paul Jones Moulds in the future. Its just that im stubborn an want to get this one working. I do have a Pioneer adjustable mould to play with and a Steve Brooks PP mould coming in.
From what i remember as a kid using Lyman moulds is that they were bad about sticking most the time.

Arnie?

I figured this being a new mould it had the thicker plate but I will check that.
Its just seems to me that this thing isnt venting properly.

Michael

[klw]

I have been casting bullets for over 30 years so I do have some experience with it. All the moulds that I have used in the past were for .30 cal, .357, and 44's.
Never had much problem with any of those.
Now Ive started trying to cast for my 40-65's and my 45-90. I am not having good luck with these at all. I cant get the base to fill out properly.
I drilled out the spout on my dipper to 3/16 and set the alloy temp to 800.
BTW these are all iron moulds. The Lyman moulds are bad about sticking too but I recall that Lymans always were. I'm using 30-1 alloy.
Any ideas?

Michael

My take on this is a bit different. The largest conventional bullets I ever cast weighed 3500 grains. In sort of non-conventional stuff, 3 inch cannon balls were kind of fun. Don't remember the weight on those.

But bullets for a 50-70 or a 500 magnum I do all the time without any problems.

But for bullets of the 45-70 class or heavier I think that the casting technique has to be a bit different. I set the furnace on full blast. I typically use two single cavity moulds and I make absolutely sure that the mould has adequately cooled before opening it. On bullets of this size you can not use the sprue hardening as a timer. Sometimes I actually use a clock to be sure that I've waited long enough.

Then too with bullets this heavy moulds may well be made for a specific alloy. RCBS 50-515-FN, for example, was made for use with pure lead. I'm positive about that because I called and asked. You can cast this bullet with linotype but production rates will be low and visual rejection rates will be high. Switch from linotype to pure lead, however, and all the problems go away.

I can not help but wonder, however, if it isn't the brand of mould that you are using. I stopped using Lyman moulds years ago because they are just trouble prone.

RCBS makes good moulds AND they are guaranteed forever. Wear one out and they will just replace it. I've had no trouble casting bullets of the type you are talking about EXCEPT with Lyman moulds.

[44man]

I make my own sprue plates and found a super smooth, lapped plate is not the way to go. I always leave the end mill marks on the plate and mold top. It just makes better boolits and makes casting easier. The tiny marks hold plate lube real good too.

[leftiye]

MLR, I don't know if anyone has suggested coating the mold halves yet or not. It makes the metal act as if it were hotter (insulates the mold so it can't transfer heat as fast). I like NEI mold prep for this. It is a graphite in a polymer carrier that dries fast, I think. Makes a nice even thin coat. Put it on the top of the mold, and the bottom of the sprue plate too for lubrication.

[Leftoverdj]

That stuff about stones and files makes me nervous. My answer to sticking moulds is an eraser. The pencil style typewriter eraser is about the best if you can find one, but an ordinary pencil works. They are just abrasive enough to remove small burrs and overly sharp edges, but not so abrasive you can do real damage with them. The Cratex points used by hand are also excellent, but not everyone has those laying around.

[Bass Ackward]

MLR,

Your guess of a venting problem might not be entirely correct although it is the most likely. But excess venting hurts nothing as long as it doesn't create fins. I assume that you are fluxing often to keep your 30-1 actually 30-1. At 30-1, it doesn't take much burn off before you have to raise the temperature.

One thing that I didn't see the guys mention is the hole size in the dipper itself. I recommend drilling it out some. You still want enough contact with the recess in the plate to effect a seal. So you can open it quite a bit. Chances are this is contributing.

This serves two purposes. It increases flow into the mold assuming that venting is working properly. The second is that it puts a wider lead column to provide heat on top of the mold which causes it to stay liquid just a bit longer. The lead will always be hotter than the dipper.

After doing this I was able to increase quality and still drop 50 degrees.

[montana_charlie]

MLR,
When I noticed this thread already had a couple of pages, I figger'd the problem had been cured...so I just looked in to see what the outcome was.
I find that you are still searching, in spite of the fact that experienced casters are providing advice.

You have received the standard 'high temperature' and 'drilled spout' suggestions, but you did those things before starting your thread.

You also got the 'break the edge' advice. I strongly recommend that you follow that, as it often helps...and even if it doesn't cure your problem, it can't hurt if it's not overdone.

To describe that process (one more time) the idea is to 'break the edge' of the top of the mould, from the edge of the cavity out to the outer wall of the mould.
That is not 'file a bevel on the edge', just 'break' it.

The desired result is a very shallow groove running from the cavity to the outside air. It should be so shallow your fingernail can barely feel it as you scratch across the closed mould...but you can see it.

I recommend that you only do one mould half, to begin with. That may make enough of a vent to let air get away from under the sprue plate, allowing your mould to fill completely...resulting in sharp corners on the bullet base. If it's not quite enough, do the other half.

Now, that I've mentioned 'sharp corners', I am reminded that you never said what the problem is with your bases. Your words were, "I can't get the base to fill out properly."

Are you talking about a rounded corner on the base, or imperfections in some other part of the base?

If it is the rounded corner syndrome, the advice already given is probably the cure...but it wouldn't hurt to loosen the sprue plate pivot screw a bit, as well.
If you are troubled with wrinkles, dimples, or voids in the baseband while the rest of the bullet is good...cleaning is probably the answer.

Also, if you examine the edges of your cavity under strong magnification, you may find out why bullets don't drop easily.
CM

[44man]

The file or stone is ONLY used at the top parting line of the blocks! Erasures or Scotch brite pads work fine on burrs at the cavity edges so don't get nervous.

[MLR]

I want to thank everyone. As soon as i'm able im going to heat up some lead and give it a try. I've used the eraser this time. Figure I will do things in steps. As I said earlier I do have experience casting but it seems these large bullets are a whole nuther animal.
I'm wearin a back brace so I kinda do this in spurts. Next spurt I hope to do better. You guys have givin me some ideas id have never thought of.

Michael

[MLR]

I used a carbide tiped scribe to cut a new vent where i thought it was needed. That seemed to help the mould fill out properly. It still sticks bad but I attribute that to it being a Lyman mould.

Michael

[Shiloh]

My iron mold works best at about 860 or so. I gives good fill and sharp edges to the lube grooves.

Shiloh