Author Topic: Extreme Casting  (Read 1035 times)

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Offline LAH

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Extreme Casting
« on: September 03, 2004, 04:47:10 PM »
On Thursday I spent a lot of the day with three moulds. I was casting from a 40 pound Magma pot. One mould was a Magma, 32-20, 115 gr. RNFP two cavity. One was a Ballisti Cast 475-400-K two cavity. The other a Lyman 457406 4 cavity.

I could dump and fill the 32 mould, then the Lyman, then the 32, then the Ballist Cast, then the 32, then the Lyman, over and over.

The 32's looked like ants beside the BC 475's and Lyman 458-490's. We cast with up to 4 moulds at a time on a regular bases but I believe this is the greatest size and weight difference we've tried.
Joshua 1:9

Offline haroldclark

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Casting Day too
« Reply #1 on: September 03, 2004, 08:23:01 PM »
Hey LAH,  I spent the mid-day today casting like a mad man too.  After inspecting, I had 670 30 caliber bullets to show for my efforts.

I used two Saeco #315 173 Grain 30 calibers

and one Saeco #315 150 grain 30 caliber.

I keep the castings in the two #315 molds separated.  I drop them in little bread loaf pans and set the mold right by the pan while working with the other molds.

I have to stop and refill my 20 pound pot, though.

Harold Clark

Offline Lloyd Smale

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Extreme Casting
« Reply #2 on: September 03, 2004, 11:39:04 PM »
Heck pal with some of the big molds ive had to run as many as 5 molds at a time to keep them from overheating. It can get to be a busy casting session!! :)
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Offline LAH

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Extreme Casting
« Reply #3 on: September 04, 2004, 12:51:12 AM »
Harold I love casting the .30 cal. bullets. I mainly cast just one and shoot the bulk of them in my ole 94.

The large bullets take time to cool. The Lyman mould is a 4 cavity that cast a 45 cal. 490 gr. round nose bullet. Without a fan I can dump that mould every 2 minutes using a 725 degree casting temp. and 92-6-2 alloy.

In contrast the 32 mould takes less than 15 seconds using a cooling fan. That's the extreme of which I was speak.
Joshua 1:9

Offline BruceB

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Extreme Casting
« Reply #4 on: September 04, 2004, 10:41:09 AM »
Gents;

This is one area where I do have some experience.  Describing the following method may make some of you doubt the claimed results, but believe me it works, and many of our fellow casters have tried it out and agree.  I also have some credible witnesses!  The method is now called "doing the BruceB" on the Cast Boolit Board at aimoo.

Using a SINGLE two-cavity mould, it's possible to cast well over four hundred GOOD bullets per hour.  A four-cavity Lyman will usually deliver as many as 1000, and a single-cavity can cast something over two hundred very nice bullets in sixty minutes.  These figures include bullets from a 100-grain .30 caliber to the 550-grain bullets for a .50 Sharps'.  By "good" bullets, I mean bullets having a maximum weight spread of less than one grain in a 200-grain .30 caliber design, and I've had less spread than that in batches of several hundred 365-grain .416s from a single-cavity RCBS mould.

The secret is speed-cooling the sprues on a wet cloth pad sitting in a shallow dish of water.  As soon as all the drawing-down of alloy into the cavity has ended and the sprue has solidified, even BEFORE it stops changing color, the mould is inverted and the sprue pressed against the wet cloth  for just two or three seconds.  This cools the sprue sufficiently that it will cut cleanly without smearing any lead whatever across the mould top.  It also eliminates the time spent waiting for the sprue to aircool to that point.  Using just one mould also eliminates the time wasted in the many hand motions required to put down one mould and pick up another one.

 If efficiency and PRODUCTION is the goal, then minimizing hand motions is a key to success. Analyse every motion, and reduce them to the bare minimum.  Such things as where the mallet is placed while filling the mould, where the sprue container is placed, EVERYTHING about the physical setup should be studied and experiments carried out to see what works easiest and quickest.

The cautions about water and molten lead deserve attention.  In my high-speed casting, the shallow dish with the rolled-up cloth pad sits right beside  the coffee can which I use for sprues.  The high sides of the can prevent any spray or drops of water from reaching the sprues, and I watch the mould after cooling the sprue until ALL WATER has evaporated from it, and ONLY THEN do I cut off the sprue and drop it in the can.  This only takes a very short time, and prevents water from being dropped into the sprue container.  I also re-melt the sprues whenever the can starts getting full.

Incidentally, if ANY water gets INTO the melt, that is, below the surface of the molten alloy, there WILL be a violent reaction. Adding alloy that is wet or has drops of water in or on it will do this.  However, a drop of water (sweat, beer) that falls ON THE SURFACE of the melt will just sizzle and bounce around until it evaporates.  Don't believe me?  Try it for yourself, cautiously.  

I use an RCBS 22-pound-capacity pot, which I run virtually ALL the time at its max temperature of 870 degrees.  My alloy is in 3-pound triangular-section ingots 10.5 inches in length (cast in an angle-iron ingot mould).  To eliminate the "downtime" of waiting for the pot temperature to recover after adding alloy, I preheat several ingots at a time on top of the furnace above the melt.  They get so hot that adding a 3-pounder only drops the pot temp about 30 degrees, and I just keep right on casting without a break.  As the front ingot is put in the pot, the row of ingots is moved ahead one notch and a cold one added to the back of the line-up to start heating.  More time saved!

An ingot is added whenever one will fit into the pot.  Keeping the melt level high minimizes variation in the flow pressure at the spout, and I have no doubt that this is another aid to consistent bullets.  

By doing all the above, my casting rate usually fills the mould four to five times per minute, or eight to ten bullets per minute from a two-cavity mould.  This will vary a bit, as larger bullets take more mould-filling time  and so does a 4-cavity mould.  I kept time one day and filled a Lee single-cavity .30-130 mould 155 times in 30 minutes, and rejected only six bullets....and I am FUSSY about bullet quality.  Note that fast casting, especially if we're water-dropping the bullets for quenching, minimizes temperature variation in the bullets being dropped and hence more consistent hardness  after quenching.

The method woks fabulously. I hope this gives y'all some food for thought.  If you want more peoples'  experiences, search on Yahoo for "cast boolits"  and come see us!
Regards from BruceB

Offline LAH

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Extreme Casting
« Reply #5 on: September 04, 2004, 10:51:47 AM »
Hey Bruce. I know we've spoke this subject before. Your numbers would be no problem. Using 4 each 4 cavity moulds I can cast 20 bullets per minute. One question and if I've asked this before please forgive. Are the bullets cast this way bright and shinny like a silver wedding band or are they a frosted color?

I could try your method myself and answer my own question but I'm so busy casting it's hard to work in shooting time. HEE HEE
Joshua 1:9