THE 8-PHASE CASTING CYCLE - Part 2


 


Introduction

In Part 1 of this article, I described in detail the eight phases of what I call the ďCasting CycleĒ and the role each phase plays in our attempt to cast high quality bullets within a narrow weight range on a consistent basis. To review, the Casting Cycle as I described it consists of the following eight phases:


Phases
 

Activity
Phase 1 Filling the Dipper / Ladle With Melt
Phase 2 Pouring The Melt Into The Mould
Phase 3 Forming the Sprue Puddle
Phase 4 Waiting for the Melt to Frost
Phase 5 Letting The Melt Harden
Phase 6 Cutting the Sprue
Phase 7 Dropping the Bullet
Phase 8 Closing the Mould and Setting-Up for the Next Bullet
   

In that article I also stressed the importance of keeping the mould at or near the same temperature for each bullet cast in order to achieve maximum results. I believe that the key to casting one bullet after another within a few tenths of a grain is repeating each of the eight phases of the Casting Cycle as close to the same way as possible from one bullet to the next. By doing so, we can keep the temperature of the mould within a few degrees with each bullet we cast, which in turn helps to eliminate wide fluctuations in weight.

Simple Accessories To Make Your Casting Better

Now I would like to discuss how you can use several inexpensive accessories that you may already own to make your casting more consistent and productive. Hopefully these suggestions will help you to achieve better results and enjoy your casting sessions a little more.

1) Use A Secondary Source Of Heat For Your Mould And Tools

Getting your mould up to casting temperature initially and then keeping it there when you take a break to flux the melt or make a run to the bathroom can be a problem. Some casters recommend heating the mould initially with a propane torch or by standing it on the edge of the pot to warm up. Others simply place the bottom of the mould directly on top of the melt in order to heat it up quickly. For me, a safe and inexpensive solution has been to use a $ 20.00 electric hotplate, available at most hardware and discount stores, as a secondary heat source.

At the beginning of each casting session when I fire up my plumberís furnace, I also turn on the hotplate and set my mould, dipper, and dross-skimming spoon on top to be heated. Ten or fifteen minutes later when the melt has reached the desired casting temperature, my tools are also hot and ready to use. After casting just a couple of bullets, the temperature of the mould is where I want it to be and the bullets begin dropping out at the designated weight I have targeted.
 
A hotplate will help to keep your casting tools hot and ready to use while you take a break or flux the melt.

If I take a break or need to flux the melt, the dipper and mould go back on the hotplate where they stay hot until Iím ready to use them again. Surprisingly, my hotplate can keep my mould at or slightly above its optimum casting temperature. Using a hotplate has eliminated the significant drop in mould temperature that I would previously encounter when taking a break. In those days, when I resumed casting after a break, I had to make a handful of bullets before the mould would return to my desired temperature again.

The hotplate also provides me with an added level of safety. Allowing my tools to heat up for several minutes on the hotplate before my casting session begins allows any moisture or condensation that might be present on my tools to evaporate. It also eliminates the dramatic temperature differential between the 800 degree melt that I use and my casting tools that occurs in the wintertime. Dipping a cold spoon or ladle into an 800 degree pot full of molten lead can certainly add an unwanted dose of excitement to your life.

2) Weigh Your Bullets As You Cast Them

Every reloader owns and uses either an electronic or manual beam scale. Using a scale to weigh your bullets as they are cast is certainly not a new idea, but I believe that it is the single most valuable source of information about how well you are casting.

After dropping each completed bullet from the mould onto a padded surface, I immediately place it on my Dillon electronic scale and start pouring the next bullet. As Iím doing so, I quickly glance at the display on the scale to see exactly, to within one-tenth of a grain, what the last bullet weighed. Knowing the weight of each bullet immediately after it is cast helps me in three ways:

Weighing your bullets as you cast them is probably the single most productive step you can take towards casting better bullet

A) It Tells Me When The Melt is Too Hot

If I have been casting my bullets consistently within a given weight range and have not broken my rhythm, and a bullet drops out of the mould several tenths above where the other bullets have been, thereís a good chance that the melt is 20 to 30 degrees hotter than the 800 degrees that I want.

The higher weight is a red flag to check the temperature of the melt and to make the necessary adjustments needed to get the pot back down to 800 degrees.

B) It Tells Me When The Mould Is Too Hot or Too Cool

Once again, if the weight of my bullets start to gradually increase or decrease over a span of 3 to 5 bullets, it probably means that the mould is either getting too hot, or is cooling off too much. In either case, equipped with that information, I can adjust the amount of time I am allocating for Phase 5 of the Casting Cycle (Letting The Melt Harden) to compensate.

If the bullet weights are increasing it means that the mould is getting too hot and I need to allow more time for the melt to harden, thereby adding several seconds for the mould to cool. If the bullet weights are decreasing it means that the mould is cooling off too much and I need to shorten the amount of time I am allowing the melt to harden, thereby giving the mould less time to cool.

C) It Helps Me To Quickly Identify Rejects

If a bullet is significantly underweight, I know immediately that there is a void inside and I set that bullet aside in a pile to be used as fouling rounds. Although I usually know from experience when I have cast a bad bullet (generally because I did a sloppy job in Phase 1 or 2) the weight of the bullet confirms that fact. The out-of-weight-range bullet is simply a red flag to do better on subsequent casts.

Some Tips For Electronic Scale Users

If you use an electronic scale, here are a couple of helpful tips:

* Plug in your scale at least 10-15 minutes before you plan to use it. If possible, plug it in several hours before you begin to cast. That will give the unit sufficient time to warm up and stabilize. If I weigh a bullet immediately after turning on my scale and then again 30 minutes later, I will receive up to a one-half grain difference in weight. This is especially important if you have to cast in the frigid confines of the garage in wintertime. Outside air temperature can definitely affect the accuracy of your electronic scale.

* Be aware that most electronic scales are very sensitive to air movement and vibration. When I first started using my Dillon electronic scale to weigh bullets as I cast them, I was very disappointed in its performance. Although it had always performed well to weigh powder charges at my reloading bench in the basement, it seemed to take forever for the scale to arrive at a final weight when I used it to weigh bullets at my casting bench in the garage. It was not uncommon for the digital display to flash a series of numbers for 10 or 15 seconds before finally arriving at a final weight.

After talking to the people at Dillon Precision Products, I learned that their electronic scale is very sensitive to both air movement and vibration. To solve the problem, I constructed a small enclosure for my scale that shields it on three sides from moving air currents. I then mounted the enclosure on four soft rubber feet to help absorb any vibration that might be transmitted through my casting bench. The enclosure did the trick! Now when I place a bullet on the scale I receive a final weight instantly, with no variation or indecision on the part of the scale.

The use of this small enclosure eliminated unreliable weight readings from my electronic scale caused by air movement and vibrations in the casting area.

* Donít forget to use some type of insulated pad under your freshly cast, red-hot bullet when you place it on your scale. I use a 1" by 1" piece of 1/4" Masonite for this purpose. Prior to that, I used the thick aluminum cap from my Lyman 55 powder measure. The first time you forget to do this, that beautiful bullet you just cast will melt a dimple into the smooth plastic platen on your scale.


3) Use A Clock To Monitor Your Casting Cycles

An inexpensive battery-operated analog clock with a second hand can be just the thing to help you keep a precise, consistent cadence when you cast. I purchased the one I use at my local Target store for about $6.00. Although many casters simply count in their heads to maintain their casting rhythm, I prefer to let the clock do the job for me.

Using a clock will help you to more precisely manage the critical phases of the Casting Cycle and maintain your cadence from bullet to bullet.

The reason I use an analog clock with a second hand instead of a modern digital clock is personal preference. Looking at the face of the analog clock gives me an instant picture of where I am in the overall Casting Cycle. I generally glance at the clock as soon as the sprue puddle on top of the mould cools enough to get that frosted appearance (Phase 4).

Itís at that moment that I start Phase 5 of the Casting Cycle (Letting The Melt Harden). If Iím allocating 15 seconds for Phase 5 and the second hand is, for example, at the 12 oíclock position on the dial, I wait until the second hand reaches the 3 oíclock position before I cut the sprue. The clock allows me to time this important phase of the Casting Cycle precisely from one bullet to the next.

Glancing at the clock also helps me keep the overall time of each Casting Cycle the same from one bullet to the next. If it takes you 45 seconds to cast one bullet and 60 seconds to cast the next bullet, that time difference is going to show up in the weight of your bullets.

Finally, the clock also helps me to more precisely lengthen or shorten any phase of the Casting Cycle to keep the mould temperature where I want it to be. Using a clock as a casting aid doesnít mean staring at it for each of the eight phases of the Casting Cycle. Simply use it as a reference to keep things in sync from one bullet to the next.

An analog clock with a second hand provides an instant snapshot of the entire Casting Cycle time period.

If you currently donít use a clock when you cast, you might find it interesting to see how consistent you are (in terms of overall time per bullet) from one bullet to the next. The next time you are casting and producing high quality bullets, have a friend or family member time you through the eight phases of the Casting Cycle. Have them record how long it takes for you to complete each phase of the casting process. Do this for 10 or 15 bullets.

After your casting session is over, take a moment to add-up the time for each bullet and analyze the results. Pay particular attention to how consistent you are in Phase 5 of the Casting Cycle from one bullet to the next. You might be surprised by the results.

4) Use a Small Fan to Regulate the Temperature of Your Mould

Hereís something that I believe holds a great deal of promise in helping to control the temperature of the mould even more. I recently starting using a small electric fan to cool the mould during Phase 5 of the Casting Cycle. Before I used the fan, I was having to wait as much as 30-45 seconds in Phase 5 for the mould to cool enough to get the weight I wanted.

Now, as soon as the sprue frosts over in Phase 4, I set the mould on a small wooden block in front of the fan and wait 10-12 seconds. The fan bathes the mould in a constant, even stream of cool air. In the two sessions where I used this method, my bullet weights were incredibly consistent. By adding or subtracting one or two seconds to this phase of the Casting Cycle, I could almost predict how much the bullet was going to weigh to the tenth of a grain.

A small electric fan seems to add a degree of stability to the casting process by bathing the mould in a constant stream of cool air.

The outside air temperature during those 2 casting sessions was 55 degrees. Iím anxious to see if I can achieve similar results in the bitterly cold temperatures of a typical Chicago winter. In my opinion the use of a small fan may add an important stabilizing element to the casting equation.

Some Additional Ways of Achieving Consistency

The secret to casting nearly identical bullets requires performing the eight phases of the Casting Cycle the same way every time while trying to keep all of the other variables the same (i.e. melt temperature, air temperature, air movement, etc...). Changing even one element in the casting equation makes your job that much harder.

So here are a few suggestions to think about the next time you fire up the pot to cast some bullets:

Start The Season With The Largest Batch of Uniform Alloy Possible

At the beginning of each shooting season, prepare your alloy so that each ingot you put in the pot during the year is exactly the same. Mix the largest batch of alloy you can manage and cast it into small, manageable ingots. If you can, purchase several hundred pounds of alloy at a time, if storage space and money are not a problem. Then load it by weight into a large 40 or 50 pound pot, melt it down, mix it to your desired hardness, and cast it into smaller ingots appropriate for the size and type of pot you are using.

Lyman and RCBS make ingot moulds that work well for this purpose. I like to cast my ingots in heavy-gauge aluminum mini-muffin baking pans which you can find at any grocery or hardware store. Theyíre inexpensive, durable, and each one allows me to cast 12 small round one-half pound ingots. I purchased 10 pans that I use when I melt down the larger seven pound ingots I get from my alloy supplier. Because they are made from heavy-gauge aluminum, molten lead doesnít stick to them and they clean up in a snap.

Inexpensive aluminum mini-muffin baking pans make ideal ingot moulds when melting down larger bars of alloy into more manageable sizes.

If you shoot several different guns and each has an appetite for a bullet with a different hardness, your batches will probably be smaller than someone like me whose primary gun prefers a 20:1 mix.

A Word of Caution!

If you do use aluminum baking pans to cast your ingots, be sure to allow the ingots to harden and the pans to cool sufficiently before you empty them. If you pick up an aluminum pan filled with lead while it is still hot, it will have a tendency to sag badly or buckle from the weight of the melt. Thatís one reason why I purchased 10 pans. It allows me to cast 120 small ingots before I need to empty the first pan. By that time, the first pan has cooled enough for me to use it again.

By mixing your alloy in a large quantity and weighing the lead and tin when you do so, you will achieve the most consistent and uniform alloy possible.

Use a Reliable Heat Source

If you use an electric furnace to melt your alloy, pay attention to where the thermostat is set and how often it cycles on and off. Measure the temperature of the alloy when the pot reaches its designated temperature and the thermostat light goes off (the high end of the temperature range). Then measure again when the light goes on, indicating that the temperature of the melt has fallen below an acceptable level and the thermostat has kicked in to start the pot heating up again (the low end of the temperature range).

How large is that temperature spread? Does your pot keep the melt within a 10 or 20 degree range, or is it more like 50 degrees from its high to low setting? Once you have tweaked your pot to produce a relatively narrow temperature range, mark the dial settings and use them every time you cast. Although you may need to adjust your settings slightly to maintain your desired temperature as the level of the melt in the pot drops, donít get into the habit of constantly changing settings during your casting session.

If you use a propane-fueled heat source like a plumberís furnace, turkey cooker, or camp stove, start with a full tank of fuel and track the number of hours you use it for your casting sessions or weigh it before and after each casting session to get an idea of how much fuel you use per hour. Then watch to see when you start to get erratic heat production. As the amount of fuel in the tank goes down, so too will the efficiency of the burner. Usually after the fuel level in the tank has fallen to somewhere between one-half to one-third full, you will notice that the temperature of the melt will drop by 20 or 30 degrees, even though the burner control valve is set at the same spot that it was when the tank was full.

I use a plumberís furnace, and after about 10-12 hours of use, I either switch to a full tank or get the one Iím using refilled. Having a reliable source of heat for your casting operation is critical for efficient and productive casting.

Develop a Standard Routine for Fluxing

Hereís a point that everyone has an opinion about: how often to flux. Some people say to flux at the beginning of the casting session and then again after every 30 to 40 bullets. Others recommend fluxing the melt after every 10 or 20 bullets.

Experiment with each technique and then use the one that seems to work for you. The key is to do it the same way every time. Once again, what we are trying to achieve is consistency. Only by being consistent in every aspect of our casting operation can we achieve the highest results.

To help me keep track of how many bullets I have cast, I constructed a simple counting device using 15 plastic golf balls that slide from side-to-side on a small diameter metal rod about 30 inches wide. It looks like a poor manís abacus, but it works. The reason I use the plastic golf balls is because they are large enough for me to manipulate while wearing leather gloves. When I have completed a bullet I slide one of the golf balls to the other end of the rod. When all 15 balls have been moved from one side to the other, I know itís time to flux the melt. Any number of other methods will work just as well (i.e. using a small calculator, a cork board with push pins, a small chalk board, or moving marbles from one bowl to another).

Add Metal To The Pot At Set Intervals

Hereís another element of the casting process with no right or wrong answer ó adding metal to the melt while casting. Some people believe in throwing their sprue cutoffs and deformed bullets back in the pot as they cast. They believe that adding material in such small amounts will have the least impact on the temperature of the melt.

Others choose to accumulate a larger quantity of material, say after 50 or 100 bullets have been cast, and then add it all to the pot at one time. I happen to be one of those who subscribes to this procedure. The reason I do it this way is because I usually need a short break after casting about 100 bullets anyway. So I welcome the opportunity to stop for a short time to allow the melt to come back up to temperature once the scraps have been added.

The reason we pay attention to this element of the casting process is because adding metal to the pot during our casting session can have a rather dramatic impact on the temperature of the melt. Adding a large quantity of metal to the pot at once can lower the temperature of the melt by as much as 100 to 150 degrees. That kind of temperature change will definitely change the quality of the bullets you are casting, until the melt returns to its previous temperature

A friend and fellow BPCRS shooter, George Liotta, casts a small quantity of ingots at the beginning of each casting session and then sets them on top of his electric pot to stay warm. George believes that using ingots made from the same batch of melt with which he is casting insures a more uniform mix. Casting the ingots at the beginning of his session also insures that the ingots will be hot when he adds them to his melt later and therefore will have little impact on the temperature of the melt. Decide what makes sense to you and then make that your standard procedure for adding metal to the pot when you cast.

Determine Which Dipper or Ladle Works Best With Your Mould

Just like every gun seems to have a particular load and bullet hardness combination that it likes best, so to do your moulds. If you own more than one type of dipper or ladle, determine which one works best with the mould you are using.

I own several dippers including ones from Lyman and RCBS, and a bottom-pour Rowell ladle. Try as I may, I cannot consistently cast high quality bullets using the Rowell ladle with my Lyman Postell 457132 mould. For some reason, my bullets will vary by as much as a full grain from one bullet to the next. On the other hand, when I use my RCBS bottom-pour dipper, I can cast bullets within a few tenths of a grain all day long.

Why? Perhaps itís because when the dipper is sitting directly on the mould as the melt is pouring into the cavity, the pressure of the melt as it enters the mould is more consistent from one pour to the next. Of course, in order to achieve this, I have to make sure that I fill the dipper the same way each time. Having the dipper half-full one time and full the next will also affect the weight of the bullet cast.

Control Your Casting Environment As Much As Possible

Although you may not have given it much thought, where and when you cast can have a definite impact on the quality of your casting. If you have an enclosed space where you can control the temperature and air flow around your casting area (keeping in mind the need for adequate ventilation) you have a leg up on those of us who have to cast in our garage or outdoors.

My casting bench was initially located at the far end of my garage and sat under a large window to the outside. I constructed a small 3-sided enclosure around my furnace and pot in front of the window (top and both sides) and placed a 20" box fan on the window ledge. This proved to be a very efficient arrangement. The box fan drew any smoke or fumes away from my casting position and vented them to the outside.

For safety reasons, I leave the garage door partially open to provide fresh outside air. Unfortunately, the outside air on any given day can vary by as much as 80 to 100 degrees depending upon the season of the year. As a result, the length of my Casting Cycle varies slightly from month-to-month based upon the temperature and humidity of the air.

Believe it or not, even changing the speed of a box fan in the window can adversely affect my casting. One day I changed the speed of the fan from medium to low. Within just a few minutes I noticed that my bullets were casting nearly a full grain heavier. I finally figured out that when I changed the speed of the fan, it reduced the movement of air through my casting area and affected the temperature of both my mould and melt. As a result, both the mould and melt were getting hotter with each bullet I cast.


When I realized what I had done and its impact on my casting, I returned the fan to its original setting and watched my bullets return to their previous weight range. If you use a fan to ventilate your casting area ó ďJust set it and forget itĒ!

If you cast outdoors, your challenge is even greater. Changing temperatures and variable air currents make your job the hardest of all. If you can, try to cast at the same time on calm, nearly windless days or days when there is a steady breeze to carry away smoke and fumes. Early morning or early evening would seem to be the best times to try to cast due to the lower temperatures encountered.

Conclusion

I hope that the information presented in this two-part article has been useful. Iím confident that if you understand the Casting Cycle and look for ways of making your casting routine more consistent, youíll soon find yourself casting better bullets more often! If you have any comments or questions about anything I have presented in this article, I would like to hear from you. Simply e-mail me at darrylray@longrangebpcr.com.

By Darryl Hedges
 

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