The Firing Line Forums - View Single Post - An open question on costs of bullet casting.

zippy13 · December 4, 2010, 09:55 AM

For the cost of operating your melting pot there are three basic variables:
• the price of electricity
• the power consumption of the pot, and
• your production rate.

For an example let's assume:
• Your electricity rate is $0.08* per kilowatt hour ($/kWh), and
• Your pot consumes 700-watts.
I'm SWAGing (scientific wild-ass guess) your pot runs full power for half an hour to get up to temp and then the thermostat has it on for 75% of the time.

So, to get your pot up to temp it costs 0.7kW x 0.5h x 0.08$/kWh = $0.028 or 2.8 cents.
And for continued operation it costs 0.7kW(x 0.75) x 0.08$/kWh = 0.042$/h or 4.2 cents per hour.

How much does it cost to cast 1,000 boolits?
• Let's SWAG you cast a slow and steady 1 bullet per minute. So 1,000 boolits requires (1,000m/60m/h) 16.67 hours.

The power would cost you 2.8(warm up) + 4.2 x 16.67(run) = 73 cents for 1,000.
Divide by the number of boolits, 73/1,000 = .073 cents per boolit.

I don't know about you, but I don't cast at 1 boolit/minute. With a 6-hole mold, a dozen/minute is a leisurely pace. Also, there's the time consumed adding more lead and fluxing the pot. My solution is to run two pots at the same time so I have little interruptions.
So with a base of .073 cents per boolit, I have to double the amount because of my two pots, and then divide by 12 because of my faster rate:

2 x 0.073/12 = 0.012 cents per boolit.
YMMV

Similar math could be applied to my hot lube/sizer, but I don't know it's power consumption. Since it has a littly whimpy power cord I'm SWAGing it can't be very much. As far as amortizing my boolit making gear, I figure at penny a boolit I broke even long ago.

* electric rates.
If your electric company is like mine (San Diego Gas and Electric), there is no simple electric rate. I downloaded a full page of schedules. Based on an energy cost of 0.0515$/kWh, the rates change based on time of year, consumption, connection category, etc...
I used 0.08$/kWh as a rough average. Whatever your rates, casting energy cost is probably in the neighborhood of 1/10 cent per boolit.

December 4, 2010, 09:55 AM	#8
zippy13 Senior Member Join Date: August 23, 2008 Location: SoCal Posts: 6,442	For the cost of operating your melting pot there are three basic variables: • the price of electricity • the power consumption of the pot, and • your production rate. For an example let's assume: • Your electricity rate is $0.08* per kilowatt hour ($/kWh), and • Your pot consumes 700-watts. I'm SWAGing (scientific wild-ass guess) your pot runs full power for half an hour to get up to temp and then the thermostat has it on for 75% of the time. So, to get your pot up to temp it costs 0.7kW x 0.5h x 0.08$/kWh = $0.028 or 2.8 cents. And for continued operation it costs 0.7kW(x 0.75) x 0.08$/kWh = 0.042$/h or 4.2 cents per hour. How much does it cost to cast 1,000 boolits? • Let's SWAG you cast a slow and steady 1 bullet per minute. So 1,000 boolits requires (1,000m/60m/h) 16.67 hours. The power would cost you 2.8(warm up) + 4.2 x 16.67(run) = 73 cents for 1,000. Divide by the number of boolits, 73/1,000 = .073 cents per boolit. I don't know about you, but I don't cast at 1 boolit/minute. With a 6-hole mold, a dozen/minute is a leisurely pace. Also, there's the time consumed adding more lead and fluxing the pot. My solution is to run two pots at the same time so I have little interruptions. So with a base of .073 cents per boolit, I have to double the amount because of my two pots, and then divide by 12 because of my faster rate: 2 x 0.073/12 = 0.012 cents per boolit. YMMV Similar math could be applied to my hot lube/sizer, but I don't know it's power consumption. Since it has a littly whimpy power cord I'm SWAGing it can't be very much. As far as amortizing my boolit making gear, I figure at penny a boolit I broke even long ago. * electric rates. If your electric company is like mine (San Diego Gas and Electric), there is no simple electric rate. I downloaded a full page of schedules. Based on an energy cost of 0.0515$/kWh, the rates change based on time of year, consumption, connection category, etc... I used 0.08$/kWh as a rough average. Whatever your rates, casting energy cost is probably in the neighborhood of 1/10 cent per boolit.