Furnace questions

[heavyd]

I have a Lee pro 4 20 and thinking about purchasing a RCBS Pro melt. The Lee has gotten on my nerves so much I no longer enjoy casting. I can't justify spending $300 extra for the Magma master pot to get the extra 20 lbs of capacity (if it's worth it please convince me). So, I was thinking about the following:

Run my Lee and a pro melt at the same time. When the pro melt starts to get low on alloy then transfer allow from the lee to the pro melt. My question is, how could this safely be done?

Also, do I need a thermometer for the pro melt?
How do I put the Lyman mold guide on the pro melt so I can use my lyman molds?
How well does the pro melt hold temp? If I get a thermometer will I be able to set the temp and not have to fool with the furnace to keep it at 700 degrees?

Thanks in advance for the help.

[1bluehorse]

The only part of your question I can answer is the mold guide part. The RCBS mold guide will work with any mold. However the Lyman is of a better design, or at least others seem to prefer it. I have a Pro Melt, just haven't started using it yet....I don't see any issue with the mold guide thats on it.

[cbrick]

First, any electric pot is going to vary in temp to some degree, it's the nature of the beast. The thermostat shuts off power when a pre-set temp is reached but the heat already produced still goes into the alloy raising the temp somewhat over the pre-set temp. When the alloy temp goes down and gets to the pre-set temp it turns on but it takes a little bit to generate the heat and then for that heat to flow into the alloy to start the cycle over. The only exception to this that I am aware of is the current Magma PID controller, it shuts off the power a bit early so the temp doesn't go over the pre-set. It also turns the power back on a bit sooner so that the temp doesn't go under the pre-set. The heating element in an electric pot doesn't produce more or less heat depending on what's needed, it's either on or off.

My RCBS pot holds temp with a pre-set of 700 degrees at about 680-685 to about 715-720. For 99% of casting needs this is good. I do use a thermometer in my RCBS and pre-set to 700 degrees.

Not trying to talk you into a PID, just explaining the realities of elctric pots.

The other issue with electric pots is that as the alloy level goes down the pot temp will go up regardless of the pre-set. The PID will also eliminate this issue. Actually this isn't just an electric pot issue, you'll get the same thing with a gas fired melting set up if the flame isn't reduced as the pot level goes down.

I have been using my RCBS pot since 1984 and see no reason or purpose in changing the mold guide.

Rick

[Rockchucker]

Most of the better thermostats have a build in heat antisapater (sp) meaning the s-tat will cut out before the set temperature is reached because of the heat build up. My pro melt thermostat is a little off also but not worth the trouble of sending it back to RCBS. Maybe my thermometer is off, one of em is anyway.

[bobthenailer]

i also prefer the lyman mould gide over the rcbs and have converted my rcbs to take the lyman mould guide by drilling two holes in the base a and using long bolts & washeres to attache .
If you have a hot plate or small camping stove put some 1/4 to 1/2 inch steel plate on it at low temp and pre heat your ingots before adding , i can run 8 cavity saeco moulds with no problem using this method about 1200 to 1400 bullets a hour.