Suggestions for Heating Element for new casting pot

[Texasflyboy]

Howdy guys,

I am at a critical stage in my manufacture of a new casting setup. My original pot was 10" in diameter and about 5.5" tall. The heating element is electrical, and I assume it’s a standard 8" stovetop element (that's what it looks like anyway).

For reasons beyond my control the new pot is 12" across and 5.5" high. I have a new electric element (8") rated at 2100 watts @ 240V. But, since I am using a 12" pot, I can actually fit three 6" elements each rated at about 1500-1700 Watts @ 240 volt. So, either one element at 2100 watts or three for a total of 4500 watts.

The way I am designing the base, I can swap out the elements if needed, but it will be a chore.

My question is, will the single 2100 watt 8" element be enough to bring the pot up to 650F as my old one did?

Is 2100 watts considered a lot of wattage for melting lead or is the 3 1500's overkill?

My current design (the 10" pot with single element) takes about 75 minutes to bring the lead to temperature (about 125lbs of melt). It's a big pot.

What do you all think? Single or three element?

[powderburnerr]

Use three and switch two of them so when starting you use all three and when up to temp you can turn one or two off to maintain heat ...kinda like a thermostat .....Dean

[454PB]

I agree with powderburnerr. For instance, the Lee 20 pounder has an 800 watt element, which is well contained, and surrounds the pot. You are describing an unenclosed pot holding six times as much lead. In case you didn't know it, three 1500 watt, 240 volt elements in parallel are going to pull about 15 amps.

[Texasflyboy]

Thanks for the help. I decided to go with three 1500 watt elements.

And if I remember my 'lectric math"

Watts = Amps x Volts

1500(3) = A x 240

4500 = A x 240

4500/240 = 18.75 (Amps)

From what I remember its best to run a circuit at no more than 80% of rating so:

30 x .80 = 24

So, I will be pulling about 19 amps or so, well under the 80% rule.

The circuit I am using is a 30A dryer circuit. So I think I am safe on the electricity.

I plan on posting the complete assembly for all to see. I have been documenting the construction with lots of photos.

[versifier]

For 30A wire it up with #10/2copper romex or the less expensive #6Aluminum cable. Make sure you use the conductive NOALOX paste (you can get in in small tubes from the electrical supplier, or borrow a tube from an electrician) on all connections with aluminum cable. Individual pieces of #10 copper wire removed from romex cable will be much easier to use for wireing the internal connections as they can be soldered. I would point all the element connections to the back, not out as you posted in the picture on the parellel thread. This will be safer in that none of the hot (in the electrical sense) poles will be sticking out the sides. The normal rheostat controls from any electric stove are fine and can easily be scavenged if you have not done so already and can be mounted anywhere convenient, like on the front away from wherever you rig the spout. After wiring the poles to the rheostats, then I would run the feeds to the individual rheostats from a small slave box that holds one double-throw 30A breaker mounted on the side of the lower housing (where it won't get hot) and feed it with a range cord. You can run the cable from your panel to a range outlet. I would use the heavier range outlet and cord (rated to either 40A or 50A) as opposed to the smaller 30A unit designed for an electric clothes dryer because the range fittings are much more rugged and will stand up better to hard use. Neither is really designed to be plugged and unplugged constantly like a 15A or 20A 110v plug and outlet, but the heavier ones (a few bucks more expensive but worth it) will last a lot longer. (Easier to just shut it off at the panel when not in use than to unplug it, though, if that is feasible and you won't have to be moving it around.) The individual rheostats will enable you to fine tune your casting temperature so you can turn two of them to low or off as suggested by powderburnerr once it's all melted.

[454PB]

Good info by Versifier. Having a seperate breaker is a good idea, and it's important that you NOT interupt current by unplugging. With that kind of load, you'll damage the plug.

The only thing I wouldn't do is using any kind of solder connections close to the heating elements, because they will melt.

I'm looking forward to seeing the finished project, that thing is going to be a monster!

[August]

This information is wonderful!!! Yet, I suddenly feel like the Red Green show is a documentary rather than a comedy..... [smilie=p:

[waksupi]

This information is wonderful!!! Yet, I suddenly feel like the Red Green show is a documentary rather than a comedy..... [smilie=p:

Red Green is a genius. Simple solutions, to life's everyday problems.