Wattage ratings for controls?

[Russel Nash]

Lee W. wrote:

I know of the thermostat in the RCBS. It is a 10mm stainless steel bulb type thermostat with a 6% of scale accuracy. (+-30F in this case)
The switch can handle 16 amps at 230 volts, so 3680 watts.

Oooppsss... I guess I didn't see your post on the first read through of this thread.

Hmmn... maybe the RCBS controls are an option still.

[Russel Nash]

I called RCBS today.

The controller, they said, was $42.

I will have to take a peek inside my RCBS Pro-Melt furnace to see what else I would need to buy.

They also said the 110V and the 230 V models take the same controller.

I guess it's all a matter of how the whole sha-bang gets wired together.

[Echo]

It seems that RCBS uses an actual thermostat - if so, it responds to the temperature of the alloy, and not the duty cycle as a controller would, so mains voltage would have little effect, other than max load allowed.

Check at a plumbing or HVAC supply for a heavy duty dimmer/controller capable of carrying 8-10 amps (whatever your heating elements will draw). Can probably buy one a lot cheaper than $42...

[DLCTEX]

I think the simplest way to switch the 3000 watt element would be to use a magnetic relay for switching and then any of the thermostats will handle the small load of the magnetic coils.

[Russel Nash]

Now... you two have got me scratching my head.

[Lee W]

You could get these items:

http://auberins.com/index.php?main_p...products_id=14

http://auberins.com/index.php?main_p...products_id=22

http://auberins.com/index.php?main_p...products_id=30

And I and others here would help hook it together.

[Russel Nash]

You guys keep this up and it's gonna turn into the mother of all birdshot makers.



Thanks for those links.

[moptop]

Hello to all! This is my first time posting here and I don't want hijack this thread but I just wanted to add a little info on controls/thermostats. I am an appliance tech by trade and if you are needing a way to regulate temp on an electric element I think I can help. Just use a surface burner control from and electric stove. It's called an infinite switch and will simplify your build, espeically since you are going to power it with 240 volts. They work as explained above in this thread by cycling on and off by means of monitoring the current draw of the element through a bi-metal contactor. Or if your want a more precise control of your pot temp you can use a bulb type oven thermostat also obtainable from an older style electric stove. Only 2 contacts, you hook it up like a light switch. Now you will have to play with the placement of the bulb because these are only designed for temps between 200 and 500 degrees. I've never seen anyone who would want to cook food at 700+ degrees,...unless she's really pissed at the husband for buying another gun!!

I built my own lead melting pot from scrap parts and it works great. I used a small stainless bowl, a defrost heater from a refrigerator, and a coffee can as a heater box.
Nothing fancy but it gets the job done and is very easy to build.

[Russel Nash]

^^^ Thanks Moptop!

And welcome to the forums!

I still need to give RCBS a call back to see if their controller does include the thermocouple. I posted pics of the innards of their Pro Melt in another thread.

Yeah, I had thought about the oven controller too, but the 500 degree max oven temp thing threw me off.

I guess if I put the thermocouple in contact with another part that wasn't so close to the melt or to the element, and was more in the range of 400 or 500 degrees that might work.

One junk yard I called to ask about old electric ovens, the gal said something to the effect because of legal reasons the owner might not want you out there scavenging for stuff.