Electric smelter idea

[sammorgan3]

Check my thinking here guys.

Flat bottom cast iron pot with a stove element brazed to the bottom along with a brazed K TC. PID control set to 700 along with some insulation should prevent melting in zinc. Worth a shot for me to prototype?

[blikseme300]

Not sure if brazing the element to the cast iron pot is a good idea as I have seen cast iron crack easily after being brazed.

A number of members here have built their own smelting pots and I can't recall any using cast iron. I copied ideas from the work others have done and black steel and SS are the materials I used. The way I did it is documented here: http://bliksemseplek.com/boolits.html

[sammorgan3]

Duly noted on the cracking. I know CI can successfully be brazed or welded with a slow ramp up and down in temperature, I'll have to look into it. Already have a cast iron 5qt dutch oven with a flat bottom, seems would be ideal. Would rather braze for thermal transfer between element and pot, perhaps something else will work. Braze element onto a steel spreader plate with Tcouple embedded in the middle? My thinking is if the heat source never passes 700* then zinc shouldn't be a problem, just dump skim and pour ingots. Of course melt times would probably be slower due to DeltaT being lower but with insulation probably not too bad.

Edit: That Mother of All Melters is insane! :shock:

[Idz]

I believe your typical stove element is about 6 kW which translates to 20,000 BTU/hr . Turkey fryer burners run about 35,000 BTU/hr and I use a weed burner torch that can put out 500,000 BTU/hr. With my insulated propane tank pot loaded with about 100 lbs of scrap it takes about an hour for a melt with my torch running about 50,000 BTU/hr. Electric is fine for small batches or if you're patient but to go into production you'll want something bigger.

[country gent]

Another issue with brazing will be the diffrent expansion rates between materials, the heating element, cast iron, braze. Alot of the electric elements are bands or inserts that are wraped around or set into holes in a plate. MAybe a false bottom with the element in it.

[ssnow]

I like the idea of a large electric smelter, basically for more economical operation, and you would avoid all the hassle involved in propane bottles. If I ever get around to building one, I would simply use steel, and avoid cast iron.

Yes, many do use cast iron pots so they certainly work.........but I would not have to worry with steel breaking, and besides, steel gives you a lot more options. You can use plate and make it whatever size you want, or there is a lot of pipe and tanks available fairly economically.

[craig61a]

I do recall seeing a pot that someone built using electric stove elements - ah... have a look at this thread:
http://castboolits.gunloads.com/showthread.php?5126-Diary-of-a-Casting-Pot-Construction

[dikman]

I wouldn't have any confidence in something like that. Welding/brazing cast iron is problematic at best and when it's subject to heating/cooling cycles like that I reckon you're asking for trouble. Maybe if you bolted the element somehow to the bottom?

[Handloader109]

If it was me, I'd do something similar to blikseme300. You can get cylindrical heating elements pretty cheap. And I would stay away from cast iron

[sammorgan3]

Hm. Perhaps something simpler? Like a large PID controlled hotplate? Could even remove the lead pot and put the big 40gal crawfish pot on it then! :redneck:

[sammorgan3]

Cylindrical element would be nice wattage wise. Would have to build a steel pot though. Biggest pipe I have laying around here is somewhere around 5.5OD x 1/4Wall. Not really as big as I wanted, would make a tall skinny pot that's difficult to work in.

[dikman]

Yeah, tall and skinny isn't good when you're dealing with a lot of hot lead! Not the best, stability-wise.

How about a propane tank, cut the top and bottom off and weld a piece of round steel plate in the bottom. Then you could attach your heating element to the bottom.

[sammorgan3]

I was just having thoughts along these lines myself. 8" round of 3/16 welded in to flatten off the bottom would work and could get more capacity. I can save my dutch oven for chile. :lol: Steel would allow easier thermocouple attachment as well, just weld on a nut.

[sammorgan3]

http://castboolits.gunloads.com/showthread.php?10127-1-Lead-Smelter

Well this guy seemed to have good luck with a stove element. Basically what I've got in mind + engineered stand and PID control.

[bangerjim]

Welding on those elements will probably ruin them. And the CI warnings above...ditto!

I still feel nat/propane is the best way. Fast, easy to control, high BTU concentration. Much faster and more efficient than anything electric. Why do you think pro chefs use gas stoves? You never see electric stoves on pro cooking shows!!!!!! You can't beat a blue gas flame.

Electric is perfect for casting.....would not have it any other way.

Good luck in your search for the perfect illusive electric smelting pot!

banger

[dragon813gt]

Has anyone sat down and done a cost/benefit analysis. I'm able to smelt hundreds of pounds on one tank of propane which costs $20. I pay around $.075 per kWh for electric. I would have to sit down and do the math which would be based on the heating element size. And the BTUs needed are dependent on a lot of environmental factors. I think propane would be cheaper if I did the math.

[angus6]

buddy did the math last year when we built a 17.5"l x12"w x 10"d pot , worked out cheap enough

[bangerjim]

With Obummer shutting down all the coal plants in the next couple years, your electric bill will far exceed the cost of a tank of propane!

banger

[sammorgan3]

My point with the electric smelter was to never let the bottom of the pot exceed 700*F. Therefore no sorting required before smelt. Maybe pick out stick ons if you wanted.

[bangerjim]

My point with the electric smelter was to never let the bottom of the pot exceed 700*F. Therefore no sorting required before smelt. Maybe pick out stick ons if you wanted.

But.......sorting is half the fun!!!!!!!!!!!!!!!!!! HA.......ha! :dung_hits_fan:

Actually I hated it when I used to mess with ww's. Not any more, I mix all my alloys. If I want something close to ww's, I make it.....all from clean pure alloys.

good luck with that pot.

banger

[DLCTEX]

A pid can be made to regulate temp on a gas fired pot by using a solenoid valve and pilot light.

[bangerjim]

A pid can be made to regulate temp on a gas fired pot by using a solenoid valve and pilot light.


Mabe in East Texas......but that would violate local codes in several areas I know of. Messing with flammable gasses with non-code controls comes under violation of local codes. Be sure you research it before going down that rabbit hole.

Sure it will work, but if you would ever have a problem, fire, or explosion...................:dung_hits_fan:....... .!

Just a head's up.

banger

[JSnover]

Wouldn't it take a while to melt, if the element never gets above 700f?

[sammorgan3]

I'm sure it would take a while with the low delta t. hoping that I can get good enough conduction to keep it from being too bad. Have pid and element on the way from evilbay. Decided on steel pot. I got a coworker checking his junk pile for an old propane tank, or I should have an old carry air tank somewhere. Pid will be in a nut welded to the bottom of the tank itself.

[bangerjim]

I'm sure it would take a while with the low delta t. hoping that I can get good enough conduction to keep it from being too bad. Have pid and element on the way from evilbay. Decided on steel pot. I got a coworker checking his junk pile for an old propane tank, or I should have an old carry air tank somewhere. Pid will be in a nut welded to the bottom of the tank itself.


Do you know what a PID-based controller is? It will not fit in a nut. The thermocouple (you did order one, right?) needs to be mounted so it is down in the molten lead to give accurate reading of actual temp. Otherwise, you are doing the same thing Lee does with their bi-metal thermostat.....indirect reading outside the pot.

It will take a significant amount of time time to heat a large pot of cold lead to melting point. 700 watts is what the little Lee 4-20 pot is and that takes a good 1/2 hour to melt 18# of lead. I guess you can turn it on, fill it, and go watch a movie or two or three. You would be much better off using wrap-around thermal elements to get high thermal concentration and wattage. I would try for at least 3,000 watts minimum!

There are several good threads on here describing how to implement a controller to a standard lead melting pot. I do not use one or ever plan to. And........I sell them!

And do not forget that old stove element more than likely runs on 220V. Make sure your SSR is rated for that voltage.

God luck in your endeavor. Let us know of your results!

bangerjim

[sammorgan3]

Yes. I'm fully aware of what a pid is. Mistyped, meant tc in nut. If I put the tc in the melt then the bottom will get hotter than that. Tc should be nearest heat source you intend to cap the temp of. Yes I ordered a tc. And an ssr, and fiberglass tube for wire insulation.
;)

Edit for clarity: I'm intending to regulate the temperature of the bottom of the pot itself to prevent zinc melting. Stove element is 2100 Watts 240v.

[jmorris]

I use a 3500 watt oven element wrapped around a 3/8" thick pipe for the element on my casting machine. Controlled by a PID and solid state relay.

http://i121.photobucket.com/albums/o213/jmorrismetal/caster5.jpg

I wrapped a section of stainless around it like a large band clamp. Had to replace it once in the last 10 years, cost $16.

You can see the remains of the pivot and pour spout that I used before a friend gave me a different melting device and I turned it into a 60 lb bottom pour casting pot.

[sammorgan3]

jmorris I remember reading the thread on that when I was but a lurker. Awesome setup there. Maybe one day I'll have a go at an auto caster. Right now time spent casting and loading governs the $ I spend shooting. :lol:

[jmorris]

The single most expensive part of that build was the then $60 magma mold but I was just giving you another idea. You don't have to get fancy with the heating element.

[bangerjim]

Yes. I'm fully aware of what a pid is. Mistyped, meant tc in nut. If I put the tc in the melt then the bottom will get hotter than that. Tc should be nearest heat source you intend to cap the temp of. Yes I ordered a tc. And an ssr, and fiberglass tube for wire insulation.
;)

Edit for clarity: I'm intending to regulate the temperature of the bottom of the pot itself to prevent zinc melting. Stove element is 2100 Watts 240v.

Excellent! Your element should have a bunch of heat transfer to crank up at first and then level out at set point. You will be inferring the temp of the melt but you can always stick a thermometer or another t/c in there to check. (Those isothermic quick-connects come in handy!) Once you get the delta, you can guestimate from there.

Let us know your final results.

Banger

[sammorgan3]

Hm. Those panel mount tc plugs are spendy aren't they? :lol: ooh well, pony up!

[sammorgan3]

Well I take back the panel mount plug being expensive, found decent price at Auberins. Of course I ended up spending $60 anyway because that box was so much nicer than the gutted computer psu I have sitting right here. :killingpc Oh well. I'll have a nice box, and a nice big power switch, with pluggable Thermocouple. And enough room in this bigger box for nice big heatsink on the ssr and 240v wall plug on back to make box totally seperable from the pot.... And any other excuses I haven't come up with yet. :lol:

[sammorgan3]

As of right now.

Evilbay:

Mypin Ta4 --- $24
9.8' K probe - $5
2mm sleeve - $4
40A SSR ----- $5 (Because why not!? :-P)
2100W HE --- $12

All free shipping

Auberins:

Box ---------- $30
Connectors - $8
15a Switch - $5
TGrease ---- $2
1' K wire ---- $2

$14 Shipping. :-(

Local cord, plugs, various, stuff I already had, etc ~$30

Grand total $140 Give or take. Got two guys hunting a propane tank, And I have some scrap steel for the bottom and some legs. Should be no big deal now that I should have most of the parts on the way.

[blikseme300]

JMorris,

The picture and description of your setup is what set me off on the path to casting happiness a few years ago. I used band heaters instead of the stove element but the outcome was similar. Thanks again for sharing.

[jmorris]

JMorris,

The picture and description of your setup is what set me off on the path to casting happiness a few years ago. I used band heaters instead of the stove element but the outcome was similar. Thanks again for sharing.

Where are the photos? Glad I had a positive influence on someone, will have to tell the wife.

[blikseme300]

Where are the photos? Glad I had a positive influence on someone, will have to tell the wife.

I edited this page on my website adding you to the credits so you can show the wife. http://bliksemseplek.com/boolits.html

[jmorris]

Very nice step by step! You didn't have to edit your page (not like I invented any of the ideas) but now I will have to show the wife. ;)