may I suggest that you do away with the heating coils and go with a heating band instead.
This is how Magma does their Master Pot (pot for Master Caster)
may I suggest that you do away with the heating coils and go with a heating band instead.
This is how Magma does their Master Pot (pot for Master Caster)
That is a great idea, but they are a little pricey. I did a quick search and depending on size and width they could be in the $80-$200 for just one:
https://www.grainger.com/category/ba...ecatalog/N-raq
I received the $20 replacement heating coil, and this one is visible thicker than the prior two ones. If that fails (again!), I will take a serious look at the heating bands
Will
I am enjoying following this thread. Hoping for an excellent outcome as I had a similar project in mind when I started casting recently.
Well, my 3rd coil failed on me
This one was the thicker one, so I had a little bit more high hopes:
But it also worked briefly before it becoming an open circuit
In the short term, since I wanted to make some boolits, I moved the pot to my propane setup:
A friend of mine told me that instead of a normal oven heating element, I can perhaps use the oven's self-cleaning heating element, which by design is meant to heat up much higher. Either that or the more expensive heating band is my next step.
Will
Excuse me all! Maybe I'm saying a nonsense!
But why not put the heating element IN and not outside the furnace?
In this way, I BELIEVE that the melted lead once the temperature set with a PID has been reached, can prevent the heating element from reaching too high temperatures and burning! In addition, the heating element of 2500 WATT seems to me enormous! You could also use one or two "cartridge" heating elements like these:
https://it.rs-online.com/web/p/risca...uccia/8606895/
https://it.rs-online.com/web/c/autom...uccia/?rpp=100
Then there are cartridge heaters with thermocouple, to be used in a PID: this prevents the heating element from reaching too high temperatures.
For a better transmission of heat you could proceed in this motion:
1) - pour melted lead with a propane stove inside the container: you save a lot of time !.
2) - turn on the electrical resistance, whose temperature is set at a level higher than that for lead: in this case the resistance will never reach temperatures so high as to burn
3) - The thermocouple inserted inside the furnace (about 350 ° C) and connected to another PID will avoid too high temperatures of the alloy.
P.S. If you proceed pouring the already molten lead inside the furnace it seems useless to use a resistance with thermocouple connected to another PID, because the thermocouple of the furnace will interrupt the ignition of the resistance at a temperature much lower than that which could damage the resistance itself !
It is advisable to introduce ingots as the molten alloy is consumed, so that the electrical resistance is always covered by molten alloy.
I do not have need nor interest in duplicating your project, but have certainly learned a few things that will benefit me in the future.
I think with the patience you have displayed, we should change your handle to Job!!
Thanks for sharing and good luck with this ongoing project.
Its been interesting reading about your project. I would love to have an electric bottom pour pot that would hold 300 or 400 pound of lead. I've looked at ceramic kilns thinking thoughts that only a caster would have!
One of my furnaces
my furnace with 1 resistence
multiple lead delivery system: up to 6 cavities
[IMG]http://i67.tinypic.com/118n5w8.jpg[/IMG
the nozzles fit perfectly to the sprue holes of various brands (Lee - photo - / Lyman / RCBS)
a furnace with two resistence
I disconnected the connections because I have to mount a PID to adjust the temperature (before I used a Lyman thermometer)
Last edited by airone46; 11-08-2018 at 04:26 PM.
This is an interesting thread. I’m interested in how the internal heating coils works out.
For the external coils version, depending on price, maybe a coil for an commercial/industrial oven might hold up better.
Those that I used, and that are seen in photos, are the electric resistances of Lee: then they were the only ones I had found at an economic price.
Also I bought from an importer through a friend who had the gun shop (now no longer has the sale of weapons!), And therefore the price was lower!
Now you can buy a lot more on the internet, and then there are cartridge heaters!
With the resistance mounted inside, the heat loss is much lower, especially if you leave the resistance always covered with lead (I never empty the furnace, but I always leave the lead so that the resistance is always covered!).
I only have to put a thermal insulator on the outside, but with the economic crisis that exists in Italy and in my city, all the small shops that sell special items have disappeared! You can buy on the internet but you have to buy at least a certain amount, which is always excessive for small jobs.
I had thought of making a very simple automatic production, ..... but now I'm old and I do not want to do anything!
It was necessary to drill the mold at the top, so as to fill it not from the side of the base but from the side of the ogive: the remaining piece was useful for powder coating, but then ... it was necessary to cut it WITHOUT LOSING VERY TIME!
Perhaps in this way, with multi-cavity molds, it is faster!
What exactly do you mean by a thermal insulator? What kind of material are you looking for?
I want to isolate the outer sides of the furnace to avoid thermal dispersions and accidental burns.
Once there was an asbestos mat, now it's forbidden!
I could use glass wool!
You need to use rock wool. It can withstand temps to 1000° C. Can you find it where you are?
https://www.rockwool.co.uk/learning/...lation-guides/
This I am following with great interest, I’ve been in the industrial boiler business for last 40 years. The rock wool will work to insulate outside of pot, don’t know how long tho. A better choice would be the white ceramic Kao-wool that’s used with higher temperature rating, if you can get it. The inside the pot design will increases the eff. And if like you say to always keep lead in the pot makes sense, it will not run too hot as to have problems. The only thing I could see wrong with it is {if] a single element went out, with a full pot of cold alloy, that would be a problem. If you have 2 elements, maybe both wont go out at the same time, you could use one to heat pot and drain to repair other one. The problem with wrapping new elements around a cylinder is, you cant get it wrapped evenly so as not to have gaps that don’t touch said cylinder and you end up with hot spots therefore burn outs. The commercial heating pots all have very good tight contact with whatever they are heating. If I were to try to make a large capacity container, would possibly consider using the internal design and always keep alloy covering the 2 purchased elements.
I know that rock wool is not the most suitable material, and that it would take ceramic wool! for this I made the "lazy" and I did not put anything, up to this moment!
If an element fails, it breaks down while the lead is melted! It would hardly fail to furnace switched off! In any case there is the other element that would melt the cold lead! It would only take a few minutes more! Generally I operate both resistances until I bring the alloy to the optimal termpertura, then I turn on one, alternating them!
So far I have never had problems! If I had to be so unlucky to burn both resistances with cold lead (DIFFICULT!) I always have an GPL torch to melt the alloy!
In fact, it is not worthwhile to empty the furnace every time you finish working, and then when you want to work again, turn the ingots into another pot and then pour everything into the electric furnace!
I think the rock wool will work for you. It nothing like fiber glass wool that is most often used for insulation. It has a much higher temp rating. Since you said it was hard to get materials where you are, rock wool can be found in most building supply stores.
Hossfly.
You seem to be the most knowledge about this. I know the ceramic Kao wool would be the best for heat resistance and insulation, but it seems he is having a problem sourcing it. Don’t you agree rock wool could work for him and be a lot easer to find. I was thinking of the ridged type. Best would be to cover it. At a minimum several layers of aluminum foil could work.
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |