Melting furnace

[bpcp7208]

I'm looking to invest in an electric melting furnace. Can I get some pointers for what brands are good/the best for the price? I have bunch of product that I'm going to need to cornflake once I'm fully prepared to process the material and want to get everything I'm going to need. I have browsed online, seen a few on Amazon but I don't want to invest in a cheap or possibly sketchy equipment. Also, if there's anyone selling their old working furnace. Any pointers would be greatly appreciated! As always, thank you all got all that you do on this forum!

 

[scwiers]

Hi BpCp,

Attached are pics of my home-built DIY 240v resistance furnace, made for a total cost of about $130 including refractory brick Kawool, 18-guage Kanthal A1, titanium electrodes (graphite or tungsten would be better), a used drier plug, 25' feet of high-voltage wire, and a power switch (on-off).

If there's sufficient interest I might go into more detail; but there are already quite a few youtubes out there.

Winding coils is no big deal; basically you use Ohm's law (V=IR) (basic formula works OK for quick and dirty, even though working with AC), to set a target power, say 3500 Watts, and work back from there to determine your length. 18 gauge Kanthal really is the minimum thickness; anything thinner and the wire starts to deform at temps above about 2000 F.

Plusses:
1) cheaper than anything on eBay or Amazon; gets up to %2400 F in 40 minutes; can melt up to 12 lbs of copper in a #10 crucible;
2) Quieter than a WVO furnace


Minuses:
1) Not as fast as my WVO furnace;
2) No ramp soaker, so temp is controlled with the on-off switch;
3) Electrodes have to be sanded down after each cool down; graphite better but I don't have any right now.

I'll try to post pics of the thing up and running; but I'm really busy right now.

Cheers,
S

Pics: Furnace; Furnace with titanium electrode on LH side; Winding jig

 

[etack]

What are you melting and how much.

Eric

 

[scwiers]

I typically inquart copper and silver with gold, 4-5 pounds at a time in a #8 or #12 crucible. Again, WVO is faster.

 

[Gsracer]

I use a 5kg size propane gas powered furnace i got on amazon for 300.00, by itself it will melt a kilo of silver in about 50 minutes and hold 2500 degrees. However when i force air with my shop vac into the venturi it can melt the kilo of crystal in a little less than 18 minutes. It will reach well over 2800 degrees (my infared tops out at 2800) it gets white hot and the fire brick starts to come apart if im not careful, i regulate the air I'm forcing into it with a valve till i get it where i want it. For smaller batches it will melt most PMs in under 10. I have had to replace the KAOWOOL already once, soon i will be replacing it again. It really plays a number on it.

 

[scwiers]

Hi Gracer,

yes, I've had similar experiences with my homemade propane furnaces. I have to watch them carefully, or I can melt thru crucibles, and the furnace itself, if I'm not careful. For me, WVO is more forgiving-- while it gets to 2400 F OK, I seem to get more control over it, and not melt my furnace and the linings.

 

[etack]

I typically inquart copper and silver with gold, 4-5 pounds at a time in a #8 or #12 crucible. Again, WVO is faster.

If this is your melt get a 15KW induction and water cooler; melt it that way.

$1100 for the setup and you will melt that in no time.

Eric

 

[scwiers]

For melting slimes, my trusty WVO furnace works well. (Pic of results attached). Can't do slimes neatly in an induction furnace.... "Cause they just won't melt, just won't melt, just won't melt..." :mrgreen:

Below: pic of 6 pounds or so shot melted from slimes along with some copper/silver/gold residues from old batches, done in WVO furnace