Melting stainless steel at home

Discussion in 'Furnaces and their construction' started by David McCauley, Apr 8, 2021.

  1. So I recently put together 2500w zvs induction heater, I was pleasantly surprised by its performance! I was able to melt and cast stainless in a matter of minutes. Unfortunately the only easily accessible 220 hook up is in my basement and my girlfriend was not happy about the smell coming from the basement... so I'm going to have to figure a solution to that.. thought I'd share for those looking for a cheap way to melt ferrous metals at home! 20210331_191538.jpg 20210331_191534.jpg 20210401_074919.jpg
     
    BattyZ, Al2O3, Jimmymmm and 1 other person like this.
  2. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Excellent! Couple Questions for You David.
    1. What was the weight of the melt?
    2. What are the crucible dimensions?
    3. What was the mold material?
    Best,
    Kelly
     
  3. I didn't weigh the melt but if I was to guess I'd say 3/4 of a pound . The crucible is 1.5x3.5 inches. The mold was resin bonded sand.
     
  4. Very nice!
     
    David McCauley likes this.
  5. I got mine from alibaba but it looks to be the same, it's a power supply from a server
     
  6. Fulmen

    Fulmen Silver

    Thanks. Like I needed more ideas...

    One question: How rugged are these units? I tried building a small ZVS driver once, but it was more of a mosfet-fueled smoke generator. These are a bit too pricey to be disposable...
     
  7. I cannot speak much as to the ruggedness as I just haven't used it or had it long enough. Although I would venture a guess and say it's as rugged as most Chinese products, which is not so much...
     
  8. metallab

    metallab Silver

    Make a fumehood or use at least some ventilation ? But what smells ? To my experience, SS melting does not cause any fumes or stench except from the electric arc. I use an arc welder, but your induction furnace does even not have that problem. It is not brass with nasty zinc fumes.

    You are talking about 3/4 lbs which is 340 grams ? Is that really possible with such a unit ? And what about heat insulation ? Wrapping Kaowool between the coil and the crucible ? Because SS is immensely hot (1600 C), hotter than cast iron which is easily lost. I did not more than 100 grams in a graphite crucible acting as an anode and holding a carbon rod cathode above the SS bath.
    Another issue is that the SS absorbs carbon from the crucible which makes it brittle.

    I am interested, I found this one: https://www.amazon.de/-/en/Inductio...keywords=zvs+induktion&qid=1619287676&sr=8-23

    And how did you power this ? Usually such DIY units are made for 48V DC which requires a 2500W (switching) 48 power supply to connect to the grid (120 or 230V).
     
  9. spelter

    spelter Copper

    I have two zvs units, both bought on eBay from seller 'wilson-su'. One about 4 years old, 2kw; one about 2 years old 2.5 kw. I've never killed either one, put in modeate use. The newer machine is much nicer--has protection circuits for the mosfets and a readout to indicate drawn power. (Watch the power indication as the load is placed into the coil to figure if the mosfet is about to get stressed.)
    Speedy. Melt zamak in a steel crucible in about 2 minutes, bronze in 5-10 in graphite. Biggest nuisance is chopping the starting materials small enough to fit the crucibles.
     
  10. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Just curious, is the loading for non-ferrous metals due primarily to the crucible mass?

    Best,
    Kelly
     
  11. spelter

    spelter Copper

    Mostly crucible geometry, partly crucible mass, partly crucible material. A crucible that just fits inside the coil draws much more than one with ample clearance. As a graphite crucible oxidizes and thins it draws less load. High clay crucibles draw way less (poor conductivity). A graphite rod in an insulating crucible does little to draw power (poor geometry match).

    Graphite, being a semiconductor, conducts better and better as it heats, so the draw creeps up with time. Metals conduct worse as they heat, so their draw falls off as they heat. As metal melts its geometry changes, seems like it could draw more, but I haven't noticed it. Ferromagnetic materials draw abruptly less as they reach their curie temperature (great for brazing steel, heats quickly to brazing temp with little overshoot).
     

Share This Page