On building a Satanite/Wool furnace lid

Discussion in 'Furnaces and their construction' started by Melterskelter, Feb 29, 2020.

  1. Melterskelter

    Melterskelter Gold Banner Member

    I did not use a binder between the layer of wool. I am skeptical of binders doing much since wool has almost negligible tensile strength perpendicular to its flat face and the wool I used was so thin that coating each piece would have been impractical. I agree that rigidizer seems to add only a little strength to fired wool.

    Unfortunately, no supplier near me seems to have the moldable stuff. I have called suppliers in a 200 mile radius and come up empty. Those sound like an ideal solution due to the omni -directional orientation of fibers. I would definitely use it if I could source it and not pay ransom for shipping.

    Denis
     
  2. Melterskelter

    Melterskelter Gold Banner Member

    Incidentally, I would not have to make a trip to a Chinatown for a large wok. Amazon has them in 20 and 22 inch sizes at acceptable prices. I will check at my local commercial-kitchen supply house. They should have them too and probably cheaper.

    Denis
     
  3. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    But that's ultimately what you are relying on at the Satanite interface. The wool/blanket I have, has a different orientation or weave of fiber at the surface.......much stronger in that vicinity. The wool load is actually more in shear at the binder interface, and like I said, the binder was much stronger and acted liked fiber reinforced ribs and also gives the hot face some minor structure to attach to......suit yourself on that. Domed or not, a thin layer of Satanite will still crack and sluff.....a 1/2" wall castable or plastic refractory probably stands a better chance of benefiting from domed structure.

    Best,
    Kelly
     
  4. Melterskelter

    Melterskelter Gold Banner Member

    Yes, I like the Satanite rib idea. So, in retrospect, I might next time butter up every 10th vertical joint as that might add a bit of strength vertically. But, yes, there is little getting around the Satanite/IFB bond as an essential aspect of the lid. I fully expect to have to patch it up every few melts. The initial run yesterday was very good as the lid did great. But one run on anything means not a lot. The thing I have finally learned (took me a while) was to learn how important it is to bring each soupy layer of Satanite up to red heat before applying the next coat. Doing so seems to make a much stronger lining. I do not think and may be wrong about this that allowing the Satanite to dry for a period of time prior to firing helps. Satanite really does not change state/bind on drying as evidenced by the fact that some Satanite not used for a coat that then dries up in the mixing container can be easily reconstituted with water. So there is no cementatious component to Satanite as opposed to the various castables including bubble alumina castable.

    Denis


     
  5. Melterskelter

    Melterskelter Gold Banner Member

    I suppose you all thought I was BSing about hammering a domed lid. While buying a wok probably is more sensible from a time-use point of view, I’ve always been intrigued by the idea of hammer-forming metal. Also the Covid pandemic has made me think 3 times about going to retail outlets to make purchases. Sooooo, I tried hammering on a scrap of 16ga about 18” in diameter using the crudest of tools—no sand bag or purpose-made hammers, just what I had. I used the old race pictured and hammers pictured. And with a couple hours gently smacking the steel managed to crown it about 4” and found I could control the tendency for the steel to potato chip and pucker around the edges. This was just a practice piece.

    I have a 22” (actually 25 which will be trimmed after forming) to start hammering on for real, this time. It will be used for the next lid. Hammering is therapy to some extent! ;-)

    Denis C842DD9A-F8E6-47E4-B7C5-5D3D713ECAFF.jpeg

    DC2DE12F-A25B-4F29-85F5-BD8C6F58A7C1.jpeg


    I get the feeling this shape could be hammered to be quite fair and the filed and sanded to look “pretty.” That’s not the goal or intention here. But the actual lid dome will likely be crowned more. It is something I’ll just work on time-to-time in odd moments over the next few days.


    Denis
     
    Tobho Mott likes this.
  6. Peedee

    Peedee Silver

    You did good, I've found an old stump makes a great bottom tool in place of a sand bag. With a ball pein it soon works into shape. (I re-floored a Mini like that, it does work if the stump is soft)
     
  7. garyhlucas

    garyhlucas Silver

    So why does everyone exhaust out the top of the lid? My SpeedyMelt commercial furnace exhausts out the side with only a small 1" hole in the lid for the pyrometer I would guess. I would think the side exit promotes the hot gasses swirling around the crucible heating it but keeping most of the combustion materials away from the top of the molten metal.
     
  8. Hey Denis,
    Thanks for the build. I found this useful making my lid. Unlike the concentric insulation idea that Kelly proposes, this can be used with small scraps of left over insulation rather than perfect roll pieces ( good for using all your material) . It packs tight and nice. Thanks for the idea.
    IMG_20201017_122732976.jpg IMG_20201017_124559768.jpg IMG_20201017_132658441.jpg
     
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