Boiling out Ceramic Shell

Discussion in 'Investment casting Ceramic shell method' started by Jason, Apr 25, 2018.

  1. crazybillybob

    crazybillybob Silver Banner Member

    This Coming from the infamous "BP" Creator Himself! :D:rolleyes:
     
  2. rocco

    rocco Silver

    I know, right? That's why I told him:
     
  3. Jason

    Jason Gold

    Well I guess I know what all you clowns are getting for Christmas!:p
     
  4. Jason

    Jason Gold

    Roy, I'm about to run another boil out process in the next day or two if I don't get stuck working. I've got 6layers now on those shutter dogs and they are getting HEAVY. One more to go, and some buildup work on the cup. That area is always a little thin on me when shelling. Then a fast seal coat and into the drink it goes. I'll video it for ya.
     
  5. Roy Carter

    Roy Carter Copper

    Thanks Jason. I assume you are referencing your site and will check it out and thanks. Actually I boiled out three pieces on Tuesday. Really nervely the first time. After getting the gas pressure setting right was able to get full, consecutive roaring boils. Recovered the wax. You are right! There were no cracks in the shells!!!
     
    Jason likes this.
  6. Jason

    Jason Gold

    That is outstanding news! I did 2 boil outs yesterday and wasnt so lucky. I think my stuff might be getting a bit old. I talked to Barry this morning and his take is the slurry will do a couple of years. BUT surface finish will suffer. So when his very expensive BARREL starts to get old, he buys a 5gallon pail and uses it for the first 2 coats. He uses the old stuff for the coarse applications. Boiling out thicker sections can be problematic too which is the fence I was up against.:(

    I'm proud of you manning up and taking the plunge! It is unsettling the first time you do it. Now let it dry a day, inspect it real close and fire it up to around 1700 and pour metal. Post some photos of it.
     
  7. Roy Carter

    Roy Carter Copper

    Wow, your reply was fast. Will attempt post of setup. Photo up! Shot prior to meltout.
     

    Attached Files:

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  8. Roy Carter

    Roy Carter Copper

    Follow up photos three shells with wax boiled out and ready for firing (hardening) prior to pouring molten metal into them. Also showing repairs at wax gate and vent with refractory cement to fourth shell. The fractures on the fourth were due not to regular handling but to an inexcusable one.
     

    Attached Files:

    Jason likes this.
  9. Jason

    Jason Gold

    Looks like a win to me! I notice your hangers and your floor. 2 things that stick out to me, remember if you suffer a leak or something catastrophic, a concrete surface will not like 2000degree metal that hits it. First the metal lands and if it doesnt splash on you, after about 30 seconds, It can cause the bound moisture in the concrete to rapidly turn to steam and goes off like a bomb! Thus throwing molten metal who knows where. Some people dont know this is why I mention it. Age of concrete, inside or outside can make a difference, just something to think about.

    2nd, the big foundries often bury shells is sand. I do not. The sand helps insulate the shells and maintains the preheat temp. It also keeps shells from blowing out and if they do, the piece is often saved from small leaks.

    Now I pour on my concrete driveway, but I place shells over a sand surface. Often I use a metal bucket with sand in the bottom. I pull shells from the kiln with scraps of kaowool and leave them wrapped. The sand gives a soft resting place and the wool affords some insulation. The bucket will save my ass from bronze running down the driveway!:eek:
    Just tossing out some ideas for you.;)
     
  10. Roy Carter

    Roy Carter Copper

    Jason as always you are a fountain of excellent and generous information. Many Thanks. Photo of boiled out shells was for sharing. Excuse my excitement at this juncture. The actual metal pour will come later, will be done outside on a gravel driveway with the metal stand suspending the shells over a metal pan containing river sand. Yeah, I have seen some videos of industrial castings with spaceage clothing, persons picking up red hot shells, tossing them up and over then placing them aggressively into sand pits ready to receive molten metal. Would be most exciting to see it first hand.
     
  11. Jason

    Jason Gold

    Got it Roy.;) I'd hate to be that guy that didnt say something when the opportunity was there. Most of us here wear big boy pants and understand the risks doing this shit at home. lol
    This isnt knitting that's for damn sure!
     
  12. Jason

    Jason Gold

    Hey Roy. Seeing I think you and I are the only ones here boiling out shell, take a look at this.
    Note how they load the shell upside down in the basket. Now that you've seen the wax float up and out of the shell, this doesn't make sense to me.
    Wax floats on water!o_O However, when a large pot of water boils, the boiling takes place on the bottom. I have to wonder if upside down might be a faster way
    to get the wax out as the pressure and agitation of the boiling entering the shell might help reduce time submerged?o_O

    What sayeth you?



    I have a theory straight water may be the wrong stuff to use. Autoclaves run much hotter. Say around 200c from what I can find. Ethylene glycol boils around 387f, so right around the same. If we could get the temperature of the boil up higher, I bet time in the bath could be significantly lowered and that would be a good thing!
     
    Last edited: Dec 12, 2020
  13. Roy Carter

    Roy Carter Copper

    Hey, guess we won't know untill tried. Perhaps with a small speciment in H2O.
     
  14. Jason

    Jason Gold

    At 40bucks a gallon, I dont think ill be trying it soon. I wonder how thick that stuff is at 100%?
    Antifreeze doesn't raise the boiling point high enough. An extra 50-75degrees isnt worth farting around with it.
     
  15. Roy Carter

    Roy Carter Copper

    I will be boiling out my fourth piece today, weather permitting. Will stay with pouring cup facing up boil out method!
     
  16. Jason

    Jason Gold

    I would. Go with works! Good luck! The real test is when it goes in the kiln. If it smokes like hell, you missed a chunk. If it smokes very little, ya did good. And if it throws a flame when ya crack open the kiln lid to peek, ya did it too fast. First time mine throw a flame at me when I looked, I peed a little.:eek: When the o2 hit that sucker it went, WOOF!:D
     
  17. Roy Carter

    Roy Carter Copper

    Thanks for the detailed insite and being such a good trail Blazer. Was concerned about what you describe. My heat up (vitrification) furnace has a drain hole in the bottom.
     
  18. Jason

    Jason Gold

    lol.. trail blazer, never got called that before.:D I really doubt you'll see any wax drain out. What little wax remains will burns up pretty fast, but oh god the smell!

    I KNOW there has got to be a good solution for us home gamers that can nip this issue in the bud. Have you seen Barry's dewax/burnout chamber yet? It's worth a peak. He has had some issues with grates burning up, I think Zap did stainless grates, but they too will burn up in time. I'm not opposed to changing grates out at all. I just want less drama doing this.. (and to save my hair and wax)

    Some place I saw the coolest rig and I cannot find it. It essentially was a bottom loading furnace with 2 different floors. The furnace gets preheated really hot and the main bottom swings away, another bottom which was a grate was loaded with shells and swung back under the furnace and lifted up into the heat. The wax came pouring out the bottom into a tray of water for collection. After it stopped raining wax, the solid floor swung back and lifted up to close up the entire show. The metal could be melted meanwhile and the shells were ready awaiting.

    Anyhow, Here is Barry's setup in Baton Rouge. Ignore the first part with the cup. He doesn't do that anymore. He has a better system these days. My only complaint with his setup is, I know he loses a ton of heat with that big side door open. His kiln here is just kaowool so you know it loses heat damn fast. Firebrick would be better for his application.

     
  19. DavidF

    DavidF Administrator Staff Member Banner Member

    Gives the brat kid a cookie to shut him up.

    Increase the pot pressure to increase the boiling point..
    Or grab a hot water heating element and build yourself a steam Lance to melt out the wax.
    I'd imagine there is a small one in your jewelry store???
     
  20. Roy Carter

    Roy Carter Copper

    Thanks Jason for sharing video. Very interesting. Too big a setup for my purposes.
     

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