Wax burnout using high internal heat

Discussion in 'Lost wax casting' started by JBC, Apr 7, 2021.

  1. JBC

    JBC Copper

    Neither :(
    But it's science! ......and small 3.75" flask diam helps.

    450g of investment at a time isn't too bad. Those 4"dia x 6" pour$ are waiting patiently.
     
  2. JBC

    JBC Copper

    This Kiln is at the perfect price.

    Is this worthy? It's your time to shine :)
    Can this be turned into a burnout kiln by adding a PID to it?

    IMG_1866.JPG IMG_1867.JPG IMG_1868.JPG IMG_1869.JPG
     
  3. You'll need tongs that can grab a flask from above instead of from the side. Haven't seen any available commercially like that, but then again I didn't go looking. And pay real close attention to the order you put multiple flasks in because you'll need to put them pretty close to last in first out.
     
  4. Jason

    Jason Gold

    That would work. Front load is easier, but I have a top load kiln and I make it work fine.

    You didnt post a link. How much is it? Craigslist is usually the place to find super cheap kilns.
     
  5. JBC

    JBC Copper

    Thats a good point. I just looked at the tongs I have for my propane kiln and the flask(s) I'm using now is way to small. I guess I'll need some heavier duty gloves to pull those out or move fast.
    I'm pouring Zamak (melting temp -810F) at approx. 900F. So I think the flask should be around 500 when ready for the pour......I need better gloves.

    How do you move the flask?
     
    Last edited: May 6, 2021
  6. Jason

    Jason Gold

    I have 2 kilns. Tongs on the front load and I use kaowool to grab shells with gloves hands. By the time I get to shell, I'll be damned if I am going to drop one jacking with tongs.
     
  7. JBC

    JBC Copper

    Thanks, I'll go that route.

    Have you tried anything like these or are your flask temps way too high?

    This comment from the listing makes these a little suspect: "Perfect for handling animal like DOG CAT BIRD REPTILE from getting bited!"

    But there might be some worthy gloves somewhere instead of using kaowool no?

    These are interesting, but getting too pricy.
     
  8. Jason

    Jason Gold

    No those gloves will not work. Commerciall available gloves to pick up 1500 degree stuff will be expensive. That's why I use a 12"x12" piece of kaowool or use tongs. And I still wear some serious gloves and can still feel heat through it.

    Tongs are the way to go picking up round flasks. You can make a set of 90 degree tongs to pull them out.
     
  9. JBC

    JBC Copper

    I think I’ll keep looking and find a front opening kiln.
    No savings are worth bad f-ups or burnt toes.

    On another note, I spent a little more time making a better tree for tonight’s 3” flask.
    The pictures don’t do it justice….it’s no Bo Derrick (from my bell-bottom days) but it’s a lot better than before. The longer spruce is of course cut off.
    Thoughts? I'm still learning this wax-tree thing.


    DF94DCC8-DC53-4BB0-918C-DAFF8F00170F.jpeg DEB8D639-CB66-4B09-AE0A-71E2D94BFF69.jpeg 28534F78-6E39-45C5-9AD3-6236B31F7C8C.jpeg F6DBE481-539F-408E-8DC8-89065F54D62F.jpeg 3075724F-9DB7-4480-8232-A33CC1A75399.jpeg Hmmmm
     

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    Last edited: May 7, 2021
  10. rocco

    rocco Silver

    Maybe a stupid question but is there anything preventing you from just turning that kin on to its side, maybe with a little spacer underneath so the door won't drag on your benchtop?
     
  11. JBC

    JBC Copper

    That’s a good question.
    It went through my mind but there are layers that come apart. I could strap them together but my ‘damnit’ radar was going off thinking about issues that might pop-up later.
    I like how you think though.
     
  12. Fulmen

    Fulmen Silver

    The biggest problem would probably be that the heating elements would be unsupported at the roof, makes my damnit-radar go *ping* as well.
     
    Jason likes this.
  13. JBC

    JBC Copper

    Casting small 3" Dia x 4" tall flasks using a microwave and a toaster oven works fairly well.
    The patterns shown here measures 44mm long 3mm thick (less than 1/8in!) and 15.5mm tall. The detail/texture was captured really well. The edges impressed me with how they turned out just like the wax patterns.
    [​IMG] Saint2.jpeg


    These thin patterns needed an additional runner to feed metal to the center. I had one out of four almost fill in completely. The rest couldn't connect the 'a' and the 'i' in 'Saint.'
    Saint1.jpeg


    It will be interesting to see how a hotter flask will handle fewer runners to fill the entire mold. And being able to keep the metal flask on the mold should help draw metal into the mold cavities. That's my assumption at this point.


    The flask didn't start cracking until maybe a minute after the pour. I expected a crack sooner and was pretty pleased when the crack didn't cause any noticeable defects in the cast.
    IMG_2818.jpg

    Overall, using a microwave and a toaster oven can give you some decent results when casting these smaller molds. If the pattern was less detailed and thicker it shouldn't be much of a problem for those of us kiln-depraved. I think larger flasks are possible too but more testing will need to be done.
    But I won't be doing it.
    I think I've found a kiln and hopefully will be driving up to get it this weekend, if the kiln-god$ smile upon me.

    Here is what I found worked pretty well;
    (Materials used are posted at the top of this thread-page 1)

    2:00 pm Invested
    5:30 pm De-waxed in the microwave to let the wax flow out.
    5 minutes on high -Sprue down.
    30 minutes on high -Sprue up so steam can escape while the wax residue is further reduced.
    6:05 pm Flask wt =497.2g
    Placed the flask into a toaster oven at 325F
    7:00 pm Toaster oven turned up to 450F (it bounced back and forth between 425-450F sadly, but hey... it's a toaster oven and that's the max temp this thing can muster!).
    Flask temp =250F (measured the exterior of the mold using an infrared thermometer)
    8:00 pm Flask wt =475g
    Flask temp =350F
    9:00 pm Flask wt =474.6g (95% of the de-waxed weight)
    Flask temp =370F

    The metal I used was Zamak 12 with a casting temp of approx. 815F with the exterior flask temp of approx. 350F (flask temp drops 100F/minute from what I've read).
    I think having the flask's internal temp at around 400F would have better. Maybe even 500F but I just don't know enough about casting Zamazk 12 (or casting anything lol).

    A quick sloppy paint job and Wa-la!
    Painted Saint.jpg
     

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    Last edited: May 8, 2021
  14. JBC

    JBC Copper

    I appreciate everyone's comments and help.
    Casting this small detailed piece helped me understand the whole process better which should help me with my real projects down the road.
    After I get my kiln I'll need to set it up with PID and automate this hobby!

    jbc
     
  15. JBC

    JBC Copper

    OK...I just read something about metal.
    A good rule of thumb is to get your metals temp approx. 200F above the melting point.
    And get the flask about 400F below the pouring temp.

    Zamak 12's melting point is 810 (I thought it was 710F). So the ideal pouring temp would have been 1010F instead of the 810 I used.
    And pour when the flask is approx. 600F.

    Huh......
     
  16. JBC

    JBC Copper

    DavidF likes this.
  17. Jason

    Jason Gold

    Thanks for that link. I wanna try one of those.
     
  18. JBC

    JBC Copper

    Before you try one let me sell you this wired dinosaur first.

    On a different note, I need to replace the oil in my Vacuum pump.
    I have a lowes near me and a home Depot not too far off.
    Suggestions?
     
  19. Jason

    Jason Gold

    I get vac pump oil from amazon.
    Wish I saw your offer earlier. I ordered that pen thing already. Post a photo of your dinosaur and a price, I might still take it.
     
  20. Jason

    Jason Gold

    Found you a kiln building video from one of our members here.

     
    Bldr J likes this.

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