blow holes

Discussion in 'Home Foundry & Casting Projects' started by sawyer massey, Jul 22, 2019.

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  1. Jul 22, 2019 #1

    sawyer massey

    sawyer massey

    sawyer massey

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    I just started casting cast irion and all my poor's so far have had blow holes at the pooring hole
    What am I doing wrong?
     
  2. Jul 23, 2019 #2

    Brian Rupnow

    Brian Rupnow

    Brian Rupnow

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    Try googling "blowholes in iron castings.
    "Such defects can be caused by air entrained in the melt, steam or smoke from thecasting sand, or other gasses from the melt or mold. (Vacuum holes caused by metal shrinkage (see above) may also be loosely referred to as 'blowholes')."
     
  3. Jul 24, 2019 #3

    sawyer massey

    sawyer massey

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    • know what causes them .how do I cut down on them ?longer runs dryer greensand?
     
  4. Aug 28, 2019 #4

    sawyer massey

    sawyer massey

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  5. Aug 28, 2019 #5

    sawyer massey

    sawyer massey

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    Getting better flywheel is 12 "x3 crank disk is 7.25
     
  6. Aug 29, 2019 #6

    ddmckee54

    ddmckee54

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    Have you tried additional vents? Or maybe not ramming the sand quite so hard so that the gasses can vent through the sand easier?

    Also have you checked in with the guys over on AlloyAvenue http://www.alloyavenue.com/, or The Home Foundry http://forums.thehomefoundry.org/? They love to hear from anybody who's pouring iron.

    Don
     
  7. Oct 19, 2019 #7

    sawyer massey

    sawyer massey

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    Governor casting is great crank not so much think I'll ad some to the diameter iron was lots hot enough an had 6lb left over
    Over filled the riser and still did not fill the casting again I'm am starting to wonder if the sand is collapsing as it is only 5/16 thick at this point .
    Or should I put it in the top box and fill from the bottom
     

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  8. Oct 20, 2019 #8

    skyline1

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    This looks like a "cold shut" it tends to happen with thin sections, it is caused by the metal "freezing" before it has chance to fully fill the mould cavity

    Notice the depression in the top of your runner this is an indication of not enough "head" of metal in the runner.

    Extending the runner height should cure this (I used to use old beer cans with the top and bottom cut off)

    As you are ramming the cope embed the runner extension in the sand a little around the runner stick and fill with sand so that the runner height extends above the cope

    A good large "cup" at the top of the runner will also help giving the casting a bulk of hot metal to draw from.

    Wide ingates are a good idea and if you still get cold shuts use multiple ones to "feed" the casting from multiple points.

    I had trouble with this too, when I first started casting iron 'til an old moulder taught me the runner extension "trick" so you are not alone.

    Some Ferro-Silicon added to your melt will also make your metal more fluid if you can get some.

    Hope This helps

    Best Regards Mark
     
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  9. Oct 20, 2019 #9

    Shopgeezer

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    What are you using to melt the cast iron, gas or electric?
     
  10. Oct 21, 2019 #10

    jimsshop1

    jimsshop1

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    I would like to see your furnace if you don't mind. I have built one and it works great for aly and brass. I just got done casting a 45 lb cylinder of bronze for a special bushing for a WWII surface grinder at work. I would like to melt some cast also. What do you use for starter ingots?

    Thank you,

    Jim in Pa
     
  11. Oct 21, 2019 #11

    sawyer massey

    sawyer massey

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    I use an oil burner
    I use electric motor end bells I work in a refinery town and the company I work for rebuilds motor's the 3 I have now weigh over 200 lb each but they are real hard to break up
     
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  12. Oct 21, 2019 #12

    jimsshop1

    jimsshop1

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    Steamman70

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    Thanks Sawyer,

    Have you thought of using a press to break them?
     
  13. Oct 22, 2019 #13

    sawyer massey

    sawyer massey

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  14. Oct 22, 2019 #14

    sawyer massey

    sawyer massey

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