Casting a Bearing Cap in Iron

Discussion in 'Sand Casting' started by PatJ, Dec 5, 2018.

  1. PatJ

    PatJ Silver

    Success.
    It looks good.
    I am quite please with the results, and I don't see any problems.
    Not bad for an amateur backyard guy with a limited number of iron pours, if I do say so myself.

    If you get your gating and runners right, then the bound sand generally works first time, every time, and gives very consistent and predicable results.
    Bound sand eliminates any issues with too much/ too little moisture, insufficient mulling, etc.

    I don't see any shrinkage problems, so if the machinability turns out ok, then I would say 2.5 oz was about right for 20-25 lbs of iron (I need to weigh the castings).

    The bearing cap numbers/letters turned out great.
    I am very pleased with that.
    The whole idea behind salvaging the existing bearing cap was to capture the old numbers/letters.
    It would have been much easier to just 3D print a new pattern, but I had no way to get those numbers copied exactly.

    I am uploading the breakout video.
    Here are a few photos.
    The mold coat did not make a perfect finish, and I may have applied it too thin, and it shrunk, but it would appear that the main reason for the mold coat is so that the sand does not stick to the casting, and in that respect, the mold coat worked fabulously, and there was almost no sand adhering to the casting anywhere, which makes cleanup very quick.

    The last test flywheel I cast did not have mold coat.
    I will look for a photo of that for comparison of the sand adhering to the casting.

    The lines on the bearing cap are the blue painter's tape that I used.
    Since you don't rap the patterns in the mold, the bound sand picks up everything on the pattern rather exactly.
    The tape allows the low spots to be slightly high, where they can be buffed/sanded off.

    The bearing cap has machining allowance on the bottom, ends, and on the tops of the ears.
    And the cap has draft angle, so there will be some machining required.

    I will try to drill one of the gates tomorrow.
    That should give a good indication of hardness/machinability.
    Worst case the casting can be annealed to make it more machinable, but I have not had to do that in the past.

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    Last edited: Sep 11, 2019
  2. Jason

    Jason Gold

    Well done Pat! Congrats!
     
  3. PatJ

    PatJ Silver

    Thanks much.

    This was my 12th iron pour.
    .
     
  4. Tobho Mott

    Tobho Mott Gold Banner Member

    Congrats, looks great!
     
  5. PatJ

    PatJ Silver

    Thanks, I am very glad it turned out like it did.
    One never knows what you will get when casting stuff.

    Here is the breakout video.

     
  6. PatJ

    PatJ Silver

    I see a lot of casting folks who use wood flasks, and generally these flasks have some gnarly burns on them.
    So on the humor side, I am happy to say that no wood flasks were harmed in the making of these castings (they are snap flasks, so you snap them off before a pour).

    :)
     
  7. PatJ

    PatJ Silver

    The weight of the bearing cap with sprue and runners was 4.0 lbs.
    The weight of the straight edges with sprue, runners and risers was 12.6 lbs.
    The remaining ingot was 2.2 lbs.

    So total poured iron was about 18.8 lbs.
    I did not measure the iron before it was melted, so I don't know the slag loss, but the slag did not seem excessive.

    I did not clean the scrap before melting it, so it went in with paint on it and some light rust at the broken surfaces.

    I don't have a measurement on the fuel, but I am pretty sure I was in the 2.8 gal/hr range.

    The gates on both castings were about 0.2" thick and 0.45" wide, and I was able to easily drill through one of the gates on both castings without problems.
    Shrinkage was very minimal, so it looks like the 2.5 oz of ferrosilicon was on the money.
    In the past, I have never been able to drill anything less than about 0.4" thick when ferro was not used.

    .
     
  8. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Congrats Pat.

    From the video, looks like you may have lost a little skin on your right index finger. Casualty of war?

    Best,
    Kelly
     
  9. PatJ

    PatJ Silver

    Thanks much, I am pretty excited about this success, especially after the windmill gear failure.
    I needed a win for a change.

    Nope, that is just burnt sand.
    But I did have a pretty good burn there on a previous pour, where I did not preheat the ingot mold enough, and the iron did the "pop" thing, splattered up on my jacket, and then ran down in my gloves.
    It was just a tiny amount of iron, but a tiny amount of iron goes a long way as far as burning off skin.
    You really can't get a glove off fast enough to prevent a serious burn with iron in there.

    Here are the photos from the "burn-pour" as I call it.
    Curad silver solution kept me from going to the doctor.
    It finally filled back in with scar tissue.

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  10. PatJ

    PatJ Silver

    I was a little concerned about the size of the runner, sprue and gates, since I went "full Puhakka" on those, and made them about 1/3 of what I normally would have made them.
    And I got rid of the pour basin, and omitted the basin at the bottom of the sprue.

    Its always risky when you change the setup a lot, but it seemed to work well, and I trust Bob Puhakka; that guy really knows his stuff, and his politically incorret videos are hilarious .

    .
     
  11. PatJ

    PatJ Silver

    I did not get the pour on video, since I got in a rush and forgot to turn on the camera, but it looked about like the Metal Museum pour, shown below, but not at night, and not during a rainstorm (that was a crazy pour for sure with all the thunderstorms raging around me).
    See 26:05.

     
    Last edited: Sep 12, 2019
    Tobho Mott likes this.
  12. Jammer

    Jammer Silver Banner Member

    Looks Great!! Nice Job.

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  13. PatJ

    PatJ Silver

    The bearing cap is in the mail.
    Good luck with it Ron.

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