Bob Puhakka on Bifilm theory

Discussion in 'Links to useful information' started by Gippeto, Feb 2, 2019.

  1. I've done my four. Have one still on 95 lbs test for a week now. I think the water has been absorbing air, the pressure is down to 87 psi and stable for four days.
     
  2. I took a stab at interpreting bifilm theory application to small flasks/castings.

    Comments appreciated.

     
    dtsh, Tobho Mott and Petee716 like this.
  3. Tobho Mott

    Tobho Mott Gold Banner Member

    It was easier to follow than Bob's explanations on Perry's YouTube. Very nice.

    Jeff
     
    oldironfarmer likes this.
  4. PatJ

    PatJ Silver

    Don't forget that Bob's bifilm theory apparently comes from John Campbell's work, and John Campbell's work includes 10 rules for good castings.
    If you pay attention to the bifilm theory and ignore John Campbell's 10 rules, then you most likely will have achieved nothing.
    The big pictures has to be kept in mind when casting metal; it is not just one theory but a number of complex interactions that must be understood.
    .
     
  5. ESC

    ESC Silver Banner Member

    Good job Andy, but no explosion:).
    Seriously, that is a lot of information all in one place. I appreciate the captions because I couldn't get the volume up enough for these old ears.
     
  6. Tobho Mott

    Tobho Mott Gold Banner Member

    Good point Pat, I'm still working my way through Campbell's 10 Rules book, but I don't have the bigger more expensiver one that I'm told 10 Rules is pretty much an excerpt from.

    Jeff
     
  7. ESC

    ESC Silver Banner Member

    If you watch the entire clip ironfarmer credits Campbell for his research.
     
  8. I think it's a bit of a stretch to say that by eliminating air entrainment in the sprue you have achieved nothing.

    And I still contend that the majority of home casters melt scrap thereby violating Dr. Campbell's first rule. There is a group making less than perfect castings who would still like to improve.
     
  9. PatJ

    PatJ Silver

    Let me reprhase that.
    If you eliminate air entrainment, then you are 1/10 of the way towards a good casting.
    9 more to go.

    Edit:
    I am not knocking what you are doing, it is great research.
    What I am saying is that it is a 10 piece jigsaw puzzle, so don't forget the other 9 pieces that have to also fit.

    What I actually said was "if you pay attention to the bifilm theory and ignore John Campbells' 10 rules, then you most likely will have achieved nothing".
    I did not say "eliminating air entrainment in the sprue achieves nothing".
    The intent was that if you control air entrainment without controlling the other variables, you can still produce a bad casting.
    If the intent is to produce a good casting, then yes, you probably will achieve nothing if you ignore the other things.
    .
     
    Last edited: Jun 14, 2019
  10. Thanks, Pat.
     
    Last edited: Jun 14, 2019
  11. PatJ

    PatJ Silver

  12. JCSalomon

    JCSalomon Copper

    You might look into the Mini Casting Handbook. Dr Campbell told me it has his latest research on the spin traps (mentioned but not worked out in the Complete Casting Handbook).

    Dunno why Amazon US doesn't carry it, but it's a bit less than $35 from Amazon UK or from the UK publishers directly to addresses here in the US—including shipping and currency exchange.
     
  13. Tobho Mott

    Tobho Mott Gold Banner Member

    Figured I'd check Canadian Amazon. Here's the first thing I saw:

    PhotoPictureResizer_190616_163151363_crop_1053x1665.jpg

    o_Oo_Oo_O

    Jeff
     
  14. Petee716

    Petee716 Gold Banner Member

    Well that's for the Canadian translated version. Maybe the US version will be cheaper.lol
     
  15. JCSalomon

    JCSalomon Copper

    £17.50 at https://amazon.co.uk/dp/1912078740; add another £6.94 for delivery to Norfolk, VA = £24.44; at Amazon’s exchange rate today of £1 = $1.32, that’s $32.23.
     
  16. JoeC

    JoeC Copper

    upload_2020-1-8_20-29-20.png


    Mini Casting Handbook
    Dr. John Campbell
    Second Edition 2018

    OK, it took a while but I have a copy

    It is $US 30.00 from the American Foundry Society, no membership needed

    They were out of stock but have some copies in house right now

    Here is the link...

    https://hub.afsinc.org/NC__Product?id=a2Z1a000000YgfHEAS

    I have the big handbook, but this is way easier and has newer details not included in the big handbook

    He fully explains (with diagrams) the entire system including the mysterious trident gate and vortex spinner

    The table of contents follows (new printer/scanner wouldn't let me OCR it)

    Chapter 4 (30 pages) explains everything

    There are 4 or 5 illustrations that show all these mysteries

    There are charts to determine sizes as well as all the math behind the charts

    It is not anywhere online as an illegal scan as far as I can see, well worth buying IMHO, support the good Doctors work

    I had adopted about 80% of these ideas from what I saw in the Handbook with great improvements and we are now going to try the spinner and rearrange our filter location for a complete Campbell system now that I see them in the new book (theses ideas were not clear in the Handbook)

    Sadly I have signed an iron-clad (Aluminum clad?) non-disclosure contract so I can share nothing...but these ideas worked for us


    upload_2020-1-8_20-32-25.png

    upload_2020-1-8_20-32-40.png
    upload_2020-1-8_20-32-49.png
     
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  17. Tobho Mott

    Tobho Mott Gold Banner Member

    $30 sounds great, another $53 to ship to Canada using the cheapest option... not so much.

    Still cheaper than anywhere else I can find it though, and most of those are used copies! I might just do this, it sounds really good...

    Jeff
     
  18. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Thanks Joe. I had already joined AFS last time you mentioned it. Good to see you here and thanks for the post.

    Best,
    Kelly
     
  19. JoeC

    JoeC Copper



    Shipping seems high

    I ordered off the AFS webstore, had to call in because there was a shopping cart glitch but they took care of it

    The charged me $US12.00 for shipping so $US42.00 total, came to $CDN 57.00 after exchange and credit card fee

    Just a bit more than 24 beer, and it will last longer
     
  20. Tobho Mott

    Tobho Mott Gold Banner Member

    Damn, I went through the link you posted, and had already pulled the trigger by the time you replied.

    I just emailed them, hopefully they can correct the shipping they charged me. $12 seems much less shocking!

    Thanks again, Joe.

    Jeff
     

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