Automotive Intake Manifold – Boss 302 Independent Runner

Discussion in 'Lost foam casting' started by Al2O3, Apr 24, 2021.

  1. Melterskelter

    Melterskelter Gold Banner Member

    Ahh, I see. You supercharged it! ;)

    Denis
     
  2. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    ....a whopping 1/2" H2O of boost, but did the trick!

    Now that I have a pattern ready to pour it's raining with more coming....:mad::mad:

    Best,
    Kelly
     
  3. Oldarm

    Oldarm Silver

     
  4. Oldarm

    Oldarm Silver

    I am in complete awe of your dedication to this project and that is quite apart from the "never say die" attitude you infuse in others.
    You have probably had dozens of "why don't you try it this way or that way" messages and I may well be joining that group with a comment or two. All this with the very, very best of intentions as I'm sure you understand. On that topic, it probably took many cooks to perfect the boiling of an egg. And still we fail!

    Have you considered the use of a vent or riser with branches to the pattern on it's ascent? This would assist greatly in the evacuation of gasses both volatile and inert.
    Have you considered filling the plenum remotely via the various ports. Tamping, vibrating and rotating to ensure a complete fill. The ports could be closed off sequentially as the process completes with a thin but stout permeable membrane glued or taped to the pattern.


    As has been said, just a thought.

    I'm not at all sure if I am allowed to post this reply as a new guy on the block as I may not have been moderated yet. Anyhow here we go.
    John
     
  5. So did the muffin fan really volunteer or did you manhandle it?

    Looking great!!
     
  6. New voices are always welcome! Kelly will be along by and by. None of us doing lost foam successfully use vents, to my knowledge. The gas is all at the metal front and can't get to the vent. Also the gas pressure helps keep the sand in place. But Kelly is the expert. Locally anyway.
     
  7. Melterskelter

    Melterskelter Gold Banner Member

    Hey, everybody! I just checked the forecast for Kelly’s area. There is a 3% chance of rain and a high of 76 today. If we hear excuses for delay due to weather, we’ll know Kelly is choking. :cool:

    Good luck, sincerely, Kelly.

    Denis
     
  8. Mach

    Mach Silver

  9. DavidF

    DavidF Administrator Staff Member Banner Member

    Looks like you can order a Buddhist monk on Amazon Japan.
    Probably want to grab one now before the sell out. Might come in handy for these difficult pours...
     
    Mark's castings likes this.
  10. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    I see you guys have been ringing me up while I was toiling in the foundry. Smell that? That’s not burning polystyrene (well maybe), it’s the sweet smell of success! A rare July day in the high 70s, so I struck while the iron was hot and the weather wasn’t.

    As it came out of the sand….

    61 As Cast.JPG 62 As Cast.JPG

    ….and marched straight to the mill to degate it.

    63 Degate.JPG

    …….and after a degating and light media blasting, she’s a beauty!

    64 Clean Casting.JPG 64.1 Clean Casting.JPG 65 Clean Casting.JPG 66 Clean Casting.JPG 67 Clean Casting.JPG 68 Clean Casting.JPG 69 Clean Casting.JPG 70 Clean Casting.JPG 71 Clean Casting.JPG

    The day in 40 minutes.



    Best,
    Kelly
     
    Haus, Rotarysmp, 3Dcasting and 13 others like this.
  11. DavidF

    DavidF Administrator Staff Member Banner Member

    Awesome, simply awesome!!
     
  12. Really great! I like your simplified gating.
     
  13. Mach

    Mach Silver

    Outstanding work! Congrats Kelly, glad it came together the second time around.
     
  14. Melterskelter

    Melterskelter Gold Banner Member

    Hear! Hear!

    The culmination of years of work learning the process, designing and perfecting the equipment, and then learning the nuances of making a proper pattern, gating it and pouring it. Way to go, Kelly.
     
  15. DavidF

    DavidF Administrator Staff Member Banner Member

    I think we should make him cast 10 more now ;):D
     
  16. That's awesome Kelly, if I stopped to describe how great that casting is, I wouldn't have time to admire it.
     
  17. FishbonzWV

    FishbonzWV Silver Banner Member

    Brilliant work Kelly!
    Great video work too.
    Did you video the machining? I'd love to see that process.
     
  18. Tobho Mott

    Tobho Mott Gold Banner Member

    That is amazing... Great job!

    Jeff
     
  19. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Hi John, of course you are. All comments welcome.

    It's counterintuitive to conventional casting, but like OIF mentioned earlier, a vent r a riser would not be able to function because it would be full of foam. In lost foam the entire surface of the pattern is the vent and the permeable refractory coating controls the rate at which the gas escapes and to a certain extent, the velocity of the advancing metal front.

    The other thing that can be counterintuitive in lost foam is sizing the sprue and runner/gates. You can put as large of a sprue as you want on a lost foam casting and it wont flow metal any faster that than the pattern can be evaporated.

    I have but in general concluded it's not a winning strategy. On this part, there would be so much sand in the runners it would become so heavy, you'd never be able to handle the pattern without distortion, damage, or outright breakage. When you fill the flask, vibration fluidizes the sand and makes it flow like a viscous liquid. It surrounds the pattern and keeps equal pressure on opposing sides of walls and pattern features so the pattern sees no net force other than compressive forces on the foam, which is strong in that regard.

    On occasion, I have packed a bonded sand into small difficult features but it can cause as many problems as it solves.

    While tilting the mold during vibration can aid filling some difficult features it can also cause problems because what filled in one position, may unfill/pack when you reorient it, and worse, cause the entire mas of sand to move and deflect/distort the fragile pattern. It's far better to pack the pattern in the position it will be poured and use the direction of the vibratory excitation to move the sand through the mold. Anything you can do to promote flow of sand through a feature will ultimately mean better packing.

    The one thing to keep in mind, though the sand is unbound in lost foam, it is in a pseudo bound state, that being mechanical bonding. The vibration causes the mold media (in my case sand granules), settle and lodge together. If you apply vibration to a container that you've merely poured sand into, it will settle/compact 10-15%. If you have an object submerged in unpacked sand, you can readily pull it out, but in vibe-compacted sand, you can often lift the entire flask because the object is so tightly captured by the compacted media.

    Using granular sand is a practical compromise for me because it is inexpensive and readily available in small quantities, but it does cause some difficulty because it the same thing that causes the high mechanical interference (the particle shape) makes it more difficult to excite with vibratory energy. Most of the media used in commercial outfits are rounded particles. I've tried but the minimum buy (typically >20,000 lbs) transportation and storage make it impractical for me. Commercial business also have fluidizing furnaces to clean and reuse the media. Though I could heat the sand to do the same, the energy cost is more than the cost of the media.

    For this iteration the three most significant changes were:
    1. Fresh mold media
    2. Pattern orientation and packing method
    3. Gating changes
    If I had done 1 & 2 on the first pour it would likely have succeeded. It's all compromises. I'm just a guy casting in his driveway and making car parts in his garage. I'm not trying to advance the science of lost foam casting with my posts and videos, just adapt it and demonstrate it's a viable method to make complex castings with tools and methods available to hobbyist.

    Best,
    Kelly
     
  20. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Thanks for the supportive remarks fellas. I certainly am relieved to say the least. Some of you may remember 6-7 years ago when I showed up on AA and my first crucible was that A60. I remember the forum faithful just shook their heads. Projects very similar to this is what I had in mind. I can remember Gypsy Tinkerer saying, "please tell me you have a lifiting crane and large sand pouring pit", and a few others suggesting maybe I should start a little smaller.....one of the few times I was able to take good advice.

    Heh-heh, there won't be 10 made with these pattern construction methods but it will be further motivation to accelerate my CAD/CAM skills. The majority of the effort in that pattern is machining and assembling those 8 runners. On the router, if that portion was done in just two pieces (upper and lower), it could be self fixturing and eliminate all that machining and assembly labor. Also, the runner geometry could become so much better, and all sorts of custom variations would be easily accommodated......one casting at a time.

    CNC machining patterns is the lost foam equivalent of printing PLA or molding waxes. Once you have the pattern, mold making and demolding are really fast, efficient, and economical for larger parts in lost foam.

    Best,
    Kelly
     

Share This Page