Automotive Oval Air Filter

Discussion in 'Lost foam casting' started by Al2O3, Oct 27, 2019.

  1. DavidF

    DavidF Administrator Staff Member Banner Member

    I'm so stuffed full of Turkey and ham I can hardly keep my eyes open. But I can still tell those came out great!!! ;)
  2. Al2O3

    Al2O3 Administrator Staff Member

    About to carve the bird......I'll be right there with ya shortly:D

    Thanks David. They should clean up like the others. Rain in the forecast for the next two days then snow:(

  3. DavidF

    DavidF Administrator Staff Member Banner Member

    Sounds like a good time to start hibernation...
  4. OMM

    OMM Silver

    Hibernation??? No way. If I am looking for a way to pour with snow outside , I don’t want to see somebody as talented shut down for the winter.
    DavidF likes this.
  5. Al2O3

    Al2O3 Administrator Staff Member

    Wont shut down. With a resistive electric furnace I can melt inside but with lost foam, the pour must be outside. I can just lift the garage door to pour but I need dry pavement to demold......must keep the sand dry for lost foam.

    Finished up the last two castings. Still have one more foam pattern to cast. Logo filter lid looks good.

    57 Four Filters.JPG

    I may have to paint one black and then sand the top surfaces back to bare aluminum to see how that looks.

  6. rocco

    rocco Silver

    I love your whole set-up but, I've always thought what's missing was a demolding station, nothing fancy, just a large but shallow sheet metal tray.
  7. Al2O3

    Al2O3 Administrator Staff Member

    It's a good thought rocco. I have a tray circa 30" x 40". It has 1" sides. It's actually one of the drip pans for my automotive lift and you can see it in the pictures and videos where I stage my ingot trays. You're right though, it would be very useful especially in the Winter time when there is snow and ice to contend with on the concrete. Otherwise, the dry concrete is hard to beat.

    Maybe if the pan had sides a foot tall or so it could contain a full flask. I'll still have to shovel it.......300-350lbs for a full flask. Not bad a shovel load at a time but that 30 gal barrel of sand spreads out over a big area or else it takes a long time to cool for reuse. If the sand isn't cooled, it will deform and damage the next pattern. Still even one flask a day in poor weather would be a bonus. Maybe I could c-clamp a couple trays together to accommodate more area but still be manageable and on my automotive lift!

  8. Jason

    Jason Gold

    I'm thinking black crackle finish with the top edges shined up purdy! Powder coating is another option.
  9. OMM

    OMM Silver

    I personally hate crinkle paint. I personally would go with flat black then high polish the flat aluminum then give A semi gloss finish to the aluminum and flat black. For the one with the Ford emblem, I would touch the top with red and a foam brush, then semi gloss finish.

    The other finishes I like are anodized finishes.
  10. Jason

    Jason Gold

    Yeah, but crinkle is so Ferrariesq.. The best thing with crinkle is it hides shitty metalwork. :D
  11. OMM

    OMM Silver

    Sometimes shîtty metal work (or castings) make things one of a kind.

    20 years ago I was working in a die shop which we used a component as common. It took me about 10 minutes to make up a certain key, for some dies I was making, I needed 40 to 50 of them. After heat treat, I found them some to be stolen sometimes. I started stamping my initials MM into them. They stop getting stolen. 10 years later I started making Gibbs and clamping devices for hire on woodworking machinery. When the customer started complaining about product, I started stamping OMM into everything I made. OMM stands for Originally Matt Matt. (I copied this a little bit off of OEM). When I’m done with these castings, they will all have OMM with a different number after stamped in them.

    Everything has artistic flair and meaning. I’m celebrating with this forum with my last picture Bing the 10,000 picture they’re holding in stock. Modern forums keep their own pictures after the photo bucket fiasco. I do believe this is why David started this forum/website.
    Last edited: Dec 7, 2019
  12. Al2O3

    Al2O3 Administrator Staff Member

    I poured the last air filter foam pattern yesterday. It went like the others and came out well. I try to learn something with every project and iteration. On this pour, I poured quite a bit cooler than I have been (1375F). The initial hesitation seemed to be shorter but the duration of the pour was the same at about 30 seconds total. There was noticeably less black carbon residue on the surface of the casting. The picture below is exactly as it came out of the sand and water bucket.

    1 As Cast No 5.JPG

    Over my last couple projects I’ve been rethinking my typical spruing and gating strategy. Part of this was driven by the desire to cast everything in my molding rig which is essentially a modified 30-gallon drum. In the past, my preference was to sprue at the top and promote a uniform plugged progression of molten metal flow from top to bottom. Much of the typical spruing and gating guidelines (as discussed in the BiFilm thread) for sand casting don’t apply in lost foam because the evaporation and diffusion rate of foam pattern dictates the metal velocity and direction of flow more so than sprue/gate geometry. Top gating in lost foam produces a naturally pressurized system. Top gating would be generally poor practice in conventional empty cavity casting. So the diagram below is what had been my general preference………introduce metal at the top with the hopes for a plugged flow from top to bottom.

    2 Plug Monolithic Flow.JPG

    I think that’s still is ok for many parts, but the filter and the intake manifold lid have very high surface area to volume ratios so the molten metal loses heat to the mold media rapidly during the pour. The parts also have long travel distances, of 25-30” cup to the very bottom of the part resulting in relatively long pour duration times of 30 seconds or so. All of this creates higher risk of short pours so I’ve typically poured very hot (1550F-1575F!) to reduce the risk of fail…….but, I’d rather not superheat the metal, especially aluminum.

    For those interested, the evolution of what I’m about to describe started here on the intake manifold lid, here.

    ….and eventually evolving into this…

    On this part, the strategy was to simultaneously deliver hot metal to as much of the pattern as possible through a more massive (than the part) runner that contacted the entire length of the pattern. The sprue and runner were made from very low density (~.5-.75lb/ft3) Expanded Polystyrene (EPS). In my mind, I imagined this would cause the runner to fill first per the red arrows, and then feed the part inward per the yellow arrows. If this occurs then the runner stands little chance of freezing because it always has new hot metal running through it and the overall travel length of molten metal looks more like half the width of the part (3”) instead of the length of the part (20”).

    3 High Contact Controlled.JPG

    So, I should be able to pour much cooler, and apparently I can!

    Tobho Mott likes this.
  13. Al2O3

    Al2O3 Administrator Staff Member

    K & N obsoleted the filter elements I used for these air filters without a replacement. So I sourced another element that is very close in size but required a slightly larger filter gland. I used to make the patterns on my pin router but here forward they'll be cut on my cnc Router.

    I was looking back on this thread. -Come a long way since I started this one.

    1 Foam Patterns Filter Base and Lid.jpg 2 Resulting Castings.JPG 3 Cast Filter.JPG

    Gavin, BattyZ and hatta like this.

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