Register now to get rid of these ads!

Technical Reinventing the wheel

Discussion in 'The Hokey Ass Message Board' started by '51 Norm, Apr 21, 2018.

  1. '51 Norm
    Joined: Dec 6, 2010
    Posts: 652

    '51 Norm
    from colorado

    Executive summary:

    I turned one of these:
    Into this air cleaner:
    The various intervening steps required a number of shop tools and equipment. Heat and sandpaper were also involved.


    Details of the various processes will be covered in individual chapters.

    Concept and design

    Wood working

    Sand castles

    Aluminum cup cakes

    Molten metal

    Machine shop

    Finish work

    Latch assembly

    Final assembly and adjustment

    End notes
    scotty t, swade41, Jet96 and 12 others like this.
    Joined: Dec 14, 2009
    Posts: 1,832


    So just a hammer and a chisel and you made up this air filter ?

    The fourth pic I assume is of you mixing up a double gin and tonic ?

    Dang, sitting patently for more, this is cooler then cool !:)
    scotty t likes this.
  3. I for one would love to learn what it takes to cast.

    Watching with interest

    Full Kustom drunk mobile posting
    Last edited: Apr 21, 2018
  4. Turning ugly to beautiful....Good stuff! Those finned bits look ace! I couldn't (wouldn't pay $$$$$$) get windscreen posts for my '36, so I signed up for night class in metal casting. My project was... A pair of '36 roadster posts. I learnt a heap (especially the safety part, no fun wrenching with one hand or eyeball), and ended up with a pair of brass posts, and a pair of cast iron posts. Bonus when you learn to cast- We used to have a "club plaque melt" in winter!
    Register now to get rid of these ads!

  5. '51 Norm
    Joined: Dec 6, 2010
    Posts: 652

    '51 Norm
    from colorado

    Thanks guys. I'm figuring on doing the chapters one at a time so stay tuned.

    I learned more than I thought possible, it was almost fun!
    Thommyknocker likes this.
  6. Can I watch?
  7. Jethro
    Joined: Mar 5, 2001
    Posts: 1,401


    Bravo!....nice work!
  8. '51 Norm
    Joined: Dec 6, 2010
    Posts: 652

    '51 Norm
    from colorado

    Concept and design requirements.

    I realized that an air cleaner of some sort was required to complete the 455 Pontiac engine that is currently under construction in my shop. The engine has an Offenhauser dual quad intake manifold and a pair of Carter AFB carburetors.

    After reviewing the several available air cleaner assemblies I determined that none of them were really acceptable to me. The problems ranged from ugly to didn't fit the theme to that will never work.

    So I bought this air cleaner so that I would have something to cover the carburetors until I found something that was more acceptable.

    eBay special ^^^^^^^^

    What I found was I hated the air cleaner so much that I decided to remove the parts that I didn't care for . This resulted in having an air filter element and nothing else.

    At this point I needed some direction and so made a list of what my goals were in relation to the air cleaner. (this would be decision making 101)

    Firstly I wanted a single air cleaner that matched the theme of the other accessories on the engine. I already had fined aluminum valve covers that I liked and most of the engine parts that could be removed were powder coated yellow.

    So a finned aluminum air cleaner with fins similar to the valve covers became the first non negotiable item.

    Other design elements were considered at this point; how the air cleaner fit (height above the carburetors, hood clearance, etc.) I also decided that if at all possible there would be no visible attaching hardware; that is no wing nuts on top.

    The air cleaner top also needed a “clean” appearance; no names or logos. Perhaps I am in the minority here but having someone else 's name cast into the top of my air cleaner seems a little gauche. Especially since my name isn't Holley, Edelbrock or even Cal Custom.

    Also, I am allergic to small, loose hardware inside an air cleaner. Something to do with “once burned, twice shy”. The eBay special has a number of small screws etc. just waiting to get sucked into an expensive engine.


    So with my requirements firmly in hand I revisited my air cleaner search and again came up empty.

    At this point I decided that the Grinch was right......”if I can't find a reindeer I'll make one instead!” or in this case a traditional looking air cleaner.

    Next episode: making patterns or back to the woodshop.

    Attached Files:

    TagMan, brEad, Murphy32 and 4 others like this.
  9. I'm following. HRP
  10. Baumi
    Joined: Jan 28, 2003
    Posts: 2,160


    Way cool! I' m watching!
  11. lostone
    Joined: Oct 13, 2013
    Posts: 839

    from kansas

    Knowledge is power ! So I'm in!!
  12. NashRodMan
    Joined: Jul 8, 2004
    Posts: 1,576


  13. '51 Norm
    Joined: Dec 6, 2010
    Posts: 652

    '51 Norm
    from colorado

    Thanks guys, please let me know if you see anything that I did really wrong. That way I can be ready to do the next one right!
  14. HJLrulz
    Joined: Jan 16, 2016
    Posts: 85


    I've wanted to try casting for a while, can't wait to see the next installment

    Sent from my SM-N920P using The H.A.M.B. mobile app
  15. I've done a bit of casting a few times, but need something better to melt the aluminum....
  16. '51 Norm
    Joined: Dec 6, 2010
    Posts: 652

    '51 Norm
    from colorado

    Making the patterns (Woodworking 101)

    Foundry work is something that I always wanted to try but had never attempted before. It was one of those things that only really skilled and experienced people could do, or so I was led to believe. Since there were none of those types of people around I figured that I would just go for it, what could go wrong?

    The first thing that I needed were casting patterns made of wood.

    I've never been too good with woodworking and so approached this step with some trepidation.

    My first thought was to carve the patterns on my CNC mill. I was saved from this nontraditional insanity by the timely failure of the Z axis servo motor driver. Thanks, Geckodrive!

    I made the top patterns out of naughty pine. This isn't the best choice of wood as I discovered. The board had a slight warp to it that I eventually sanded out (I don't have a planer, yet). The naughts also had holes and low places that needed to be filled. Don't you just love spell checkers?

    I cut the pattern fins using a table saw. I then sanded them so that they had some taper (draft). The inner corners were shaped with Bondo and considerable sandpaper. I was careful to make the pattern as accurate as possible knowing that any errors would be faithfully reproduced in the casting. Then when the inevitable revision occurred I was sure to have the maximum amount of work to redo.

    After rough cutting the oval outline with a circular saw the basic pattern was ground to shape on a 12” bench mounted disc sander. Once it was shaped I ran the router around it to make the curved outer edge. Right after that I found that Bondo is also good for fixing the place where I didn't want the router to go.

    It was during the pattern making phase that I made my first major mistake. Well... second if you count deciding that it was a good idea to make an air cleaner.

    I had read that aluminum castings shrink as the molten metal cools. This makes sense. The information that I found listed the shrinkage as anywhere between 1.5% and 2.5%. Since the locating rib in the air cleaner needed to fit the air filter element relatively closely I needed to account for that shrinkage.

    This is important since the air cleaner ended up being 22” long and that would result in a noticeable dimensional change due to the shrinkage, even at 1 1/2%. As a compromise I made the pattern 2% bigger than the finished dimension needed figuring that would be close enough. This turned out to be an error.

    I briefly toyed with the idea of casting a length of aluminum from a pattern with a known dimension and then calculating the shrinkage. I decided that wasn't necessary since I found the shrinkage percentage on the internet, what could go wrong?

    As cast the air cleaner overall shrinkage was very nearly zero resulting in an interference fit between the air cleaner and the filter element. This is a long way to say that I had to fix the mill and learn how to cut an arc in G code. I wasn't about to try to file off the excess.

    At this point I still was not sure what fin spacing and style would look the best and so made two top patterns figuring that if I had both tops I could swap them back and forth. As the project dragged on I abandoned that plan due to the amount of labor involved. As a result I am required to say that the top pattern that I used is the best one.


    The top pattern is a two piece affair with the filter locating rib part detachable to facilitate ramming the mold. Having it detachable also allowed me to use one rib pattern on both tops. The screws for attaching the rib pattern are intentionally asymmetrical so that the pattern is always installed in the same orientation.


    The bottom pattern was pretty straightforward and made out of 1/4” plywood. It wasn't until later (during the actual metal casting) that I discovered my second major mistake. That will be covered in the metal casting chapter.


    Feeling pretty frisky at this point I carved the pattern for the air cleaner hold down latch bracket in one go. If I make another bracket I will “tune up” the pattern a bit but all in all it went pretty well. I think that I also need a shorter name for the part.


    The latch bracket is installed between the carburetors and is held in place using the carburetor hold down bolts. It is needed to meet the “no visible top hardware” requirement. As a result of the bracket being installed on top of the carburetor mounting flange the hold down bolts need to be longer.

    The sexy dog bone shape is to make sure the bracket clears the idle mixture adjusting screws, etc.

    After getting the patterns sorted out I needed a cope and drag to put them in. I put angled brackets on the cope so that it would be somewhat self aligning with the drag. This turned out to be a good thing since the cope is pretty heavy when filled with packed sand. It is also fragile and so needs to be handled gently.

    While researching how to make this stuff I discovered the various names for foundry equipment. I hope that I am using the terms correctly.

    There are ribs around the inside edges of the cope and drag to help keep the sand in place when handling the mold.


    I made top and bottom boards out of 1/2” plywood. These boards are for convenience when turning the cope and drag over; since they also help keep the sand from falling out. They are also handy to keep the mold covered so that stuff don't fall in.

    When I cut the gate and vents I found that having a board on the back acting as a support helped keep the sand from “blowing out” and making big craters in the top of the mold.


    Also needed was a screen for the sand. I made the screen frame to fit onto the top of the plastic bin that I was using to store the sand. Then I got a different size bin, such is life.

    The screen is just a double layer of 1/4” hardware cloth. It seems to work OK as long as the sand has cooled off some after a pour. Not surprisingly the sand is pretty hot after dumping molten metal into the mold.

    So on to making the sand mold.
    brEad, kiwijeff, Murphy32 and 2 others like this.
  17. 340HilbornDuster
    Joined: Nov 14, 2011
    Posts: 1,784


    Very Cool / Inspirational!!
    Maybe I'm getting ahead of the story...
    What kind of sand are you using?......Lots of it here in Hawaii!

  18. '51 Norm
    Joined: Dec 6, 2010
    Posts: 652

    '51 Norm
    from colorado

    You are only a little ahead of the story. But better too soon than too late!

    I am using Petrobond sand that I bought at an estate sale. I found out later that I had gotten a screaming deal on it since it is kinda pricy.
    The down side is that I didn't get any advice on how to use it. It worked pretty well and so far I have used it six times. I really don't know how many re uses are in it; guess that will become obvious when I get there.

    There is a lot of advice on using (and making) green sand on the internet. I didn't need to go there since I had the Petrobond.
  19. I talked my way into some free casting sand from a local foundry. What the guy told me is it has some clay mixed in for a binder. According to him, you can re-use it indefinitely, simply add a bit of water to the mix in between. You do want to 'bake' the mold after forming the sand to remove any moisture.
  20. Awaiting the next installment.Nice read.
  21. nrgwizard
    Joined: Aug 18, 2006
    Posts: 1,094

    from Minn. uSA

    Hey, Norm51;
    Good job on the write-up so far. Not slamming or bagging on you, but I get a kick out of the "naughty pine" [knotty pine?], & the "naughts" [knots?]. I gotta wonder just what the piece of pine did wrong, maybe it was math - Jethro style? :D . Seriously, this gave me a good chuckle - thanks for the humor. I know what you meant. Seeing if I'm awake? :D . You're doing better than me, I don't post pics yet, & don't have any from the late 70s-early80s when I did this stuff. Still have some of the finished pieces though. Somewhere.

    As for the choice of material to use as a pattern, poplar is soft, but decent. If you want to make lots of castings from that pattern, use a harder wood. Or, if the 1st piece from the mold is too big, you could use that & pour the 2nd, it'll shrink the ~ 1.5%. Anyways, in college, eons ago, I did a couple of kinda complicated patterns, but used foam for the body & candle wax for fillets, hole filling, & some smoothing . Gotta use extra-fine screened sand, & pack it, then pound it very carefully. 'Course, you only get one shot & one piece that way. Have used both beadboard & blueboard [& also cutup some foam egg cartons for smooth thin pattern pieces], depending on what surface finish I was after. The sand we used was oiled, but we used it over & over. Did smoke like a demon while pouring, & cooling. Definitely need some good ventilation.

    Am liking this thread - keep it up.
  22. 392
    Joined: Feb 27, 2007
    Posts: 897


  23. Petejoe
    Joined: Nov 27, 2002
    Posts: 10,064

    from Zoar, Ohio

    Skill, patience and creativity. Amazing the skills people have on this forum. Your work is inspiring. Thanks for the great write up. Very time consuming. Looking forward to the next installment.
    LBCD likes this.
  24. '51 Norm
    Joined: Dec 6, 2010
    Posts: 652

    '51 Norm
    from colorado

    Thanks for the advice. After making the patterns (and using them) I have stored them for future use, after I get healed up from this go!

    I understand that the Petrobond sand that I am using has some sort of petroleum based binder in it and yes it smokes when pouring so that part of the project occurs outside. My question is how long will the binder last before it needs to be "refreshed" or replaced.

    After a pour the sand next to the metal gets "crispy" and needs to be ground up with the screen. It is also noticeably drier. I mixed it with the unaffected sand before using it again and so far so good.
  25. '51 Norm
    Joined: Dec 6, 2010
    Posts: 652

    '51 Norm
    from colorado

    Thank you for the kind words.
    And yes writing up a posting of this length is time consuming but I feel like I owe the HAMB community for all of the helpful information that I have gotten from the creative folks that one meets here.
  26. The clay binder I have used is called "Bentonite".
  27. 19Fordy
    Joined: May 17, 2003
    Posts: 6,376


    If your casting use PetroBond sand. Reusable and high quality.
    I used it in high school metalshop years ago.
    Kids today are missing out. Sad.
  28. '51 Norm
    Joined: Dec 6, 2010
    Posts: 652

    '51 Norm
    from colorado

    We didn't have foundry work when I was in high school forty odd years ago. So here I am learning it as a retirement project, now that's sad!
  29. David Gersic
    Joined: Feb 15, 2015
    Posts: 1,901

    David Gersic
    from DeKalb, IL

    We did sand casting with lead in 7th grade shop class. That would have been about 1980.

    Sent from my iPad using The H.A.M.B. mobile app

Share This Page

Register now to get rid of these ads!


Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.