Register now to get rid of these ads!

TECH- How to SAND CAST Aluminum Car Club plaques at Home!!!

Discussion in 'The Hokey Ass Message Board' started by Pins&Needles, Jul 15, 2009.

  1. Pins&Needles
    Joined: Apr 8, 2006
    Posts: 381

    Pins&Needles
    Member
    from Santa Cruz

    Here's my Tech article for the Baileigh Bailout contest. At first I was going to do a post on metal shaping/ making a gas tank, but I figured I should mix it up a bit an do something off the wall that everyone can do at home with little money and still have great results. Besides if I just happen to win I'll be doing quite a bit more posts using my new Baileigh Industrial tool:D! So without further adieu...

    This tech post will go through all of the steps to cast car club plaques from scratch, however the general rules of sand casting can be applied to any sort of casting project that you might have.

    Step 1
    Making the wooden buck that you will use to make the sand cast. I generally do all the wood work by hand. For plaques specifically I actually use different layers of wood. I start with a base in the rough shape of the final piece, and then add on. For this plaque (which is acutally for our clubs bike plaques), I used 1/4 inch bass wood, which you can find at any local hobby store that sells remote controlled airplane kits. I use bass wood instead of balsa because it is more dense and less pourous which will be a big deal later when you coat the wood with varnish, but it is also easier to work with than hardwoods and can be cut with an exacto knife. I generally buy couple pieces of flat 1/4 inch, and a couple stringers (thin strips). Take your drawing of the plaque and trace the letters on to the wood with a piece of carbon paper one at a time (this is because you have to bevel the cutouts). I genreally use a few different tools to cut out the letters, a knife, small scroll saw blade, small hack saw blade, finger nail file, small jewlers files, and some smooth grit sand paper. You want your end product to have between a 1 degree to 3 degree bevel from top to bottom of the letter (this is so the sand holds its form). The more intricate the piece the more degree I put on the cutouts. once the pieces are cut out (hours of work). Take them and glue them to the base. take the stringers and cut them to fit around the outside of the piece so that they make a border around the letters (this will give the plaques the look of being routed instead of cut out by hand. Once every piece fits the way you want it to glue the pieces to the base, for this I use super glue becasue its quick and thin, you don't want any excess coing out the sides because it will ruin the clean look of the piece(and possibly the mold). Bevel the sides of the outer edges the same way you did the letters. Once done you can glue the whole piece to a stiff board, so that it won't warp.

    Step 2
    Use a thick varnish that dries slowly and put coat after coat onto the piece, do this with a nice brush so that you don't get streak marks in the final product. You will want to have a nice thick smooth coating on the piece so that it fills in the grain, as well as builds up anywhere the letters meet the base. You want to have whats called a valley between horisontal and vertical pieces. This is a sloping transition instead of a hard edge. Once that is done coat the area on the board around the plaque, so that sand won't stick later. After it is completely dry lightly sant the tops of the letters with 320/400 grit and a block so that they are all the same plane, and smooth.

    Here is the final product:

    [​IMG]

    Step 3
    This step could be skipped if you are a daring and adventurous individual that doesn't care too much about wasting time... I learned the hard way one time loosing a buck when it caught fire (sand was too hot). So now I always make a silicone mold of the original just in case, its quick to do, and though a little pricey worth every penny considering it takes up to 40 hours to make the original.... Make a thing aluminum (or whatever isn't porous) outer ring. You want the ring to sit away from the buck at least a half inch. and Make sure the ring sits above the buck at least a 1/4 inch. This way the silicone doesn't loose shape.

    [​IMG]

    Duct tape the ring to the wood base really well so that it creats a liquid tight seal (nothing worse than watching $30 worth of silicone run onto the floor). Mix your silicone together in a disposable container, do this well but not vigorously so that you can keep the bubbles to a minimum. once it is thoroughly mixed poke a whole in the bottom edge of the container, set it on a table, and let the silicone run into the ring that you made. Let it run into one corner only and flow to the other, this is the best way to eliminate bubbles, and air pockets without having a vacuum chamber.

    [​IMG]

    Once the mold has set up you can remove the outer ring ( but retain this so that the mold will hold its shape.

    [​IMG]

    You can then remove the silicone from the buck (but do this carefully so that it doesn't tear).

    [​IMG]

    Now you are ready to pour a plastic copy of the original buck. I do these for two reasons, one is to make sure the mold looks good, and two, to make multiples if I plan on casting more than one at once.

    [​IMG]

    Step 4

    It is finally time to start setting up for the sand casting. Most hobby casting store or web sites sell casting kits like the one I have here. These are very good for small items but for really large stuff you need more professional equipment.

    [​IMG]

    One of the most important parts of the sand casting process it what is called the Cope and Drag. It is two halfs that have centering pins to align them up with each other once the buck it removed. The one pictured here is a small flask style used in jewlry making.

    [​IMG]

    It is a little too small for the plaque that I am doing so I made my one revised version out of flat stock. I left the centering pins off of mine because I'm only concerned with picking up the detail of one of the sides.

    [​IMG]

    I then cut the corners once it was bent in a rectangle and tappered them out then wleded it back up which helps the sand stay in form once it is pressed.

    [​IMG]

    [​IMG]

    [​IMG]

    More to come!
     
  2. stude_trucks
    Joined: Sep 13, 2007
    Posts: 4,755

    stude_trucks
    Member

    Looks good so far. Nice post!
     
  3. Gigantor
    Joined: Jul 12, 2006
    Posts: 3,805

    Gigantor
    Member

    oooohhhh... haven't done this since 3D sculpture in college... always wnted to do it at home.
     
  4. hotrodjeep
    Joined: Feb 3, 2009
    Posts: 867

    hotrodjeep
    Member
    from Tama, Iowa

    Awesome.
    Type faster, I need imediate satisfaction !!!!!!!!!

    Great idea for a tech piece.

    Jeff
     
    Register now to get rid of these ads!

  5. Intoresting very intoresting
     
  6. SlamCouver
    Joined: Jun 26, 2006
    Posts: 2,002

    SlamCouver
    Member
    from Brazil, IL

    Lets see how this goes. cant wait.
     
  7. notrod13
    Joined: Dec 13, 2005
    Posts: 984

    notrod13
    Member
    from long beach

    this is my first subscribed thread
    i cant wait to read the rest
     
  8. hotrodj54
    Joined: Jun 1, 2007
    Posts: 604

    hotrodj54
    Member

    cant wait to see the rest.......................john
     
  9. Pins&Needles
    Joined: Apr 8, 2006
    Posts: 381

    Pins&Needles
    Member
    from Santa Cruz

    Alright on to the next step!

    Step 5

    Place the original buck on the table and use liberal amounts of parting powder all over the piece, make sure you get every edge so that the sand comes off without sticking. you can put it in a tamping bag or use your old ladies make up brush to dust it... make sure you wash the make up brush out afterward ( I learned the hard way on that one too!:eek:). Make sure you get the surrounding areas on the board

    [​IMG]

    [​IMG]

    Take the cope and place it over the buck.

    [​IMG]

    Get out yer sand!

    [​IMG]

    The sand itself should be very sticky If you don't want to buy a kit, they sell and additive for sand that makes it sticky like this, but make sure you find the smallest grain sand you can because it will affect the outcome of the cast piece.

    Use some sort of sieve ot sift the sand through directly onto your mold. You want to do this for two reasons, to break up the particles of sand, and to strain out any old bits of metal or debris.

    [​IMG]

    [​IMG]

    Once the sand is full in the cope, use some sort of tamper (I made this one) to compact the sand down into the cope and onto the buck. You want this sand really compact because you want it to pick up all the definition of the buck as well as not fall apart when you remove the cope.

    [​IMG]

    [​IMG]

    Make sure that the top of the cope is leveled off ( I use a piece of flat stock and run it over the top. (This is because you will be turning it over and using it as your base, and you want it to be level).

    [​IMG]

    Repeat the same process with the drag. If you are doing a plaque use some sort of flat surface (I used 1/8 steel) If you have an objecty that has multiple sides flip the cope over apply parting powder, and start packing the sand in.

    [​IMG]

    [​IMG]

    Now you are ready to take the buck out of the cope (and drag). This is do or die at this point. If you move the cope while lifting it you can break the sides out and you have to start all over. lightly tap the sides of the cope to loosen all it from the buck. Take a minute and pray, and then lift and hopefully it will come out perfect.

    [​IMG]

    On the drag side (now the top) figure out where the ends of the buck negative start and bore two holes using a thin hollow tube. One will be for pouring the other will be for letting out air from the mold. In some cases with bigger or more complex pours you will want more air holes and to alieviate pressure. You may also want sprues which are little valley within the mold that act as excess chambers for metal to flow which feed the piece as it cools (metal expands when hot and shrinks back when cool) sometimes without these sprues you end up with low spots or missing areas. In this case the plaque is not that big so It wont be much of an issue.

    [​IMG]

    Place the cope and drag back together and get ready to melt some metal!
     
  10. Pins&Needles
    Joined: Apr 8, 2006
    Posts: 381

    Pins&Needles
    Member
    from Santa Cruz

    Alright on to step 6 I think it is!

    First off before you start to melt any metal set up everything you need to do so. This is by far the most dangerous part and it has to happen really quickly so you need all your ducks in a row before hand. set up an area for your cope and drag to sit on, make sure its level so that when you pour not much metal runs out one side of the mold.

    [​IMG]

    Get some sort of crucible, they have ones made of refractory which looks like plaster but holds a lot of heat, but for the case of aluminum or lesser metals I use a small cast iron pot. Make sure you have a hot plate of white brick or something that can withsand temps up to 2000 deg. it seems simple but the obvious is overlooked more often than not... ( what do you do when you start heating up molten metal on your wood work bench and the bench catches fire all the way around your melting pot? where do you put that molten metal that wont also catch fire?... been there done that its hard to think when your watching your garge catch fire!)

    [​IMG]

    I used a torch to melt the small aluminum bits that we used, but usually the best way is to melt it in a blasting oven (you can make one for pretty cheap). For this much metal I can use a torch, anything more, and I'd be building an oven. Aluminum melts at around 1600 degrees depending on the alloy. There are other metals that melt at much less heat, but expierement with these prior to use, they sometimes have different properties such as porocity issues.

    [​IMG]

    Once the aluminum is molten I generally put a over over the crucible to keep the heat in for a while and keep heating... (oh and buy the way not the best idea to play with fire around a compresses tank, even if it is inert gas) Not our brightest idea but we kept an eye on it to make sure.

    After you have heated the aluminum to a cerry degree (it sould be fairly fluid in your crucible), you need to add a pich of borax. That right borax!... this cleans all of the impurities out of the molten metal. You then need some sort of instrument to draw the impurities off the top, I use a steel spoon. Once this is done the molten metal should be very shiney. You are ready to pour!

    Make sure that you have some good protection on, long thick gloves, best would be a leather apron, and a face shield. Remember its liquid metal you'll burn a hole in your weiner berfore you even know what hit you! Don't follow by example. Also make sure that you have some sort of tongs of something that gets you and your hands as far away from the mold as possible. You will be holding the crucible above the mold for awhile, and the heat coming up off the molten metal is rediculous! The last thing you want to do it drop it! Start pouring!

    [​IMG]

    Notice the metal rising out of the air hole, if you put it too far into the center of the drag, it can still trap air at the other end, be weary!

    [​IMG]

    [​IMG]

    Once it is poured it is a waiting game, the sand retains heat very well, and it will take about 30 minutes or more depending on the size for the piece to cool enough to extract. You don't want to wreck it just trying to look at it. Once the time is elasped break it loose of the sand and see what you got!

    [​IMG]

    Use some sort of brush, a soft scraper to get all of the sand off the piece, for the final look! I had a little leak out of one end because I didn't seal the cope and drag toether before I started, but all's well that ends well!

    [​IMG]

    Just take a die grinder, and sanding disk, bench grinder and finish off the sides. Paint it! And sand the letters down and there you have it an awesome car club plaque done at home with way too much time and effort put in to it! :)

    No seriously, it really isn't that complicated to do, just trial and error, If you have any questions PM me and I'll try to answer them. I'm just a novice when it comes to casting so there might be other tricks that you guys know that I don't so feel free to chime in, correct me, or just explain how you've done it. Thank you for reading! I hope this helps anyone who was thinking of testing the trial and tribulations of sand casting. Oh and don't forget to vote for the Baliegh Bailout contest!:)
    -Chris
     
    Last edited: Jul 15, 2009
  11. Awesome!! Very cool work!! Makes me think about college again...
    But we only did an ashtray :mad:


    So, do you also take orders???
     
    Last edited: Jul 15, 2009
  12. yamadafacka
    Joined: Aug 14, 2008
    Posts: 505

    yamadafacka
    Member

    fuckin awesome!!
     
  13. hotrodjeep
    Joined: Feb 3, 2009
    Posts: 867

    hotrodjeep
    Member
    from Tama, Iowa

    Very nice. I did that in high school in the shop foundry, Made a few sets of bookends
    and key chains. We used alot of brass too. It shines up soo pretty.

    This seems like the right place to ad this site as a referance:
    http://www.backyardmetalcasting.com/
    Lots of good tips here. That could help someone out.

    Great thread Chris

    Jeff
     
  14. mattcrp1
    Joined: Aug 20, 2007
    Posts: 401

    mattcrp1
    Member

    thats came out awsome! make it look easy
     
  15. Ian Berky
    Joined: Nov 28, 2007
    Posts: 3,643

    Ian Berky
    Member

    That's so bitchin'!! Seems like a lot of work though!!:eek:

    Ian
     
  16. Old-Soul
    Joined: Jun 16, 2007
    Posts: 3,481

    Old-Soul
    Member

    Ha! How cool is that??

    Thanks for taking the time to show us how to (potentially) burn our garages down, burn 'holes in our weiners" and blow ourselves up!

    The final product looks awesome man, good job!
     
  17. KreaturesCCaustin
    Joined: Sep 3, 2008
    Posts: 1,258

    KreaturesCCaustin
    Member
    from Austin, TX

    Man, that's pretty cool! A lot of tech articles are written for people who already have access to a full machine shop or who are already very experienced in one area or another. This is one of the first I've seen that can benefit ANYONE. I've been wanting to do resin sculptures and this gives me an insight for that as well. Big Thanks! You've got my vote!
     
  18. Kustom7777
    Joined: Mar 3, 2001
    Posts: 5,171

    Kustom7777
    Member

    very informative and well written,,,i definitely wanna try that now,,,,NICE design work on the plaque as well..
     
  19. greasy50chevy
    Joined: Dec 24, 2008
    Posts: 547

    greasy50chevy
    Member

  20. Nice, nice work, Chris. I've gained a whole new respect for the amount of work that goes into a fairly simple casting. Great job.
     
  21. Crankhole
    Joined: Apr 7, 2005
    Posts: 2,511

    Crankhole
    Member

    I wish I had the patience. Great Tech...thanks.
     
  22. blkcat77
    Joined: Jan 29, 2007
    Posts: 130

    blkcat77
    Member

    Thanks man! This is a great tech that you don't need a specialty tool or 15 years of practice for.
     
  23. we did this in high school as well, there are some very important safety items to be aware of, but the basic process is fairly easy and straight forward as was explained here. And the best part of practicing is, is you screw it up, you just make another mold and melt down your screw up.
     
  24. hr31hr
    Joined: Nov 30, 2006
    Posts: 221

    hr31hr
    Member
    from PA

    Been trying this for a while. Stuck at the sand stage. I have plans and can post picks od a propane burner if anyone is interested. Thanks for the indepth tech article.
     
  25. Search online for "Petrobond"; basically, it is sand mixed with a small quantity of oil.
     
  26. Pins&Needles
    Joined: Apr 8, 2006
    Posts: 381

    Pins&Needles
    Member
    from Santa Cruz

    hr31hr: What is getting you stuck at the sand stage? Did you mix ur own sand (petro bond), or is store bought? At first I had trouble at the sand stage because I wasn't packing it down hard enough.... It is a little un-nerving tamping down really hard on a buck that you have so much time in:).
    -Chris
     
  27. Pins&Needles
    Joined: Apr 8, 2006
    Posts: 381

    Pins&Needles
    Member
    from Santa Cruz

    Unkl Ian ya beat me to it! :D
     
  28. dirtbag13
    Joined: Jun 16, 2008
    Posts: 2,540

    dirtbag13
    Member

    bad ass ! reminds me of high school shop class !
     

Share This Page

Register now to get rid of these ads!

Archive

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.