How to cast the item in the pictures

Discussion in 'Sand Casting' started by Greg, Aug 20, 2018.

  1. Greg

    Greg Copper

    Just ok..Explain Iowa to do this process.
    Thank you
     
  2. Jason

    Jason Gold

    Well, if you can carve, sculpt or basically make that part in wax. I can invest it in shell and pour you one. Or you can invest that thing into ultravest, melt it out and pour in the metal yourself.
    Lots of ways to skin cats these days. Some methods are quicker. Like sand casting. The trouble with your part as you have learned is it's shape. When shapes get tricky, the pattern must be constructed to come apart. Part of it will go in the cope, the other part in the drag. I'm no sand guy, but I cast weird shapes not suitable for doing with sand. That's why I run ceramic shell. The cost and equipment is a bit more than sand, but the results work well for the kind of junk I cast.

    You have the original there right? Well, let's say you made a silicone mold of your part. You then cut the silicone to remove your part. If cut carefully, the silicone will close back up and allow you to pour in wax. You can almost go in the caravan awning part business from here. The downside is, the wax copy will be slightly smaller than the original part. After the wax is invested and cast into metal, it will be smaller still. Here in lies the problem when duplicating a current existing part. Shrinkage must be accounted for. That's why I suggest just creating a wax version of what you have and maybe a little larger, THAT wax would get invested and with any luck, you'll be able to use the final metal part.

    IF you can get a replacement, I'd go that way. OR take a closer look at your part and how it functions. If you can wrap your brain around what's important and what's not on your part, you can eliminate the areas that are screwing with you during your sand molding. Such as grinding off parts of it that interfere with the ramming process. IF you are successful in ramming up your part, remember it will still be a little smaller than the original and will need some fetteling. <<<<<<<<< I like that word. The Brits use it. Does any of this help you?
     
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  3. Jason

    Jason Gold

  4. Greg

    Greg Copper

    That will not fit my Awning.
    This is the problem. I think my awning is to old.
     
  5. Greg

    Greg Copper

    The silicon mold . How is this done. The silicon is it from a silicon gun .
    Can you explain in point step how you do this . This is a new field for me.
    Thank you.
     
  6. Jason

    Jason Gold

    You could pour a block silicone mold of that thing. Basically, you hot glue it down to some cardboard and glue down 4 walls around it. Then ya fill it with silicone. After it sets up, ya remove the card board and cut up the side of the block to release your part. Here is a good video of the process.
     
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  7. Greg

    Greg Copper

    This silicon where do I get the silicon from.
    I noticed you mixed two parts .
    WhenI make a wax mold and remove from the silicon do I then make a plaster Paris of the wax mold and melt the wax out then pour the alliminum in.
    Is this correct .
    Please advise.
     
  8. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    You talkin to me? LoL.

    If that part can be pulled from a green sand mold as HT1 suggests, I think you'd be miles ahead to just do so for two parts.

    Lost foam and lost wax are similar processes in that they both use expendable patterns. If you look at the threads in the Lost Foam sub forum you'll get the gist. Lost foam will only require common materials such as dry sand, styrene board, and maybe some drywall/gypsum mix.....usually a couple dollars of material and after you have the ability melt and manage molten metal, is the lowest cost of entry to casting metal parts. Lost wax will require a significant investment in pattern and mold materials such as silicone, wax, ceramic shell slurry and fused silica, and a means to fire the shell at very high temperatures. Here is a thread that discusses Pros/Cons of the lost foam process.

    http://forums.thehomefoundry.org/index.php?threads/lost-foam-pros-cons.120/

    You need to be able to carve/machine the pattern from expanded or extruded polystyrene board, but the material is soft, easy to work, and can be glued together from multiple pieces to make complex shapes. I use wood working tools and sand paper to make my patterns.

    http://forums.thehomefoundry.org/index.php?threads/machining-xps-foam-patterns.14/

    Once you have the styrene pattern it can be brush coated with common materials for better finishes (or left as is), placed in loose sand and packed with some vibration. When the molten aluminum is poured it evaporates and replaces the space in the sand occupied by the styrene pattern. Here's where my fascination with the process began. I have refined my methods quite a bit since then but it does give you a good idea of the process from start to finish.

    http://forums.thehomefoundry.org/index.php?threads/tubular-lost-foam.11/

    Best,
    Kelly
     
  9. HT1

    HT1 Gold Banner Member

    image.jpg alright, I'm a card carrying Journeyman Molder, I can get that out of green sand or petrobond... of course I can do this so we might have an apple to oranges situation... and for two parts get close and fix it with a grinder
     
  10. DavidF

    DavidF Administrator Staff Member Banner Member

    I'm certain you could, but could Greg?
    Still say lost foam would be best bet for quick success..
     
  11. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Man, those tea cup and spoon molding exams are impressive.....bravo HT1. A ways back, I was going to do one of those in lost foam but after thinking it over decided it defeated the point.......unless the point was it could be done in lost foam without being a Journeyman Molder :)

    Best,
    K
     
  12. Greg

    Greg Copper

    This is a photo of my oil burner furnace
     

    Attached Files:

  13. Greg

    Greg Copper

    I have just casted the item in sand and it turned out one hell of a mess.
    There must be a better way
    It is that bad it is not worth taking a photo of
     
  14. Greg

    Greg Copper

    With the styrene do I carve the shape out then mold it in sand then the alliminum melts the styrene.
     
  15. HT1

    HT1 Gold Banner Member

    This is one of the Subjects that could lead to Months of conversation... Bitter end skill levels VS Amateur ... Throw in some peoples accidental success that they cant explain and probably cannot duplicate... ( I see this in a lot of peoples Furnaces) some peoples success seems too good to be true... and they cannot explain it... and of course none of us have enough Money to do real experiments on subjects like that... let me Build a dozen furnaces with only tiny differences to see which is most effective.. NOT!
     
  16. Tobho Mott

    Tobho Mott Gold Banner Member

    I would not use your greensand for lost foam, you'll never get the stink out. Plus it's not necessary, nor necessarily even helpful. You want the sand as permeable as possible to vent the vaporized polystyrene.

    The way I set up lost foam molds is shown at about 7:30 here:



    Take care to orient the foam pattern such that sand can get into all the nooks and crannies; any spaces touching the foam that are filled with air will be filled with metal. If you can bury a foam pattern so it's poitioned tall rather than wide, do so. This part looks small enough that I do not believe there is much risk of sand float (a weird looking type of casting defect sometimes seen in lost foam casting) but a more vertical orientation and better vibration means still less risk. Pour hot.

    That is the very basic, quick and dirty, bare bones, least effort to get a viable part that just has to function way. To learn about how to make foam patterns and cast parts that look factory made, see Kelly's lost foam posts and videos and you'll see how to add all the bells and whistles.

    Good luck!

    Jeff
     
  17. DavidF

    DavidF Administrator Staff Member Banner Member

    Take a picture any way. It will hep us to point you in the right direction...
     
  18. Tobho Mott

    Tobho Mott Gold Banner Member

  19. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Greg, I'm sure you will continue to receive a lot of help here but you also need to do your homework. Have a look at the links in post 28 and many of your questions may be answered wrt to lost foam.

    Best,
    Kelly
     

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