Casting; A Walk Through

Discussion in 'Construction' started by JustinScott, Jun 5, 2008.

  1. JustinScott

    JustinScott Well-Known Member

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    Now, first off I want to say this is my first time ever making a cast. So, don't take this thread as a 'how to'; but more as a look at how I did it.

    I am pretty happy with my results. They are exactly what I was trying for.

    Now, I didn't photograph making a mold... So I (or someone else) will have to document that later at some point.


    I created a two piece mold as the piece I wanted had the ledge in it.... I actually tried a one piece, and it failed miserably.


    Here is the two piece mold, the original, and attempt (failed) #2:

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    The mold is two colors, because I ran out of material 1/2 way through & bought new (apparently updated) stuff.

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    Notice the pour (large) hole & the air escape hole. If I had put the air escape hole in during my first cast attempt.. I would have saved around 1oz of resin. And in the upper right corner, you will see my failed attempt #1

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  2. JustinScott

    JustinScott Well-Known Member

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    OK,

    So what does it look like to cast? For this cast, I'm making the D-Turret adapter.. you can see them in the Tirpitz Refit thread.

    Visit this site

    Firstly, you want to heat up the mold... They recommend a microwave, but since I don't have a microwave in my GARAGE... I used the heat gun.

    So the mixing process is very hectic, so I didn't take any photos of it... Its just me mixing resin anyway. However, it is critical to get it right. What you want to do is --> Mix like crazy for about 20 seconds (look at the consistency below) then pour like crazy.

    If you don't mix enough, the result doesn't dry completely & sections break off. (see failed attempt #2) If you mix too long, the resin dries in your cup. (See failed attempt #1)

    ...Remember we are talking about 60~90 seconds from start to finished part.

    Look at the color... that is what it should look like when you are ready to pour into your mold.

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    It will then start to change color... This is only like 2 minutes time lapse TOTAL! IT IS REALLY QUICK.

    If it starts changing color in your cup... you are too late.

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  3. JustinScott

    JustinScott Well-Known Member

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    Well, at this point... its time to relax. Go slow from here on out.

    VERY carefully start bending & pushing at the mold to break its seal to the part.

    [​IMG]


    Then slowly work it until it comes off the mold.

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  4. JustinScott

    JustinScott Well-Known Member

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    Finally, cut off the excess & sand it...

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    Here is the part that needed the two piece mold:

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    And finally:


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  5. Gettysburg114th

    Gettysburg114th Well-Known Member

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    Very good information Justin, thanks for posting.
     
  6. Kotori87

    Kotori87 Well-Known Member

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    Looking at those photos leaves me with just one question. how the @#$% do you unscrew the magazine caps to the turret with the two-part casting, if the hexagonal magazine caps are touching face-to-face? (I know it's not directly related to casting and molding, but I'm still curious)
     
  7. JustinScott

    JustinScott Well-Known Member

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    Uuuuh, uh oh. [:0]

    Just kidding. There is like 1 thou tolerance between the caps. They do spin, but any closer and they would bind.

    Actually loading with the assembled cannon in place?

    It probably looks tougher in the pix than it is in real life. Pull the turret off, then come in from the sides between the barbette with your fingers & twist. Then get your BB loader & also come in from the side... Not too bad. I'll probably wind up bending the tip of the loader for simpler access.
     
  8. Cannonman

    Cannonman Ultimate Hero :P -->> C T D <<--

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    This is too cool. How "battle damage resistant" is the material? Is the material you used for your barbette the same a Greg used for the turrent covers? It looks similar in the pics.
     
  9. JustinScott

    JustinScott Well-Known Member

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    The barbette is the same hard foam (the pretty out side)

    But the cannon to ship adapters is a hard plastic.
     
  10. Ragresen

    Ragresen Member

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    Justin those look about the same quality of my first molds I did for casting. With more pratice you will get cleaning molds and castings. Everything looks spot on other wise.
     
  11. JustinScott

    JustinScott Well-Known Member

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    Thanks John! :)

    My casting finish wasn't smooth because I used fiberglass resin to seal the 'master' before I made the mold.

    I knew going in it wouldn't be smooth & frankly, for these parts, I didn't care. If I was casting superstructure parts.... I would pay much more attention to the master & make sure it was pristine before even thinking about a mold.