Customs: translucent casting?

Discussion in 'Creative General Discussion' started by Megatron31, Jan 11, 2012.

  1. Megatron31

    Megatron31 I Belong to Nobody!

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    has anyone ever done this and the cast comes out sticky?

    i have done 2 or 3 parts and they come out this way, im using all matching brands and i think is a very minimal amout of dye.

    anyone else had this issue?
     
  2. Zildjian

    Zildjian Well-Known Member

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    Yep.... you need to get the measurements for both parts EXACTLY right before mixing and you need to heat cure a lot of them to get it right. What brand are you using?
     
  3. Megatron31

    Megatron31 I Belong to Nobody!

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    Allumilite. And define heat cure.
     
  4. The621

    The621 Fuck you, that's why!

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    Funny. My casts resulted in destroying my molds I made. The only casts that came out right were head casts.

    You mentioned that they came out sticky, right? Was it difficult to pry the cast out? Or did you use mold release and it still came out sticky?
     
  5. JazzEd

    JazzEd Truckasaurus!

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    I have had that issue before. When I let parts cool in colder places, like in my garage. Soon as I let the cast cool indoors, I didn't have that problem anymore. And I'm totally sloppy with equal parts. I always eye ball it. I also use Alumilite.
     
  6. big hank

    big hank Resident Slacker-Basher

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    I use a small postal scale that reads in .001 g, which is basically milligrams.

    It really helps in accurate ratios. I put the cup on the scale, zero it out. Put part a on and zero it, then part b. Then mix.
     
  7. Megatron31

    Megatron31 I Belong to Nobody!

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    ya i usually eye ball it with both cups side by side (semi clear cups with measurments on them) and have never had an issue but this clear resin seems to not like it and i wondered if maybe it was the dye so i wanted to ask and see others experiece.

    My process

    working in my kitchen

    heat the mold in the microwave (30-45 seconds depending on size)
    pour resin into respective cups let set to air out for a few minutes
    add dye to and let it rest after stirring so the air bubbles escape
    mix the 2 resins and let combined mixture set to de air
    then pour mold

    this particular resin has a 45 minute potlife and a 18-24hour cure time
     
  8. Zildjian

    Zildjian Well-Known Member

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    You need to heat the mold for quite a lot longer and more evenly. Don't microwave them, put them in an over at 150-200 degrees for 1-2 hours before pouring the resin. I know it is not the same company..... but read this information sheet from Smooth-on regarding their crystal clear product (all I use) specifically the processing recommendations section:

    http://www.smooth-on.com/tb/files/CRYSTAL_CLEAR_200_TB.pdf
     
  9. Megatron31

    Megatron31 I Belong to Nobody!

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    thanks for the link that is a first (the instructions for this stuff do not mention this step)

    but am i reading it right that it says you can post cure but placeing the part itself in the oven for 6 hours ant 150 if the part comes out tacky?

    cause at this point the part looks fantastic its just kinda soft and tacky 3 days past its 24 hour cure time
     
  10. The621

    The621 Fuck you, that's why!

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    Does heating the mold always require a pressure pot?
     
  11. Insane Galvatron

    Insane Galvatron is not insane. Really!

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    I have used their black and tan with no issues, but the white does this every time. Not sure why. Sucks because white is the easiest to add dye to so you can get other colors. I've never used their translucent.
     
  12. Zildjian

    Zildjian Well-Known Member

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    You would have to post cure it while it was still in the mold..... also, you can give Smooth-on a call. They will help with anything, anytime.
     
    Last edited: Jan 13, 2012
  13. Zildjian

    Zildjian Well-Known Member

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    Neither have anything to do with the other.
     
  14. The621

    The621 Fuck you, that's why!

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    Now I'm lost. Why do molds require heating, then?
     
  15. Zildjian

    Zildjian Well-Known Member

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    My advice to you..... take a step back and do some extensive research on molding and casting. Molds require heating because the reaction between the resin and hardeners is a chemically based thermodynamic reaction. Heating the molds help to prevent any "cool" spots from ******ing sections of a cast from hardening.

    Pressure pots are used to force air bubbles out of a mold as well as to force resin into the small areas.
     

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