Sunday, December 21, 2014

Chocolate Mold Round 2

I bought a sheet of HDPE plastic (note: they are called sheets, not blocks, even though this 'sheet' is 1 inch thick) and milled out a bunch more mold positives.

Then I cast them with Smooth-Sil 940:

And then I spent all of this morning making a huge mess in my kitchen and burning myself repeatedly. Here are some very messy first tries:

Verdict: Pouring chocolate is a real pain.

What didn't work::
  • Screw-top plastic squeeze bottles
    • Plastic becomes softer when warm, tip clogs, then applying pressure just causes the cap to explode off the bottle
  • White Ghiradelli chips burn before they melt. Cherry chips burn before they melt. Old candy melts burn before they melt.
  • Ziploc piping bag
    • You have to keep readjusting your grip as the bag empties--not enough fine control
  • Improvised double boiler--didn't get as hot as I wanted and chocolate ended up solidifying in the wrong way (basically it only hardens in the fridge/freezer and it is too soft and pliable)
  • Spoon -- not enough fine control
  • Thick and tall mold walls--I didn't think about this, but the thicker and taller mold walls make it harder to release the chocolates without breakage. This means having to pour the chocolate fairly thick to make it strong enough to survive release.
    • I can cut down the existing molds with a knife fairly easily
    • I can get a new block of HDPE and mill everything again ($24 and a few hours sitting in front of the CNC)

What did work:
  • Microwave method. Much cleaner, less moisture, you can reheat whenever.
  • Syringes (oral syringes, plastic kind).
    • The trick is to empty them then pump a few times between uses, to avoid having the tip clog. If there is a big enough hole left in the tip to allow suction of the liquid chocolate, then the hardened chocolate in the tube will be melted by the newly suctioned chocolate.
  • Actual chocolate, and candy melts that aren't very old. These melt fine in the microwave.
  • Tapping/dropping the mold repeatedly
    • Rather than trying to put the chocolate in an even layer, it is possible to just put some in the center then repeatedly shake/drop the mold onto the countertop until it settles in a flat layer

What might help make the process better:

  • Gloves, to avoid leaving melty fingerprints on the chocolate when demolding
  • Better quality chocolate
  • A brush or a toothpick for cleaning up details in the first pour
  • A temperature controlled rig for keeping the chocolate ready for pouring (expensive, but probably very helpful)
  • A candy thermometer for checking the temperature
  • Cocoa butter/veggie oil/butter/coconut oil for the syringe (should make it a lot easier to pull the chocolate into the syringe)

So what's next? I was only able to obtain one syringe in stores today, so I went online and ordered a bunch more in various shapes and sizes. I've spent a lot of money on this project so far but I'd rather learn to do things right than to just get some mediocre results out cheaply and quickly. And I guess that reveals that the whole point of this project--not to create cool looking chocolates, but rather to learn about mold making.


  1. Hello,
    sorry I don´t speak very well English, but I found your Blog in Internet and I would like to make this Mould too.
    I saw in the first Round a wood Mould with the design and later this one was in the HDPE plastic. I don´t understand how did you make it. Do you bought this plastic with this figure or had you make it? How can I make it too? Thank you. Regards.

    1. I know this is probably nearly two years past when you were hoping to get a reply...but...

      I used a CNC milling machine to take my file and create the plastic mold positive.