Concrete Christmas Present Candle Mold (with surprise inside!)

A silicon mold, mold I whipped up as I lost track of time and realized Christmas is just a short time away.  The 3d print will result in a positive for pouring in silicon to then create a silicon mold (or you could just use the box, lid, and snowflake as is, but that's boring and flammable if used as a candle!).  Concrete is then poured into the cured silicon mold to create a candle holder.  Full steps below as well as links to all products used (Most products can be used for many multiples of the candle). 

Print settings:

• 0.20 Layer Height

• 10% Lightening Infill

• Snug Supports only on bottom of Bottom and Top With Bow Parts (see 3mf files)

• Fuzzy Skin outside walls

  • 0.1 thickness

  • 0.05 point distance

• Tools Needed:

  • Hot Glue Gun

  • Hobby Knife (Exacto Blade)

  • Vacuum Chamber (optional)

• Supplies Needed:

  • 2 Part Silicon

  • Silicon Mold Release

  • Candle Wicks

  • Candle Wax

  • Concrete

  • Glass Fiber

  • Concrete Dye (optional)

  • Crafting Popsicle Sticks

  • Rubber Bands

3mf project files are included for a few different printers with layout of multiple plates configured. MK4S was used for the pictures, it's the only one confirmed to work, but all should work. 

Once all pieces are printed out begin assembling.  The part labeled base goes on the bottom of the assembly.  Next dab a small amount of hot glue on to the bottom of the part labeled bottom and stick it on to the base, centered, ensuring there is room for the parts labeled Shell to fit around with a gap.  Once the glue is set place the Shells around the bottom ensuring that the base is held in place by the shells with the assistance of some more hot glue.  Once everything is all lined up and there are no gaps (except in between the bottom and the shells) run a bead of hot glue around where the base meets the shells and where both of the shells come together.  Do this part carefully to ensure proper coverage and no gaps for the silicon to leak out of!

If everything is secure give the inside of the mold cavity a good spray of mold release.  Pour out approximately 45 Ounces (1300 mL) of each part of the 2 part silicon.  Combine these parts per the manufacturers instructions and allow to degas (allow the bubbles to come out).  This is where I used the vacuum chamber. If you do not have a vacuum chamber that is fine, just wait 3-5 minutes after stirring before you begin pouring. Once degassed pour the silicon into the mold using a high pour technique (6 or more inches above the mold, this helps to prevent bubbles in the silicon further) until it reaches almost to the top (1/4 in. or 6mm). I did this part in a baking pan lined with parchment paper just in case there were any leaks. Place aside and allow to cure per silicon manufacturers recommendations.

Once the mold is fully cured you can begin to demold the 3d print.  Carefully cut around the edge where we applied hot glue earlier using the hobby knife and remove the shells.  Carefully work the base off the silicon and the bottom (hobby knife may be used here).  Once the base and shells are removed, you can "roll" the silicon up (more of a slow work back and forth and pull) until you are able to extract the 3d print from the mold.  Congrats, you now have a reusable silicon mold!  We will use this for the concrete, not the 3d printed mold parts.  The Top With Bow piece may need to have an "x" cut in the silicon going from corner to opposite corner to assist with removing the 3d print (as seen in the picture).  This does not affect the final product.

Reuse the base and shells from above and do the same procedure as before, except this time use the Top With Bow piece in place of the Bottom piece. If the base or shells were damaged when removing the first mold, simply reprint them again.  Less silicon can be used as well.  We only need to cover the bow by 1/2 in. or 12 mm.  Same process can be applied to the snowflake if you choose to use the hidden snowflake feature.  This will give us 3 silicon molds, 1 for the box, 1 for the top, and 1 for the snowflake.

Concrete is mixed per the manufacturers instructions, except that dye is added for desired color and glass fiber is added for strength, a little goes a long ways with the glass fiber.  Concrete can be a little more wet than normal as we will be pouring this in to the mold.  Ensure you spray the mold with the mold release and then begin pouring the concrete into the mold.  Allow to harden and remove from mold as in the previous step (should be a lot easier though). This process is repeated for the other 2 molds.  A vibration table would ideally be used here to get any air pockets out.  Do your best to shake and tap the mold for 5 minutes to help ensure air pocket removal.  With this method some of the air pockets should come out, it will never be perfect. Use popsicle sticks and rubber bands to brace sides if needed, or better yet would be to reuse the shells from earlier.  Allow concrete to fully harden and remove from silicon molds in the same manner as removing the 3d printed pieces.

Melt candle wax per manufacturers instructions and add any colors or scents you might like.  Place wick on wick holder, use sticker to mount it to bottom of candle hole.  Slide concrete (not 3d printed!!!) snowflake over top of wick so it falls to the bottom if you are using this feature.  Pour in candle wax until it is 1/3 in or 8 mm from top of concrete.  

Allow wax to harden, place lid on top.  You may choose to paint or to keep the basic concrete/industrial design aesthetic.

Items Used (not affiliate links):

• Mold Release I used: (https://a.co/d/50Sp735)

• Silicon I used: (https://a.co/d/6nM34Ir)

• Candle Wicks I used: (https://a.co/d/dnnQxrK)

• Candle Wax I used: (https://a.co/d/4YHbM0l)

• Concrete I used: (https://a.co/d/aQZbb3g)

• Fiber I used: (https://a.co/d/dKpsTvP)

• Cement Dye I used: (https://a.co/d/8LkFJqT)