Using SolidWorks I was able to sketch my mold and determine the exact volume of silicone required for the mold, in addition to calculating how much resin was required to cast each peg. This was a huge help in estimating how much material to purchase
Here are the laser cut hardboard pieces used for the mother mold. I cut two extra pieces to help with alignment and spacing of the glass test tubes.
This tabbed boxed was designed using my favourite box generator makercase.com. It is assembled with masking tape on the edges so it can be easily be taken apart later, and also to prevent any silicone from leaking out. The two 1/8" thick h
Here is the mother mold assembled and ready to receive the test tubes.
I forgot to photograph this step on the mold I have been showing you, so what you are seeing is an earlier attempt at the same thing. I used an acrylic face for the top aligning layer in this case. I'm using a bit of hot glue around each tube to sec
The tubes are inserted one at a time with a hot glue treatment after each. Here they are secured and ready to move to the next step.
Here is the mold flipped over.
Next, the base and spacing inserts are removed.
Close up. I think it looks kind of funky.
Ready to mix up the silicone! Here I am using Mold Star 20T. The 20 refers to the shore hardness which is scale used to tell how hard rubber is. The lower the number, the softer and more flexible the rubber is. This silicone is mixed in equal
A good suggestion I was given to ensure proper mixing is to colour the silicone two different colours with a compatible dye. Since the UV dyes I was going to use in the resin casting were compatible with the silicone, I decided to use
Parts A and B were mixed into one large clear container. Mixing must be done thoroughly and quickly! This silicone has a working time of 6 minutes, and cures in 30 minutes. The batch was then poured into the mold. I like to pick
My calculations were perfect. <insert happy dance here> I had exactly enough silicone to fill the mother mold. If you ever find your self short, it's not a problem to pour an additional batch on top. Silicone sticks to itself very well.
30 minutes later it's time to bust this thing apart! This step did take some elbow grease since there wasn't any mold release applied.
With the help of some needle nose pliers, and a lot of patience I was able to release the final part of the mother mold. As you can see it was meant for one time use only. Good thing hardboard is so cheap. The test tubes were cleaned and used again
With all the hard mold making steps behind me, I was excited to start pumping out batches of pegs.  I was lucky enough to have access to a fume extractor for mixing the resin under. The product didn't really have an odour from what I reme
To save on cups and making more waste than I needed, I decided to reuse my Part A cup over and over, and Part B would be a fresh cup each time. Part A gets poured in cup B and mixed thoroughly before pouring. These beer cups were the perfe
I found that by over filling the mold a bit and creating a thin consistent layer across the whole top of the mold made it easier when demolding. I was able to peel back that top layer of cured resin and clean the mold quickly. If I didn't do th
After an hour these puppies were ready to be released! The bottom of the mold was only a 1/4" of silicone so it was easy to flex the spots under each peg with my thumbs, they would pop out about 3/4" and a handy pair of pliers took care of the rest
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