Thanks for visiting my instructable! Today we are going to learn how to make a 2 piece mold for your sculptures and 3d Prints. Once completed this mold will allow you to make exact copies of your sculptures and 3D prints in minutes! So Lets get to it!
And the total cost to replicate this product in a matter of minutes is...Around $130.00. BUT most of the materials above are reusable for the next several molds and depending on the size of your current mold, you will probably get more than one mold out of your trial sized kits. Not too shabby!
Most of the materials in this tutorial can be found here: http://www.reynoldsam.com
Mold: This is the actual rubber you will be pouring around your object.
Cast: This is the final product that you'll pour in to and pull out of the mold. Typically either resin or plastics.
Positive: This is the actual sculpt or 3D print that you are making the mold of.
Viscosity: referring to the thickness of a liquid. Example: water has a low viscosity.
Step 1: Sculpt your first half!
Now we will sculpt the first half of the mold out of the non-airdrying modeling clay. Always try to envision which way the air is going to flow out of the mold. My mold will actually be flipped upside down (from this photo) when I'm pouring the resin in. This is what I call "subtractive thinking" and may hurt your brain at first. But hang in there, it's worth it!
Step 2: Place your sculpt in the half
It's important to give a wide enough border all around your sculpt to make room for keys holes and to ensure your mold doesn't deform when pouring. Also, if you are molding a sculpture it's always a good idea to make sure that it's cooked (I use Super Sculpey or Sculpey Firm) so you don't deform it while you're sculpting the first half and building the mold around it.
Step 3: Fill in the Gaps Cont…..
Press the clay up nice and snug to the sculpt because Moldmax 14NV has a low viscosity (which means it's really runny). So it's important to tightly press in all the clay around the seams so that the rubber won't escape when we pour in the first half.
Step 4: Add the Pour Spouts
Sculpt your pour spouts out of the Sculpey III in a similar shape to a funnel so they are wider at the top and then taper down almost to a point. Then bake them in a conventional oven at 275 °F (130 °C) for 15 minutes per 1/4 in (6 mm) thickness. DO NOT MICROWAVE. Baking should be completed by an adult.
Step 5: Build the Outer Wall
We want the sculpt to be completely encapsulated in the rubber so we need to build the wall up past the sculpture a good amount. Also ensure those Legos are pushed together nice and tight!
Step 6: Adding Vents
Vents should be added where you envision air bubbles collecting.
Step 7: Adding the KeyHoles
We like hexagonal shapes. Anything that really helps to lock the two halves in place is a good idea!
Step 8: Spray on the Release Agent
This release agent ensures that the mold won't adhere to any of the surfaces in the mold including the clay sculpt itself as well as the legos. We want everything to release from the mold easily later on so using more release agent is always better than less.
Step 9: The Mix Ratio 100/A to 10/B in Grams
Numbers are hard right? No worries all this aint too bad. The Mix ratio is A=100 to B=10 in grams so get out your trusty gram scale (be sure it's set to grams). To minimize rubber waste always try to mix less rubber as opposed to trying to mix the exact amount to be done in one pour. The rubber takes a minimum of 8 hours to set so you don't have to worry about it setting while your away mixing more rubber . You may have to go back and re-measure and mix several times over to get the right amount of rubber in the halves. I'm starting with 300/A and 30/B in grams.
Step 10: Mixing the rubber Cont...
Make sure you mix it for a good long while as in improper mix will cause the rubber to take forever to set or won't set at all. Be safe and mix it for a good 2 to 3 minutes until a smooth consistency is reached.
Step 11: Pour Away!
The higher you can pour from above the mold the less bubbles you will get as they will pop in the rubbers stream.
Step 12: Mix and Repeat
Step 13: Let Dry for 10 Hours
Let it dry for at least 10 hours. When the time is up, softly touch the top of the rubber to ensure it's solid before you proceed with the next step.
Step 14: Removal of Modeling Clay
Now that you've waited at least 10 hours for the rubber to set, It's time to first touch the rubber to ensure it's properly set up. If it's tacky then let it dry another few hours and try again. Next we'll flip the mold over to reveal the side with the clay and begin removing it. Peel slowly as to not remove your baked sculpture (positive). Sometimes its good to allow a lamp to shine on the clay to warm it up slightly for easier removal. Don't let it heat too much as it will stick to the mold and be a mess to remove!
Step 15: Cleaning the Mold
The rubber we've chosen to work with is so runny that some of it will have almost always bled through to our new clean half. When this happen it's important to peel it off and use a razor knife to keep your molds seams nice and clean. Next be sure to analyze ALL of the seam around your sculpt to ensure no more modeling clay is present! Double and triple check it for best results!
Step 16: Build up Wall Again if Needed
When I sculpted my first half in the modeling clay I didn't make it thick enough overall. Lets build up the wall with another few layers of Legos to ensure we get the thickness in the second half of the mold we need. If I were smart I would have got it right the first time around :( No worries this is the solution!
Step 17: Don't Forget the Release Agent
In my younger days (last month) I forgot to apply the release agent which incapsulated the sculpt within the mold with no means of releasing it....This was a sad and costly day! I wasted about $75.00 in mold material and costly hours in sculpting the figure itself! Learn from my mistake and DON'T do this! Give your mold a nice thick layer of release agent from ALL angles. You wont regret it ;)
Step 18: Mixing the Rubber Again
Second mix same as the first.100/A to 10/B mix ratio. Stir well and pour!
Step 19: Separate the Two Pieces
Make sure you've waited at least 10 hours and then gently touch the surface to ensure it's dry. If tacky wait another few hours and check back. It may not come apart super easily but don't worry! As long as you used your release agent, it should separate with a good peel!
Step 20: Mold Clean up
Don't hesitate to take a razor knife to the mold to refine it but be careful for both your personal safety and the life of your mold is at stake! When cutting be methodical and patient. In this case I had to remove some rubber that bled over in front of my vents. You will mostly likely need to refine each mold before you can get great pours and it may take several pours to get there. Hang in there!
Step 21: Measuring and Mixing the Resin
Now time for the resin. Resin is easy to mix as it's a 1 to 1 ratio. In order to find the exact amount to pour into the mold you can do a water test. This is done by closing the mold and wrapping it as if you were going to do a pour, but then filling the mold with water. Once you've filled it all the way up you can pour the water out into a cup and measure it in grams. Once you've got your measurement just divide it by 2 and you've got your measurements for part A and part B. Back to the resin, once you've got the two parts combined in a cup the clock begins to tick. Be quick and thorough about mixing and then pour the resin into the spouts carefully. Avoid contact with hands and skin as the resin will heat up a lot in the setting process.
Step 22: Release the Resin Cast
After at least 15 minutes (I prefer 20) has passed, It's time to remove your cast. Take your time!
Step 23: You've Made it!!!
What a beauty! Once you've removed your cast you can sand it and carve it to clean up any seams. Now you can make exact copies of your product in minutes! Congratulations!!!
Step 24: Examples and About Me
I am actually a 3D artist by trade and have spent a few years working in both the video game and film industries. During my time making characters for games I started to realize that there was a real desire to step away from the computer screen and do something truly 3D. So I drove to the nearest arts and crafts store and bought me some super sculpy modeling clay. Ever since I've been hooked! I have since been continuing my career as a 3D artist and selling over a hundred of my likeness sculptures and custom wedding cake toppers on the side. Although I love traditional sculpture I am well aware that times are changing and I have always wanted to get in to 3d printing to see all of my 3D models come to life. Thanks for playing!
To see more of my work head on over to:
To learn how to make wire armatures for sculpting head on over to my other instructable: