Introduction: Glowing Ghost Heart With a Heartbeat

About: Computer programmer by day, hopeless artist and inventor by night

An old school friend's daughter wanted to be fully decked out to go as a ghost bride for Halloween. They had the dress already and had it all wired up with fairy string lights but it was still missing the part she wanted most: a big red glowing heart with a heartbeat. She didn't want just some simple flashing light so my friend reached out to me.

At first she was just curious if I knew of anything she could just buy off the shelf but the conversation quickly moved to possibly making one. Several ideas were bounced around a few times about maybe using something like an Arduino of some flavor but that soon changed.

We later got to talking about all the old surplus electronic project kits I had in storage. I figured I could easily make something simple that would meet all their needs. After some more talking back and forth about what she believed her daughter would like this project was born. Not only would I be making the control circuit for the light but I would also be making the heart from scratch as well.

In this article I will not be going into all the specifics of circuit theory, breadboarding, or soldering (if needed) as there are many other good resources and tutorials out there that could help you. I will just be touching on the specifics that are important to this project. Check out "How To Build Your 1st Circuit" right here on Instructables for a good start.

The main goal of this project was not just to make something my friend's daughter would love but to also design around and only use the items I already had on hand. It was already far into October and my free time was limited so the clock was ticking for a fast turnaround.

If properly scheduled out this project could be completed as a whole in about three days and can be split into two very separate phases of electronics and art. You do not have to do both if you just want to make the heart or the lighting circuit by themselves. Just focus on the aspects that interest you the most for what you want to build and accomplish.

I present the electronics first so that when we get to the next part we know how big to make it to fit everything.

Step 1: Materials

Please note that the resistors and capacitors listed below are for the specific timing I wanted with the parts I already had on hand. You can use these exact item values if you want to match what I did or you can use the steps that follow to figure out the values that will work best for you.

Also be aware that plaster of Paris can be very soft and more than likely you will break away thin details and undercuts when you pull your final piece. If this possibility worries you and/or you know you will want to cast multiple piece I would suggest using a stronger molding compound like Ultra Cal 30. Again this is what I already had on hand and does well for quick one-offs.

Circuit tools and materials:

  • Wire snips (or something to cut wire)
  • Wire stripper (optional)
  • Soldering iron and solder wire (maybe optional)
  • Small breadboard
  • Jumper wires
  • 555 timer IC x 2
  • Resistors: 100 Ω x 2, 220 Ω x 2, 470 Ω x 1, 2K Ω x 1
  • Capacitors: 1000 µF x 2
  • 9 volt battery and connector
  • Doorbell wire / 18 gauge wire (or what will be snug plugged into your breadboard)
  • Long two strand cord (e.g. old device power cable)
  • Shrink tubing and/or electrical tape
  • Cheap LED tap light (battery powered)
  • Clear plastic bracelet beads
  • Clear tape (maybe optional)
  • Loctite Go2 Glue (maybe optional)
  • Small container to house circuit

Containers and mixing tools:

  • Paint stirring sticks (or large disposable plastic spoons)
  • Small disposable plastic spoons
  • Mason jars x 2 (or other screw tight disposable container)
  • Large disposable mixing bowls x 2
  • Large disposable measuring cups x 2
  • Large butter tub (or other destroyable deep lidded container)
  • Disposable drip pans (optional)

Sculpting and molding materials:

  • Non-hardening modeling clay
  • Plaster of Paris (or other stronger stone molding material)
  • Parchment paper
  • Marker
  • Small screwdriver or metal pick
  • Toothpicks
  • Paper towel
  • Toaster oven
  • Scissors
  • Liquid soap
  • Cotton swabs

Heart casting materials and tools:

  • White school glue
  • PEG 3350 powder laxative (Clearlax, MiraLAX, etc.)
  • Food coloring drops: Red x 2, Blue x 1 (you might only need one red)
  • Borax powdered detergent
  • 100% Silicone clear tube caulking x 2 (second one just in case)
  • Caulking gun
  • Rubber gloves
  • Aluminum foil

Step 2: Figuring Out Time

We will be using both of the 555 timer chips for our project in their astable mode. This means that they will be wired in a way that each, when powered, will produce rectangular pulses at regular intervals. We will be tuning those intervals by using the formulas pictured above. These pulses will become the foundation for our heartbeat rhythm later. We will only be familiarizing ourselves with these now and will not be calculating anything until the next step.

The above formulas are actually two different paired sets of equations. The first pair is what the high and low timing would be based on what resistors and capacitors are being used. This ends up being how long the power coming out will be on (high) or how long it will be off (low) for a single 555 chip. Observe how R1 ("resistance #1") only affects the high timing but R2 ("resistance #2") will affect both the high and low.

The second pair is kind of working backwards from other known values to figure out what your resistors should be to get the timing you want. With this set if you know your desired frequency (how many on/off cycles in a second) and your duty cycle (percentage of how long the power is on) you can work out what resistor values you would need.

In both cases notice that the larger the values are for C (capacitance) the smaller the values of the resistors need to be and vise versa. You will also more than likely need to mix and match different resistors to get the total value you want for both R1 and R2. Just make sure to check your timing with the equations again once you settle in on a close enough value to see if values will need to be tweaked again.

You can choose to use either set of equations for your approach but note that things do not always work out exact. There is always some margin of error in the parts you will be using and everything will add resistance along the way. You might have to play with your values again once you have your circuit laid out to get something just right. In the end I had to drop a resistor myself to get it feeling right.

There are many calculators available online that will help figure these values out so all you need to do is search for a "555 astable calculator" if you get stuck.

Step 3: Timing the Heartbeat

The stylized heartbeat we were going for was that of a beat (light up), short pause (off), beat (light up again), and then a long pause (off again) before repeating the cycle all over.

The simplest way to do this is by cascading one 555 circuit after another and powering the second one by the output of the first one. By doing this the shorter beats and pauses are handled by the second 555 circuit while the longer pause is handled by the first.

What would be going on is that the second 555 would only be powered while the first one is high during its cycle of timing. During that time that the first 555 is high the cycle for the second 555 needs to be faster to do the actual work of beating on to light up.

The timing I was shooting roughly for was about a half second for the light to be on and the short pause off. I decided that the long pause off should be about the same as the sum of the short pause and two beats. So this gave me the target of 1.5 seconds on and off for 555 #1 and 0.5 seconds on and off for 555 #2.

Notice that we are going for about a cycle and a half for 555 #2 for every half cycle of 555 #1. To put it another way this is a target of a 3 to 1 ratio. Again please note that we will not be able to get this exact due to the available resistor and capacitor values and/or minor tolerance errors. The values I started with are listed below but I ended up not using the 220 Ω on 555 #2 R2. You just might have to fiddle a bit with it as well if you want to do something different.

555 #1:

  • R1 = 220 Ω
  • R2 = 2K Ω + 100 Ω
  • C = 1000 µF
  • Time High = about 1.608 seconds
  • Time Low = about 1.455 seconds

555 #2:

  • R1 = 100 Ω
  • R2 = 470 Ω + 220 Ω
  • C = 1000 µF
  • Time High = about 0.547 seconds
  • Time Low = about 0.478 seconds

Final light sequence timing:

  1. On for 0.547 seconds
  2. Off for 0.478 seconds
  3. On for 0.547 seconds
  4. Off for 1.491 seconds
  5. Repeat

Step 4: Circuit

Now that we have figured out how to get the timing we want for our heartbeat we can work on putting it use. Above is the basic circuit diagram I ended up using along with the resulting breadboard I made for this project.

Depending on the light you choose to activate you might have to use a relay to isolate a different power source to supply it. For my needs I was able to power everything from a single 9 volt battery without using a relay or a transistor.

A quick breakdown of a breadboard can be seen as two basic parts: the bus strips and the terminal strips. I will be describing their layout in relation to the image of my breadboard above. Note that some breadboards will only have one bus strip set or possibly none at all.

The bus strips are what you use to power your circuit and are the two red and blue lines on both edges of my breadboard. Everything in each of these four columns are connected together in each of their own lines and can be treated as the same wire.

The terminal strips are everything else that is between the bus strips. These are all connected individually in rows with a split in the middle and is where you will be placing your components. So each row on either side of the gap can be treated as the same wire as well.

On this step you will be taking your breadboard and placing your components on it to wire up the timer chips by using the breadboard to route everything with the help of jumper wires for power and signal. As mentioned before I will not be going into more detail on this. There are many online resources available to help in greater detail such as "How To Build Your 1st Circuit" right here on Instructables.

Since this piece was going to be used directly for the costume I wanted to make sure that it would survive. Because of that, after I tested my circuit, I glued my capacitors in place using Loctite Go2 Glue. I also ran some clear tape across the top of them to clamp them down. Everything else at this step should easily stay in place due to the snugness of the press fittings.

Step 5: Lighting and Diffusion

More than likely the tap light you will get (definitely once you take it apart) will just come across as individual sharp points of light. What you want to do is diffuse that light so it spreads out more and carries through to the silicone. I accomplished this in my build by using basic clear bracelet beads.

You might want to check out different bead shapes and/or translucent colors to get the effect that pleases you the most. For my project the end lighting color is entirely due to the intrinsic tinting of the silicone heart like we will be making later.

Step 6: Dismantling the Light

To be able control your tap light and use it in the heart later your are going to have to take it apart. Be aware you want to pay attention to how it is wired and constructed as you take it apart so you will know how to hook it up later and to not break components or tear away wiring.

Not all tap lights are made the same so take some time to look over yours before cracking it open. Some will have visible screws while others might hide them in the battery compartments. Others might actually not use any screws and are glued closed and/or use tabs to hold themselves together.

However yours is constructed take care when dismantling it as it might have thin wires you could damage or rip away. For my build this was not a concern as I soldered new wires on anyway to have something stronger and easier to test with. You might decide you do not want to solder anything and you might be able to get away with that in some cases.

If you do not want to solder wires try to be delicate and save what you can of the power wires so you can twist some longer wire onto them later. Just make sure you still use shrink tubing or electrical tape to cover your splicing.

Step 7: Rewiring the Light

Like mentioned earlier if you are able to save/use the existing wiring and do not want to solder anything you can skip this step. Just remember if you do decide to do any soldering to take all safety precautions and have proper ventilation and airflow.

Here I remove the existing wires as I wanted something that would be a little more stronger and not get torn away easily. I went and snipped some lengths of doorbell wire (18 gauge solid wire), stripped the ends, and soldered them in the same places the prior wire were ran to. This is why it is important to note these things when you were taking your light apart.

This step might seem redundant to some in the following steps as you might be wondering why I I would not just hook up the longer cord directly. This setup let me test easier with the breadboard as it fit snugly in place and was smaller to handle. It also gives more surface to wrap wire to later to extend and is easier to solder it.

Step 8: Adding a Longer Cord

In this step you will be extending the lighting power cord so that you can have the control circuit farther away from the final heart piece. Make sure you have a long enough cord that will work for your purposes. Here I use an old power cable from some broken appliance or device.

  1. Snip the end off of your cord
  2. Split the cable into a Y shape
  3. Strip the wires
  4. Wrap the finer strands together
  5. Twist them together with the wires coming from your light
  6. Solder them together (if you want or need to)
  7. Cover with shrink tubing or electrical tape

Step 9: Securing the Cord

Knowing that this part of the piece will inadvertently get tugged at the most I decided to do what I could to secure the wiring. All I did was use some Loctite Go2 Glue again on the longer cord against the tap lighting and clamped it in place while it set. This wont totally protect the cord from coming loose if yanked on too much but it is a good prevention measure.

Step 10: The Other End

Since we are using the breadboard as the final usable device we will want our lighting cord to fit as snugly as possible into the breadboard so nothing comes loose during its use.

  1. Cut some lengths of doorbell wire (18 gauge)
  2. Strip both ends of these
  3. Snip the other end off of your cord for the light
  4. Split the cable again into a Y shape
  5. Strip the wires like before
  6. Wrap the finer strands together
  7. Twist them together with the wire lengths you just cut
  8. Solder them together (if you want or need to)
  9. Cover with shrink tubing or electrical tape

Step 11: Battery Connector

Since we will want a snug fit into the breadboard with the battery connector as well we will be extending it too. You will be doing the same things as you did in the last step but with the wires on the 9 volt battery connector instead.

Step 12: Put It All Together

Now that everything is all extended and given snug connections we need to connect everything now back to the breadboard. Make sure to wire the battery connector to the right bus strips and the light cord to the right terminal and bus strip.

Once everything has been tested and verified to work go ahead and add some clear tape to help hold things into place. I choose to use clear tape here so I can easily see if anything works its way loose to help troubleshoot any future problems that might pop up.

At this point we are now done with the electronics part of the project and will be moving on to creating the heart that will be housing the light.

Step 13: Heart Concept

Before we get started working towards physically making the heart we must first figure out roughly what we want it to look like and how we want it to work. First and foremost we want it to light up and glow as much as possible.

To accomplish this goal we need to make the heart hollow instead of trying to back light a very thick piece. We also want to make the light spread out as much as possible through out the whole piece. We will accomplish that with the help of the clear bracelet beads we talked about earlier. So we need to make it more like a pocket with as much thin walls as possible without making it weak.

Since we will only be tinting the heart a single color instead of painting all the fine details our visual design should only focus on the major shape concepts that help make it read as a heart. Do not worry about it needing to be too anatomically correct as most people will not be able to tell the difference. Again you are just creating something stylized enough to convey it as a heart.

Step 14: Design for Molding

There will be several factors that will help guide what you can or will need to sculpt for your heart:

  • The size of the lighting
  • The size of the container you are using for your mold
  • Will you be able to get your clay out of the mold once set
  • Will you be able to pull a casted piece out of the mold


You will want to figure out your available working space with the container you will be working with to make your mold in.

  1. Take the container's lid and trace it on parchment paper
  2. Mark inside this a buffer line that is a little extra to give yourself a safe sculptable area
  3. If the lid has any dips in it make sure to make your marked buffer inside of it
  4. Draw your heart inside of this buffer zone making sure to break it up into different parts


You will want to mentally plan the shape and curvature of what you will be sculpting to make sure you will be able to clean out the mold as well as not having your final piece get totally stuck inside of the mold.

  • Think more about half circles or curves that are wider at the base than at the top
  • Do not have overhangs or anything bridging
  • Do not have any caverns, holes, or internal voids
  • Try to think more about a single solid piece with little or no appendages

Step 15: Sculpting

Using your parchment sketch as your different section boundaries and your mental shape as a guide

  1. Break down each section into balls of clay that are roughly the volume and thickness you want in each area
  2. Set all these balls of clay aside and work them back in slowly
  3. Work on the biggest section first and rough out the shape, thickness, and curvature
  4. Add in each additional area little by little and try to work back to front to layer
  5. Smooth little by little since you might want to adjust your work with each addition
  6. You do not have to be too detailed but smooth and blend where possible

You can do most of the shaping and smoothing with just your fingers and/or with a plastic spoon like I did. I did not spend too much time on the heart and maybe spend at most 30 minutes sculpting. That time was mostly elongated by constantly taking photographs I would later not even use. Above is a series of what I believe are the key steps in the end.

Once you have finished the sculpt you will want to carefully transfer it to the lid of the container you will be using to make your mold in. Once you have done this you will want to support the back of the lid with something if it is not flush with the table surface.

If you do not support the lid it could flex later and the sculpt with come free when you are pouring the plaster. You will also want to smooth your sculpt into the lid as to not have any gaps that plaster can get under and behind.

Step 16: Mold Box

Once you have your sculpt secured onto the lid you will want to cut the bottom out of your container. After you do this carefully mate it back together with its lid. To stop any possible leaking later you will want to go around the edges of the lid with an unbroken bead of clay to fill the gaps tightly. You could also use a hot glue gun and do the same thing.

Step 17: Plaster Time

Always read the directions for the products you will be using and always use these instructions as a good starting point. You will also want to keep these things in mind:

  • Always mix more plaster than you think you might need
  • Be careful when mixing to not stir too fast or hard and introduce air bubbles
  • Poor slowly and away from your sculpt and never directly on it
  • Try pouring in a long thin stream to help remove air bubbles but be careful not to splash
  • Let the plaster flow up and over your piece and never down and away
  • Make sure you totally cover your sculpt with enough plaster to be strong
  • When you are done pouring gently tap your mold for awhile to help loosen any air bubbles

What I do is have a container of water with how much I think I need and add plaster little by little. I keep adding plaster until a tiny island forms out of the water that will not collapse or dissolve fast back into the water. I will then mix and add just a tiny bit more water and mix some more.

The down side to my approach is that the mold has a greater chance of breaking and is softer. But for my purposes I like mixing my plaster a little thinner so that it pours better and has less chances for air bubbles.

If you are following what I did then we will also not be letting this mold totally cure before we start handling it. We will only be letting it sit undisturbed for a few hours until it is just hardened and cool enough to the touch.

Step 18: Freeing the Mold

Once the mold is hard and cool to the touch after a few hours you will need to carefully remove it from its container. Be very careful as it can be somewhat soft and easily broken. You might need to use scissors to cut and tear away the container to set the mold free.

The reasons we are setting the mold free early is just in case any plaster did get up and behind your sculpture. Now will be the easier time to chip away plaster to help free your sculpt. Again just be very careful so you do not break it.

Step 19: Removing the Sculpt

More than likely some amount of plaster will have seeped behind your sculpture and will need to be carefully remove. Using a small metal pick or small screwdriver carefully chisel away the plaster. Angle your tool towards the center of your piece so you do no chip or scratch the details on the inside surface of your mold.

Once you have cleared away the plaster that can be covering your piece you can use the edge of your tool you were using and lightly run around the entire outline edge to smooth it a little from any possible sharp edges you left behind.

After you are all done with the previous items you can now carefully grab your clay and gently remove it. It might not come out all in one piece so be patient and careful with your actions as you do not want to break away fine details. Do not use your metal tool to remove clay you can not easily pull away. We will be dealing that in the next step.

Step 20: Cleaning the Mold

If there is still clay and other debris in your mold carefully use a tooth pick to try to remove it along with using a piece of clay to grab it. We are using the toothpicks and clay together to make sure we minimized the scratching we can do to our mold and to prevent any damage to thin and fragile spots.

You might also notice air bubble at this step. Do not try to fill these with more plaster as that will not work out well. Since we are using the mold as a push mold those can just be filled in as needed with clay. You could also look into using a two part epoxy putty to fill them in.

Step 21: Let the Mold Sit

Since we started to work with the mold earlier than when it would be fully cured we will still need to let it sit for for the remainder of the time up to 24 hours. Since we used more liquid than called for it will want to sweat all this extra water. You will want to have paper towel down and possibly wrap your mold to soak this up as much as possible.

Step 22: Drying the Mold

Even once fully hardened the mold will still be full of water and will need to be dried out. Letting sit at room temperature this could take over a week to do.

You can speed this process up by by putting your mold in a toaster over between 100°F and 150°F (or the lowest setting you can do) with the door open slightly. If the door is not cracked like this the moisture will not be drawn off.

You might need to do this for around 12 hours depending on how much moisture there is, the size of your mold, and the temperature you are running at. Do not try to run at a higher temperature as it will damage or break your mold completely.

Step 23: Mold Release

This step you will want to wait to do until you are actually ready to cast your piece. Make sure to give yourself some time as this can take longer than you might think trying to deal with all the nooks and crannies. So I would recommend you do this right before you start mixing your silicone. Your part can get stuck in your mold if you do not do this.

What you want to do is mix a little bit of water and some dish soap together for your release agent. You will not want to make any suds so just stir lightly when mixing. When mixed dip cotton swabs into the solution and lightly coat the inside of your mold. You will want to take your time and get everything possible and be careful not to be too rough and break thin details.

Step 24: Secret Sauce

Here we will be mixing what I have figured out over time that will give the silicone color, makes it workable, helps it cure faster, and gives it some texture for gore. The instructions given here are my standard batch sizes so I have these on hand ready for other projects. You will more than likely not be needing as much as this makes so feel free to cut the ingredients in half.

You will want to most likely use Mason jars for these so that you can shake them to mix better and to store whatever you do not use. You will want to mix the red solution first so you do not accidentally stir it with the spoon you will use for the Borax solution.

Make sure you get the lid on it securely to be able to shake it and to make sure no Borax solution splashes into the mix. Also be aware that you need to use a fresh spoon for measuring and mixing the borax solution.

Red Solution:

  • 1 cup white glue
  • 1 cap full of PEG 3350 powdered laxative
  • 1/4 to 1/2 cup of water
  • 2 bottles of red liquid food coloring
  • 8 drops of blue liquid food coloring

Borax Solution:

  • 1 to 1 1/2 cups water
  • 1 to 2 spoons Borax powder

We are not done with the Borax powder and will need a little later. It will be easier to use if you set about 3 spoon fulls in a small container for later now. Just make sure to keep this out of the way of the red solution and what you are mixing until you are ready for it.

Once you have both solutions mixed let it all sit for at least an hour or so before using. This would be a good time to add the release agent to your mold.

Step 25: Start of the Gore

From this step on the clock will be ticking for how long you have to work with what you are mixing. There is about 30 to 45 minutes of good usability after you have mixed the ingredients and let it sit for 10 to 15 minutes. This might seem like a lot of time but it can quickly get away from you when you still need to knead the mix and work carefully to get all your details in the mold.

You will want to make sure you have good ventilation moving forward as you will be hit with a strong vinegar smell while you are working. You will also want to make sure to be using rubber gloves since the raw silicone will want to stick to everything and you can easily dye your hands with the red solution later. Only use bowls or containers that are specifically for this project and will not be used later for food ever.

  1. Cut the end off the 100% Silicone clear caulking giving it a big hole
  2. Take the rod on the caulking gun and poke it into the silicone tube to break the seal
  3. Wiggle it around to make sure you have made a wide opening
  4. Load it into the caulking gun
  5. Empty about 75% of the silicone into a bowl
  6. Set aside the remaining 25% for later (the second tube is just in case you forget or did not save enough)

Step 26: Mixing in the Red Solution

Carefully pour the red solution over the silicone just enough to cover it. You should only need about half a cup to do this. Using a fresh paint stirring stick or large plastic disposable spoon mix it into the silicone. It will ball up some but it should be easily workable. Let it sit for a minute or two.

Step 27: Adding the Borax Solution

Next you will want to pour about a 1/4 cup of the borax solution over what you just mixed. Quickly try to evenly stir that into mix. It will go from being a ball like earlier to flowing a bit. If this does not happen add a little more borax solution and mix but do not add more than a 1/2 cup total.

Step 28: More Silicone and Borax

  1. Add in the remaining 25% silicone and fold it into the mix (or add from a second tube if needed)
  2. Sprinkle about 3 spoons of borax evenly over the mix (unfortunately not pictured)
  3. Quickly try to evenly mix this into everything
  4. Once it looks like lumpy oatmeal let sit for 10 to 15 minutes

We need to let the mix sit so things can firm up a bit and start to cross link. Once it has sat for awhile it will not be so tacky to the touch and will not stay stuck to your hands (with gloves on) like the raw silicone would.

Step 29: Kneading the Mix

  1. Pinch off a small amount of the silicone mix
  2. Roll it into a ball with your hands
  3. Squeeze the ball over the bowl to catch water
  4. Fold it over itself
  5. Roll it back into a ball
  6. Repeat the squeezing, folding, and rolling for the same ball a few times
  7. Set the ball aside in a different bowl
  8. Do this with the rest of the silicone mix

Try not to spend too much time doing this as it will eat into your total working time. But also do not rush through this because this step is important to making the silicone stronger and not crumbly when it finally sets. Spend no more than about 10 minutes doing this to leave yourself about 30 minutes (max) of decent working time left.

Step 30: Filling the Mold

  • Start with the indented details like veins first
  • Take just small amounts of the mix at first to fill in the surface details
  • Start from the center and work your way out
  • Keep layering and pushing into what you put down before
  • Be careful not to press too hard and break details
  • Press and smear to blend different sections
  • Work all the way up to the edges of the mold

Remember that we want to make this into a pocket with some thinner walls. Just do not make it too thin that it will not hold up. We will still want to make some thicker sections at the top and bottom to add strength and to add anchor points to later.

Step 31: Making the Void

  1. Take some foil and make an oval shape
  2. Make sure that shape will big big enough for your light and beads
  3. Make a large flat patty out of the silicone mix
  4. Cover the back of your piece
  5. Make sure to press in and tuck your edges and thicker areas so the back will bond to the front
  6. Take a toothpick and perforate a line into the back down to the top edge of the foil
  7. Using the toothpick still now turn that dotted perforation into a full slit
  8. Make sure this is wide enough that your light will fit in later
  9. Fold some foil and insert into the slit so it doesn't seal shut when setting

Step 32: Adding Anchor Points

Through the thicker sections at the top and bottom insert some toothpicks and wiggle them around to widen the holes. We will be leaving the toothpicks in while the silicone mix is setting so the holes do not seal up. Take some of the last remaining silicone mix and add some more reinforcement behind where you inserted the toothpicks. These will be your anchor points to tie or mount the heart to something.

Step 33: Leave It Alone

We will now need to leave the piece to cure for at least 10 to 12 hours. After 2 to 4 hours it might seem like it has set to the touch but it is still rather soft on the inside and will tear. If you have leftover silicone mix go ahead and make some nuggets for fun and to see how well it is setting without disturbing your actual important piece.

Step 34: Freeing the Heart

Once cured we will need to remove our piece from the mold. If you are using plaster of Paris and mixed it like me you will more than likely break fine details and undercuts away removing your piece. Even after knowing this you will still need to be careful as to not tear your piece tugging too hard.

Start by working around the edges and pulling a little up and away to loosen the piece. Find a section that will be strong and pull a little more again up and away from the mold. You will need to work it little by little. Even with using a mold release the piece can be a bit stuck or locked in by some details in the mold.

It might take some time and effort with a lot of fine wiggling but you will finally get you piece free. Plaster might end up coated on your part in places and details that broke away stuck in cracks. We will be cleaning those away in the next step.

Step 35: Cleaning It Up

Now that it is free we will want to clean it all up. Go ahead and rinse your piece while gently rubbing into the surface with your fingers. This will help loosen and break away plaster that might be stuck. And plaster that is in cracks you can clean out with toothpicks. Also remember to remove the foil and to clean and rinse the inside pocket. Make sure your piece is dry before trying to insert any electronics.

Step 36: Finish It Off

At this step I am pretty sure you know what you have left to do. What we really only need to do is insert your lighting and fill the pocket with beads. You might need to squeeze your heart from the sides to help open the pocket a bit.

You can also use a pen or a marker to try stretching out the anchor holes some if you need them larger. All that might be left is putting the breadboard and battery into a small container to protect it and deciding how you will conceal it on a costume.

Step 37: Enjoy!

This project was a very rapid and quick turnaround to be able to have this prop to the little girl in time for all her Halloween events and parties. Hopefully you like this as much as she has been looking forward to it. It is now being all boxed up and delivered to her right on cue. Her excitement made the whole project worth it to me.

Feel free to ask any questions you might have in the comment section below. I will try to answer things when I can and if time allows.


Halloween Contest 2018

Participated in the
Halloween Contest 2018