Casting Plaster: Plaster Pencil Holder

Supplies

Part 1:

• Pen / Pencil
• Metal Ruler
• Box cutter / Cutting knife
• Polypropylene - 30x20cm
• Tape
• Card - 30x20cm

Part 2:

• Plaster
• Bucket
• A cup - 135 mL (yogurt cup)
• Water - 270 mL
• Plaster - 405 mL
• Small Juice Box - 200 mL
• Food coloring (color of choice) - 10 mL
• Sanding board

Step 1: Making a Net

Materials:

• Card - 30x20cm
• Pen / Pencil
• Metal Ruler
• Box cutter / Cutting knife
• Tape

The measurements of the net are in the first photo. The longest side is 28cm, the second longest side is 10cm and all of the other sides are 5cm. To be able to make the folds nice, you have to score all the edges that you will be folding with a cutting knife. After you've done all of that, you need to fold all the parts and hold them together with tape.

Step 2: Tracing and Cutting Out the Net Onto Polypropylene

Materials:

• Pen / Pencil
• Metal Ruler
• Box cutter / Cutting knife
• Polypropylene - 30x20cm
• Tape
• Finished card net

You need to use a pencil or pen to trace the finished card net onto the piece of polypropylene. You also have to draw the guidelines from the card onto the polypropylene to be able to make the accurate folds. After all that, you need to score the lines again to be able to make precise accurate folds. Once you fold it, make sure to use tape and cover up all the holes on the outside so that no plaster can get out once you pour.

Step 3: Mixing the Plaster

Materials

• Plaster
• Bucket
• A cup - 135 mL (yogurt cup)
• Water - 270 mL
• Plaster - 405 mL
• Liquid Food coloring (color of choice) - 10 mL

You need a big bucket to be able to mix the plaster in. The water to plaster ratio is 2:3 and a singular small yogurt cup (135 mL) is what you should measure with 270 mL of water is approximately 2 full small yogurt cups and 405 mL of plaster is approximately 3 full small yogurt cups. You also need a lot of food coloring because the plaster mixture will really dilute the color if you put in too little.

The next few steps need to be done quickly because the plaster does not take a long time to harden. The first thing you should do is measure out 405 mL of plaster and put it aside. Next, you need to measure out 270 mL of water and pour it into the bucket. After that, you have to slowly pour in the plaster that you measured earlier into the bucket and mix it fully for 30 seconds. The last thing you have to do is put in the 10 mL of liquid food coloring into the mixture and mix for another 30 seconds but make sure the color is completely blended in.

Step 4: Adding the Core and Pouring

Materials

• Tape
• Plaster Mixture
• Finished Polypropylene Mold
• Small Juice Box - 200 mL

First, you have to pour some of the plaster mixture up until about a third of the polypropylene mold and then take the juice box and try to hold it in for about 30 seconds about an inch above the bottom of the mold. Once 30 seconds are up, pour the rest of the plaster mixture in until the very top of the mold. Leave it there for about another 30 seconds and make sure that the core is centered. Lastly, you have to get some tape to hold the core in the middle. Tape one side and go across the top all the way to the other side and tape it there too. Do the same with the two remaining faces. Now set aside for a day or more.

Step 5: Un-molding and Sanding

Materials

• Box cutter / Cutting knife
• Sanding Board

After waiting a few days, get a cutter and cut along the edges of the polypropylene that had been taped. Once the final piece is out of the mold, there may be a few rough edges and you need to use the sanding board to sand them down. Make sure not to sand too much and you're done!