Portable Cast Concrete Mono Speaker

What Inspired me?

This was my college project and I loved the design so much I felt like I needed to show you guys! This is a cast concrete speaker mounted on a Clay hand I made. This a great product used for house parties, a small get together, camping, and just enjoying music in your room.

You Will Need;

Materials

- Acrylic (any colour, I used black, make sure its above 2mm in thickness.)

- Ready mix concrete

- Modroc (mud rock in bandage form)

- Air drying clay

- Styrofoam

- Aluminium wire (2.5mm)

- Sand

Machines/ tools

- Laser cutter.

- Band saw ( any type of saw that can cut through Styrofoam).

- Vacuum former (I used this to make the mould, but you can either make one by hand or fashion one from house hold materials).

- Soldering iron (plus solder and maybe a PCB clamp, depending on how good your soldering is).

Step 1: Making the Hand

This step is probably the most important as it makes up the main body of the speaker. to complete this step, you will need sand, wire, a stand of some sort, string, a rubber glove, modroc, and patience!!!!!!

first, use the wire to make a skeleton of the hand. this would look like 5 fingers, connected at the bottom via string or tape. when this is completed, insert the skeleton into the rubber glove. after, pour in the fine sand. this will allow you to apply modroc onto the surface without squishing it. tie the rubber glove at the bottom to prevent any sand from leaking out. use glue, string, tape or a glue gun to attach the glove filled with sand onto your base (I used an old solder wheel).

cut the modroc bandages into equal lengths then submerge in water, when the bandage goes soggy, apply it to the surface. continue until the hand is covered, build up the layers until its about 4-5 mm thick.

when you complete this, wait for the surface to harden.

Step 2: Step 2 - Making the Mould

this step is one of the easiest. cut three equally sized Styrofoam blocks and use PVA to secure them on top of each other. when this is done, use a coping saw, a rasp, a file and sand paper to shape the base. make it as tall, wide and as weird as you want. make sure it is well balanced and it needs a 60mm hole running through the centre. this is where your circuit will go.

Step 3: Step 3 - the Hand

Use hot glue to attach the hand to its base.

use air dry clay to seal the gap between the hand and the base, this will also make the hand as a finished product a lot better. continue to roll out very thin 30mm by 30mm pieces and applying it to the surface, make sure you keep your hands wet to allow the clay to seal properly. continue until you have filed the surface of the product then wait until it hardens.

Step 4: Step 4 - Making the Concrete Mould

cut two pine blocks to each other via PVA. use a hole saw to drill a 64mm hole in the centre of the block. when this is done, use a tenon saw to take away any material around the outside to get a circular, curved edge. like the picture above. use a belt sander, file or sand paper to get a smooth surface. make sure you taper the block as it makes it easier to get out of the mould after.

insert the piece into a vacuum former. if you are not able to complete this step by your self, get someone else to do it, eg friend, parent or teacher. wait until the plastic is bouncy then pull up the mould, turn on the vacuum and wait a few seconds. use a Stanley knife to get the wood out then tape the holes up.

make some loops using wire and insert into mould, spacing them out. this will act like support to prevent your concrete from breaking. add water to your concrete mix, and then out into the mould. tap the mould on the table a few times to prevent air bubbles. this also removes moisture from the mix, making the concrete set harder. take the concrete out of the mould when set.

Step 5: Step 5 - Cutting the Covers

using a laser cutter or basic hand tools, design a cover for you speaker. also, make a loop with the same diameter as the cover, and make the second hole bigger then the speakers diameter. this is what will hold the speaker in place. ontop of this, design and cut a bottom piece. thus needs a 20mm hole, and three 3mm holes.

once cut, use araldite to attach the pieces together. DO NOT GLUE THE TWO TOP PIECES TO THE CONCRETE YET, THATS THE NEXT STEP!

Step 6: Step 6 - the Circuit

I ordered the mono speaker from kitronic and I only had to solder on the AUX, speaker and battery pack. use hand drill (5mm) and drill a how where you want your speaker. for example the middle of the hand. glue the speaker into the loop and wait until it sets. feed the wires threw from inside of the hand to the speaker and solder these on. this is the step where you glue the top pieces of acrylic to the concrete. using the 2.5mm wire. make three 50mm strips, bending one end about 60 degrees. using the hand drill, drill three 3mm holes where the wires will sit. insert the wires from inside of the cast concrete into the holes you drilled. use araldite o secure them in place. wait until its dry then test your speaker.

Step 7: Step 7 - Finished Product

you are now finished. you can add spray paint, lights and other decoration to the surface. I added blue LED lights I made in a previous task and also I made an MDF box to house my speaker. enjoy!