Wildcard Week


- Design and produce something with a digital fabrication process not covered in another assignment, documenting the requirements that your assignment meets, and including everything necessary to reproduce it. Possibilities include (but are not limited to) composites, textiles, biotechnology, robotics, and cooking.


Files for my mold done in Fusion 360 (iges/stl) and svg for laser cutting

Cool "How to" sites about growing mycelium plastic

Grow Objects With Mushroom Mycelium

Making Mycelium

Big Fab Mushroom Guitar Pickup

In wild card week I have chosen to make a homemade guitar pick up. See the video below where I'm testing my pickup.

"The Homemade Guitar Pickup made from home grown Biodegradable Plastic and Junkyard Scrap"

Since I have played the guitar from the age of 7 and as music has always been a big part of my life I really want to use this week to immerse myself in guitar fabrication and more specifically in guitar pickups. I have this idea that I want to try making my own biodegradable plastic for the pickups and see if I can find everything else from scrap. So kind of a Junkyard pickup.

In my fieldstudies of the pickup, while trying to understand the construction and electrical function, I found some really great semi-homemade pickup designs as you can see in the pictures. There is one really beautiful piece made from a brand called Wiggins. The pickup frames are made from warm colored hardwood with some laser engraved features.

To make this happen I need to make a schedule and start growing the oyster mushroom. Later I will extract the mycelium and then let it grow into a composite of sawdust and mycelium texture from which I hope to make the biodegradeble plastic. So this week's assignment takes a lot of preparing because I need to "grow the plastic" and also visit the local junkyard to see if I can find some materials for the pickup.

I need the following pieces for the guitar pickup


-Small steel rods or steel screws

-Copper thread for the winches

-Small cables red & black

And the following pieces for growing the Oyster mushroom

-Fresh Oyster Mushroom

-A box (something that could provide darknes for the mushrooms)

-A plastic bag



Prepare the Growing Environment for the mycelium

After a thorough search on the web on everything from "How to grow mycelium" to "Biodegradable plastics", I found out that the mushroom that is "easiest" to grow is the oyster mushroom. I bought a package at the market and chose a package where the bases of the mushroom was fairly long on each of the them because you only use the base as this is the reproduction part which will grow within the cooked cardboard. I used a really sharp knife to cut tiny slices of the base and inserting them in the carboard layers.

To prepare the growing environment I cut the cardboard into pieces that fit well into the sterile bag (Here I used freezer bags designed for food). Stack them up and cook the carboard for 10-15 minutes. You may need to weigh them down so that they are fully immersed under the water. When I took the cardboard up it had to cool down and dry somewhat, and after a while I could easily separate the sheets and make my sandwich of cooked cardboard and the thin base cuts of the oyster mushrooms.

Add a layer of cardboard to the bottom of the bag. As you form the layers you need to have a corrugated sheet and a flat sheet. The corrugated layer gives the mycelium space to grow into. Alternatively you can use corrugated sheets for all layers. Spread the little pieces of mushroom evenly and fairly close together and cover with a sheet of cardboard. Repeat until you have filled the container and the layers are filled with mushroom (And remember to use the top of the Oyster mushroom for your evening dinner, they are delightful).

Now I have my growing environment for the mycelium ready and wrapped up. I stored it in a dark place at room temperature (but still a bit chilly like 16 degrees C). Every day I opened the box to let some air in and out. Without any air exchange the carbon dioxide level builds up and your mycelium will have stunted growth. I made a kind of humidore (constructed like the ones you are storing cigars in) by using a old coolbox where I put a container with a cloth I could keep wet to achieve a constant moisture in the box and at the same time make sure that the mushrooms were in a dark place.

Big Fab Mushroom Farm

After 8 days, I had enough growth in my mycelium to dare going on to growing the mycelium further on in a homemade substrate of finely chopped dried straw, wheat bran and sawdust. All cooked for 30 minutes.

So right now I am preparing a mold for the composite in which I will grow the mycelium. For this purpose, I use Fusion 360. At the same time, I have made different cut-outs on our laser. For this I have worked with Inkscape and 2D files to prototype.

The mold in machinable wax

The mold I created in Fusion 360 (to grow to mycelium in) I have milled on the Roland CNC in blue machinable wax. I created the mesh (.stl) and the two pathes in Fabmodules. One "wax rough cut (1/8)" and the other a "wax finish cut (1/8)" using a flat head CNC cutting tool for the rough path and a ball head for the finish cut.

I had some trouble with the ratio between millimeters and inches under the unit settings. My mold came exported from Fusion 360 as a STL-file measured in millimeters. So I had to change the settings "Units/in" to 25,4 and now my dimensions where more precise: 90.000 x 40.000 x 10.000 mm.

The pickup frame that came from the mold did not apear as nice as the one that was the laser cut from a mycelium plate. I think that the mycelium mass in the mold would have been really goodt if the mass had been finer when molding such a small object. The struture was nice and really very strong which surprised me.

Winding My Single-coil Guitar Pickup

Winding a pickup requires exercise, exercise and exercise. I first tried out with a drilling machine as shown in the picture. Winding the pickup very slowly, but it ended up in total knot disaster several times, so I actually ended up winding my pickup by hand. It was actually very cozy, but extremely time consuming.

Baked and ready for the laser cutter

Now the flat plates (3 mm thick) of the biodegradeble plastic or composite, where ready for the laser cutter. I wanted to try my svg-file and try cutting it as if it were plywood. I had prepared two sheets that were baked slightly differently. One plate was baked at 200 degrees celcius for 40 minutes, the other was baked at 130 degrees celcius for 30 minutes. I have read a few different recommendations for baking times online. I think that the plate baked at the heighest temperature seems to be the hardest, so now it's exciting how the laser burns and engraves in the material. The material is actually looking a bit like cork and has a very nice structure so at the moment I'm really pleased.

Today I have been testing laser cutting and engraving my mycelium composite. I actually think it went pretty weel. The settings for cutting through was (as you can see in the picture) power: 100%, Speed: 8% and PPI: 100. For the engraving parts I used the following settings: Power: 88%, Speed: 100% and PPI: 500 on our Universal CO2 laser.

What I will do differently next time.

As usual, there are a lot of things I will do differently the next time I try to grow this composite. One of the most eye-catching things is the structure of my composite. The sawdust I have used is very rough, which gives a very nice structure to some things, but it also complicates filling the composite in one form, and even burning it evenly on the laser cutter.

Another important observation is the air flow. It is important that the mold you create is perforated so that the substrate also gets air around and from the bottom. I think that my spores or mycelium would have grown deeper into the substrates if it had got a tiny air flow from below. I can see in pictures from others who grow this kind of biodegradeble plastic that their molds are perforated with a lot of small holes.