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I wanted to make sure the mycelium was fully dry before photographing it, so I let the pieces dry for a number of weeks as opposed to just the couple days recommended before baking. Now I have two bases with three slices each, and an additional bottom slice that may be attached to one of the larger sections.
Today I tried to remove the weights (books) from the mycelium and pull the plastic away from the sides so the white coating can start to grow. I had some metal toilet paper holders, so I clipped the plastic bag to the holders to pull it away from the mycelium. There will probably still be some places where the plastic touches, but it should allow much more of the coating to develop than my last attempt. In the process, I accidentally pulled one of the layers off of the base, so I added the books back. Hopefully it will stitch together again (and be stronger than it was before).
Today I demolded the mycelium slices and stacked them. The cups do seem to have taken up more space in the mold than the last spacers I used, which explains the extra mycelium I had. Since my oven can only fit 3 slices stacked at once, I chose not to add the fourth slice at this stage. I might add it after they are fully dry, or maybe not at all.
While stacking the slices, I tried to press them together a little bit to help fill in some of the gaps that were left in my first attempt, so we will have to see how that works.
In a few days I will try to pull the plastic away so the mycelium can grow the white coating over it, then I will leave everything out to dry.
Today I filled the molds for the second base. It took a long time for the mycelium to hydrate because my basement was too cold, so after five days it had not grown at all, but it seemed ready today. I used plastic cups as spacers this time since I knew I would need the spacers, unlike last time.
I used the same amount of mycelium, but I was actually able to fill a fourth mold this time. It is probably because I did not compress the mycelium as much, but we will have to see.
Today I hydrated the mycelium to make another piece using the molds from the previous foot stool. I purchased three bags again because I am trying to recreate existing one, not fill the molds entirely. In five or six days I should be able to fill the molds, this time using actual spacers rather than the plastic wrap and paper towel that I used last time. Once I have both pieces, they can be table bases, or if they are the same height, I might be able to use them to make a bench.
I have renamed this project to foot stool, since it is no longer a side tablet (too short). In the last post, I mentioned the possibility of sanding and coating the mycelium for a better finish, and I have decided to do just that. I started hand sanding the stool, which worked for the mycelium itself but didn’t get very far with the hemp hurds, so I switched to a sander. Some of the more even points of contact blended well, but there are still raised areas and deep gaps. When I tried to keep sanding down the raised areas, I ended up reaching a point where the mycelium started to crumble away instead of sanding down, so I had to stop.
I found that milk paint could work for covering the piece after I smooth it out. Milk paint is biodegradable and zero VOC. Lime activates the proteins in milk which cause it to stick to the surface. I will order some, probably in white, to paint with, and since it ships as a powder I can store it before use.
I thought of using a starch based glue mixed with the sawdust from sanding in order to fill in gaps, but since starch based glue is water soluble, I won’t be able to paint over the piece after filling the gaps, so I am not using the glue after all. I started researching alternatives that I could use to smooth out the entire piece now that bits are beginning to pull away, and it seems that there is a sustainably sourced resin coating that could work, but it is not available in the US. I might look into making a bioplastic and using it as a form of joint compound or skim coat, but it will have to be water-resistant.
The mycelium component of the foot stool is now dry, and I baked it to kill off the fungus. There are some brown/orange spots and the seams don’t line up, so I might sand it down and put some kind of finish over it before adding the bamboo top, but that won’t happen for a while. It is now a single piece, so the growing the slices together worked.
Today I removed the stacked mycelium from the incubating bag and set it out to air dry. The slices seem to have grown together well, so it should stay in one piece. The areas where the bag touched the mycelium are not fully coated in the white powdery coating, but I’m fine with it. The white part seems to flake off and get all over everything in my previous tests, so I may need to scrape/sand it off, or maybe even seal or paint the final piece.
Because I only have three slices, the resulting foot stool should fit into my oven, so I have brought the piece home to air dry, and I will bake it when I have a chance.
Yesterday I worked on my presentation. I created a diagram showing the textures of the mycelium throughout the growth process, and I redesigned some previous slides.
Today I removed the slices of the side table from their molds. It was surprisingly easy to remove them, much easier than the plastic mold I purchased from grow.bio. I was able to get out the spacers that I had put in to reduce the amount of mycelium needed for each piece, and then I stacked the three slices. I put everything in a larger bag, and after sealing it and poking holes for condensation to escape, I put two heavy textbooks on top to keep everything in place. In two days I should be able to take the piece out and let it air-dry. I am a little bit worried about the three slices growing together because the sides that touch are not fully flat, but I think it will be more of a visual issue.
Today I broke up the three bags of mycelium and filled the molds to form the slices of the side table. It did not go as planned.
I think I miscalculated the volume of mycelium that I would need, so I did not have enough to fill all of the molds. I noticed that the three packages did not look like much when I received them, but I did not think anything of it. It took 2.5 bags just to fill 2 molds, so I wanted to place cups in the center of the molds to take up space that would not be structurally important to the final shape. I could not access any cups in time, so I had to resort to crumpled up paper towel wrapped in plastic wrap. This is not at all sustainable, since I will probably have to through it all out later, but my work is more of a proof-of-concept. If this were to be manufactured, no paper spacers would be needed, just like cardboard and tape molds will not be used in a manufactured version.
I also ran into a timing issue, so I had to stop working and cover everything in the morning before coming back to work in the afternoon.
I ended up with two almost fully filled molds and one that will be thinner. The piece will have to be a foot stool since it will probably only be 10 inches tall (I couldn’t make all of the slices). Now I have to wait 5- days until I can start growing the pieces together (I still have to figure out how to hold them together without a stabilized clamp. I need to make sure they can at least air-dry by the time winter break starts, then I will bake the piece after break.
Today I rehydrated the three bags of mycelium for the side table. I followed the same process as in the original test (following the written and video instructions from grow.bio). Now I need to wait four to five days (12/8-9) before I can break it up and fill the cardboard molds to start the growing process.
Over the last two days I have begun working on the side table to grow out of the mycelium. In order to create cardboard molds, I needed to figure out what pieces I needed to create the conical shape. I modeled the design in Fusion 360, but it does not have an easy way to unroll the 3d shape into a template, so I recreated it in Sketchup, which has an extension to to the unwrapping. I could not figure out how the export the file correctly, so I tried Rhino3D. I knew Rhino could do exactly what I wanted, but I had already used up the trial. I ended up taking a screenshot of the result because I couldn’t export anything, then I resized it in Photoshop. I printed it as a poster to tile the image across multiple pages. After trimming all of the pages, I could tape them together to get a full template.
I cut a piece of cardboard to match the template, then I tested out how the shape would look. I liked how it had a teardrop shape instead of being perfectly round, so I decided to keep the design that way.
The next day, I cut the thinner strips from the full cardboard sheet because I need to grow the mycelium in thinner, 4 inch thick, sections for better airflow. Grow.bio has a tutorial for making cardboard molds, and they recommend covering the cardboard in packing tape so that the mycelium will not grow into the paper, so I spent the entire day working on that. I then cut teardrop shapes as base pieces and attached them to make sure that the mold hold their shape. This is not the most environmentally friendly, since I am covering everything in plastic, but if this product was produced, a single reusable mold would be used instead of a cardboard and packing tape one.
After calculating the volume of the table, I found that I need about 2.5 bags of mycelium, so I ordered three. I will hydrate them when they arrive, then I can begin growing the pieces for the side table.
Today I cleaned up the edges of the mycelium test objects and photographed them. I hope to try sanding some of the pieces to see if it is an option for smoothing. Originally, I thought it would be a bad idea to sand the pieces because I would lose the white coating on top, but it leaves a residue on anything that touches it, so leaving the pieces without the coating is not that big of a deal. I also want to try breaking the pieces to see how strong they are. The texture seems styrofoam-like, so I don’t know that it will be strong enough.
I am thinking of switching the order in which I try out shapes for the mycelium. Originally, I planned to try the most complicated seat design and then simplify it if it did not work out, but it makes more sense to build up to a complicated design so that I have something even if the next trial does not work. I think I will start by making a side table/stool, and then try a coffee table or a two piece chair design with the mycelium as the seat and back ‘padding.’ If everything works out and I still have time, I might move on to trying out a single piece chair.
It has been over a week since I last attempted to dry the mycelium. I have been checking on the air dry process, and two days ago I realized that all of the pieces are around 50 percent of their original mass and not getting lighter, so they are probably fully dry. The instruction from the grow.bio are probably for a different mycelium mixture that they used to sell, so the the final mass could be different. To check, I ordered a moisture meter that I need for the full chair anyway. It arrived today, and each mycelium piece registers as 5 percent or less moisture, which is the low end of what grow.bio says. They say that a full dry piece should be between 5 and 12 percent moisture, so everything is dry.
I can now continue the design for the chair which I began last Wednesday, and then possibly order more mycelium. I checked the sizing of the kilns at school, so I know what size I can make the chair, and I have a space to work, so I just need to set everything up.
Today I tried to bake the mycelium test pieces that have been air drying for 2 days. The pieces are supposed to be baked at 200 degrees Fahrenheit for 30 minutes, and they are supposed to end up about a third of their original mass.
When I checked on the pieces before baking them, I noticed that some had started to yellow or turn brown around the edges. I’m not sure what caused that, but it isn’t too noticeable (the planter is not white because it was in a mold, so the color on it is from the crop waste itself. I could have let it grow in a bag for a few days to turn fully white, but I didn’t).
It didn’t go ask I planned. I ended up baking some of the pieces for an hour, and the rest for the 30 minutes, but none of them are fully dry. One piece was even damp to the touch after baking. I’m going to air dry them for another day or two, then I will bake them again. Hopefully it will work.
Today I removed the mycelium test pieces from their molds and set them out to dry. Removing the planter proved extremely difficult until I realized that hitting the mold with a mallet in the same spot over and over would release the opposite side, and I had previously been rotating the piece around.
I weighed each piece to determine their wet mass, that way I will be able to weigh them again once they have dried to make sure they are about a third of their original weight, meaning that they are fully dry.
The piece need to dry in open air for 1 or 2 days before I can put them in the oven. And once I do, I will be able to see how the final piece turned out.
Today I completed step two of the mycelium growth process for testing. I removed the mycelium out of its filter bag where it had been starting to grow for 5 days. I crumbled all of it up, added flour, and then split it in half to add the sculpting mix to half of it. I hope it was grown enough, because I left it for 5 days and the instructions said 4-5, but the outside was not all white, and it was really easy to crumble.
I filled the planter mold that I purchased from grow.bio with the regular mycelium mixture and compressed it. I was surprised that it took half of the mycelium to fill the mold when the walls are actually pretty thin. I guess it just compresses a lot. Once that was complete, I covered the mold in plastic wrap and poked holes for condensation to get out.
After that, I started working with the sculpting portion of the mycelium. I had to mix all of it in, and then I started to make a miniature model of a chair. It was good that I did this testing now, because I learned that the mycelium doesn’t stick to itself that well even with the sculpting mix. If you compress it, it does stick, but trying to get any complex shape is difficult. I has to use large curves and thick sides to make the chair, and then I just made a mound to use as a base since I could not make anything resembling legs.
I had extra sculpting mix mycelium, so I tried out making a thin sheet, which would be what a tabletop or flat chair seat would be. This was easier than a complex shape, but getting a nice circle wasn’t too easy. I also tried to make a cylindrical base as if this was a miniature table, but instead of compressing it I left the mycelium fairly loose. This was much easier, and it will be good to know if it is actually a method I can use and have it be strong.
I also made some mini items, like some bricks that may or may not release from the mold, and a sphere because I thought it would look cool. Getting the spherical shape was surprisingly difficult because every time I tried to smooth it out, the compression would release and it would fall apart.
Now that everything is covered and growing, I need to wait 4-6 days before I can weigh the objects and start drying them on October 24-26. Hopefully they are all stable.
Today I rehydrated the small batch of mycelium for testing. I now know why the instructions said to wear goggles to stop alcohol from getting in your eyes. The mist from spraying it stays for a while, and I ended up inhaling some. It was not fun. The mycelium will now sit for 4-5 days (until october 19th or 20th) before I can move on to the next step where I will crumble it up and then split half to add the sculpting mix. It is great that I can leave in the fridge for 2 weeks after 4-5 days so I don’t have to worry about exact timing.
I ordered a single order of mycelium last week, and it arrived last Friday. I still need to re hydrate it before I can test anything, but I have everything I need to begin testing. I also purchased a small mold to see how that process works, as well as a batch of the sculpting add in that should allow me to test how sculpting the chair seat could work.