Prototyping process for an acoustic panel in mycelium

Prototyping tests: heat pressing and (de)moulding Research for bachelor thesis “Arc nouveau, a biodegradable acoustic panel with mycelium�

Ellen Comhaire | 3IPO | June 2019

Heat press tests A - 9/02/2019 - VUB lab 200°C - 20 min. Turn halfway, because the heat is only at the top part of the press. As you turn, amplify the pressure by turning the screw.

When you press it in a mould and then put it in the oven for 10h (still under pressure) you end up with a kind of wood fiber board. The outer layer of mycelium (if it was grown in a white layer) is no longer visible. The end result is very strong.

The outer layer of mycelium in the heat press, in contrast, is still visible.

Balance process between: -

Extracting all the moist Don’t (over)bake the outer layer Dense enough for strength

Process Variables tested with Tested?

Variable Growing Substrate mix Species Species/substrate ratio Duration of growth inside mould Duration of growth out of mould Growing temperature 1 or 2 phases (if remixed with other species and substrate) Heat pressing

x

Temperature (°C)

x

Pressure (bar)

x

Duration of pressure (minutes)

x

Thickness of material

x

Outer layer of mycelium or not (on large surfaces)

x

Grown together piece or loose bits

Which hemp ? ? ? / ?

1

200 175 150 ?

10 20 25 5-8 8-10 20 35-40 / 1 side Loose Grown together Mix

1. Test A1: Thick block

Front and backside of test 1 before heat pressing.

Description Temperature (°C) Duration (min) Weight (g) Thickness (mm) Length x Width (mm) Remarks

• • •

Before White surfaces at the sides Saw cut on top and bottom Grown together piece

After

200 25, turned after 10 min 317 (130g after 10 min) 73 35-40 5-7 200 x 120 210 x 128-138 Still felt quite moist after 20 minutes. Have given it 5 min extra.

The sides are burnt (where the moist pass longest?).

After drying out, it was bent.

Front and backside of test 1 after heat pressing.

Thickness of test 1 after heat pressing.

Test 1 curved after drying.

2. Test A2: 3 medium blocks Description Temperature (°C) Duration (min) Weight (g) Thickness (mm) Length x Width (mm) Remarks

• • •

Before White surfaces at the sides Saw cut on top and bottom Grown together piece

After

200 20, turned after 10 min a) 83 a) 12 b) 84 b) 12 c) 104 c) 14 +-20 a) 150 x 70 a) 151 x 75 b) 150 x 75 b) 150 x 80 c) 150 x 80 c) 155 x 83 Burnt colour at upper side (which first touched the heated surface).

Front (up) and backside (down) of test 2a, b and c after heat pressing.

3. Test A3: Loose bits together Description Temperature (°C) Duration (min) Weight (g) Thickness (mm) Length x Width (mm) Remarks

Before After Loose bits of a grown through block, in pieces of 2 to 3 cm diameter max. randomly put together.

200 10, not turned 104 16 +-20 2 130 x 120 152 x 140 Dried much faster than a grown through piece. Expanded more to the sides under the pressure.

Front and backside of test 3 after heat pressing.

4. Test A4 - mix of shapes and blocks Description Temperature (°C) Duration (min) Weight (g)

Thickness (mm)

Length x Width (mm)

Remarks

• • •

Before White surfaces at the sides Saw cut on top and bottom Grown together piece

150 10, turned after 5 min a) ? a) 6 b) 55 b) 8 c) 60 c) 5 d) 45 d) 5 a) variable (5-10) a) 2 b) variable (5-13) b) 2,8 c) 8-10 c) 2,2 d) 5-8 d) 1,7 a) Heart shape a) Heart shape b) 100 x 95 (witte b) 105 x 97 laag aan 1 kant) c) 100 x 85 c) 105 x 90 d) 100 x 85 d) 100 x 86 Felt moist after the pressing.

Front of test 4a, b, c and d after heat pressing.

After

5. Test A5 - Mix of grown together and loose parts

Test 5 before heat pressing.

Description Temperature (°C) Duration (min) Weight (g) Thickness (mm) Length x Width (mm) Remarks

• •

Before After At 2 sides: parts with white surfaces at one side In between, randomly arranged loose pieces

150 20, turned each 5 min +-290 54 variable 2,5 ? ?

Test to see the difference in 1 piece

Front and back of test 5 after heat pressing and after an extended dry out period which caused curving and shows a break line between one of the grown together and parts and the loose fibres.

6. Test A6 - Various shapes at high temperature Description Temperature (°C) Duration (min) Weight (g)

Thickness (mm)

Length x Width (mm)

Remarks

• • •

Before White surfaces at top (or not) Saw cut on top and bottom Grown together piece

After

175 20, turned after 10 min a) 117 a) 20 b) 60 b) 12 c) 82 c) d) 50 d) 12 e) 53 e) f) f) 93 a) 3-23 a) b) 21 b) c) 18 c) d) 8 - 28 d) e) 15 - 30 e) f) 12 -22 f) a) 180 x 120 (1 a) white surface) b) b) 140 x 60 (only c) white sides) d) c) 150 x 75 (only e) white sides) f) d) 100 x 65 (1 white surface) e) 103 x 60 (1 white surface) f) 110 x 82 (1 white surface) Weren’t sufficiently dry after 20 minutes. After 5 days (unattended) they were getting molds. After drying in the oven at 200°C for another 55 minutes they turned dark brown.

Parts where the mycelium already was dying (turned yellow) turned black after heat pressing.

Front of test 6a, b, c, d, e and f before heat pressing.

Front of test 6a, b and c after heat pressing.

Front of test 6a, b, c, d, e and f after extra drying.

Back of test 6a, b, c, d, e and f after extra drying.

Conclusions • • • • • • • •

200°C creates burnt parts on the surface which first touches the heated part of the press.

150°C creates a darker brown, but not burnt surface colour.

There’s a caramel smell. Probably of the polysaccharides produced by the mycelium.

The top and bottom surfaces with a white mycelium layer create a much stronger end result.

Loose bits take less long to dry out and expand more.

Loose bits at first sight seem to bind as strong as grown together bits without an outer mycelium layer (if they overlap enough).

The pieces seem to go to 1/4th till 1/6th of their weight after pressing/drying.

Thickness can go from 1/4th to 1/10th of the original, depending on the applied pressure.

Parts where the mycelium already was dying (turned yellow) turned black after heat pressing.

Next tests: • • • • • • • • • • • • • •

Varying temperatures and duration for drying: 100°C - 120°C - 140°C Growing external layer (on both sides) Check moisture content before inoculating the fibres, before pressing and after pressing. (eg. through weight) Different start thicknesses to get to 2mm end thicknesses (to see the results of different pressures) Try blending with recycled cardboard (pulp) if choosing for pulp moulding process Try mixing with PLA or starch Try out difference of blending fibre thin before or after growth Combine textiles and heat press to create lid. Soft and hard structures Find long hemp fibres Try to remove as many variables as possible. And then bring variables into the process step by step to understand it best.

Look up wettability of the fibres Find hemp boards + check binder Try mixing with corn starch Look into more natural products, made by Easycomposits (UK) or Webshop Voschemie (BE).

They should have some biobased alternatives.

• •

Tip of Nel: Check Htv (t-shirt) vinyl to transfer on mycelium. Works well. Glue is biodegradable, but vinyl isn’t yet. A biodegradable one would be into research.

Check Maurizio’s work, as he is trying for smaller samples.

Look up • • • • •

Thermoforming prices Mould making prices for heat pressing (e.g. aluminium covered with stainless steel) Mould covered with gauze for fast drainage and less heating time Hammer mill use available nearby? https://www.bioizol.eu/en/price-lists  Voor hennep matten, maar die zijn behandeld tegen schimmels

Heat press tests 01/03/2019 - Glimps lab - Tests for temperature and duration Test B1 - slow cooking

Top of test 1a, b before heat pressing.

Description Temperature (°C) Duration (min) Weight (g) Thickness (mm)

Length x Width (mm) Pressure Remarks

Before After • White surfaces at the sides • Saw cut on top (and bottom) • Grown together piece 80°C (40min) - 100°C (20min) - 110°C (10min) 70 = 60 (turned every 10 minutes) - 10 (turned every 5 minutes) a) 48 a) 12 b) 53 b) 8 a) 10-15mm (only white at edges) b) 10-20mm (white on tip side) No clear shape Started from 45mm (open press) to 2-3mm As soon as the pressure was applied, some water came out. No very strong thermal reaction (no steaming or hissing). After 10 minutes a lot of water was still present in between the heat press (as it didn’t steam away and couldn’t run away as it is a flat surface). After 40 minutes it was still very moist at 80°C so I turned it up to 100°C. At 110°C The pieces seemed to dry out more quickly and the smell started changing to a bit more caramellike.

Top of test 1a, b, after 20 minutes.

Back of test 1a, b, after 20 minutes.

Test B2 - 150 degrees Description Temperature (°C) Duration (min) Weight (g) Thickness (mm) Length x Width (mm) Pressure Remarks

• • •

Before White surfaces at the sides Saw cut on top and bottom Grown together piece

After

150 10 (turned every 5 minutes) a) 40 a) 6 b) 42 b) 5 +- 10mm 2-3mm No clear shape Started from 45mm (open press) to 2-3mm As soon as the pressure was applied it started steaming and hissing and some water came out. Surface dark brown on (first) top side.

Top of test B2a, b after heat pressing.

Back of test B2a, b after heat pressing.

Test B3 - Hammer time - Pulping and cardboard mix

Top: before and after hammering grown mycelium, bottom: cardboard, pulped with hot water and stirring.

Tests B3a, b, c before heat pressing.

Description Temperature (°C) Duration (min) Weight (g)

Thickness (mm) Length x Width (mm) Pressure Remarks

• •

Before Hammered while wet after growth Same + pulped cardboard

After

150 20 (turned every 5 minutes) a) 55 (without cardboard) a) 7 b) 100g = 25g hemp + 75 b) 11 g moist cardboard pulp c) 10 c) 108g = 68g of hemp + 40g of water (and mushed and mixed some more after this with a spoon) +- 10mm 2-3mm No clear shape Started from 45mm (open press) to 2-3mm As soon as the pressure was applied it started steaming and hissing and some water came out.

Tests B3a, b, c after heat pressing.

Conclusion -

Hammering the fibres after it had the mycelium grown on it, while still wet, was significantly easier than trying to hammer them apart while dry and without growth.

80°C is too low to make the water go away easier, it takes a long time to dry.

Stirring and pulping the fibres mixed with water seems to make them entangle more.

Mixed with cardboard the plate was much stronger and didn’t make cracking sounds as easily while bending.

To test next time • • • • • • •

Varying temperatures and duration for drying: 120°C - 160°C - 200°C Different start thicknesses to get to 2mm end thickness Growing external layer on both sides Blend fibres before growing: wet and dry Blend fibres after growing: with added water and without adding extra water Heat pressing hemp fibres without mycelium: wet and dry, with and without blending Press with tissue in between for flexibility.

Tests C - 07/03/2019 - Glimps lab Samples grown on 28/02/2019 Each time 10% of weight was Coriolus versicolor spawn and 90% were moist hemp fibres: • • • •

3x 125g rounded square box 150x100mm 1x 160g rounded square box 150x100mm 1x medium fine fibres in round box (by hammering on them while dry) +-95mm diameter 1x fine fibres in round box (by hammering on them longer while dry) +-95mm diameter

Grown samples after 1 week of growth (07/03/2019).

Test C1 - 160° bake and turn

Test C1 before heat pressing.

Description Temperature (°C) Duration (min)

Weight (g) Thickness (mm) Length x Width (mm) Pressure Remarks

Before After Fully grown through piece with white all around

• 160 30 = Turned after 1,5 minute, no caramelisation after first turn, After 3 minutes (some slight caramelisation at sides from top, see picture), After 4,5 minutes (some more caramelisation at surface from top, see pictures), After 9,5 minutes (no further caramelisation, see picture) After 14,5 minutes (no apparent colouration) After 19,5 minutes (still felt moist) After 24,5 minutes (still felt moist) Took out after 30 minutes 119g 16g 15-20mm 3 mm 150 x 100 mm rounded 165 x 110 mm rounded square square Started from 40mm (open press) to +-1mm During the first turn I let quite some water run away by tilting the aluminium foil in which it was trapped.

Test C1 top after 1,5 minute.

Test C1 top after 3 minutes.

Test C1 bottom after 3 minutes.

Test C1 top after 4,5 minutes.

Test C1 top after heat pressing.

Test C1 bottom after heat pressing.

Test C2 - 200° bake and turn

Test C2 top before heat pressing.

Description Temperature (°C) Duration (min)

Weight (g) Thickness (mm) Length x Width (mm) Pressure Remarks

Test C2 top after 1,5 minute.

Test C2 bottom before heat pressing.

•

Before After Fully grown through piece with white all around

200 Turned after 1,5 minute (some decolouration at top surface, none at bottom, a lot of brown water came out, After 3 minutes (some slight decolouration at top surface, no apparent extra at bottom surface, After 4,5 minutes (some more decolouration at top surface), After 6 minutes (little more further decolouration) After 11 minutes (no apparent decolouration) After 16 minutes (still felt moist) After 21 minutes (still felt moist) Took out after 26 minutes 120g 23g 15-20mm 2-3mm 150 x 100 mm rounded 164 x 105 mm rounded square square Started from 40mm (open press) to +-1mm Compared to the 160°C test, there was more dark decolouration.

During the first turn I let quite some water run away by tilting the aluminium foil in which it was trapped.

Test C2 bottom after 1,5 minute.

Test C2 top after 3 minutes.

Test C2 bottom after 3 minutes.

Test C2 top after 4,5 minutes.

Test C2 bottom after 4,5 minutes.

Test C2 top after 6 minutes.

Test C2 bottom after 6 minutes.

Test C2 top after 11 minutes.

Test C2 bottom after 11 minutes.

Test C2 top after 16 minutes.

Test C2 bottom after 16 minutes.

Test C2 top after heat pressing.

Test C2 bottom after heat pressing.

Test C3 - 120° bake with cold pre-pressing

Test C3 top before heat pressing.

Description Temperature (°C) Duration (min)

•

Before After Fully grown through piece with white all around

120 Prepressed cold for 1,5 minute to see if much water would come off with cold pressing as well, but only a little came out. Really nothing compared to the heat pressing water spill in the first minutes.

Turned after 1,5 minutes (some decolouration visible on top, a lot of water came out) After 3 minutes (some decolouration visible on top, quite some water still came out) (From here on turned every 5 minutes) After 8, 13, 18, 23 minutes still some water came out.

After 28 minutes no more running water came out.

After 48 minutes I took it out, still feeling a little moist.

Weight (g) Thickness (mm) Length x Width (mm) Pressure Remarks

118g g 20-25mm 1 mm 150 x 100 mm rounded mm rounded square square Started from 40mm (open press) to +-2mm During the first turn I let quite some water run away by tilting the aluminium foil in which it was trapped.

After about 5 minutes the hissing stopped.

Test C3 top, bottom and side after heat pressing.

Test C4 - 200° blend and bake

Test C4 a, b top before heat pressing.

Description Temperature (°C) Duration (min) Weight (g)

Thickness (mm) Length x Width (mm) Pressure Remarks

• •

Before After Fully grown through piece with white all around Blended (super fine and medium fine) before growth

200 20 minutes, turned every 5 minutes. a) 33g (Very fine fibres (hammered a lot a) 8g before growing), fully grown) b) 12g b) 53g (Medium fine fibres (hammered less before growing), fully grown) a) +-15mm a) 2-3mm b) +-2 mm b) +-3mm +-95 mm diameter +-95mm Started from 40mm (open press) to +-2mm When trying to bend they clearly make less sound (so stronger texture) then with the larger fibres. Smoother surface.

Tests C4a, b after heat pressing.

Test C5 - 200° blend and bake cocktails

Test 5a before heat pressing.

Test 5b before heat pressing.

Test 5c before heat pressing.

Test 5d before heat pressing.

Description Temperature (°C) Duration (min) Weight (g)

Thickness (mm)

Before After Blended fibres in different combinations

• 200 20 minutes, turned every 5 minutes. a) 48g blended after a) 10g growth mycelium b) 19g hemp c) 14g d) 7g (1g of fibres lost at sides and b) 40g blended after through manipulation) growth mycelium hemp + 8g caseïne c) 40g blended after growth mycelium hemp + 8g maizena d) 48g dry blended hemp (no mycelium or water) a) +-10mm a) +-1,5mm b) 3-4mm c) 1-2mm d)3-4mm

Length x Width (mm)

+-95 mm diameter

Pressure

Started from 40mm (open press) to +-2mm C5a feels very brittle at the sides. Ieces come off easily when you touch it.

C5b feels very very strong. Only somewhat brittle at the edges too.

C5cis very thin compared to the other samples of this batch.

Although the sides feel a bit brittle too (probably more maizena then fibres), it keeps together better than C5a.

C5d has a bit of a tapestry feel to it. Quite flexible, but falls apart easily. Though still a bit of a kept together pancake in the middle.

Remarks

a) b) c) d)

+-100mm +-105mm 110-115mm (irregular shape) +-90

Test 5a after heat pressing.

Test 5b after heat pressing.

Test 5c after heat pressing.

Test 5d after heat pressing.

Conclusion • • •

The decolouration is less present when turning more frequently and with letting out the water in the second minute.

Cold pressing doesn’t get rid of the moist. Heat is needed, both to bake, as to get the water out of the piece.

Not clear whether first decolouration is due to the residue on the aluminium paper from last trial or newly formed in matter.

Connection tests D 13/03 27/03 - Glimps lab Biological connections Moulds with wooden planks. Inoculated corriolus on 13/03, put in mould on 20/03. Weight 500g at moulding. At 27/03 well grown through at bottom and sides. White-yellow rim nearly allover (95%).

Top mainly fluffy, at the sides a better consistency in certain places. Fibres at top layer mostly still quite visible.  492g at demoulding, corner burst a bit. Some fibres (6-8 chips) stuck to the mould.

Pleurotus and corriolus with 6 plugs. Inoculated on 13/03, put in mould on 20/03. Weight 200g at moulding. At 27/03 well grown through at bottom and sides. White-yellow rim nearly allover, no visible fibres. Completely fluffy on top, with chips vaguely visible.  176g at demoulding.

Corriolus with tissue around 3 and 4 sides. Inoculated corriolus on 13/03, put in mould on 20/03. At 27/03 well grown through at bottom and sides. Top mainly fluffy, at the sides a better consistency in certain places. Fibres at top layer mostly still quite visible. Tissue is also vaguely visible through the mycelium.

1. Wood planks grown in substrate

Wooden planks in before growing.

Wooden planks in after growing.

Wooden planks in mould before growing.

Wooden planks after oven drying.

o o

Wooden planks after more drying.

Method  I autoclaved the planks (without adding moisture before) and put them in the mould surrounded by substrate. Only the top - where the attachment would be was free.

Result  Originally it stayed quite well attached after drying as the contact surface for growing was suite big. After further drying out at room temperature however the wood shrank more than then the fibres and thus shrank itself loose from the whole.

o

Conclusion ďƒ For this to work, the planks would best be put in the middle of the loose fibres so they’re completely surrounded by them. Maybe even with holes or an open structure in the plank so the lose fibres can grow in between to connect themselves in between the wood and with the planks on a 3D way.

2. Linen grown around the substrate

Linen and substrate before growing.

Linen partially covered with mycelium.

Mycelium on linen showing mould details.

Linen wrap after drying.

Linen and substrate after drying.

Linen and substrate easily disconnecting.

o

o o

Method  I autoclaved the linen (without adding moisture before) and put it in the mould before adding the substrate. In one test I left the top open, so the linen covered everything but the top. In the other test I completely turned the linen around the substrate so it covered 4 of the 6 sides like a wrap.

Result  Doesn’t grow together well with the fibres and the connection is very weak. Gets loose if you tear it even slightly. It did give an elegant finish to the substrate though. Some of the linen got contaminated.

Conclusion  Might be a good idea for finish texture, but for it to work, it probably needs to be more in the middle and more interwoven with the substrate.

3. Wooden plugs grown in substrate

o o o

Method  Autoclaved plugs without adding extra moisture. Put them into substrate after inoculation.

Result  Didn’t connect strong enough with the fibres. You could easily pull them out.

Conclusion  For this to work, I think the plugs should be connected to a plate that in turn is binded by the mycelium in the mould halfway the substrate.

Physical connections 1. Fibreboard screws o Method  Drive a screw through the back of the panel and from there straight into the dried mycelium tile (without predrilling). o Result  The tile is attached but it feels like the screw have too much space around them, so by wiggling the tile a bit, or could easily pull them off the screws by using some force. The connection doesn’t feel qualitative. o Conclusion  The thread might need to be wider or the tiles thicker and the screws longer. Or the connection should be strengthened with glue or something filling the spaces between the screw and the fibres.

2. Universal plastic plug

o

o

o

Method  I predrilled the dried mycelium tile through the back panel, with the given drill according to the plug size (diameter 6 in this case). I pushed the plug in by hand, first through the panel and then into the tile. I couldn’t get the last 3mm in although the hole was deep enough for the entire plug. I had to hammer the plug in because of the hardness of the back panel, and then drove a screw into plug.

Result  The connection feels strong. It doesn’t wiggle when I try to move it and when I pull, it doesn’t move either. While I put the screw in, I only heard very small cracks of the fibres being pushed out. The mycelium didn’t get broken, squashed or cracked, but the contact zone with the underlaying surface was visible as the bits sticking out showed some flat and bruised parts. While driving the screw in nothing sounded strange or different. It went very smooth and nothing sounded off.

Conclusion  This is a decent solution. Only the fact that it works with plastic is not ideal, although the HDPE plugs can be recycled.

3. Spiral drywall plug (plastic)

o

o o

Method  I predrilled the dried mycelium tile through the back panel, with the given drill according to the plug size (diameter 8 in this case). Then I screwed in the plugs by hand with a screw driver and afterwards I screwed them to the surface with the accompanying screw. For both of the spiral plugs screwing the plug in went very well. The thread clearly caught the fibres well without pushing them away. It seemed to gently cut its way through the mycelium. But with the plastic plug the screws only went in halfway. Then the mycelium started lifting from the surface as I tried to get it in further. I think the expansion is too big and it rather pushes away than expands. At one side it also broke through the mycelium and pushed the fibres out of the shape.

Result  It couldn’t connect well to begin with and started cracking very quickly when driving in the screws. Afterwards, with the screws driven in halfway, it wiggled.

Conclusion  It expands the mycelium too much when driving in the screws. It might be an idea to put in shorter screws, as the connection of the plugs themselves with the mycelium seem very substantial.

4. Spiral drywall plug (metal, self-screwing)

o

o o

Method  I predrilled the dried mycelium tile through the back panel, with the given drill according to the plug size (diameter 8 in this case). Then I screwed in the plugs with an electric screw driver and afterwards I screwed them to the surface with the accompanying screw. With the metal plug it went in just as well and felt very satisfying as it was smooth and it didn’t sound or feel like anything was breaking, snapping or cracking. But at the end of the screwing it also sounded as if something inside wasn’t going too well. The fibres cracked but didn’t get displaced visually.

Result  It connected well and didn’t wiggle.

Conclusion  By the sound of it I am not convinced of this being a good solution.

The connection did feel solid, with a tiny bit of wiggling though.

Chemical connections 1. Pattex classic PVA wood glue D2 (for indoor use) 2. Pattex one for all (polymer based) 3. Tec7 (Polymer based) o

o

o

Method  For the polyvinyl acetate (PVA) wood glue I covered the entire contact zone of the panel by spreading it and then pushed the dried tile into it. For the polymer based glues I just put a few dots (6-8) on the panel and then pushed the tile into it.

Result  All connected well without wiggling. With the PVA glue I do think the possible lack of flatness of the back surface of the tiles might be a problem as it will eliminate quite some connection space, whereas the thicker polymer based glues will connect better in holes and 3 dimensions of wobbly contact surfaces.

Conclusion  Gluing created by far the fastest, most efficient and qualitative connection. None of the three tested glues contain substances that are super toxic for the environment and humans. Some claim all should in the long term be biologically degradable as they consist of quite simple polymers. However PVA glue has much better ecological standards and is considered harmless, it is not compostable. Putting it into nature would cause microplastics to get into the natural environment.

4. Dubblesided tape  Not enough flat surface and stickiness to connect the tile. Fell off quiet quickly. Not interesting.

Filling the prototype moulds - Mycelia lab Duration of petri dish growth: Ganoderma (not sure which kind: lucidium or resinacium) grown on agar agar for 1 week. Completely colonised after 3 days. From inoculum of about 7x7mm.

Procedure of autoclaving: All are a mix of more or less 1 volume of chopped hemp, 1 volume of flax and 1 volume of powder straw. Volume total = 0,03012m³. Mixed everything dry. Added 7 liters of water. Which is less than needed, but more is added through condensation in the autoclaving process. But we did end up with quite some water in the autoclave in the end. After mixing the substrate, it was autoclaved immediately. The autoclave started at 8.30 and it was cool enough to take out at 12.30. (it takes a while to depressurize). It worked for 20 minutes at 121°C. We started filling the moulds around 13.45.

1. Polystyrene mould 2mm - inoculated with 1 petridish of Ganoderma Thickness: 26-30mm. Top doesn’t touch the substrate 2. Polystyren,e- mould 2mm - inoculated with 2 petridishes of Ganoderma, Thickness: 33-38mm top doesn’t touch the substrate 3. Polystyrene mould 2mm - inoculated with 1 petridish of Ganoderma, Thickness:+-29mm top doesn’t touch the substrate 4. PET mould 0,6mm - inoculated with 1 petridish of Ganoderma, thickness: 28-38mm Top touches the substrate a bit User experience from moulding the prototypes.

-

-

Probably the front side of the moulds will need more relief in it.  deeper mould Now it was unequally filled  have a clear height notice When the surface is completely flat it might not have a good gas exchange when resting on a flat board.  having it grow on a grill?

Having a lid that has a lose fitting is a risk for contamination but might allow more gas exchange.

Use (sticking) tape for the final moulds to keep them together + paper clamps for extra strength To have a flat back surface we could o Use a metal roll to even it out o Use a flat board to even out.

0,6mm PET is too flexible. Harder to work with (sterilize) and keep shape.

After demoulding - It is advisable to have a flexible mould. Demoulding the top in a non-flexible mould is too hard: some pieces stick and it rips the whole apart.

- We inoculated 1 petri dish, in one model 2 petri dishes per mould. This was about 1% of the substrate. It took way too long to grow.

- Some of the mycelium was too wet, causing bad growth and contamination.

Demoulding -

Fails with PS, PET better due to flexibility and probably more oily surface, slow growth as we didn’t use enough spawn 2 moulds are contaminated We will grow again in the moulds putting tape on the inside of one and plant oil (maybe mixed with bees wax) in another.