alumcrystalsilk.md



ALUM CRYSTALS ON SILK

Tactility & sound impression


Description
Alum crystals - that have triangular facets - grown on a silk substrate. The technique used here is called precipitation from a solution.

Physical form
Surface treatment
Color without additives: transparent and translucent white. (Turns opaque after baking in the oven for 10 minutes at 100 degrees Celcius.)

Fabrication time
Preparation time: 1 Hour
Processing time: 1 day or overnight
Need attention: None. Leave in a warm place, don't move or touch it.
Final form achieved after: 1 day

Ingredients


Alum powder (also: potassium alum - 125 g (plus some more just in case)

we will try to reorganize these molecules into crystals.


Water - 400 ml/gr

To dissolve the alum powder and reorganize into a crystal


Water - 1000 ml/g

to create a bain marie


Silk - a 10x10cm swatch

As a substrate for the alum crystals to attach to


Tools

Cooker or kettle
A piece of silk

A smooth glass jar or bowl big enough to fit your piece of silk without touching the sides or having to fold or crease it. Make sure this it totally clean.

A wide heat-resistant bowl or oven pan this is the bain marie: the glass jar should fit inside this bowl and have some space for hot water
Spoon

A stick or chopsticks that are long enough to stay put on top of the glass jar.

Clips to fasten the silk to the stick


Yield before processing/drying/curing
About 80-100% of the alum powder will attach itself the silk in the form of larger crystals.

Method


Preparation

Weigh the alum
Prepare the silk by attaching it to the wooden stick with clips. When you hang it inside the glass jar it should not touch the bottom or the walls of the jar
Boil the water
Put the glass jar inside the wide oven dish/pan. Pour as much boiling water as possible into the bigger pot, without making the glass jar float. This is the bain marie that will keep your crystal solution warm and help it cool down very very slowly (resulting in bigger crystals).
Put this in a (warm) place where you can leave it for 8-16 hours without anyone moving or touching it.


Dissolving the alum

Measure 400 ml and put it in the glass jar (which is already inside the bain marie to keep it warm).
Spoon by spoon, add the alum while stirring. When no more alum dissolves and just sinks to the bottom, your solution is saturated. If there are grains on the bottom, pour off the liquid and clean the jar before continuing. You don't want anything on the bottom of the jar.
Now suspend your silk into the jar, again making sure it doesn't touch any sides or the bottom, and not folded in on itself.


Let the crystals form

Now leave the crystal to grow. The less you touch it, the easier it is for the molecules to find each other on the silk and form big beautiful crystals.
If you have the patience, give it 16 hours. But pretty decent-sized crystals will have formed as soon as 6-8 hours later.
Rinse them under cold tap water and let them dry.


Drying/curing/growth process

Mold depth:  				 N/A
Shrinkage thickness:      N/A
Shrinkage width/length:   N/A

Shrinkage and deformation control
N/A
Curing agents and release agents
None.
Minimum wait time before releasing
6 hours
Post-processing
Store the crystals in a dry place. They will re-dissolve immediately when the are submerged in hot water, starts to dissolve after an hour in water at room temperature, and is completely dissolved after being in water at room temperature for 4 hours.
Don't throw away left-over liquid or unused crystals, they can be redissolved a next time.
Further research needed on drying/curing/growth?
More research on colorants could be done. Black soot ink results in black crystals, purple crystals can be achieved by adding some chromium alum powder (or: potassium chromium sulfate dodecahydrate) to the solution.

Process
Silk inside the bain marie, Loes Bogers, 2020
Improvised suspension system, Loes Bogers, 2020
2-3 cm crystals on silk, Loes Bogers, 2020
2-3 cm crystals on silk, Loes Bogers, 2020
Alum crystal on an LED (top) turned opaque white after 10 mins in the oven at 100 degrees celcius. On the bottom: a borax crystal (recipe here), Loes Bogers, 2020

Variations on this recipe

Add a colorant such as black soot ink (other natural dyes are still experimental!)
Turn your crystals opaque white by putting them in the oven for 10 minutes at 100 degrees celcius.
Use different textiles (e.g. velvet attracts many small crystals)
Lay your silk flat in a bowl to cover the entire surface with smaller crystals
Let the crystals grow without the bain marie to see what happens
Glue a piece of silk on an LED with hot glue to grow a crystal that you can use in electronics projecs instead of plastic casings (see video below).
The same technique can be used with epsom salt, sugar and borax.
Adding conductive paint to the solution creates crystals that can be used as capacitive sensors.


Cultural origins of this recipe
Add here
Needs further research?   Not sure

References this recipe draws from
This is a variation on: Alum Crystals in "Textile as Scaffold" by Anastasia Pistofidou for Fabricademy 30 October 2019. Lecture notes: https://class.textile-academy.org/classes/week088/

Known concerns and contestations*
add here
Depends what it is compared to.. Not so bad compared to blood diamonds but it is still a finite resource that involves mining practices.

Sustainability tags

Renewable ingredients: no
Vegan: yes
Made of by-products or waste:  no
Biocompostable final product:  yes
Reuse: yes, dissolve and regrow in hot water

Needs further research?:  yes, local producers seem reluctant to share sourcing information about these products. It is unclear where it comes from, whether it is natural or synthetic and what kind of mining practices are involved.

Material properties

Comparative qualities
It is clear and faceted with great definition so it is often compared to diamonds. However these can get so big that it is not really credible that they are diamonds, but they play with light in similar ways.

Technical and sensory properties


Strength: medium

Hardness: rigid

Transparency: transparent/variable (turns opaque after 10 mins at 100 degrees celcius)

Glossiness: glossy/satin

Weight: heavy

Structure: closed/variable

Texture: rough

Temperature: cool

Shape memory: high

Odor: none

Stickiness: low

Weather resistance: poor

Acoustic properties: needs further research

Anti-bacterial: needs further research

Non-allergenic: needs further research

Electrical properties: needs further research

Heat resistance: low/needs further research

Water resistance: low

Chemical resistance: needs further research

Scratch resistance: high

Surface friction: sliding

PH modifiers: none


About this entry

Maker(s) of this sample

Name: Loes Bogers
Affiliation: Fabricademy student at Waag Textile Lab Amsterdam
Location:  Amsterdam, the Netherlands
Date: 27-02-2020 – 27-02-2020


Environmental conditions

Outside temp:  5-11 degrees Celcius
Room temp:  18 – 22 degrees Celcius
PH tap water:  7-8


Recipe validation
Has recipe been validated? Yes
By Cecilia Raspanti, Textile Lab, Waag Amsterdam, 9 March 2020

Estimated cost (consumables) in local currency
2,00 Euros for a 400 ml saturated solution

Copyright information
This is a variation on: Growing Gems Crystal Project by Home Science Tools Learning Center: link
It is unclear if this recipe is copyrighted, further research required.
##References


Textile as Scaffold by Anastasia Pistofidou for Fabricademy 30 October 2019. Lecture notes: https://class.textile-academy.org/classes/week088/


Dark diamond mining by EJTech, 25 February 2020: https://wikifactory.com/@ejtech/dark-diamond-mining


Growing Gems Crystal Project by Home Science Tools Learning Center: https://learning-center.homesciencetools.com/article/growing-gems-crystal-project/


Grow your own simulated diamonds with a big alum crystal, by Anne Marie Helmenstein for ThoughtCo, 13 February 2018: https://www.thoughtco.com/growing-a-big-alum-crystal-602197


Images of final product
Large crystals grown on silk, Loes Bogers, 2020
Large crystals grown on silk, Loes Bogers, 2020
Smaller crystals grown on silk (lay it flat in a wide glass bowl), Loes Bogers, 2020
Smaller crystals grown on silk on top of a black bowl, Loes Bogers, 2020
Alum crystals on silk (right), and on velvet (left), Loes Bogers, 2020