(short description of the project + goals)
- Not dyeing my curtains, but painting instead?
Dyeing polyester is a chore. Maybe I can just paint them instead, using acrylic paint.
I could make my own fabric medium (for thinning down acrylic paint) using glycerin, vinegar and water. I have some old glycerin that I wanted to throw out anyway.
This video looks very similar to what I want to try. They came out a bit blotchy but I think that’s a cool look, if I didn’t want that I could wet the fabric beforehand to make the paint stick more evenly.
Would need a hot iron to completely cure the acrylic onto the fibres. Or perhaps an oven, or a blow dryer.
To be continued
- Dyeing my curtains
I want to dye my curtains. When I moved into my current place I really needed curtains and I bought the first ones I could find that were cheap, “blackout” and at least somewhat close to the colour palette I wanted for my room. But they turned out to be “greige”, while I wanted beige. Now I have them I think I’d like them better in a shade of brown.
For some reason, I have a complete extra set of these curtains, so I shouldn’t be afraid to experiment. Also, I don’t mind if it turns out a bit more “rustic”; the colour doesn’t have to be perfectly consistent. Finally, it doesn’t have to be the most permanent dye, because I rarely (if ever) wash my curtains.
Of course, I don’t want to make things easy for myself and just buy fabric dye. I want to see if I can make my own.
I’m thinking of walnut husks, or iron oxide. I don’t necessarily want to go for natural dyes, but they seem the most accessible and I want to dye it my curtains a natural colour.
I’m doing some research and it looks like polyester is typically dyed in pressurised machines at 130°C to swell the fibre and open it up for dye penetration. It is possible to dye at lower temperature, but the compounds needed to swell the fibres at a lower temperature are generally toxic (benzoic acid, dichlorobenzene) and even though I could probably source them, I don’t think it’s environmentally responsible to use those. In general, polyester fibres are hydrophobic and will not absorb water-soluble dyes.
Alkaline treatment can help make the fibres hydrophilic, although this comes at the cost of some fabric weight loss.
Apparently somebody found that the bark of a tropical tree can be used on polyester, in combination with a copper sulfate mordant it would give the colour I want.
One study looked into madder as a natural dye for polyester, at different temperatures and using different mordants, and found that at 100°C the mordants performed no better than without, however copper sulfate seemed to perform similarly to using no mordant at 60°C. It gives a bit of an orangy-beige colour. Apparently potassium sulfate can work as a mordant too and I could experiment with magnesium sulfate too.
Continuing reading, I’m starting to realise that this would be a logistically challenging project. Even the commercial fabric dyes would need close to 100°C to work, and I don’t think we have a pot big enough to fit even just 1 of the curtains on our stove. I might be able to borrow a vat that I could dump them in together with boiling water, but I probably won’t be able to get it over 60°C. Maybe I can throw a heating element in.
One study found that vanillin can be used as a sustainable carrier for low-temperature polyester dying. The results are promising! It’s not as good at colouring as the carcinogenic ones, but, well, it’s not carcinogenic. (Para-)vanillin is easy to get and relatively cheap in low quantities and improves the K/S value (I guess this is the maximum colour uptake value?) from 2 to 3.5 compared to using no carrier. Ortho-vanillin could get to 7.5, but I can’t source it.
Other essential oils (Cinnamaldehyde, Thymol, Geraniol) may function similarly. Acetone may solve as a co-solvent?
One study used iron sulfate and fatty acids to colour polyester at boiling temperature.
This study managed to dye (green) using ethanol extracted chlorophyll from sweet potato leaves at 60-80°C. They used metal ion mordants and found that copper sulfate works best, at a very low pH around 3. I really like the idea of dyeing with leaf matter, and I think green curtains would work well as well.
I would need:
- A vat with a heating element and a thermometer
- A bunch of green leaves, they dried at 50°C
- Ethanol to extract chlorophyll – they used 100g dried leaves per 1L 60% ethanol
- A pot to boil the leaves – they extracted for 100 minutes at 90°C
- Copper sulfate
- An acid
Still, metal ions aren’t great to dispose of in the sewage system and it’s still a lot of hassle.
To be continued.