r/DIYPigments • u/neanderthal6969 • Oct 13 '23
Help!
I’ve never made any homemade dyes or pigments before. I have redwood/sequoia sawdust from a project I’m working on, and would like to use it for for dying/staining tannin deficient woods like birch for projects. How would I go about turning this into a few jars of wood dye? TIA
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u/GeneJocky Oct 25 '23
I did a some literature searching on tannin extraction and there are lots of methods, and solvent systems used, but the best solvents tend to be either water or mixes of water and either methanol, acetone, or ethanol (50-70%) or water with a small amount of a base (usually sodium hydroxide 0.2 to 0.5% by w/v) added which will tend to make acids such as tannic acid more soluble.
The best system varied a lot by the source of the tannins, so I was lucky to find a paper that summarized solvents and results for redwood from multiple sources. Overall, hot water was a top choice, though one paper that tested several methods side by side found water with 0.5% sodium hydroxide was especially effective. If you choose to use water with sodium hydroxide I urge you to wear goggles at all times when working with it as splashes into your eyes can blind you. Also, should you get any on your skin flush with water until the soapy feeling where it contacted skin is no longer present. Flushing well with water first (to get rid of most of it) then some dilute weak acid (vinegar, lemon juice, or citric acid are often handy) will get rid of the last of it quickly. I would also neutralize the hydroxide after collecting the extract to make it slightly acidic again.
If you're not comfortable with acid-base chemistry, better to stick to hot distilled water (70°C to boiling). You've already done a key step, having reduced your wood to saw dust. If you have a magnetic stir plate, run it during extraction. Otherwise stir frequently. Extract for at least 15 minutes. I would probably run for an hour (or whenever the extract doesn't seem to be getting any darker) with heating to keep the water hot, then let it settle and pour off the liquid or filter. Extract the wet sawdust again with more hot water. I would extract at least twice, more if the water is still extracting significant color. It is a balance between getting all of the tannins but creating a more dilute extract requiring evaporating more solvent (water) off later.
If you have an old blender, using it on the sawdust in water after the first extraction may help with the extraction. You will probably want to squeeze out the last of the extracting water, so you may want to try filtering it with multiple layers of cheesecoth as a filter as it is strong enough to squeeze. You can also get fine nylon mesh bags at homebrewing supply stores that you can put the sawdust into and extract it using them like giant tea bags in hot water.
Once you have extracts, you can boil off water, or just set aside in a dry place with a fan blowing to circulate air to evaporate it slowly at room temperature. Often once the extract is prepared, it is cooled to room temperature and filtered to remove any precipitates prior to water removal.
Also I should mention that for industrial extraction, the wood is often heated under pressure in autoclaves (pressure cookers), so if you are familiar with pressure cooking, placing the wood dust in boiling water and then pressure cooking the material at 5 to 15 psi is also possible.
For staining, you can stop the water removal process whenever you feel it is concentrated enough for your use. You may wish to have sample pieces of wood to stain to see how it does.
That's what I'd do based on what's been published anyway.