Wednesday, March 21, 2012

Staining with Tea


I've been experimenting with making my own stain; I want something completely non-toxic. I've used tea in the past, but it really didn't seem to do much to the wood, but then I got to thinking about making it stronger somehow. Here's what I came up with.

I started with about two quarts of water. After the water got to a rolling boil, I added six teabags and just let it keep boiling. After about twenty minutes or so, I removed the bags and kept boiling the water down until I had about one cup left.

As you can see, it became quite strong tea:


To test it out, I divided a board into four sections:


Then I left one section unfinished and stained the other three:


After several applications, here were the results:


The first section was left unstained, the second section had one application of stain, the third section had three and the fourth section had five applications.

Conclusions/Thoughts:

  • Well first, it obviously works. Cool.
  • Second - since it's water based, I realized that you have to wait for the previous application to be completely dry before adding another. If you don't, the wood doesn't absorb the stain and not much happens. I think I could have achieved similar results with fewer coats if I had figured this out sooner.
  • Third, the blotchy spots are due to my sloppy application and could easily be avoided.
  • I'm curious about what might happen if I strained the tea through a coffee filter. Would it act more as a dye rather than a stain?


Next steps:

I'll oil part of the test board and see how that looks.

Also, now I'm curious about coffee...


25 comments:

  1. Interesting....what type of wood did you stain? I've done ebonizing with a vinegar/steel wool concoction and had similar results but have always wondered what some tea would do to the mix.

    ReplyDelete
    Replies
    1. Andrew - I've always wanted to try ebonizing, but haven't gotten around to it yet. I think the ebonizing (iron) solution reacts with tannic acid in the wood? I wonder what would happen it you stained with the tea (tannic acid) first, and then used the ebonizing solution?

      Delete
    2. Oh, I forgot - I just grabbed a hunk of 2x6 from the scrap pile so it's probably spruce or fir...

      Delete
    3. Vinigr and wire wool works well for ebonising oak

      Delete
    4. Vinigr and wire wool works well for ebonising oak

      Delete
  2. Hi Dan,

    That is an impressive and unexpected amount of colour on your sample board.

    I have read that food-based stains/dyes are more prone to fading than commercial stains/dyes. Have you ever heard this? Do you find it to be true?

    Also, aren't aniline dyes disolved in water safe if you aren't breathing in the powder?

    Chris

    ReplyDelete
    Replies
    1. Hey Cris,

      I don't know, but I wouldn't be surprised if some food based dyes faded quicker. Although, since my main goal with staining (which I don't do all that often - hardly ever actually) is to "age" the wood, if the stain started to fade as the wood developed its own patina I wouldn't mind...

      As for aniline dyes - I don't know much about them. I think the powder is more of a concern, but I just did a quick check and OSHA considers liquid aniline dyes "moderate" as far as toxicity (based on a MSDS sheet for a commercial brand). Once they start talking about "central nervous system" I start getting nervous (no pun intended).

      Delete
    2. I don't think aniline dyes are actually made from aniline anymore - aniline is highly toxic. I think the name stuck, but the aniline went away a century ago.

      Delete
  3. I hear about these tea, vinegar and iron recipes, and I keep wondering if they really are non-toxic. You're dealing with two acids (acetic and tannic)as well as at least one mineral. I don't know what the result of that is, we'd have to find a chemist. Also, since it's a chemical reaction, how do you make sure it stops, so that it doesn't continue to darken with time? Some old violins have turned black because the chemical reaction in the varnish was never neutralized.

    ReplyDelete
    Replies
    1. PR - That's a good question. I tend to operate on a basic common sense level with chemistry. I'm not worried about vinegar and tea as they are food. But add in the iron and now I start wondering.

      As for the neutralization of the acid, I think I've read articles where the author has done a baking soda wash to stop the reaction.

      Delete
    2. I've done a little more research; mixing vinegar and iron gives you iron (ii) acetate and hydrogen gas. The hydrogen just escapes into the atmosphere, and the iron acetate is what you have left over, and is probably not very concentrated due to the fact that vinegar is mostly water. The good news is it's not a carcinogen. However it is a serious eye, skin and respiratory irritant, here is a link to an MSDS for it (note this is in it's most concentrated/solid form):

      http://www.lookchem.com/msds/2011-06%2f3%2f339199%283094-87-9%29.pdf

      Unfortunately I have not found information about the chemical formed by tannic acid and iron (ii) acetate.

      Delete
  4. I have tried ground coffee in the past with less than satisfactory results, although I did not distill it as much as I could have had I boiled it as long as you did your tea. On the other hand, I have used INSTANT COFFEE (far easier to achieve concentration) with wonderful success. Using it on white ash achieves a warm look that resembles aged chestnut. Give it a try. Larry

    ReplyDelete
    Replies
    1. Larry - Cool idea - I'll have to add that to my growing list of things to try. Thanks!

      Delete
  5. I've tried instant coffee on SPF and it was nearly non-existent.

    ReplyDelete
    Replies
    1. Dean - I wonder how much variation there is board to board. My sample was SPF - maybe I'll try another and see what happens. Thanks for the information!

      Delete
  6. What brand tea did you use? I have seen and used a combination of instant coffee and Tea with good results. Some have even combined other ingredients in with the mix. I can only speak on my results with Pine. Watch out for mold growing in the tea if you don't use it within a few days(unless my container wasn't airtight?).

    Thanks,
    Scott

    ReplyDelete
  7. Dan,
    Great idea for an organic stain!
    I recently read an article on staining oak black with a black coffee wash first, followed by vinegar that had rusty nails soaking in it for a couple of days. He had some pretty impressive results as well. I want to try some of these tricks out. I have thought that beet juice would make an awesome stain on pine for a kind of purple heart look.

    ReplyDelete
  8. Impressive! This is an interesting finishing technique! :) Have you ever tried coloring wood with food colors (like Kool Aid for example)? That's a thing I've planned to try..

    -Saara, Finland

    ReplyDelete
    Replies
    1. Saara - No, I've never tried that, but it sounds interesting. I've also wondered about berry juice or beets etc. Thanks for commenting.

      Delete
  9. Thanks for this! I recently tried to stain some fir with black tea and was dissatisfied with the results. I'd never considered reducing the tea.

    ReplyDelete
  10. I have just used tea to stain the front of a (Cremona 1626 ?) violin that I have just glued together. The front was shattered and required multiple glue joints as well as addition of narrow strips of new spruce where wood was missing. The glue result was good but of course the new (white wood ) wood stood out.

    I would describe the original colour of the violin as “amber” . So I boiled 5 teabags in about 200 ml water abd used this to stain the white parts, allowing them to dry in the hot Mediterranean sun in between applications. Result – excellent. I have used tea for staining a clavichord – this was a replica of a “gemein” (=poor man’s) clavichord with a pine case. The colour is nice and warm and it hasn’t faded over the years.

    ReplyDelete
    Replies
    1. Thanks for commenting George! That sounds like a challenging and fascinating project. I'd love to try working on musical instruments at some point, although it does seem like there might be a lot of pressure when working on something so unique/valuable...

      Delete
  11. Wow Great information on this blog thanks for this wonderful info.
    online coffee store

    ReplyDelete
  12. Hi guys, its really interesting reading your posts...Dan's logic is on the money...the iron oxide taken from rusty nails or disolved from the steel wool in vinegar creates iron acetate...& Dans right in there is a reaction between the acetste & the tanins in the wood (like oak which are high in tanins)...for wood low in tanins, staining them with black tea which is high in tanin (its what stains cups) & then again with iron acetate will creat an imediate ebonising effect which is very reistant to sun fading because...the iron oxides infuse into the wood cells...also with tea staining, needs to dry between dressings, for oxidising of the tea (from the air) to take effect & darken, the oxidising happens much slower in water there being much less oxygen present & it being less freely available in the reaction. Applied enough times and you create a truely jet black ebony effect which unlike artificial commercial stains, still retains the grain contrasts I think because the reaction is being pulled right into the wood cells, not simply covering it...cheers from New Zealand

    ReplyDelete
  13. This post is old as hell, but I used this technique to stain a wooden smoking pipe I stripped down. It worked really well, I ended up w/ a pretty deep golden brown at the end after starting w/ a blonde wood. I found I had to reboil my mixture, it was originally too liquidy; I boiled it down until in was a slightly thick concentrate and just slathered it on to great effect

    ReplyDelete