91 replies to this topic

[Doug Sanders]

Sergey- I thought I'd start a new topic thread for your question-

I've had some experience dyeing tagua nut with alder cone dye. I only wanted a light stain, to sit in the recesses of the carving. No preparation work was done; I just soaked it in warm dye solution until the color was where I wanted it.

http://www.dougsande...e/goldfish.html

this will get you to my webpage photo. Sorry about the quality- This was my first batch of photos years ago and the quality is poor.

Tagua isn't something I'll be carving much of anymore- I still use it for inlay detail on other carvings, but I've had a number of problems that crop up after the piece was finished. I've had inlays and onlays pop off after about a year. I think that as the nut continues to dry, oils migrate to the surface causing glued inlays to loosen. It seems to go through dimensional change over time.
Also, the himotoshi I carved cracked right between the two holes (months after carving), making the piece unsaleable.
Like all nuts, tagua is oily. If we look at old netsuke carved from tagua nut (I think there's also another sort called corozo nut?) they have darkened considerably to a deep honey color. This needs to be kept in mind when conceiving the subject you wish to carve.

If you soak the nut for several hours in warm water, it becomes easier to carve. Once dry and cooled, it is hard again and can be more finely carved and polished.

Good luck with your carving

Doug Sanders

[sergey_osipov]

Thanks Doug,

This is a valuable advices for me! I never carved tagua nut
previously.

I try carve Argonaut(Argonauta argo) - the variety of the octopus. And
thinking about that, as this coloring...

That will if delete the butter from nut with using solvents?

Serge

[Janel]

Hi Sergey,

Your question, "That will if delete the butter from nut with using solvents?", is a good question to ask! What a good concept for learning more about. Do you have any suggestions about particular solvents that might be used?

Which solvents will disolve vegetable oils? Non water based would be my first choice if I were to start testing. Another thought might be dish or laundry soap or detergent, since the oil is vegetable rather than mineral. There are products that are not scented that might be useful.

I am concerned about soaking the nut in water and then drying; would it not increase the risks of cracking? Years ago, I did soak and dry a piece of a nut. The piece expanded from absorbing water, and left the water a little milky. That was long enough ago that I do not remember if the piece dried to a smaller dimension or if its properties had changed.

I have chosen to carve the well-aged nut dry and not whole. I prefer knowing where the drying cracks are and will remove them, using only the uncracked part of the material. The carving of the dry nut is less easy, but fewer risks are taken with the investment of time in the piece.

Included below is a piece from a half of a tagua nut, which had dried for years before carving:

Hiding Peeper, 2002
Tagua Nut

Hiding within the curled oak leaf is a tiny spring peeper. The translucent tagua nut, known also as vegetable ivory, allows light to pass through it, as does the body of a spring peeper when seen in sunlight.

Dimensions:
1.25 x 1.0 x 0.6 inches
3.2 x 2.6 x 1.6 cm


Janel

[Janel]

PS

Sergey, I like seeing the octopus just beginning to emerge from the carving! Each carving we do grows through so many stages, each interesting on its own.

Janel

[Doug Sanders]

I've thought that the warm water used for the dye may have caused the nut to swell and crack later on. Maybe, maybe not. My problems seem to crop up down the road, time-wise, so I think any dimensional change from water-induced problems would have subsided. I do think that as the nut ages, the oils go through a chemical change and do migrate to the surface. Oxidation I suppose. Most nut and seed oils are classified as drying oils so they will harden over time.

I've noticed some nuts are more white and translucent, while others are more cream or flesh-colored and opaque. Any thoughts on why?

Re: solvents for nut oils, I'll check with a painting conservator friend of mine for her thoughts. It's not something us paper conservators (day job) are as familiar with. My first impression is that any solvent use would just have surface effects; not really getting to the heart of the matter.

_Doug

[Janel]

Hi Doug,

The removal of the oils from the surface would be done so that the surface of the nut could be prepared to accept color. The consideration that the oils might migrate would have an affect on the coloration over time, if the oils in fact migrate.

I have thought that older seeds might be more stable, but it makes sense that they might be susceptible to humidty changes, like ivory or wood.

I think that seeds darken with age. Stephen Paulsen, a turner of the tiniest forms, knows about tagua and a wealth of other materials, woods and nuts. I'll give him a call, I do not have an email address for him.

Non-water solvents, might they be able to prevent absorbtion and swelling of the nut material?

Janel

[Doug Sanders]

Well, I did a literature search in the Art and Archaeology Technical Abstracts run by the Getty in CA. Two citations came up for 'tagua nut'.

-"Tagua, the Vegetable Ivory Substitute" by Fred Hunger, Fine Woodworking 1990 July-August. The abstract says it's mostly about how to turn it, but there is some mention of conservation. If someone can track down the article, I'll follow-up on any references it might contain to scientific studies.

-in the Philosophical Magazine, issue 24 from 1844 (yep, 1844) someone bothered to study the composition of tagua:

"The specific gravity of vegetable ivory from the taguanut, popularly called Cabeza de Negro is 1.376 at 53°F. The composition is given as: gum 6.73, legumin or vegetable casein 3.8, vegetable albumin 0.42, fixed oil 0.73, ash 0.61, water 9.37, lignin or woody matter 81.34."

Gum is water soluble but generally not in alcohol. It is a sort of sugar.
Casein is a protein- so is albumen (I think...)
I'm not sure what the term 'fixed oil' means, but maybe there is not migration of it and it's chemically bound to the other materials.
Of course the woody matter is what makes it carveable...

Doug

[Janel]

I spoke with Stephen Paulsen last night. One recollection he had was learning that some tagua nuts were stained with green tea. He also mentioned aneline (SP?) dye, but was not more informative about that.

This bit of information implies that the nut might loose the oils from the surface, or open up, and accept color.

One might try hot, water based stain/dye solutions for testing pieces of tagua before committing a completed carving to the rigors of staining and drying.

Any more information gathered yet?

Janel

[sergey_osipov]

Janel, Doug, much thanks!

I also did some experiments with tagua nut. I did attempt remove the
oil from this in hot concentrated solution of the food soda. The tagua
nut has gained the creamy colour and has lost the transparency. I
think, transparency was conditioned presence of the butter. A certain
transparency of surface not much comfortable for carve. Eye to tire,
for want of thick shades.

The depth of coloration aproximately 3 millimetres. More deeply nut
remained white. I think, this will possible bleach subsequently in
H2O2.

I expect that possible to remove the oil from the tagua nut in light
solvent such as benzine, acetone etc.


Sergey
-------------------------------------------------------------------
My Webpage

[sergey_osipov]

Welcome Kathleen!

I hope we shall soon hear all about tagua nut!

You like carve in tagua? That you carved?

Sergey

---------------------------------
My Webpage

[sergey_osipov]

The tagua nut it much was well bleached in H2O2! Absolutely white!

The suckers-suckers... The octopus nearly completed. Remains the
polishing and colouration.

The work in progress here


Sergey
---------------------
My Webpage

[sergey_osipov]

Hi Kathleen!

Yes, H2O2 is a hydrogen peroxide. This is a good agent! I use 30%
solution.

We hope to see your works from tagua nut soon.

Thanks!


Sergey
---------------------
My Webpage

Attached Images

• 

[lotzla]

Doug Sanders, on Jan 26 2005, 09:03 AM, said:

I've thought that the warm water used for the dye may have caused the nut to swell and crack later on.  Maybe, maybe not.  My problems seem to crop up down the road, time-wise, so I think any dimensional change from water-induced problems would have subsided.  I do think that as the nut ages, the oils go through a chemical change and do migrate to the surface. Oxidation I suppose.  Most nut and seed oils are classified as drying oils so they will harden over time.

I've noticed some nuts are more white and translucent, while others are more cream or flesh-colored and opaque.  Any thoughts on why?

Re: solvents for nut oils, I'll check with a painting conservator friend of mine for her thoughts.  It's not something us paper conservators (day job) are as familiar with.  My first impression is that any solvent use would just have surface effects; not really getting to the heart of the matter.

_Doug

<{POST_SNAPBACK}>

Hi Doug,

I've noticed that several of my Tagua nuts had developed dark streaks that were not there when I first bought them.

I picked out a really fine colored one and carved a small portrait of my daughter. I was horrified to see it start to develop a similar dark streak before I was finished carving it.

I wanted to try save my sculpt in a bleach bath. It worked to bleach it back to the fine translucent color I wanted.

The way the dark discolorations formed made me believe my collection of nuts was exposed to some kind of fungus or bacteria that was growing and spreading. I believe the bleach killed the fungus and removed the discoloration.

Unfortunately I was called away due to an emergency while I was handling the wet nut. I returned to find that I had accidently left the nut out of the water bath in my haste. It was totally destroyed with 2 horrible cracks.

This bleaching process might have worked fine if I had dried the nut in VERY controlled conditions so it would dry very slowly.

As far as trying to remove the oils: I would be more inclined to try to keep the oils inside the nut by sealing it with tung oil rather than trying to remove an important component of this nut. We try to keep our wood healthy and the pores sealed. Do you soak oily woods in solvents or do you work with them as they are?

I worry that trying to chemically change the nuts by removing all oils could possibly change the nut's internal structure leading to more significant damage over time.

Jean

[Doug Sanders]

I think you're probably right about oil removal leading to dryness/cracking in the future.
Regarding bleaching, since the nut is mostly cellulose -like paper- there can be a chance of deterioration setting in which is bleach induced. Using hydrogen peroxide (H2O2) is fine as it will reach a chemical dead end after rinsing in water. Other bleaches like Clorox (Sodium hypochlorite) will continue to bleach and cause problems after rinsing. Typically, in any large amount, these require an anti-chlor to halt the chemical reaction.

I've read a bit more about tagua on some scrimshaw info pages in the Net. They recommend waxing the polished tagua before taking a needle to do scrimshaw work. This is because of the porosity of the nut being such that when one goes back to wipe over the scrimmed area with ink or shoepolish, the non-scrimmed areas will pick up some pigment. The wax acts as a resist.

Has anyone on the forum ever selectively stained by using a wax resist on wood?
It would be a great way to isolate one portion of a carving from another in the dye bath.

-Doug

[Ersatz]

I was recently carving a tagua nut and noticed a nasty smell every once in a while when i was carving. I finally noticed it was coming from the nut where i had started carving out the natural hole where the "plant" is so I split it open and there was a nasty looking grey mold/fungus inside the internal cavity. I threw it into h202 wich seems to have killed and dissolved the fungus. from now on i plan to presoak them in h202 or enthanol befor I start carving to kill off any fungus/mold.

[Janel]

Welcome Jean and Ersatz! Glad to see you here.

Thanks for the interesting information on tagua from all of you!

Janel