Mordant recommendation

[yancypup]

I made a tincture of alcohol and course cocobolo sawdust yesterday.  It is an absolutely beautiful color!  I need recommendations on adding a mordant so that I can apply it to wood as a stain.  I really don't understand how mordants work but I've been told I need one.  I don't get around very well so stuff like nosehair of a yak is probably out of the question.  I would like to use something simple and available in a grocery or hardware store.  Thanks in advance, Dan.

[Don Noon]

I don't know about mordants, but you might want to do some tests to see if the color is light fast or not.  Natural dyes and stains often don't do well.

[Michael_Molnar]

A mordant attaches the dye stain to the wood. Alum, tannic acid and even common salt are some that come to mind. If you do not have a mordant the dye could wash away. I think a mordant also stabilizes the dye reducing fading and color changes.

[Bill Yacey]

You want to be careful with cocobolo - The natural oils in this wood will prevent oil varnish from drying. It requires sealing before application of any oil varnish. With this in mind, you may want to do a number of tests with your dye stain to ensure these oils aren't extracted with the dye coloring.

 

Cocobolo also tends to darken from a light orange yellow to deep brownish purples over time,  and I suspect dyes made from this will also tend to darken.

[yancypup]

Thank you Michael, a pinch of salt it is!  I just read that salt is slightly soluble in ethanol.  Don, I know what your are saying.  I figure any fading will be somewhat offset by the natural darkening of the wood.  It's going over a violin with almost no figure so my aim is getting the finish as dark as I can with the varnishes I have on hand.  Bill:  yes I will be sealing it before I put on oil varnish.

[nathan slobodkin]

If you are looking for a nice orange- red for spirit varnish then try dragon's blood resin. Break up the cake. cover with alcohol and leave it until  the alcohol turns dark blackish red and the resin has turned to mud.  Pour off the tincture into a wide mouth jar, take it outside and light a match to it. When it stops burning you will have a black goop in the bottom of the jar. Let it cool, then pour your varnish into the jar and let it sit for a few days before pouring the varnish through a filter into a clean jar. This makes a very nice red and my test strips have been sitting on a window sill for twenty years and are getting darker over time.

[yancypup]

Thanks Nathan!  Well, I pulled the trigger and applied the tincture to the violin I am finishing.  It is beautiful!  It looks like 24K gold, only richer.  If it messes up the finish, I can always use it as a canoe paddle.  I will say that I believe I have read there is something toxic in cocobolo and well as most other rosewood species.  I didn't get skin irritation but, after a while, the fumes made me cough.  It will be covered up by many layers of finish so I'm not worried about it being a hazard once it done.

[Bill Yacey]

I don't know so much about the fumes being an irritant, but the dust sure is! I've heard of some people being affected just from skin contact.

 

I'm fine in that respect, but I got some sanding dust in my eye once, and it almost swelled shut. That, and the dust irritates the sinuses causing sneezing and a runny nose. These days I wear a mask.

[yancypup]

Good advice.  I also turn pens and I have gotten cocobolo dust up my nose.  Not pleasant.

[Michael_Molnar]

A book could be written about mordants. I think the best all round one is alum, but you need to test what works best for your stain. If you are like me you want to stick with historical mordants - none of that newfangled stuff for me. 

 

Why are you guys messing with cocobolo? I never touched the stuff and would like to learn what is its attraction.

 

Mike

[joerobson]

Same color source + mordant A = color A

Same color source + mordant B = color B

and so on

Joe

[Michael.N.]

If you are looking for a nice orange- red for spirit varnish then try dragon's blood resin. Break up the cake. cover with alcohol and leave it until  the alcohol turns dark blackish red and the resin has turned to mud.  Pour off the tincture into a wide mouth jar, take it outside and light a match to it. When it stops burning you will have a black goop in the bottom of the jar. Let it cool, then pour your varnish into the jar and let it sit for a few days before pouring the varnish through a filter into a clean jar. This makes a very nice red and my test strips have been sitting on a window sill for twenty years and are getting darker over time.

 

I've never tried Dragons Blood. Isn't that the one that can turn a little greenish? If so I wonder why yours has stayed OK some 20 years on.

[Bill Yacey]

Why are you guys messing with cocobolo? I never touched the stuff and would like to learn what is its attraction.

 

Mike

Cocobolo is probably the one of most stunningly beautiful hradwoods there is. Colors range from bright yellow through reds, purples and brown.

From a working standpoint, it cuts beautifully and is self-lubricating due to the natural oils, unlike rosewood.

 

I built my bass guitar out of this years ago, as well as a three electric guitars and a few violins.

[Michael_Molnar]

Thanks, Bill. I got rid of all my "non-traditional" wood such as koa, hoping to focus on a classical appearance. Nothing wrong with using other woods.

 

Joe mentions how a mordant shapes (literally) the color of a stain. (The combination is called a lake.) The mordant actually twists the stain molecule which alters it electronic structure and in turn affects it color. I think Michelman's book shows those results nicely for madder lakes formed with different mordants. The color shift can be dramatic or subtle, depending on the stain's molecular structure and mordant. In any case, we must experiment with mordants before applying. 

[Alma]

And I don't think salt is a mordant, although it may perform other functions in the dye process. Plant yellows and oranges are common natural dye colors that I have used, but only with alum as mordant.

[Michael_Molnar]

I mentioned salt because dyers use it. Technically and strictly speaking, a mordant should have a metal. Some organic chemists insist that the metal have a valence of +3.  

[Oded Kishony]

google is your friend

 

https://en.wikipedia.org/wiki/Mordant

 

ok

[Dwight Brown]

Salt kind of has a metal in it.  Sodium is in group one on the periodic table, alkali metals, with one valence electron, but combined with chlorine it becomes stable and does not really behave anything like either of the two elements in the compound.  You wouldn't want to put either Sodium or Chlorine on your french fries :-)

 

 

DLB

[Michael.N.]

Common table salt is the 'mordant' that is used with Rit dyes. I use it (Salt) with some of the natural dyes that I use for dyeing veneers.

[nathan slobodkin]

I've never tried Dragons Blood. Isn't that the one that can turn a little greenish? If so I wonder why yours has stayed OK some 20 years on.

because the problem is from using the resin itself rather than extracting the color. I just saw a violin spirit varnished with this stuff that was sold in 1997 that looked absolutely great .Dark red but not garish and has been played hard and nicely retouched by the dealer who sold it. no way to tell if it is 18 years old or 80

[Michael.N.]

Yes, I see what you mean.

I'm off to try it!

[Alma]

Sorry, textile chemistry was so long ago; as I recall, salt is used with RIT to  force the dye out of solution, not to mordant the dye. Salt could affect plant dye hue thru changes in pH. My stupid question of the day is, since violins don't go thru the laundry, why is a mordant necessary?  Is mere application of dye & sealing under varnish an insufficient deposit?

[FredN]

Hi Nathan, you certainly increased my confidence in using Dragons Blood. I always swore it knew how to sneak light into a dark room to speed up fading-

[yancypup]

Michael, cocobolo is a stunning wood as someone has already mentioned.  I had some course sawdust from turning pens so I thought I would try a tincture.  That beautiful color came through!  I don't know about colorfastness but someone has already mentioned that cocobolo gets darker and darker with age so I'm betting on the dye I made to do the same.  On maple, it produced a slightly brown gold and on spruce it produced a really deep rich gold.  I have read that cocobolo is in the rosewood family only it's much prettier than any rosewood I've ever seen.  Another wood I'm interested in trying is (forgive the spelling) goncalo alves.  It's just as rich.

[Michael_Molnar]

All natural pigments fade to some degree. Madder is among the best. I wonder whether fixing the cocobolo to a lake using a mordant would help lock in and stabilize the color. Again, I wonder.

 

Mike