Mike's Oud Forums

dying mahogany veneer BLACK

Edward Powell - 8-27-2012 at 05:26 PM

Does anyone have any advice on how to dye mahogany veneer black to use for purflings?

I am guessing that it is enough just to take some black fabric dye and boil it up together with the veneer?

Has anyone done this and have the black go all the way thru 0.6mm veneer?

thanks

fernandraynaud - 8-27-2012 at 06:24 PM

There's always that intriguing black shellac at http://www.shellac.net

freya - 8-28-2012 at 04:57 AM

Ed,

I've used this stuff for necks and bridges and it works pretty well for that. Stains anything it comes in contact with....

http://www.stewmac.com/shop/Finishing_supplies/Colors,_tints,_and_s...

cheers

Edward Powell - 8-28-2012 at 08:46 AM

looks like very useful stuff, but I need something that will penetrate 0.3mm... will this stuff do that?

can you make a test at home? For example take a small piece of any hardwood 0.6mm veneering, and paint this stuff on both sides --- let it dry, then start sanding the veneer and see if you can "sand off the colour". If you keep on sanding until there is no wood left, and you could not get back to the original colour of the veneer, then this black stuff did actually penetrate all the way thru...

jdowning - 8-28-2012 at 12:21 PM

For what it is worth I did a quick test this morning coating a piece of mahogany veneer with 'Indian Ink' (ink made from a shellac base) and black Analine, water soluble, wood dye. When applied cold, the dyes do not penetrate beyond the surface.
Boiling the veneer in these solutions might achieve better results. Commercially dyed veneers are made by subjecting the veneer to the dyes under relatively high pressure and temperature. If you have an old pressure cooker this might work for small samples.

Edward Powell - 8-28-2012 at 12:30 PM

aha... yes a pressure cooking might work... i wonder what kind of black dye would work the best? Cloth dye?

Back home I have a small tub of black powder which is used for tinting varnish and paint - appearantly it is made from chimney soot --- the black colour is incredibly powerful - if you spill a bit it gets everywhere and is hard to clean up..... i wonder if boiling the veneer simply with this stuff would work - - - - - or do these clothing dyes have some special curing and penetrating properties that the simple black soot powder would not have.

BTW I used that black soot powder to mix with fiberglass resin and it made an amazing pure black resin for making a flight case.....

freya - 8-28-2012 at 01:57 PM

I just dipped a piece of 0.5mm maple purfling in the dye. I'll let it dry overnight and cut through it with a new xacto blade tomorrow AM and see if the cross-section is black all the way through...

Edward Powell - 8-28-2012 at 03:39 PM

Quote: Originally posted by freya  
I just dipped a piece of 0.5mm maple purfling in the dye. I'll let it dry overnight and cut through it with a new xacto blade tomorrow AM and see if the cross-section is black all the way through...


did you just dip it in once, and are letting it dry..... or are you soaking the piece in the dye all night?

my guess is that if you just dip it in once, it will not soak in all the way.... perhaps letting the veneer soak in it all night might work?

jdowning - 8-28-2012 at 05:38 PM

Boiling the veneer for a time in the dye solution might help drive out any air trapped in the wood cells and then leaving the veneer immersed until the solution is cold might result in the dye being drawn into the wood?
In this case the dye would need to be water soluble.

Edward Powell - 8-28-2012 at 06:02 PM

john, do u know if there is any difference between "dye" and just "coloured powder"?
...what I mean, is that if my black soot powder is water soluable will it it in this case - - - well. obviously, i just need to try it for myself:bounce: ....but i'm curious about possible 'expert' opinions here.

I have seen turkish luthiers dye their own maple veneer black, but it came out kinda grey (and just to get it these 'semi-black' he said he had to boil it for days!).... although after it is varnished it goes a bit more black.

fernandraynaud - 8-28-2012 at 10:30 PM

It's tough to do black. There's a whole body of superstition to "piano black". Because the darkest pigment is fragile, it seems that it always comes down to protecting and "bringing it out" with a clear coat. My Sukar model 14 has a French Polished "piano black" bowl. But the finish didn't hold up very well, Sukar found out that it scuffs easily, betraying a lighter color. So they stopped shipping them like that, making the wonderful "black oily walnut" model 14 harder to find. I'm going to try adding a few coats of that dark dark shellac.

Edward Powell - 8-28-2012 at 10:43 PM

it's for this kind of veneering that I need it... not a whole body black...

9.jpg - 34kB

fernandraynaud - 8-29-2012 at 01:59 AM

I understand, I was just mentioning some issues with the pigments. And not much penetration. Aren't there some iron salts that are quite black and water soluble?

freya - 8-29-2012 at 04:53 AM

Ed,

I seems what you are trying to do is very close to the purfling that violin makers use. So it seems to me that there are actually two considerations - first, that the dye penetrate completely so that no lighter color appears during final scraping but also that no "bleeding" occur from the dyed strips to the lighter rib during whatever finishing process you use.

I sliced thin strips off of the dyed maple purfling I did last night and the dye penetrated completely. I'm soaking a much thicker walnut sample right now (1cm x 0.5cm) to see just how far in the dye will soak. I'll let you know tomorrow.

As far as preventing bleeding, this could be more problematic with the dye I referenced. Not really an issue for fingerboards but might be for purfling that has a finish applied over top, esp if that finish has solvents. Violin makers seem to have solved the problem a long time ago. I'm sure you can do your own searches but just as an FYI, there is this page:

http://www.doranviolins.com/workbench/making-purfling/

cheers

jdowning - 8-29-2012 at 12:06 PM

Analine dyes for staining wood come in powdered form and are made into solution be mixing with water or alcohol. Soot is not soluble in water or alcohol as far as I know but can be used to colour media such as shellac or resins to provide an opaque finish. However a shellac based finish will not penetrate deeply into wood.

Tannin rich woods like Walnut or oak can be dyed black by chemical reaction with iron salts as suggested by fernandraynaud.

All these procedures require significant soaking times after boiling to allow complete penetration of the dye when using even thin veneer. The process can be accelerated considerably if sealed pressure or vacuum chambers are used to force the dye into the wood cells - but all at extra cost.

A quick check on the Internet reveals much useful 'hands on' information about dyeing veneer and making purfling.
I have used commercially available dyed black maple veneer in the past to make B.W.B. purfling without experiencing problems with bleeding of colour. Violin makers sometimes use non-veneer components like fibre (or even paper) for making purfling.


.

Edward Powell - 8-29-2012 at 12:43 PM

do you know is mahogany also high in tannin?

Edward Powell - 8-29-2012 at 12:55 PM

I ask about mahogany because I have a ton of mahogany veneer.... I just found this tip which says mahogany IS high in tannin....

but this tip seems to be concerned with using the dye as a paint rather than soaking right into the whole veneer - - - but I like the idea of using rust and vinegar... I wonder if this method could be modified to get the black all the way into the veneer?

Vinegar Homebrew

Let's start with a traditional homemade formula concocted from vinegar and rust. The mixture works best on oak, walnut, mahogany and other woods high in tannin; low-tannin woods will not get as dark. If you have ever seen the blue-black stains that form around iron nails in old oak, that's the color you' ll get.
To make the brew, pour some vinegar into a glass jar and drop in a handful of rusted iron parts -- nails, hinges, whatever. No rusty metal around your shop? No problem; throw some water on a couple of steel-wool pads; you' ll have plenty of rust within a day.
Put the jar lid on loosely so that gas can escape but the vinegar doesn' t evaporate. Let the jar sit in a warm part of the shop for a week or more. Then remove the metal and strain the black liquid through cheesecloth or a coarse filter cone. Sponge it liberally onto the wood and let it dry overnight. Reapply once or twice if you want to darken the color. When the wood is dry, scrub it with a stiff bristle brush to remove any renegade steel-wool fibers. Then wipe it off with a slightly damp cloth and, after it dries, seal it.

Edward Powell - 8-29-2012 at 01:21 PM

this guys seems to have done it...

http://www.penturners.org/forum/f45/dying-lighter-colored-veneer-bl...

freya - 8-31-2012 at 07:51 AM

Ed,

Sounds like you are inclined to go the vinegar/rust route. In any case, I used a razor saw to cut in to the 7mm x 2mm piece (I had the dimensions wrong before) of walnut that I soaked in the black leather dye for about 5 minutes and it looks like the dye soaked in about 0.8cm all around with some minor variation due to grain irregularity. Good luck with the vinegar/rust - let us know how it turns out.

cheers

Edward Powell - 8-31-2012 at 08:23 AM

Quote: Originally posted by freya  
Ed,
I used a razor saw to cut in to the 7mm x 2mm piece (I had the dimensions wrong before) of walnut that I soaked in the black leather dye for about 5 minutes and it looks like the dye soaked in about 0.8cm all around with some minor variation due to grain irregularity.

cheers


do you mean 0.8mm ? or cm, which would be 8mm and bigger than your piece?

Do u have a small piece of regular 0.6mm wood veneer you can make a test on - - it sounds like you method might work.
(or perhaps a combination of your ink plus the vin/rust?

freya - 8-31-2012 at 08:24 AM

Oops 0.8mm (I still think in english measurements bu default...)

Edward Powell - 8-31-2012 at 08:42 AM

well soaking in 0.8mm in just 5 minutes is extremely extremely good! That would work perfectly for these tiny purfling strips ---

jdowning - 9-3-2012 at 11:24 AM

This article by Kai-Thomas Roth "How to Make Purfling" (published in the Strad magazine, Sept 2007) may be of interest.
It includes information on how to dye the veneers used for the traditional 'black - white - black' purfling used on violins.

Note the preparation for dyeing step to degrease the veneer using caustic soda (sodium hydroxide caution - corrosive to skin!) - to ensure even penetration of the dye.

The black dye used is extracted from log wood chips but I imagine that substitution of an analine dye would work just as well (and comes in all colours including black).

The veneers are shown glued together using hot hide glue in the traditional way but an alternative method would be to use PVA carpenters glue.
Apply the glue with a roller to all the surfaces to be glued. Allow the glue to dry. Then using a household iron at high heat setting iron the veneer laminates together. PVA glue is a thermoplastic material so will temporarily melt gluing the laminates firmly together - a process similar to using hide glue.

PVA could also be used without heat if the laminates are clamped between two flat surfaces to dry. To assist the drying process place a few layers of absorbent paper on each side of the stack of veneer.
This 'cold gluing method' is how I have made purfling in the past using commercially available dyed veneer.

Attachment: MakingpurflingTS.pdf (144kB)
This file has been downloaded 539 times