Dyes and Other Decoration
Graeme Young   from: THE CNEW SKEW VOLUME 18 ISSUE 1

This month's program was a talk on using dyes and other surface decoration techniques. I had a number of pieces to show the different effects that could be achieved. I have not included any photographs here because the striking colors lose a lot when printed in black and white.

Dyes are available in powder form, as a concentrated liquid or premixed and ready to use. They can be mixed with water, denatured alcohol or petroleum-based solvents. Powders are generally specific to one solvent. I use Transtint dyes, which are a concentrated liquid best diluted with either water or alcohol. They can also be mixed with epoxy and some oil-based carriers, not those with a high proportion of mineral spirits. Transtint can be expensive (about $16 for a 2oz. bottle) if you use a lot of one color, but can be mixed in very small quantities. Powders can be cheaper but have to be mixed in larger quantities and have a limited shelf life once mixed (the powder should last forever as long as it is stored properly).

You will often see dyes referred to as aniline dyes. They most likely aren't. Aniline, derived from coal tar, was the chemical used in the first synthetic dyes. But that was back in 1856 (the chemist responsible for the discovery, William Henry Perkin, was trying to synthesize quinine but missed). The term “aniline” soon became a generic term used to describe any synthetic dye.

The primary difference between dyes and paints is the size of the pigment particles. Dyes have much smaller particles, which means they don't have the covering power that paints do. Dyes also absorb into wood fibers rather than sit on the surface like paints. Dyes give a different effect from paints and pigment stains. They allow the grain and to some extent the color of the wood to show through.

Dyes can be used to enhance an attractive grain pattern – lighter colors tend to be effective for this, as in the maple yellow and red bowl. The striking “hedgehog” grain pattern is shown up nicely by the yellow dye used on the outside. The pattern is still there but not nearly as obvious under the red dye on the inside.

Dyes can also enhance the appearance of a dull or unattractive piece of wood - darker colors work better in this application. The cherry bowl was a dirty and blotchy (beginning to spalt?) mix of heartwood and sapwood without the bordeaux and brown mahogany dyes.

As in “flat” woodworking, dyes can also be used to blend different shades of the same wood closer together. The red oak segmented bowl was made from at least two different boards, of slightly different shades. The orange dye blends the colors together nicely.

Apply dye with a cheap foam brush, synthetic brush or spray. Paper towel is not a good applicator – it absorbs too much of the dye. I mostly use an airbrush, which works well for the size of turnings (8–12” diameter) I generally make. Airbrushing gives a more even coat than brushing, especially when using alcohol as the solvent. The airbrush I have gives a spray about 1-2” wide from a distance of 6-8” – this is not a full-size spray gun! Alcohol dries very fast, within a couple of minutes, which can make life difficult if you try to brush an even coat over a large area but makes it easy to keep spraying light coats. If you apply dye with the piece turning on the lathe, run the lathe as slowly as possible. 100 rpm is good, anything over about 200 rpm will get more difficult as centrifugal force throws the dye towards the largest diameter. Donʼt apply so much that it forms puddles or major runs. Keep some paper towel handy for mopping up excesses. Because it dries more slowly, a water-mixed dye is much more forgiving than one mixed with alcohol.

You can use any finish you like over a dyed surface but expect some of the dye to migrate back into the finish, especially if the finish is a solvent for the dye. Unless you spray, don't try to apply finish over two different colors of dye at the same time. The airbrush does not work well for finishes – even diluted a lot the finish is too thick and just splatters. Be careful sanding the finish: it is very easy to sand through the dye layer too. If you have a choice, experiment on the outside not the inside. Damage is easier to repair on the outside. And if you mix custom colors, mix enough just in case you do need to apply another coat in some areas.

The rest of this article describes the various pieces I had to show. Most are test pieces made for this demonstration.

Christmas Ornaments: The two with finials are white maple branch wood, dyed with green and red Transtint in alcohol. Notice the pale band around the centre - the dye does not penetrate so well here because we have face grain with no end grain component. Even going over the area a second time does not help much. The one with no finial is also maple but from a piece of dirty grey-colored wood. It looks much better dyed than not but is not as bright as the others – you can't totally ignore the color of the wood with dyes as you can with paint. The striped one shows what the maple branch looks like undyed. The brown areas come out looking different when dyed.

Black Locust bowl: Turned green with three beads on the rim, dyed and finished immediately.

Outside dyed with green Transtint mixed in water, applied with foam brush with lathe running at 100 rpm. Took 20 minutes to dry.

Inside coated with glazing liquid colored with black Transtint (plus dilute green/blue Transtint plus gold PearlEx, neither of which had much effect). First coat wiped off immediately, leaving a very thin, ugly washed out effect. Second coat allowed to dry for 30 minutes, then won't come off evenly. Leaves a heavy ring inside rim and blotches in the transition from side to bottom. Sanding with 800 grit has no effect except to polish it a bit. Allowed to dry thoroughly then scraped, making even more mess. After sanding out most of the scraper damage inside rim is bare. Glazing liquid (used to give faux grain effects) is difficult to control on turnings.

Another Black Locust bowl: Airbrushed inside and out with yellow Transtint in alcohol, lathe running at 100 rpm. There are two areas of torn grain on the outside which the dye does nothing to hide. If anything it makes them worse.

Inside brushed with 3 coats of diluted polycrylic finish and a synthetic brush, then sanded with 800 grit. The dye comes off like crazy – do not switch colors doing this, and transfer your finish to a small container.

On this one, the dye is really struggling to brighten up a wood that was really too dark for it to begin with.

A Third Black Locust bowl: Inside sprayed with green/blue/black Transtint in alcohol, lathe running at 750 rpm. The dye runs out in rings and bleeds over the rim, following the grain.

The outside gets a coat of brown mahogany paste filler, wiped off with denim with the lathe running at 200rpm. Then sanded 320-400, which muddies it up and does nothing to hide the sanding marks that were there previously. This time, the colouring has not added anything to what was there before.

Black Locust with wide rim: Sanded inside and out to 400. Not very well because scratches show up on the outside, mostly near the rim. The more details you put in, the more careful you have to be about thoroughly sanding right up to them, or the dye will make the scratches more obvious.

Top rim is painted with Black Cherry acrylic. Closest colour I had to purple, which is the complement of yellow- green, which was what the wood mostly seemed to be.

Outside dyed with Transtint (Honey Amber plus Green) mixed in alcohol. Applied with Taklon brush at low speed. The dye dried in 2-3 minutes: much faster than water-mixed but it looks uneven going on. There is a great temptation to mess with it too much. Dyed areas burnished with paper towel to avoid having all the dye colour the finish.

Carving the rim with a V-tool gives a pronounced effect going through the paint, less effect going through the dye. Mainly because of the different colors – the contrast is greater against the dark cherry paint.

Bleached Maple bowl: Sanded inside and out then bleached. This has no effect on the ugly green stains in the otherwise white wood. Sanded again and abandoned. Not worth returning to because there are serious sanding marks on the outside and no possibility of power sanding.

Black Sassafras with gold rim: This was originally painted black inside. Maybe dyed also. I do remember I had a terrible time trying to get the colour even by brushing it on. Finally I picked it up again and airbrushed the inside with black Transtint in alcohol. That evened out the colour.

Dusted the inside with PearlEx (gold coloured dust, available from craft stores) and wiped off with toilet tissue then brushed with several coats of dilute polycrylic finish, with another dusting of PearlEx in there somewhere. Now it looks good, the gold is showing and the finish goes on evenly and dries in less than 30 minutes. The rim is painted with Liberon gilt varnish (Trianon), two coats. The outside is finished with two or three costs of Formbyʼs Tung Oil Finish (my usual finish).

Mulberry Saucer: Top sanded to 180 then dyed with Transtint yellow in alcohol and sanded from 240 - 600. Page 5 THE CNEW SKEW VOLUME 18 ISSUE 1 The idea was to sand most of the dye off, leaving it mainly in the pores. This didn't work, the dye has soaked in thoroughly and has penetrated through to the bottom surface in places.

The bottom is turned as several shallow steps, sanded and colored with broad Prismacolor markers, alternating steps green and blue. These are never going to give a uniform depth of color (try coloring a sheet of paper with these things) but they are more controllable here than dye, and do not penetrate into the wood. They are good for highlighting a rim, where the color variations will not be noticed.

Blue Clouds Form: Another piece of undistinguished, dirty looking slightly spalted maple, enhanced with blue and blue/black dye. The finish is Formby's Tung Oil Finish applied with a rag – the dye does not mix with the finish and largely stays put. The collar on this piece is walnut, ebonized with steel wool in vinegar. That didn't work very well, the variations between heartwood and sapwood are too great. Even black dye over that does not turn the surface totally black. Next up: black shoe polish.

Flat natural edge ash plate: Another “what not to do”. The piece was wet-sanded with oil then dyed with water- mixed dye. Surprise: oil and water don't mix! The dye only takes in the areas where sanding had not been very thorough. Ash Box: This is heartwood with random color swirls of different browns through it. Thoroughly sanded up to 600 grit before coloring with brown mahogany paste wood filler, applied with a rag and quickly rubbed off with the lathe running. This works best on spindle oriented turnings because you are rubbing across the grain: rubbing along the grain tends to pull the filler out of the pores. The knob (flat top with four small beads) is not filled but dyed with brown mahogany Transtint. Wood filler here would be impossible to get out of the grooves. The paste filler tints the wood, pulling the color variations together and improving the look of the piece.

Spalted Ash Plate: Another ugly piece of wood to begin with. Sanding out all the tear out left the surface smooth but very uneven. Then the piece was coated with Minwax Whitewash Pickling Stain, sanded and coated again. The pickling stain is more like a paint than a dye. You might expect it to collect in the pores and emphasize the grain but it doesn't. And it is so thin that wiping it off when wet takes off almost all of it, like the glazing liquid. But if you let it dry for too long it will block up and look as if you applied six coats of paint then stripped most of it.

Resources

Homestead Finishing
http://www.homesteadfinishing.com
Jeff Jewitt's web site. Lots of information about dyes and finishes. Maker of Transtint dyes (Woodcraft also carry them).

Liz & Michael O'Donnell Decorating Turned Wood Lots of ideas for coloring and other surface treatments.

Russ Fairfield Colouring Wood with Aniline Dyes http://www.woodcentral.com/russ/finish12.shtml
Russ takes a different approach, much more thorough and time-consuming that my one coat, slap it on and be done with it. Russ has also written a number of articles about various aspects of finishing, all available at the WoodCentral web site.

For Vibrant Color, Use Wood Dyes Chris A. Minick in Fine Woodworking, October 1995

Craft Shops: A.C. Moore and Michaels are the big ones in central Mass. Prismacolor markers, PearlEx, acrylic paints, brushes and lots of other stuff to experiment with.

Coloring Wood with Jan Sandera. In our video library.