Darkening mahogany chest

[Mark Bellonby]

I would love some advice on water dying an almost complete african mahogany chest. The piece is a combination of paneled solid wood and slip matched ebony plywood. There is a second chest of cherry, which I plan on allowing to darken naturally.

My better half wants a darker look than the natural mahog would produce, as she wishes to match the bed. I am thinking about the following finish procedure:

1. Sand to 180
2. Unwaxed shellac seal coat on ebony only
3. Multiple brushed laquer coats on ebony - sanding betw coats to fill voids
4. Mask off ebony
5. Spray dye coats on mahogany
6. Unwaxed shellac seal coat on mahogany
7. Multiple spray laquer coats on mahogany - light sand between

Have used fillers before on mahog, but don't like the process, and sometimes get a muddy look, so have left this out of the equation. The ebony veneer has a fairly open grain, so I may need quite a few laquer coats to fill.

USL water based topcoats are an option to save me from shop fumes.

Any suggestions would be appreciated.

[Jim Becker]

You may need to chemically darken the piece since you've already put the ebony in place.

[Mark Bellonby]

Thanks - I looked this up, and you must mean Potassium Dichromate?

This looks promising, as it seems a process to accelerate natural darkening, and might not affect the ebony if there is some bleed at the margin (the ebony is on a slightly different plane from the mahogany).

Can this stuff be sprayed?

[Conrad Fiore]

Mark,
PD is some serious stuff, make sure you follow all the precautionary measures.

potassium dichromate
Emergency Overview
DANGER! STRONG OXIDIZER. CONTACT WITH OTHER MATERIAL MAY CAUSE A FIRE. CORROSIVE. CAUSES SEVERE BURNS TO EVERY AREA OF CONTACT. HARMFUL IF SWALLOWED OR INHALED. AFFECTS THE RESPIRATORY SYSTEM, LIVER, KIDNEYS, EYES, SKIN AND BLOOD. MAY CAUSE ALLERGIC REACTION. CANCER HAZARD. CAN CAUSE CANCER. Risk of cancer depends on duration and level of exposure.

[Mark Bellonby]

Right, I realized just after posting that spraying such a chemical would be pretty stupid.

I found some web info on using P.D. on mahogany, and it might be an answer for me. But if I brush it on, there will be some bleed onto my ebony, and I don't know the effect of the chemical on ebony.

Since it reacts to the tannin, and the ebony is so dark, this might be o.k. The ebony also would be protected with a finish.

[Joe Cunningham]

NO! No spraying. This is a toxic chemical that is highly reactive, esp to the respiratory system. Read up on it before you do anything.

http://www.sciencelab.com/xMSDS-Potassium_dichromate-9927404

Personally I'd leave the mahogany alone, maybe use a varnish (like Waterlox) and call it a day.

[Prashun Patel]

If you're using ebony, why do you have to mask it? The brown dye isn't going to affect it much.

I think the simplest way to do this is with Transtint Brown Mahogany or Medium Brown dye.

Work on a test piece, but here's what I did:

Start at 2% in water. Raise/knock grain, then sponge it on. How it looks wet is how it'll look with a topcoat; it'll dry muddy; don't be alarmed. Work quickly to avoid lap marks.

Then I filled the grain with a slurry of boiled linseed oil and rottenstone. The BLO won't lift the dye, and the rottenstone is not aggressive enough to sand through. It also darkens the piece more. Pad it on in circles and wipe off the excess across the grain. Do this two or three times and let it dry for a few days. Lot of legwork, but decent results. For quicker results, you can also replace 1/2 of the BLO with spar varnish. The varnish binder, however, will require a little sanding (320-400) after drying.

I topped with alkyd varnish.

[Mark Bellonby]

I rarely use dyes or stains. Cherry looks beautiful after years of aging.

However, this african mahogany is fairly light, and I feel the piece would look better darker. And my client is to be considered.

There is quite a bit of surface area to treat.

The choice seems to be spraying a water dye after a protective finish and mask on the ebony, or brushing the P.D. wearing a space suit.

[Mark Bellonby]

Thanks, Shawn - interesting alternative. I am wary of altering the ebony - it's slip matched, and looks good as is. I don't want to hide the pattern.

I do have transtints you mentioned. I'll think on this, and do a test.

[Jim Becker]

Mark...the simple solution to the question about how things will affect your ebony is to test it off the project...which is something you should always do with any finishing regimen. I think that Shawn is spot-on, however...check it out.

[Mark Bellonby]

I appreciate all this good input.

I'll give Shawn's recipe a shot on a test piece, with both woods. Does the rottenstone impart any light color to the voids? Sounds like an oil and varnish rubbed on finish, with solids added as fillers.

I had a bad experience with wenge and a "natural" filler, which ended up a light contrast to the dark wenge.

[Prashun Patel]

I appreciate all this good input.

I'll give Shawn's recipe a shot on a test piece, with both woods. Does the rottenstone impart any light color to the voids? Sounds like an oil and varnish rubbed on finish, with solids added as fillers.

I had a bad experience with wenge and a "natural" filler, which ended up a light contrast to the dark wenge.

The rottenstone dries dark grey/black in the pores and will darken the rest of the wood a tad too. Test it first. *I* like the effect; you might not.

[Joe Cunningham]

Ah thought you had honduran mahogany, which got surprisingly dark with a coat each of waterlox sealer and high gloss. Started off a little on the pinkish side, but with the varnish, ended up that gorgeous, deep mahogany color.

I have no experience with the african variety. Different animal altogether from what I gather reading about it.

[Prashun Patel]

Yep, that's why I dyed mine. It's that dark turn-of-century Cuban mahogany that everyone's trying to copy. Truth be told, I think af mahog is a different SPECIES from what most people think of mahogany as.

[Mark Bellonby]

I would never recommend African Mahog myself; Honduran would be much better. I have had a sizable stock of African for 8 or 9 years now, and have almost run through it. Results are all good, but the wood can be difficult to work, with lots of switchback grain, and some of the boards are downright bizarre.

Locally (Northern Va.), Honduran is very expensive. My source for Mahog. plywood now carries African veneer on the plywood instead of Honduran.

Give me Cherry any day, or Walnut.

One question for Shawn - do you recommend any particular Spar Varnish for your oil/varnish finish?

Thanks for your help.

[Prashun Patel]

I used Cabots (ex McCloskey's) spar varnish!!!! I'm not an expert. I'm just relaying what worked for me. Also, I wasn't suggesting mixing rottenstone in your topcoat - only as a grain filler. The spar varnish is there to help lock it into place. You gotta sand it back, though.