Matching stain for old mahogany?

[crosscuts]

The mahogany trim for a 1908 AA OTCA is dark and beautiful. Not so the very light fresh cut mahogany to replace missing seats and thwarts. Can someone suggest a stain that will bring the new wood closer to the color of the old. Thanks for any help.

R.C.

 

[Michael Grace]

Hi R.C. Great to see you here again on the forums. As for mahogany, Rob Stevens recently posted about using lye (sodium hydroxide) to darken new wood. It certainly works as you probably know if you've ever used the two-part track cleaner/bleach solutions (part 1 is a strong base like sodium hydroxide or potassium hydroxide). My experience with these makes me worry about leaving such a strong base on the wood un-neutralized. And neutralizing, which is what part 2, an acid, of the 2-part system does. Neutralizing returns the wood to a nice bright color. One possibility is the use of potassium dichromate. It makes new mahogany look spectacular - dark and rich, in my experience a beautiful match for old mahogany. Potassium dichromate is a carcinogen, however, so it must be used with care for the user and the environment. If you do use it, just make a saturated or near-saturated solution in water, which is bright orange, and simply brush it onto the wood. After about 10-30 minutes, rinse in fresh water. The color is extremely stable - I've got mahogany in boats that was treated this way 10-20 years ago and it still looks the same.

Attached here is a photo of a 1922 mahogany thwart with one coat of 1:1 thinned varnish on it to show color, along with two new replica Central American mahogany thwarts.

The second photo is of those two thwarts after applying potassium dichromate, letting it sit for 15 minutes, then rinsing with water. They are still wet in the photo.

Now that they all have been varnished (maybe 6 coats; no photo yet), the old and the new thwarts are indistinguishable.

By the way, I've never tried leaving sodium or potassium hydroxide on wood to see what happens in the long run. Does the wood degrade in any way or is it fine over time? Does the color fade or does it seem stable? Does varnishing have any effect - does varnish adhere well; does it change the color? I don't know, but perhaps Rob can chime in on this.

Hope this helps,
Michael

 

[Rob Stevens]

In my use of lye solution, I always neutralize the wood with several washes of clean water. Of course, this leads to some grain-raising, which I accept as inevitable. Light sanding smooths the surface without affecting the colour. It appears the chemical effect extends into the surface of the wood. I have only oiled the result, not yet varnished, but suspect varnish will result in the usual darkening.

 

[JClearwater]

What I did for the restoration of our Anderson canoe was use Minwax English Chestnut stain on both the old and new Mahogany. In the attached picture the deck plates, king plank and seat frames are original to the boat. The gunwale caps and side caps are new Mahogany. Came out well I think.

 

[Todd F]

Looks great!

 

[crosscuts]

Many thanks to all for suggestions for staining new mahogany. I will strip and finish the original pieces to see how they look then bring the new pieces to match.

R.C.

 

[Michael Grace]

For what it's worth, here's a photo of the three thwarts above, here after a few coats of varnish. The two new ones were treated with potassium dichromate; one is original and has nothing on it but varnish. More varnish is needed on them and the lighting is terrible, but this gives a good idea of the appearance. No disrespect to anyone else's techniques, but pigment-based stains to my eye make the wood too uniform and muddy-looking. Maybe it's just me but while I have lots of Minwax and Varathane stains, I don't prefer them for most applications and use them sparingly and judiciously.