reddening of mahogany when applying nitro

[Mike Horan]

Here's a problem our shop has been grappling with for years without an adequate solution:
When shooting nitro finish on bare mahogany during touch-up, it has a tendency to redden, sometimes to an almost cherry hue. Sometimes the redness is on the bare wood that is receiving the new finish, sometimes on the border between old and new finish.
I'm currently working on a 1949 D-18 neck that needed part of the heel and heelcap rebuilt. The redness is occurring at the border between old and new finish. Any thoughts would be greatly appreciated.

[Russell Vance]

When we leave our machined mahogany in the racks it goes from light golden brown to a very nice aged cherry red over time - try refinishing the timber just before you use it. And, our Brazilian mahogany does this and the same species plantation grown in the Phillipines and Fiji does likewize - I suspect its the extractives in the timber taken up from the soil type that are responsible.
But, in all my years of spraying nitro I haven't really experienced a hue change apart from the normal tendancy of lacquer to darken the bare wood.
I would also suggest that the finshed mahaogany on this 1949 instrument has faded to a golden brown from the original tobacco/mahogany stain they were finished in and in this case I would go looking for a particularly light hued piece of mahaogany or if you have some time on your hands why not bleach the finished repair piece and spray tint shader coats over a neutral base coat to match the finish. Good luck comrade. Rusty.

[Greg Mirken]

To prevent wood from darkening on a lacquer touchup, first paint the bare wood with sizing made from thinned glue- either hide or Titebond work fine. I use 1 drop of glue to about 3 drops of water. Let the glue soak in and dry; it will prevent the lacquer from soaking into the damaged wood fibers and darkening the wood. Works for spruce or cedar as well, of course.

Greg

[Donald A. Fortune]

Hi mike - Ive been involved with finishes for quite a few years in the cabinet trade and Ive always put a light coat of catilized(spell check please) laquer primer over any wood that has been re finished. Also there are tints that you can get from Stew Mac to tint the base coat -- then put on your final top coat and the rest is history.. just a sugestion to help out here.. Best to you...
Donald