Mahogany question

[McQualude]

I am working mahogany for the first time, beautiful wood, works nicely, I can see why it has been a preferred furniture wood for several hundred years... anyway:

Now that it is sanded (60,80,120,150,220,320), there are white marks showing up. They look vaguely like scuff marks but I cannot sand them out, nor can I feel them with my fingers, but I can see them. When I wipe the wood with mineral spirits the white 'scuffs' disappear. They are not uniform but most of them are in one board (the center board of my tabletop). Is this similiar to the rays that appear in quartersawn oak or something else? thanks,

[Frank McVey]

Hi Mac,

Some of the "mahoganies" have quite a high silica content in their pores, so its quite probable that's what is showing on the surface of your boards. You can't get rid of it by sanding, as you observe, because when you get rid of one layer, it exposes another. You'll probably find that your finish will permanently kill the whiteness (as the white spirit does while it's still wet), so experiment with a couple of offcuts.

Regards

Frank

[SteveC1280]

This is common with mahogany. Wipe with denatured alcohol and they will disapear.

Remove the 'remove' in my address to e:mail me.

[P van Rijckevorsel]

Frank McVey schreef

so it's quite probable that's what is showing on the surface of your boards. You can't get rid of it by sanding, as you observe, because when you get rid of one layer, it exposes another.

• + + Yes, except it is not silica, and it occurs only in the real thing. PvR

[McQualude]

P van Rijckevorsel spaketh...

Ok, I give up... what is it

[P van Rijckevorsel]

• + + Well, silica is sand, and I don't know any wood where it is directly visible with less than a microscope. It usually shows in the wear on tools. That answer it? PvR

[McQualude]

P van Rijckevorsel spaketh...

It clarifies your previous post.

I asked this question to quite a few other woodworkers (what were the white 'scuff' looking things in the mahogany) and a lumber dealer... no one knew, but several suspected they would only appear in quartersawn mahogany.

[P van Rijckevorsel]

visible with less than a microscope. It usually shows in the wear on tools. That answer it?

McQualude schreef

white 'scuff' looking things in the mahogany) and a lumber dealer... no one knew, but several suspected they would only appear in quartersawn mahogany. --

• + + If we are talking about the same thing it occurs in the vessels (pores), and shows on all three surfaces, but only in certain qualities of genuine mahogany.

There is all sorts of white stuff that can occur in wood. In Shorea, ao meranti, seraya, etc (aka Philippine mahogany) there is a white resin which occurs in rings parallel to the growth rings. This will show up particularly well on the flatsawn surfaces. PvR