What to do about tiny traces of white lines in mahogany? - created 11-23-2009

Savage, Charles - 11/23/2009.18:14:04

I have this in some material I'm making some solid body necks out of. Being new to lutherie I was wondering if there are any remedies to clear it out or if the grain filler will help hide it. I certainly don't want to see it when I finish in cherry stain.

Schaeffer, Clay - 11/23/2009.19:50:10

Have you tried staining some scrap to see if the white lines will take the stain?

Savage, Charles - 11/24/2009.10:12:06

Not yet. Its my first time working with mahogany and I was hoping someone knew what it was and what can be done about it. It seems to be centralized in the pores of the grain. Kinda like a fungus but is solid. I tried picking at it with a pin but its following inside the tunnel of the grain. Had I known it was there, (I didn't see it until after I cut inside of it) I would have sent it back and gotten another board.

Is this sometimes typical in mahogany?

Davis, Larry - 11/24/2009.10:24:06
Gallery Hardwoods

Yes, this is typical of mahogany and other species as well. It's what creates the white layers in Wenge.

Parenchyma, a component of wood tissue is the culprit and it has several means to present itself. I have seen it more in old growth stock than new woods.

Usually this will disappear under finish, so test by wiping with Naptha...it should disappear and then reappear after the solvent evaporates. Some fillers disappear it, but I cannot speak to which ones.

Savage, Charles - 11/24/2009.10:30:50

Thanks Larry. I'll wipe on a bit of stain and see what I get. I'm going for a 59 Gibson cherry finish so hopefully it will be enough and only look slightly pinkish as a worst case scenario. Because I'll be actually using tinted lacquer on these guitars and not stain applied directly to it I'm hoping to get a similar result.

Schaeffer, Clay - 11/24/2009.10:35:39

Some of the true mahoganies from the west indies have calcium oxalate deposits in the pores. A wood dealer told me this was one way to identify what he called "Santo Domingan mahogany". Supposedly they can be dissolved with alcohol. Try it and please report back.

Savage, Charles - 11/24/2009.10:46:43

Thanks Clay, Now that you mention it, it sure did scratch like it was calcium. The pin I used crumbled the surface like powder. The seller sold it as African Mahogany and it looks like it but I'm not sure because of my lack of experience with the wood. But if alcohol dissolves it then I'm ok with it just the same.

Davis, Larry - 11/24/2009.11:12:18
Gallery Hardwoods

Some of the true mahoganies from the west indies have calcium oxalate deposits in the pores

Swietenia mahogoni?

Are there other species in the West Indies?

Schaeffer, Clay - 11/24/2009.13:55:20

Hi Larry,

Some of the true mahoganies, i.e. those from the west indies, have calcium oxalate deposits in the pores .

Perhaps other mahoganies from other areas have this same feature? I know it is a bit O.T. , but can you tell me how to distinguish one mahogany from another and possibly where it might have come from?

Davis, Larry - 11/24/2009.14:37:35
Gallery Hardwoods

ha!! If I could do that, I'd write a best seller wood book. It's difficult telling some Genus Khaya species from true mahogany in a shop setting. I once nearly shipped a Spanish Cedar body blank out as mahogany, but my gut feeling things weren't quite right won over. :)

Moore, John - 11/24/2009.14:48:46
MIMForum DXF guy

I read somewhere that the white deposits could be some kind of carbonate that would dissolve in muriatic acid. Might be worth a try to brush some on scrap wood, with gloves and ventilation and see if it goes away.

Daniels, Barry - 11/24/2009.15:21:13
MIMForum Staff

Lime, carbonate, whatever will easily dissolve in most any acid solution, even weak ones. I would try it with some dilute vinegar, and would not be surprised if it dissolves it quickly.

Savage, Charles - 11/24/2009.15:40:30

Larry, I tried the Naphtha but it didn't quite do the trick, but it did hide it for a brief moment. So then I tried Clays suggestion of alcohol and did work. At first I used it sparingly with a cotton rag and it left traces of it. Then I went over it again a bit heavier and bingo-no more white streaks!! Guess it needed to set in a bit deeper to clear it all out.

Thanks for the tips!!!

sysop - 11/24/2009.17:00:01
Deb Suran

Muriatic acid is very nasty stuff, I'd stay away from it.

Davis, Larry - 11/24/2009.17:41:33
Gallery Hardwoods

That's good news, Charles and means you are on the way to a solution. Maybe try some filler over a cleaned area to see if it stays gone?

Savage, Charles - 11/24/2009.19:55:48

Larry, I'll let you know when I get more into the finishing process at a later date. I'm not comfortable mixing this stain yet as I'm quite new to this. Deb, I have no intention of dabbling with acid either when I can use alcohol.

Clift, Tom - 11/25/2009.00:25:28
Subscriber from the Inland Empire

Muriatic acid is very nasty stuff, I'd stay away from it.

I agree. It's very useful in masonry, but I'm not sure I'd be wanting to use it with wood.

As always, use with gloves and proper breathing protection.

Johnson, Dwight - 11/29/2009.20:03:59
Sandpaper is my friend.

Ace hardware has a Muriatic acid substitute that is less nasty. It works well cleaning brick. I don't know what it would do to wood.

Douglass, Tim - 12/10/2009.23:40:30
Developing my skills at hiding mistakes.

I have no intention of dabbling with acid either when I can use alcohol.

Such a change from my teen years....

Tweedy, Chuck - 12/11/2009.00:41:47
Midnight Lutherie ... because that's when I work

Thanks Tim, it took all my will power to refrain from making a comment to that. It had to be said!