Why am I getting dark spots when sanding teak.

[Cindy]

I am refinishing the teak on my boat. It is weathered bare wood. I cleaned it with oxalic acid and let dry thoroughly. When hand sanding a few places got noticeably darker instead of lighter and would not lighten with more sanding, in fact it seemed to get worse. I first thought I had burned the wood because it was getting hot while sanding. But I have not seen any reference to this in any article I have read. Another larger piece did the same thing when I tried to belt sand it. Does anyone know what caused this? How do I get rid of these dark places?

 

[Sean]

BLACK TEAK

Cindy, It would be my guess that there is still a little bit of moisture in the wood. It needs to dry out more before sanding. It may also be caused by using a tool that turns too many revolutions. (RPMS) You can burn the wood if it gets too hot. Hope this helps. Sean

 

[Forrest B True]

Teak discoloration

Cindy, you didn't note whether the teak you are sanding is plywood or solid wood. If you are sanding plywood you have sanded through the veneer which is almost paper thin. I have sanded solid teak many times and have never left black marks.

 

[LaDonna Bubak - Catalina Owners]

Oxalic acid

I've never used it on my teak but what neutralizer did you use? Do you just use water to rinse? Whatever you use, it may have not done the job. Maybe a little oxalic acid is still sticking to those spots. I know that with Teaka A&B you have to thoroughly rinse the A with the B or it will stay dark & keep "cleaning" (read: eating away) the wood.LaDonna