Dark patches in maple.

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Forum topic by madts posted 08-07-2013 07:22 PM 1232 views 0 times favorited 11 replies Add to Favorites Watch
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1855 posts in 2302 days

08-07-2013 07:22 PM

Topic tags/keywords: maple finishing

Can anyone explain why I am getting these darker sploches in the maple on this cutting board. I belt sanded and then used a ROS for the fine finish. Finished with Mineral Oil. I then get these dark sploches that do not look good.
Any good thoughts?

-- Thor and Odin are still the greatest of Gods.

11 replies so far

View Finisherman's profile


227 posts in 1812 days

#1 posted 08-07-2013 08:58 PM

First of all, maple often has a tendency towards blotchiness. This is usually more of a problem with staining, however, because the mineral oil soaks into the wood, I could see how the same issue might arise here. Is there a special reason why you’re using mineral oil as your finish in lieu of danish oil or, better yet, a wiping varnish? If this were my project, I’d wash away the mineral oil with an abrasive pad and some naphtha. Then apply a coat or two of one of the above mentioned finishes. Waterlox will provide more protection for your cutting board than will mineral oil, however, no finish is designed to stand up to repeated washings. You’ll have to renew the finish periodically.

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Rex B

320 posts in 2213 days

#2 posted 08-07-2013 09:06 PM

Finisherman, mineral oil is a petroleum by-product. It can’t go rancid.

-- Rex

View Finisherman's profile


227 posts in 1812 days

#3 posted 08-07-2013 09:13 PM

Rex: Good catch. I edited my posting accordingly. I was thinking of one of the food oils, or else not thinking at all. LOL!

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Rex B

320 posts in 2213 days

#4 posted 08-07-2013 09:16 PM

No worries, I figured you were probably thinking of vegetable oil! Madts, sorry, I’m of no help on the dark patches issue. Nice looking board though!

-- Rex

View Dallas's profile


3599 posts in 2450 days

#5 posted 08-07-2013 09:52 PM

I’ve made a few cherry/maple/Black Walnut end grain boards.
The dark could be coming from the bleed over of the darker wood, especially Black Walnut.
I’ve had it happen a lot when sanding with a power sander.

-- Improvise.... Adapt...... Overcome!

View a1Jim's profile


117060 posts in 3540 days

#6 posted 08-07-2013 10:10 PM

As it was said earlier this appears to be blotching. Mineral oil is a treatment not a finish. The subject is covered very well in this post.

-- wood crafting & woodworking classes

View billykidder's profile


3 posts in 1659 days

#7 posted 10-13-2013 06:46 PM

Hi Guys, new to this post. I am having something similar, I think. I am making a dining table out of maple and one of the planks has 2 brown patches… I haven’t put any finish on as yet, but I will be spraying on a clear polyurethane to keep it natural, how can I get rid of the patches? The other problem is there is 1 extremely light coloured plank compared to the rest of the table… sticks out like a sore thumb… Any ideas on how i can resolve these issues?

-- Measure twice, cut once :)

View tefinn's profile


1222 posts in 2400 days

#8 posted 10-13-2013 08:03 PM

Welcome to LJs billykidder! What the OP is asking about is the darkening that occurred after applying the finish. Your problem is dark patches in the wood itself. Dark patches in maple could be sapwood, minerals in the wood or just dark grain. You might be able to use a chemical wood bleach to lighten it up. This might also help to even out the color between the boards. The best thing would have been to match your boards for color and grain before glue up.

-- Tom Finnigan - Measures? We don't need no stinking measures! - Hmm, maybe thats why my project pieces don't fit.

View gfadvm's profile


14940 posts in 2653 days

#9 posted 10-14-2013 01:13 AM

Ambrosia beetles also leave dark areas in maple as well as sycamore.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View billykidder's profile


3 posts in 1659 days

#10 posted 10-14-2013 05:03 AM

Thanks gentleman for the welcome and advice. Going to try the bleaching to lighten it. If it is the Ambrosia beetle, will the bleach work on this?

-- Measure twice, cut once :)

View Woodknack's profile


11475 posts in 2343 days

#11 posted 10-14-2013 07:52 AM

Old post but I believe maple does this if the spalting fungus is present even if there is no visible spalting. Once a finish is applied, especially a petroleum based finish, it kills the fungus and it turns black/dark.

-- Rick M,

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