# Why did the maple end grain turn dark?



## Old54Woodworks (Jan 11, 2011)

I made a 3D cutting board a couple of weeks ago. The problem I have is some of the maple turned dark after I put the mineral oil on it. Anybody know why? The maple is not from the same board, I used cut offs from different boards. This is the cutting board http://lumberjocks.com/projects/153450. I have a couple of people that want me to make them one but I need to find why first so I can prevent it from happening again. Thanks for your help.


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## BinghamtonEd (Nov 30, 2011)

I think you answered your own question :
"I put the mineral oil on it" 
"I used cut offs from different boards"

Maple is going to darken a little bit when you oil it. The end grain is like a bunch of little straws and you filled them with oil. Using different boards, probably from different trees, too, will often yield subtle differences when finished, due to differences in grain/pores/density/etc. It could also be possible that you put some of the maple heartwood in the board. Sapwood will be whiter than heartwood.

When possible, use the same board for all pieces of the same species. Cut out and omit the heartwood (in the case of maple).


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## Earlextech (Jan 13, 2011)

End grain should always be sanded to twice the grit that the face grain was sanded to. Like Ed said "The end grain is like a bunch of little straws…" By sanding to a higher grit you can help seal off some of those open pores and prevent so much absorption, which is what makes it darker.


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## wormil (Nov 19, 2011)

You might also have walnut dust in the maple pores.


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## Dark_Lightning (Nov 20, 2009)

The end grain turns dark because the light is ducted into the fibers. I used to teach Physics, and one of the demonstrations I used was to put gravel and/or sand on a sheet of glass. When the water is poured onto the surface, it gets dark on top, because the light goes through the water like a waveguide. So, the surface gets darker, as the light goes deeper into the substrate. The light is visible on the bottom of the glass as proof that it goes through.

Sanding the end grain to a higher grit reduces the size of the light-guiding grain fibers; plugging of the fibers with sawdust also helps, but if you do a good job of wiping prior to finishing, it will eliminate that as a source.

Physics lesson for the day.


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