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Discussion Starter #1
Pun very much intended. PLEASE help me figure this out! Sorry for the novel.
Ok. Yesterday I cut into a large (30") green ash log from the base of a tree felled in the fall. I cut a few inches of the end to get to clean fresh wood. Within minutes the cut surface started turning pink. I've seen this before so no big deal. After cutting some blanks I decided to turn a small hollow form from an area with some spalting.
The contrast between the plain white wood and the spalted area was what I was trying to feature. It was looking great until the white became pink! It's still interesting but not what I was going for.
I've roughed out several bowls from this tree and they didn't change color. Some of the chainsawed scraps from this piece turned color and others didn't.
I decided to experiment today so I turned a sphere from a cutoff and guess what. No change! I looked at the scraps on the floor by the bandsaw...deep pink! Same piece of wood! Shavings from the sphere...pink!
I cut a bit off this scrap piece to show the before and after. Pics were about 2 minutes apart. And look at the bottom of the HF which was the last part to be cut...it stayed white as did the spalted wood.
What's going on here?
 

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not a clue but that is purty dang cool:thumbsup:
 

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First -- great hollowform you made there :thumbsup:

If it's a chemical-thing (which I suspect it is, most likely oxidation of something in the wood juices) you might be able to change the reaction by shifting the pH of the cut surface.

Do you have time to experiment? See what happens if you cut another piece of scrap and wet one cut face with vinegar (or lemon juice) and the other with a solution of baking soda.

A third test could be to wet the surface with Hydrogen Peroxide.

I have no idea what you'll get out of this -- but if you find something that stops the reaction and can get oil/varnish/shellac on it quickly, you might be able to seal it before oxidation starts.

Personally, I like the effect ... ;)
 

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Discussion Starter #10
duncsuss said:
First -- great hollowform you made there :thumbsup:

If it's a chemical-thing (which I suspect it is, most likely oxidation of something in the wood juices) you might be able to change the reaction by shifting the pH of the cut surface.

Do you have time to experiment? See what happens if you cut another piece of scrap and wet one cut face with vinegar (or lemon juice) and the other with a solution of baking soda.

A third test could be to wet the surface with Hydrogen Peroxide.

I have no idea what you'll get out of this -- but if you find something that stops the reaction and can get oil/varnish/shellac on it quickly, you might be able to seal it before oxidation starts.

Personally, I like the effect ... ;)
Thanks, and sadly I won't be back in the shop for a week but I'm absolutely going to try that when I get going again. There is plenty of wood and since this doesn't seem to be a common issue I figure its worth spending some time on. I'm not familiar with the term "wood juice". Must be a botanical term:). But that's exactly what I think is happening. There is just some variable I am overlooking and ph is as good a place as any to start.
 

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I was thinking it was more of a moisture to metal contaact thing more than just pH. Kind of like tannins in white oak being stained by metal contact. Maybe one face (pore structure...) has a higher moisture content that can then react with the metal from the tools (microscopic level). Just a guess.
 
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