Finishing question - Ash turns grey

[DennisM]

Would appreciate help in solving a preplexing problem. Just finished turning a vessel from ash. Looked pretty good after sanding etc. I applied a coat of Deft and after it had dried I found that the end grain on the vessel in spots had turned grey/black. The ash did not show this discoloration before the finish coat was applied.

I have had similiar experiences with sycamore - another somewhat light wood - where under the finish the wood is not as atttractive because of graying.

Two part question - first is there any suggestion has to how to salvage the finished piece? Second, when finishing ash or sycamore pieces, what is an appropriate finish to keep this from occurring.

Many thanks
😕

 

[Jeff Jilg]

Dennis - can you post a pic? Just use the "manage attachments" when you post or edit.

I've processed quite a bit of ash and used both tung oil and boiled linseed oil. While those finishes darken the wood somewhat they have never created any gray spots. Will be interested to see what others think this may be.

 

[DennisM]

Pictures comming

Bit late to figure out to do it tonight. I will attempt to post a picture of the problem tomorrow morning. Keep your fingers crossed that I can get it done.

 

[drjcbarton]

If you used steel wool to prep the surface for the finish it can cause the discoloration. Outside of iron exposure I don't know what would cause this problem.

 

[DennisM]

Photos - help requested

Tried to attach the photos but am not having any luck. I go to manage attachments, select the pictures I want attached. The screen says uploading - but nothing hapens. What am I doing wrong?

Any ideas?

 

[Mark Mandell]

Tried to attach the photos but am not having any luck. I go to manage attachments, select the pictures I want attached. The screen says uploading - but nothing hapens. What am I doing wrong?

Any ideas?

Think you may have hit the rate-this-thread button instead 😀

Anyway, go to the main page and look through the How to Post pictures thread at the top of the list.

Good luck on the next try.

M

 

[Jeff Jilg]

I just made a short tip on how to add pics to text postings:
here

I also added the tip to the "How to post photos" sticky tip.

 

[MichaelMouse]

Would appreciate help in solving a preplexing problem. Just finished turning a vessel from ash. Looked pretty good after sanding etc. I applied a coat of Deft and after it had dried I found that the end grain on the vessel in spots had turned grey/black. The ash did not show this discoloration before the finish coat was applied.

I have had similiar experiences with sycamore - another somewhat light wood - where under the finish the wood is not as atttractive because of graying.

Two part question - first is there any suggestion has to how to salvage the finished piece? Second, when finishing ash or sycamore pieces, what is an appropriate finish to keep this from occurring.

😕

No picture, but are you sure you're not dealing with black mildew spots? They are one of the reasons for my extremely brief fling with Anchorseal on bowls. The black mildew would grow underneath, and If I were less than careful about turning the ends away, it would be there to surprise me afterward. Hairy mildew, the fuzzy white stuff, doesn't seem to discolor as badly. They can go fairly deep in small-pored stuff like maple, and very deep with large-pored stock. More visible on lighter woods, obviously.

If so, the answer is to turn more away, if you've got room, and find another way to control moisture loss on drying.

 

[DennisM]

Thanks for your thoughts

Wood was turned green. I don't think that it is a fungus problem. Not the steel wool issue either since I don't use steel wood in the finishing process. After a great deal of struggle, I have succeeded in getting pictures attached.
This may help you understand the problem.

One picture is of the side with the blacking. The other picture is of the opposite side of the neck.

 

[MichaelMouse]

Sure does look a lot like mildew tracks in the end grain around the neck, but the well-defined spots below are not anything I've seen.

When you said "turned green," were you implying that you might have lacquered over something not fully dry? If so, still my guess.

Steel does not corrode with MEK and toluene, so a dry piece should be no problem with steel wool, other than what always happens when the broken tiny pieces hide in end grain. Which is also what happens sometimes when using SiC to sand. You can get shadows from pieces of grit embedding.

 

[DennisM]

Yes, the finished was applied before the wood was fully dried. Your eye is good, the well defined spots are marks left when I did the final parting. The vessel popped of the lathe and got marked up a little before it hit the floor. I suspect those spots will come off when I apply a final coat of polish.

 

[Mark Mandell]

Dennis,

I tend to agree with Mr. Mouse on the grey mold cause. Same goes for the two spots; I've had those show up in maple at the finish stage. Don't think the finish or technique is the problem. You could probably get the color to "reveal" by wiping a little water or even some MS on the dry sanded wood. Since your finish is Deft, you can remove it without too much trouble if you think that's an issue. Once stripped, you can try to remove the color that remains with 2-part wood bleach, but you'll have to be careful about further sanding the wood (very lightly) after the treatment or you'll cut through the whitened fibers to the "normal" dark stuff underneath.

Caveat: No warranty as to whether the "spots" will bloom again in the future.

Good luck! 😀

PS Note to File: Putting finsh on wet wood is a no-no.

 

[DennisM]

Bleach

Sounds like it is worth the time to try a two part wood bleach. I have had this same thing happen on a number of woods. Some where dry, some a little green. Might need to bleach any "white" wood before the final finish.

Thanks for all your help.