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Segmented Turning wood movement (ebony) question with pics

Joined
Mar 4, 2008
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I am on WR Woodturning forum as well as Woodnet but first time post here. I have been bitten (hard) by the segmented bug and that is pretty much all I do now. I just finished this piece and have experienced some movement between rings. The problem seems to be only with the ebony accent rings. I am getting some small movement or raises in between the ebony and the maple. The ebony was bought from Edensaw (Seattle area) about a month ago. Dry bolts with no measurable moisture and wax sealed ends. I waited at least 4 days after final glueup to turn to allow the titebond II to dry but I am still getting what seems like a small ridge or raised area at the ebony seam. This is my 3rd or 4th time using ebony and it happened on the other pieces as well. Is this normal with ebony? Did the ebony absorb moisture from the glue and it is just taking more time to dry? I sealed with sanding sealer and probably 4-5 coats of waterlox. I will have to resand and refinish to get rid of the problems.

Thanks,
Tom
 

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Good news and bad. Good is the glue has enough creep to keep the piece together without snapping itself or the thin wood. Bad news is the density of the ebony allows it to lag considerably behind the other woods in readsorption or loss of moisture, so it'll probably always be a touch off. You have done as well as you can in slowing the total effect of RH, so no resand or refinish will do better.

The danger in sanding or planing on uncured glue is that there will be a furrow, not a ridge at the junction of the two pieces. Wood that was expanded with moisture contracts and lowers below the surface because you trimmed it when it was expanded.
 
R

Ron Sardo

Guest
When I use ebony as you did, I rough turn the piece and then let it sit for a month or two until it finishes moving. Then I re-turn the piece close to finished size and let it rest a couple of days. Then I finally finish turn.

Work well for about 95% of the time
 
Joined
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Location
Joseph, Oregon
The danger in sanding or planing on uncured glue is that there will be a furrow, not a ridge at the junction of the two pieces. Wood that was expanded with moisture contracts and lowers below the surface because you trimmed it when it was expanded.

Thanks all for the replies.

Michael, I looked at the ebony with a jewelers loop and there is a furrow, not a ridge. The ebony shrank (shrunk?). I just can't leave it this way and have already started sanding the finish down to remove the furrows. Luckily, it isn't too deep and a light 320 is cleaning it up.

Ron, I hate to wait that long for a piece to dry but may have to fit more time into the finishing schedule.

Malcolm, I have only had this problem with the ebony. It is possible there is moisture in it but not enough to read on my meter. This happened with another bowl with ebony I bought from a different source. That is why I was waiting the 4 or more days to dry. I will try the titebond I to see if there is a difference. I never really thought about it but it is cheaper than the II and I really don't need the water resistant properties of the II.

Malcolm, not to suck up or anything :D but your work is an inspiration and "upper bar" for everything I make.

Tom
 
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Ron Sardo

Guest
Malcolm brings up an excellent point about the moisture content of ebony.

Most ebony that is coming into this country is green and ebony doesn't like to be kiln dried in anything over 1/2" thick.

Because ebony is so dense, a 2"x2"xWhatever section of ebony can take 5-8 years to really dry.
 
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