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Padauk phenomena

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Padauk phenomena

#1

Padauk phenomena

RP

I have cut, glued up, turned and finished a 10.5" diameter segmented bowl. It has 48 segments per ring. Each ring is composed of Padauk, Purpleheart, and Cherry. The different woods produce a geometric pattern on the bowl. I have finished it with thinned Fast Dry Poly. About six or seven coats. Light sanding between coats. The segments were cut on a wedgie sled, using Jerry Bennett's technique (making a straight line on one face and a squiggly line on another face). That means, every other segment's outer edge is from the opposite side of the board once a ring is made up.

On some of the Padauk segments, something is wrong. I've never seen this before. The segment appears like it has not taken a finish. On some, the adjacent Padauck segment appears that it has taken a finish and the other hasn't. I can feel the change. The problem is isolated to only one segment (it does not cross the joint line). No other wood has this problem. The affected segment feels and looks dry (no sheen) and not slick like the others. This occurs on all rings at several, various/random places on the ring. It's not end grain.

Does anybody know what is happening?

Did i describe the problem properly?

Can it be fixed?

Thanks.

RP

Re: Padauk phenomena

#2

Re: Padauk phenomena

Ed Davidson

Grain orientation? Could it be that some pieces have end-grain exposed and others do not...?

Re: Padauk phenomena

#3

Re: Padauk phenomena

Jorge

RP, I had that happened to me in a couple occasions, one was traced to CA glue the other I never knew. I am not a segment turner, but an area of a bowl finished bright with epoxy, as per directions of the person that order it. I always put my bowls in a vacuum pump, if they hold vacuum they get walnut oil finish. That bowl was a heavily patterned spalted red maple and it did not hold vacuum, so in close examination I spoted an area punky, and that got the CA glue next day I sanded the whole thing and a layer of low viscosity epoxy was applied, the whole bowl was shinny and a very dull spot where the CA glue was. The client refused to take it.

Re: Padauk phenomena

#4

It sounds to me like reaction wood

Keith Newton

In hardwood, reaction wood is called tension wood, which has a higher content of cellulose than normal. Not only will it not take a finish like the rest, this is what makes some wide boards turn into pretzels when ripped. The sooner you can recognize this and cull it from your projects the better.

Most of the time in rough lumber, a zone of reaction wood will be wooly where the saw didn't get as smooth a cut. After being surfaced, there is usually tear out, and a duller appearance, along with a color change.

Re: Padauk phenomena

#5

Re: Padauk phenomena

JOE MOHNIKE

turn the bowel upside down, and see if the image reverses, could only be grain orientation.

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