Kevin Miller said:

Greg G. wrote:

After gluing the veneers into place, apparently some kind of chemical
reaction occurred, turning spots in the maple veneer layer a grey
color instead of the normal whitish color. The glue was Titebond II.

Kind of ruins the effect I was after...
Any suggestions?


If I were to hazard a guess I'd bet that it wasn't the glue, but sanding
it that did it. Probably some really fine walnut dust has stained the
maple. Next time use purpleheart. If it's light purple instead of grey
then you've found the culprit.

Might be a good tack rag could have helped w/that, or maybe some mineral
spirits on a cloth...

...Kevin

Hello Kevin,

Happened only to the veneers, not the remainder of the solid stock
maple or walnut. Some of the veneer was glued up into stacks before
assembling into the feature ring, as shown by this photo:

http://webpages.charter.net/videodoc...erSpots01l.jpg

The spots are clearly visible. This occurred within several hours.
It was clamped between clear kitchen plastic wrap and cawls, so no
contamination from an external component could have occurred.
No sanding contamination either. Just glue and veneer.

I am beginning to suspect a possible cross reaction between the two
species of wood used. One of them is an exotic I am otherwise
unfamiliar with. I believe it is called Makore (Pommelle).

I will have to run more tests to determine the exact cause, and what
materials are involved. I bought the veneers as an assortment of
species. I think I got about 68 sq ft for $25 on special.
Perhaps that's why it was on special... ;-)

Incidentally, I always wipe down my projects before finishing, and
again, the discoloration began before any sanding or finishing was
begun.

It's not a total loss, as it looks good enough to put popcorn in, but
the greyed maple veneer lessens the impact of the thin detail lines.

http://webpages.charter.net/videodoc...tedBowl05l.jpg

Thanks,


Greg G.