Christ is in our Midst!

God Bless Gerry,

The next time you spray water to make the grain raise, do not spray the ends
of the wood.. Only spray the surface and look at the ends how deep the water
has penetrated the wood.. I've seen ARC absorb a light spray of water on the
surface of a piece as much as a 1/4" and that was only what I could see..
I've seen Black Walnut and Red Oak absorb a light spray of water as much as
1/8" to a 1/4" into the wood.. The more porous the wood the deeper you can
see a fine mist go into the wood. And if you can see where the moisture has
gone 1/4" into the wood, you can add another 1/16" to an 1/8" to the most
porous places on the surface you just sprayed that you can not see.. Now
after you wipe the water from the surface of the piece and apply your
varnish, that water is trapped under the surface of the wood and when it
finds a place in your finish to evaporate, and it will, the wood will shrink
under the finish causing what I call "Microcracks" to form in the finish
which will allow the wood to breath better and absorb the moisture it lost..
The process of evaporating, microcracking will continue until the
microcracks will weaken the bond between the varnish and the fibers of the
wood allowing the varnish to chip or fluff off until you have a re-finishing
job and a PO'ed customer wanting you to refinish the piece.. I have seen
this MicroCracking occur on pieces within 2 years. Which is why I always use
Paint Thinner (Mineral Spirits) to raise the grain of a piece I am getting
ready to finish.. The added oils in the mineral spirits tends to help the
finish by resisting humidity and curves the need for raising the grain with
water that is absorbed by the wood..

Please forgive me, sometimes I will comment on something assuming it is a
well known concept and feel no need to go into great detail.. I will try and
mend my ways on future comments.

God Bless,
Michael

www.cedar-art.com


"GerryG" wrote in message
...
IMO your water comments need to be qualified a bit. Nearly all wood has
some
water in it, and the amount slowly changes during the year. Finishes slow
down
but do not stop the exchange. Look at design aspects that take into
account
wood movement. Also include the common technique of spraying with water to
raise the grain before finishing. What you're describing take an awful lot
more water to cause those issues. As you mention, the wood moisture
content is
your best guide.
GerryG

On Mon, 09 Aug 2004 18:50:05 GMT, "Mike Zuchick"
wrote:


Christ is in our midst.

I think I would find a better varnish unless you may be exagerating
about
having to wait for below 65% humidity. I live in Houston TX where the
humidity is rarely below 80% and I don't have those problems. Granted
dry
time tends to be a bit longer but it certainly does not prohibit
applying
a
varnish of any kind.

The more moisture the has wood absorbed the more likely the Seal you use
will fail.. It may not fail ASAP on a piece of scrap wood, but it will
fail.

Failure is caused when the water that is placed on the wood eventually
finds
an exit. This will cause the surface of the wood where the water was
applied
to shrink whick causes tiny fractures in the Finished Surface and will
lead
to a costly re-finishing job..

I am sure you've seen these fractures on a finished surface.. The same
will
happen if you use wood with high moisture content. But eventually the
finish
will chip or floof off the surface of the wood turning your finish into
dust. This is why I suggest that if you wish to see how the wood will
appear
before you add the Finish Sealer, use Mineral Spirits.

Water does not have much effect on the finish when used on scraps and
does
not have much effect if you are using a water based varnish.

I've tried the water base Polyurethane once and was not impressed and
went
back to the Oil Base Finishs.. They last much longer.

God Bless,
Michael