As per previous posts, my wife insisted on replacing our old rotten wood
vanity top with a new one which I am making out of stained white oak
with multiple clear coats of West Epoxy on top and on the edges...

The question is whether I should seal the bottom (whether with epoxy or
polyurethane). However, I wonder whether sealing the bottom would be
more of a bad thing since if water does penetrate the top then it has
nowhere to breathe out of and since the bottom side doesn't/shouldn't
get wet maybe there is no advantage to sealing it.

Any recommendations?

"blueman" wrote in message
...
As per previous posts, my wife insisted on replacing our old rotten
wood
vanity top with a new one which I am making out of stained white oak
with multiple clear coats of West Epoxy on top and on the edges...

The question is whether I should seal the bottom (whether with epoxy
or
polyurethane). However, I wonder whether sealing the bottom would be
more of a bad thing since if water does penetrate the top then it has
nowhere to breathe out of and since the bottom side doesn't/shouldn't
get wet maybe there is no advantage to sealing it.

Any recommendations?

Seal it. It's a bathroom, high humidity area and eventually, if
conditions are right, mold will form. Not a good thing.

Bob S.

Seal it. If the two sides have uneven moisture content, it will warp.
Use the same stain and epoxy coats as the top so both sides are treated
equally.

Like DJ said, seal it all over with the same number of coats to avoid
warpage. The issue is the ambient moisture much more than the spills.
It takes weeks for the moisture to enetr the inner cells of a board so
the humidity in the bathroom is the real issue. If it is moisting and
drying from one side only you will introduce stress, of expansion and
contraction thus warpage. Try laying a newly glued up panel flat on a
concrete floor and in a day or two you'll see what I mean.

White Oak won't be rotting on you any time soon. Even if there is
intrusion I wouldn't worry about it. They are still digging up old
wood boats of English White Oak and that wood is still in good shape,
a few splashes of tooth paste isn't going to hurt anything.

Also, if you have the option and like the look, go with quartersawn
and it will be even more stable and resist warpage.

Not sure about what look you are after but all Oak (I think) can
really benefit from some grain line darkening. You can do it without
all the trouble of classic grain filling which is really about
flattening any way. I stain or dye to whatever color I am after, then
do a thin wash coat of shellac, maybe a one pound cut. Then use a
super dark gel stain (I use General jet black) and rub it into the
grain then wipe it all off across the grain and all the grain lines
will now really pop. This is super dramatic with red oak but good on
white also. Gel stains have poly inthem so you can coat directly over
that with anything, or nothing. Not sure if epoxy solvents will free
the gel stain so maybe another barrier coat of thinned shellac after a
week of the oil stain drying, then epoxy.

Sorry for unsolicited finishing advice but I am doing finish
formulations and testing lately so my head is all around this stuff
right now.

On Mar 10, 8:35*pm, blueman wrote:
As per previous posts, my wife insisted on replacing our old rotten wood
vanity top with a new one which I am making out of stained white oak
with multiple clear coats of West Epoxy on top and on the edges...

The question is whether I should seal the bottom (whether with epoxy or
polyurethane). However, I wonder whether sealing the bottom would be
more of a bad thing since if water does penetrate the top then it has
nowhere to breathe out of and since the bottom side doesn't/shouldn't
get wet maybe there is no advantage to sealing it.

Any recommendations?

Good info and I certainly would seal it all around just to make sure
but....

It begs the question, why don't you seal white oak flooring and boat
decking all around?

Bob S.


"SonomaProducts.com" wrote in message
...
Like DJ said, seal it all over with the same number of coats to avoid
warpage. The issue is the ambient moisture much more than the spills.
It takes weeks for the moisture to enetr the inner cells of a board so
the humidity in the bathroom is the real issue. If it is moisting and
drying from one side only you will introduce stress, of expansion and
contraction thus warpage. Try laying a newly glued up panel flat on a
concrete floor and in a day or two you'll see what I mean.

snipe of good post.....

Dam fine question. Not really sure on that one.

My speculation: on flooring the underside is pretty concealed from the
environment, not getting any air flow for exchange of moisture in\out.
Also, I seem to recall one fo the forst steps in doing floors is to
determine the moisture content of the substrat and to apply moisture
barrier in most cases. In fact, certain floors are not supported for
us over concrete floors IIRC.

Boats, I guess they are going to get pretty saturated from the
ambient in a fairly consistent manner and kind of always stay at a
high saturation.

.... all speculation, but really just slighly more so than most of my
posts ;^)

On Mar 11, 2:05*pm, "BobS" wrote:
Good info and I certainly would seal it all around just to make sure
but....

It begs the question, why don't you seal white oak flooring and boat
decking all around?

Bob S.

"SonomaProducts.com" wrote in message

...
Like DJ said, seal it all over with the same number of coats to avoid
warpage. The issue is the ambient moisture much more than the spills.
It takes weeks for the moisture to enetr the inner cells of a board so
the humidity in the bathroom is the real issue. If it is moisting and
drying from one side only you will introduce stress, of expansion and
contraction thus warpage. Try laying a newly glued up panel flat on a
concrete floor and in a day or two you'll see what I mean.

snipe of good post.....

On Mar 11, 12:01*am, DJ Delorie wrote:
Seal it. *If the two sides have uneven moisture content, it will warp.
Use the same stain and epoxy coats as the top so both sides are treated
equally.

I'm a countertop specialist. Seal it. Seal the hole for the sink edge
as well...and the tap hole(s)

On Thu, 11 Mar 2010 14:20:07 -0800 (PST), the infamous Robatoy
scrawled the following:

On Mar 11, 12:01*am, DJ Delorie wrote:
Seal it. *If the two sides have uneven moisture content, it will warp.
Use the same stain and epoxy coats as the top so both sides are treated
equally.

I'm a countertop specialist. Seal it. Seal the hole for the sink edge
as well...and the tap hole(s)

Has Alan from Oz piped up yet? I haven't seen his post if he has.
He's had jarrah countertops for a couple decades and should have some
really good input, too. No doubt he'll confirm your advice, Toy.

--
There is no such thing as limits to growth, because there are no limits
to the human capacity for intelligence, imagination, and wonder.
--Ronald Reagan

"SonomaProducts.com" writes:
Like DJ said, seal it all over with the same number of coats to avoid
warpage. The issue is the ambient moisture much more than the spills.
It takes weeks for the moisture to enetr the inner cells of a board so
the humidity in the bathroom is the real issue. If it is moisting and
drying from one side only you will introduce stress, of expansion and
contraction thus warpage. Try laying a newly glued up panel flat on a
concrete floor and in a day or two you'll see what I mean.

White Oak won't be rotting on you any time soon. Even if there is
intrusion I wouldn't worry about it. They are still digging up old
wood boats of English White Oak and that wood is still in good shape,
a few splashes of tooth paste isn't going to hurt anything.

Also, if you have the option and like the look, go with quartersawn
and it will be even more stable and resist warpage.

Not sure about what look you are after but all Oak (I think) can
really benefit from some grain line darkening. You can do it without
all the trouble of classic grain filling which is really about
flattening any way. I stain or dye to whatever color I am after, then
do a thin wash coat of shellac, maybe a one pound cut. Then use a
super dark gel stain (I use General jet black) and rub it into the
grain then wipe it all off across the grain and all the grain lines
will now really pop. This is super dramatic with red oak but good on
white also. Gel stains have poly inthem so you can coat directly over
that with anything, or nothing. Not sure if epoxy solvents will free
the gel stain so maybe another barrier coat of thinned shellac after a
week of the oil stain drying, then epoxy.

Sorry for unsolicited finishing advice but I am doing finish
formulations and testing lately so my head is all around this stuff
right now.

OMG - no apologies - I'm the one who should be THANKING you for that
incredible lesson.

Regarding the grain, I ended up filling it with thinned down Wundefil
Wood Filler (which is recommended for that usage and surprisingly is the
only product that Rockler had for filling grain other than some
water-based clear fill). I used walnut which seemed to be the darkest
version they had in stock.

I typically (in my own amateur way) like to play around with mixing
stains and gel stains -- and have had good experience with General gel
stains. HOWEVER, in speaking with West System tech support, they
referred me to an article on "Epoxy adhesion over
stains". http://www.epoxyworks.com/21/epoxy_adhesion.html

Suprisingly (to me), the popular minwas oil stains FAILED the adhesion
test even after 4 days of drying. This (and a follow-up phone call to
tech support) has led me to be very cautious about which brand of stain
to use. Unfortunately, the list of tested stains is rather short and
doesn't include the General line. From personal experience, I have found
the General gel stains to be a bit "tacky" so I was concerned that they
too might fail the adhesion test. The West tech support guy said that
they have long used the Pratt & Lambert Tonetic line so I went off and
bought some.

Bottom line is that based on this, I am being (overly?) cautious about
what types of coating to apply under the epoxy topcoat. For the same
reason, I am staying away from shellac layers etc.

But, I plan to take note of your advice and use it in other projects
where I don't plan on clear coating with epoxy.

"SonomaProducts.com" writes:
Like DJ said, seal it all over with the same number of coats to avoid
warpage. The issue is the ambient moisture much more than the spills.

Since I am using epoxy as my topcoat which is quite impervious to water
do you think I really need the SAME number of coats on the bottom side?
I was planning on applying 4-5 coats on the top to build up a good thick
physical barrier in addition to a moisture barrier. Since the underside
only needs to protect against moisture and since epoxy is pretty
moisture impervious, can I geta away with maybe just 1-2 coats on the
bottom. Also, on the bottom, since I am not looking for a perfect smooth
finish, I could apply each coat a bit thicker to compensate.

Does this make sense?

"SonomaProducts.com" writes:
Dam fine question. Not really sure on that one.

My speculation: on flooring the underside is pretty concealed from the
environment, not getting any air flow for exchange of moisture in\out.
Also, I seem to recall one fo the forst steps in doing floors is to
determine the moisture content of the substrat and to apply moisture
barrier in most cases. In fact, certain floors are not supported for
us over concrete floors IIRC.

Well at least in the old days when the subfloor was just loosely spaced
and knotty wide planks the underside would be pretty exposed. On the
first floor, the undeside would get pretty good circulation with damp
basement air...

Boats, I guess they are going to get pretty saturated from the
ambient in a fairly consistent manner and kind of always stay at a
high saturation.

Though in the Northern climates, Boats get taken out of the water in the
winter so I would think the range in extremes from total saturation in
the summer to total dryness in the cold winter air in the winter would
be a lot more extreme than say a bathroom where the moisture level is
high but all-in-all pretty uniform over the time scale that wood
exchanges moisture with the environment.

Also, I would think that boats would be particularly susceptible to such
warping & stresses since the wood is often "bent" and applied under
stress. Plus the fitting needs to be particularly tight relative to
countertops and flooring where a little expansion/contraction/warping
may be ok.

n ... all speculation, but really just slighly more so than most of my
posts ;^)

All good and helpful speculation, but for me at least the question
remains...

On Wed, 10 Mar 2010 23:35:32 -0500, blueman wrote:

As per previous posts, my wife insisted on replacing our old rotten wood
vanity top with a new one which I am making out of stained white oak
with multiple clear coats of West Epoxy on top and on the edges...

The question is whether I should seal the bottom (whether with epoxy or
polyurethane). However, I wonder whether sealing the bottom would be
more of a bad thing since if water does penetrate the top then it has
nowhere to breathe out of and since the bottom side doesn't/shouldn't
get wet maybe there is no advantage to sealing it.

Any recommendations?


As with most wooden furniture, finish ALL sides to keep it as stable
as possible. I'm sure more are left unfinished than not, either due
to cost or laziness.

Yeah, I suppose a good coat on the bottom is all ya need.

I also agree, oil stains can be sketchy under any film finish. I think
gel stains are a lot safer because they conatin poly and will dry out
for sure, but be careful is best.

On Mar 12, 6:48*am, blueman wrote:
"SonomaProducts.com" writes:
Like DJ said, seal it all over with the same number of coats to avoid
warpage. The issue is the ambient moisture much more than the spills.

Since I am using epoxy as my topcoat which is quite impervious to water
do you think I really need the SAME number of coats on the bottom side?
I was planning on applying 4-5 coats on the top to build up a good thick
physical barrier in addition to a moisture barrier. Since the underside
only needs to protect against moisture and since epoxy is pretty
moisture impervious, can I geta away with maybe just 1-2 coats on the
bottom. Also, on the bottom, since I am not looking for a perfect smooth
finish, I could apply each coat a bit thicker to compensate.

Does this make sense?