I'm assuming it's a water based poly correct? If it's an oil based poly, you
should not be having this problem. If it is water based poly you're using,
it's an easy fix. Stop sanding so hard. Instead of taking the "fur" of
that's poking out the top coat of poly, you're actually removing the poly
and exposing the raw wood each time you sand. Next coat of poly raises the
grain all over again, so you sand again. Vicious circle huh?
After you apply the poly, use a sanding block on the panel surfaces and only
use "hand held" paper if you absolutely have to. Doing this allows any
pressure you're applying to be evenly distributed across the sanding block
and greatly reduces any chance of a "sand through". When you sand (between
coats), "scuff" with 220. Go over it once, maybe twice, and lightly at that.
Apply a second coat, repeat the "scuffing" process. Apply a third coat and
change your 220 paper to 320 if you choose. You can now sand a bit harder,
but be careful of "point" pressure. Apply as many coats as you want now,
using 320 paper between them. If you break through the hardened film at any
point and expose raw wood, the grain will raise again.
To answer your other question, yes, there's a sealer you can use. Zinsser
had developed a de-waxed shellac (de-waxed is vital if you plan on putting
another substance over top of it) in a can. It's brand name is "Seal Coat".
Please note that this is not the same product as "Stain Blocker" or any
other Zinsser product. This one is special as it's the only de-waxed
ready-made shellac on the market. Use it as is (you can cut it if you wish,
but it's a 2lb cut out of the can) and apply a nice even coat. Because
shellac is alcohol based it, like water will raise the grain of the wood and
cause fur. Sand it off (as described above) and carry on with poly or stain
or whatever you're using. Of course you can also roll your own shellac and
de-cant it if you wish...nothing wrong with that at all and in fact f you
want any color other than blonde, you'll have to do exactly that.
good luck
Rob
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"Evon" <[email protected]> wrote in message
news:[email protected]...
> I'm working with Red Oak. On the table tops I'm trying to get a smooth
> finish. I am applying poly U and sanding between each coat. But no matter
> how smooth I get it between coats the next coat raises the grain again. Is
> there a sealer I could use to stop this action?
>
>
There is certainly something wrong with that picture. You'd have to really
work at it to have that happen on purpose.
You do not say whether you are using water based poly or oil based but let
us assume worst case (for grain raising) situation and you are using water
based.
Even if you chose not to pre dampen, let dry, scuff off the fuzz, apply
finish and apply the poly, let it cure, then scuff off the fuzz the wood
should be more then sufficiently sealed to halt any further fuzz rising.
The only thing I can think of that would cause what you have happening is if
you were grossly over sanding the first coat.
Raising the grain is really a misnomer. The purpose of the exercise is to
lightly dampen the wood and it will swell. You let it dry and the cells
shrink back to their normal size. When they do severed strands of wood
remain proud of the surface giving the wood a fuzzy feel and appearance. You
then LIGHTLY sand or scrape off the fuzz. Sand or scrape too hard and guess
what, you sever more strands and you are right back where you started from.
In addition, if you sand to soon the more absorbent part of the wood, which
will swell more then the less absorbent, will be, when they shrink back to
size, lower then the harder less absorbent parts of the grain. You end up
with a distinct grain showing through your finish, think sand stone erosion
or drift wood, and you have to take the whole thing down again and start
over.
Now, if you are putting on a coat of poly and letting it cure fully, then,
when cured, other then the fuzz left standing at that point, there is no way
for more to raise with the second coat unless you are sanding right through
that first coat.The first coat of poly would be acting as the only sealer
you would need.
--
Mike G.
Heirloom Woods
www.heirloom-woods.net
"Evon" <[email protected]> wrote in message
news:[email protected]...
> I'm working with Red Oak. On the table tops I'm trying to get a smooth
> finish. I am applying poly U and sanding between each coat. But no matter
> how smooth I get it between coats the next coat raises the grain again. Is
> there a sealer I could use to stop this action?
>
>
If you are using a water based poly you can use a sealer first. You might
want to try clear de-waxed shellac on a scrap of oak. Let it dry and try
the water based poly. I think you will find it works.
Neither the water based poly nor the clear de-waxed shellac will yellow the
wood. Don't use orange or waxed shellac. They won't work.
Joe.....
"Evon" <[email protected]> wrote in message
news:[email protected]...
> I'm working with Red Oak. On the table tops I'm trying to get a smooth
> finish. I am applying poly U and sanding between each coat. But no matter
> how smooth I get it between coats the next coat raises the grain again. Is
> there a sealer I could use to stop this action?
>
>
In article <[email protected]>, "Evon" <[email protected]> wrote:
>I'm working with Red Oak. On the table tops I'm trying to get a smooth
>finish. I am applying poly U and sanding between each coat. But no matter
>how smooth I get it between coats the next coat raises the grain again. Is
>there a sealer I could use to stop this action?
>
Is this water-based poly, or oil-based?
--
Doug Miller (alphageek at milmac dot com)
How come we choose from just two people to run for president and 50 for Miss America?
what you need is a good pore filler. There are some water based and
solvent based. I like the stuff that I bought for floors; trowelable
Zar latex based Red Oak. I fill the pores BEFORE staining, because this
product takes the stain well so that the filled pores don't look weird.
There are lots of pore filling techniques. I suggest you Google, or
wait for more knowledgeable folks tell you how they do it. Trying to
fill oak pores with poly is a true PITA and a time waster.
I fill the pores by rubbing it on with a coarse cloth and rub off the
excess; it dries super fast. When it's truly dried ( a few hours at
most) I sand with 220. On the floor I used 80 grit. Then stain as
usual ( I use an oil based product; I'm sure you could use water based)
and apply the finish coats.
Leon will probably answer your question better than I can...
dave
Evon wrote:
> I'm working with Red Oak. On the table tops I'm trying to get a smooth
> finish. I am applying poly U and sanding between each coat. But no matter
> how smooth I get it between coats the next coat raises the grain again. Is
> there a sealer I could use to stop this action?
>
>