its sounds like fisheye. search the web for its causes and fixes.
heres a cut and paste from the site i have bookmarked:
25.2. I have a question referring to fisheyes on paint. What exactly causes
it? How can it be prevented?
Fish eyes are caused by contamination usually containg silicon, that screws
up the surface tension of the paint. To prevent them you need a very clean
surface and a clean air supply. As a last resort you can use some fish eye
eliminator, but use caution since it might result in loss of adhesion.
randy
"JR" <[email protected]> wrote in message
news:[email protected]...
> I've been practicing staining and clearcoating on a piece of birch before
I
> move onto my real piece. The problem is that everytime I add clearcoat, I
> get little rings in the surface as it dries. It looks similar to craters
> on the moon. Does anyone know what causes this?
>
> Thanks!
JR wrote:
> I've been practicing staining and clearcoating on a piece of birch
> before I move onto my real piece. The problem is that everytime I
> add clearcoat, I get little rings in the surface as it dries. It
> looks similar to craters on the moon. Does anyone know what causes
> this?
>
> Thanks!
I'm assuming you're spraying this? The other posts that suggest fisheye are
good advice, based on what you've told us. In addition, if your compressor
has not been drained, then make sure to drain it before spraying. Even
water will cause fisheye. Drain your compressor, and make sure you have a
water trap installed. I drain my compressor before every spray job, and at
convenient points throughout a spray job as the situation allows. I also
have a water trap in the line as well as one on my gun. I use those orange
bulb type traps that you can find at any automotive paint store, or even
NAPA on the gun. Those do the best at grabbing the smallest amounts of
water - but you've got to get the tidal wave out of the compressor first. I
keep one of those orange traps on each gun at all times and I've painted
several cars with the one that's on my finish gun now - they last a long
time.
--
-Mike-
[email protected]
Fish eye. Caused by any of several types of contamination on the surface of
the wood that changes the surface tension of the finish over the area
causing the finish to flow away from the contamination. Silicon is a primary
candidate because once something is contaminated with it it's a bitch to
remove.
Commercial fish eye eliminator will correct the problem but you have to be
cautious with it since. It's usually a silicon and if you get it on anything
else, including tools or applicators, that will, in turn, become
contaminated and you enter a vicious circle.
Best bet is to seal it off from any subsequent layers is one or several thin
and lightly applied coats of finish. Dewaxed shellac will work also. Saw an
article on a couple of methods for doing so but can't pin it down right now.
--
Mike G.
[email protected]
Heirloom Woods
www.heirloom-woods.net
"JR" <[email protected]> wrote in message
news:[email protected]...
> I've been practicing staining and clearcoating on a piece of birch before
I
> move onto my real piece. The problem is that everytime I add clearcoat, I
> get little rings in the surface as it dries. It looks similar to craters
> on the moon. Does anyone know what causes this?
>
> Thanks!
Aha, thanks! I'm working with birch vaneer and I accidentally sanded
through the vaneer in a couple of places. I'm betting the glue underneath
is what's causing this problem.
"xrongor" <[email protected]> wrote in
news:[email protected]:
> its sounds like fisheye. search the web for its causes and fixes.
> heres a cut and paste from the site i have bookmarked:
>
> 25.2. I have a question referring to fisheyes on paint. What exactly
> causes it? How can it be prevented?
> Fish eyes are caused by contamination usually containg silicon, that
> screws up the surface tension of the paint. To prevent them you need a
> very clean surface and a clean air supply. As a last resort you can
> use some fish eye eliminator, but use caution since it might result in
> loss of adhesion.
>