Sorry, I know, another dining-room-table-finishing post... My question
is how to best apply Behlen Rockhard tabletop varnish without leaving
bubbles. Background: brand new table had some very thin coat of finish
on top, over an oak veneer, which I dry-sanded with 320 grit then wiped
with a tack cloth. I bought what I thought was a nice brush (china
white bristle for stain/varnish), didn't shake the can, and brushed on
the varnish slowly, and I still got quite a few bubbles. Most of them
"settled" out and disappeared as the coat of varnish kind of spread
out/flowed on the table, but several are still there. It was fairly
humid, which I thought would be good to prolong drying time and allow
more bubbles to pop without leaving a mark. I plan to let this dry
several days, dry sand again with 320, and then add a second coat of
Rockhard. Would thinning with mineral spirits help reduce bubbles on
the next coat? If so, would 10-25% min spirits make a difference, or
should I go for 50%? Should I apply this with a rag, thinned or
unthinned?
Finally, what difference does it make to wet-sand, and does that
involve water or mineral spirits? Does wet-sanding help at all between
coats, or only at the end?
Thanks very much for your advice and opinions,
Andy
Andy,
I've not had to thin my varnish. So I don't have experience with that.
The biggest point of entry for bubbles is through the brush if you
haven't shaken the can. The angle of the brush while spreading the
varnish is probably the main reason for the bubbles. Hold at a
realatively high angle and let the varnish drain out of the brush.
Don't push down on the brush to hard. The flatter the brush on the
surface the more turbulance is created within the brush causing bubbles
within the brush and at the tip that are released onto the surface.
What happens is most people push down harder on the brush as the brush
dries out. They are trying to get the most out of the brush without
going back to the bucket or can. Avoid this habit. As the varnish runs
out while holding the brush high go right back to your container. Be
very careful not to create bubbles by pulling the brush over the edge
of the container. Instead lightly squeeze the flat brush against the
side of the container.
I think you will find fewer bubbles on the surface.
The finer grade sand papers clog easier. Especially on varnish. So
Wet-Dry Sand paper used with either water (my choice) or mineral
spirits is the best choice. The moisture help the sandpaper stay open
longer.
Good Luck in your finishing.
Roy
Really, you should not use the can anyway. It is best to pour out what
you think you might need into small paper bucket or plastic bucket (or
cup) size depends on quantity. The reason for this is that you don't
want any more then is necessary to be exposed to the air for long
periods of time.
Beside that ridge on the top of the can is to tempting to use to pull
off the material.
Roy
Another source of bubbles is varnishing in a situation where the piece gets
hotter after laying the varnish on. Air in the wood expands and makes
bubbles. This is often a problem with work that has to be done outdoors
(boats). I suppose it could happen in a shop that heats as the day
progresses. Good luck.
Dave
C & M wrote:
> Hi Roy, I hope that you don't mind an off-group query regardy your
> suggestion below. How to you proceed when you're dealing with a full c=
an?
> I have used a clean piece of wood but it dries me nuts to lose the mate=
rial
> to waste.
> TIA,
> Chiz
>=20
> "ROYNEU" <[email protected]> wrote in message
> news:[email protected]...
>=20
>>Andy,
>>
>>I've not had to thin my varnish. So I don't have experience with that.
>>The biggest point of entry for bubbles is through the brush if you
>>haven't shaken the can. The angle of the brush while spreading the
>>varnish is probably the main reason for the bubbles. Hold at a
>>realatively high angle and let the varnish drain out of the brush.
>>Don't push down on the brush to hard. The flatter the brush on the
>>surface the more turbulance is created within the brush causing bubbles=
>>within the brush and at the tip that are released onto the surface.
>>
>>What happens is most people push down harder on the brush as the brush
>>dries out. They are trying to get the most out of the brush without
>>going back to the bucket or can. Avoid this habit. As the varnish runs
>>out while holding the brush high go right back to your container. Be
>>very careful not to create bubbles by pulling the brush over the edge
>>of the container. Instead lightly squeeze the flat brush against the
>>side of the container.
>>
>>I think you will find fewer bubbles on the surface.
>>
>>The finer grade sand papers clog easier. Especially on varnish. So
>>Wet-Dry Sand paper used with either water (my choice) or mineral
>>spirits is the best choice. The moisture help the sandpaper stay open
>>longer.
>>
>>Good Luck in your finishing.
>>
>>Roy
>>
>=20
>=20
>=20
I tried his tips on the last Varnished rail I did -- worked fine -- fwiw.=
I used steel wool for the abrasive between coats -- not much in the way=20
of bubbles to knock down.
--=20
Will R.
Jewel Boxes and Wood Art
http://woodwork.pmccl.com
The power of accurate observation is commonly called cynicism by those=20
who have not got it.=94 George Bernard Shaw
Hi Roy, I hope that you don't mind an off-group query regardy your
suggestion below. How to you proceed when you're dealing with a full can?
I have used a clean piece of wood but it dries me nuts to lose the material
to waste.
TIA,
Chiz
"ROYNEU" <[email protected]> wrote in message
news:[email protected]...
> Andy,
>
> I've not had to thin my varnish. So I don't have experience with that.
> The biggest point of entry for bubbles is through the brush if you
> haven't shaken the can. The angle of the brush while spreading the
> varnish is probably the main reason for the bubbles. Hold at a
> realatively high angle and let the varnish drain out of the brush.
> Don't push down on the brush to hard. The flatter the brush on the
> surface the more turbulance is created within the brush causing bubbles
> within the brush and at the tip that are released onto the surface.
>
> What happens is most people push down harder on the brush as the brush
> dries out. They are trying to get the most out of the brush without
> going back to the bucket or can. Avoid this habit. As the varnish runs
> out while holding the brush high go right back to your container. Be
> very careful not to create bubbles by pulling the brush over the edge
> of the container. Instead lightly squeeze the flat brush against the
> side of the container.
>
> I think you will find fewer bubbles on the surface.
>
> The finer grade sand papers clog easier. Especially on varnish. So
> Wet-Dry Sand paper used with either water (my choice) or mineral
> spirits is the best choice. The moisture help the sandpaper stay open
> longer.
>
> Good Luck in your finishing.
>
> Roy
>
Well now, that didn't work out at all like I planned - Ha!! Some days I've
gotta wonder... about myself. Apologies to all.
"C & M" <[email protected]> wrote in message
news:[email protected]...
> Hi Roy, I hope that you don't mind an off-group query regardy your
> suggestion below. How to you proceed when you're dealing with a full can?
> I have used a clean piece of wood but it dries me nuts to lose the
> material
> to waste.
> TIA,
> Chiz
>
> "ROYNEU" <[email protected]> wrote in message
> news:[email protected]...
>> Andy,
>>
>> I've not had to thin my varnish. So I don't have experience with that.
>> The biggest point of entry for bubbles is through the brush if you
>> haven't shaken the can. The angle of the brush while spreading the
>> varnish is probably the main reason for the bubbles. Hold at a
>> realatively high angle and let the varnish drain out of the brush.
>> Don't push down on the brush to hard. The flatter the brush on the
>> surface the more turbulance is created within the brush causing bubbles
>> within the brush and at the tip that are released onto the surface.
>>
>> What happens is most people push down harder on the brush as the brush
>> dries out. They are trying to get the most out of the brush without
>> going back to the bucket or can. Avoid this habit. As the varnish runs
>> out while holding the brush high go right back to your container. Be
>> very careful not to create bubbles by pulling the brush over the edge
>> of the container. Instead lightly squeeze the flat brush against the
>> side of the container.
>>
>> I think you will find fewer bubbles on the surface.
>>
>> The finer grade sand papers clog easier. Especially on varnish. So
>> Wet-Dry Sand paper used with either water (my choice) or mineral
>> spirits is the best choice. The moisture help the sandpaper stay open
>> longer.
>>
>> Good Luck in your finishing.
>>
>> Roy
>>
>
>
In article <[email protected]>,
"Andy" <[email protected]> wrote:
> Would thinning with mineral spirits help reduce bubbles on
> the next coat? If so, would 10-25% min spirits make a difference, or
> should I go for 50%? Should I apply this with a rag, thinned or
> unthinned?
Thinning will probably help the situation. I don't have a can of Rock
Hard on my desk at the moment but review what the directions say about
thinning. (You don't have to use their proprietary solvent - any
petroleum solvent will work with Rock Hard. I prefer VMP Naptha as it
evaporates more quickly than spirits or turps.) If the can doesn't state
percentages I'd try a 25% and see how that goes.
I've had excellent results with using the Rock Hard, thinned, as a
wiping finish. Dampen the rag (old cotton flannel works well) with the
finish and wipe it on. Cover a decent sized section and then return and
rework it after some solvent has evaporated and the varnish is a tad
tacky but before it gets too sticky to work. Wait for a bit and then
return with a clean cloth and rewipe - similar action and process to
waxing and buffing a car. When you're finished wiping and rewiping, the
surface should feel fairly dry to the touch and not very tacky at all.
Let it sit for a day and then repeat until you have the build and gloss
you're after. You won't need to sand between apps. because there won't
be any bugs or dust in the surface to smooth out if you wiped it "dry"
before stopping the previous day's application.
Make sure you dispose of the rags appropriately - these are the ones
that self-combust and burn down the shops and houses. I like to drop
them into a can and set them ablaze since that's what those buggers want
to do anyway - and I'm a bit of a pyromaniac. Ooooo, look at those
dancing flames - they're sooo pretty.
--
Owen Lowe
The Fly-by-Night Copper Company
__________
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