spar urethane and bubbles

[Brian Runau]

Howdy.

I am getting some bubbles in a brush finish using spar urethane. I have thinned it some, ig I thin it more will this eliminate the bubbles?

Thanks

Brian

[Phil Phelps]

In my forty plus years in the display business, I've never had that problem because my dad told me never shake the can. Many know how to elimate this problem, but if I wonder if you strain it through a nylon stocking, as if you were pouring a beer down the side of a glass, if that wouldn't to the trick. Be patient, real solutions will follow.

[Jim Finn]

Apply the thined solution with a rag. Not a brush.

[Scott Holmes]

Brian,

What are you finishing and what type of wood is it?

[Brian Runau]

The wood is cherry and it is a wooden serving tray.

Thanks.

[Phil Phelps]

This might help. http://antiquerestorers.com/Articles/SAL/bubble.htm

[Rich Engelhardt]

In my forty plus years in the display business, I've never had that problem because my dad told me never shake the can. Many know how to elimate this problem,

Gary Shade.....

He used to be a painter I dealt with back in the 1970's.
He went through a lot of varnish.

He always had us put the cans on the shaker!

Claimed he *knew* how to get the bubbles out.
I asked him - no make that - I begged him to know how, but he never revealed his secret.
Since he was always busy & always buying varnish,,,,, I figured whatever he knew was working.

I do know that when I was a raw rookie - my first week on the job back in 1967, I stuck a can of satin varnish on the shaker w/out knowing any better. My boss had me mark the can and set it off to the side so it wouldn't get sold by mistake.
That was in early June and by the end of August, it still had bubbles in it.
The following June ( I worked part time in Summers), the can was gone - but - nobody remembered when it got sold.

Anyhow - next to improper mixing (shaking or too vigorous stirring) - overbrushing/improper brushing is probably the chief cause of bubbles.

Carefully remove a small amount of varnish from the original container.
Place it in a fairly large open container w/out a lip.
Using a high quailty natural bristle brush, immerse the bristles no more than 1/3 into the material.
Gently press the brush against he sade of the container to remove the excess - Never drag the bristles over the edge. That will give you brush marks and it will introduce bubbles..
Flow the material out in one long continuous stroke until it begins to "drag" ever so slightly. After some experience, you'll get to know the correcr "feel".
Go back into what you've just laid out - once - to level it.
Repeat the above steps with subsequent strokes, overlapping by 1/3 to 1/2.

If the above doesn't work for you - & * I'll be the first to admit that I don't have "the knack" for a near spray like brushed finish - then consider an alternate method such as spray or padding.

*FWIW - I'm usually Ok with a satin or semi gloss finish, as far as getting a near spray applied appearance. I'm just not able to get that result with a gloss finish.


Phil.
Good link. Pretty much says the same (& a bit more) that I did above.

I did forget one important thing, that the link touches on.
You should never apply so much pressure to the brush that the bristles deflect.
The bristles on the brush should only bend ever so slightly.

You want the tips of the bristles - the parts designed either by nature or machine - to do the work.
The sides of the bristles are just there to hold the material, not apply it.

[Brian Runau]

great advice.