Varnish and air bubbles

[Bluechipster]

I need some help....on about the 8th coat of some Tasmanian oak varnishing for interior work of my Austral 24 and am being besieged by lots of air bubbles. Am using Feast and Watson Spar Varnish with Badger Hair Brush and laying on varnish as per all the instructions. I.e minimum strokes , no shaking / stirring varnish etc etc. Only thing is am varnishing in about 75 fahrenheit. Am now on my third sand back and try again !!!! Any hints very welcome. I am becoming obsessed with varnish nightmares!!

 

[snowleopard]

The best finish I have obtained on paint or varnish was with a roller. The key was that after applying it I smoothed out with a Jenny brush. Because they have no bristles they provide a smoother finish. There are two types of foam brush: the cheap ones are just a wedge of foam on a stick but the best have a central layer of flexible plastic that helps give an even stroke. For varnish work you need to use a fresh one every time but for paint you can wash and re-use a few times. The price is comparable to a cheap conventional brush but they don't shed hairs or leave brush marks and bubbles.

 

[gull1066]

Varnish

Hi,

the air bubbles you are getting are from solvent pop. This is usally from applying heavy coat or from the surface film drying to quickly. Best bet would be to varnish in a lower temperature, make sure the varnish in the tin is not sat in the sun and add a small amount of thinners or white sprit. 5% should be enough. Also try standing the tin upside down for awhile before use.

 

[xtiffer]

Do your varnishing first thing in the morning when it's cooler.
Make sure your Badger is perfectly clean ( use a brush spinner).
Only use manufacturer's thinner.
Clean surface with denatured alcohol and tack rags prior to varnish application.
Ensure varnish tenperature and surface temperature are the same.
As a pro that is what I do.
Cheers,
Chris

 

[Amulet]

I need some help....on about the 8th coat of some Tasmanian oak varnishing for interior work of my Austral 24 and am being besieged by lots of air bubbles. Am using Feast and Watson Spar Varnish with Badger Hair Brush and laying on varnish as per all the instructions. I.e minimum strokes , no shaking / stirring varnish etc etc. Only thing is am varnishing in about 75 fahrenheit. Am now on my third sand back and try again !!!! Any hints very welcome. I am becoming obsessed with varnish nightmares!!

If they are TINY air bubbles, do explore the possibility that your are fooled, and in fact it is dust.

I've been there, done that, and been convinced by the wisdom of this forum that I was misguided - it was dust, despite my protestations to the contrary.

I've also had air bubbles due to "outgassing" when varnishing on a rising temperature, but not on the 8th coat.