tiny little bubbles

[LookingForCruiser]

If I was making champagne I'd be thrilled. But I'm varnishing...

So I stir the can carefully. No bubbles at all. Dip in the foam brush and apply some varnish to the wood. Bubbles! Tiny little bubbles everywhere!

Maybe they'll disappear by morning, but I doubt it.

What'd I do wrong? Is a foam brush not the thing to use?

[Sailormann]

No.

Use a very good quality regular bristled brush - badger's hair or the equivalent will produce the best results.

Foam brushes are okay for bottom paint.

[tjmiksa]

I second that I've been doing custom stairs and trim in house for quite a while and foam brushes most always leave bubble

[sailingdog]

poor bastage... you're varnishing with a foam brush... Get a good bristle brush at least and save yourself some headaches..

[bloodhunter]

Agree with everyone that you should be using a bristle brush, preferably badger hair.
Also get a clean coffee can, punch a hole on each side near the top of the can and run a wire through the holes. After you load your brush with varnish from the can run each side of the brush gently over the wire. This will remove any bubbles you may have picked up. When you're finished varnishing for the day pour the varnish from the coffee can back into the varnish can.
Another trick, if you're doing multiple day's varnish jobs. At the end of the day load your brush with varnish then suspend it in a jar/can of water so bristles are completely covered. The next day remove the brush and paint out all the varnish on some scrap wood and you're good to go. Saves a lot of time and brush cleaner over cleaning your brush properly at the end of each day. Never tried leaving the brush in water for multiple nights before using it but as long as the brush is really loaded with varnish see no reason why it shouldn't work (within reason)

[JohnRPollard]

Okay, here I am the contrarian again, but I varnish with cheap foam brushes and achieve good results.

The trick is to use the "point and tip" method just like when applying nice finish paint.

Apply the varnish in short up and down stokes, then tip it out with long opposing strokes, from the wet edge back to the already finished area. Keep moving quickly to maintain the wet edge.

Don't try to re-use the brushes. Once you're done for the day, dispose of it properly and use a new brush for the next coat.

P.S. Another source of bubbles can be a hot surface. MAke sure you're not varnishing in direct sunlight, and it's preferable to have ambient temps falling rather than rising.

[LookingForCruiser]

The guy at West Marine said to use a foam brush... we hates the guy at West Marine...

[LookingForCruiser]

and who's the unlucky guy who has the job shaving badgers to make brushes?

[T37SOLARE]

Foam brushes all the way, but I've found some brushes are better than others, I buy them by the box from Jamestown Foam Brushes

Make sure your not applying pressure when you applying the varnish as that will create bubbles.

[LarryandSusanMacDonald]

John Pollard was spot on in every point he made.

I would add (and I've done this professionally for many years so I know whereof I speak) there are two qualities of foam brushes (that I am aware of). The cheap variety is usually black and is very coarse. It does not hold up well. The better ones are grey and are very fine textured.

You can get an equally good finish with either the better quality foam brush or a good quality badger brush. The badger brush will put down thicker coats with longer brush strokes because it holds more varnish.

However, it is time consuming to clean them. We often superficially clean them and then suspend them in thinner when we're doing a job and have to leave them overnight for several nights in a row. I've actually had mine in thinner for months at a time when we're doing a lot of varnishing - but you have to keep an eye on them and change out the thinner frequently.

BTW the bubbles will usually mostly go away when you 'tip it out'. If you're not in direct sunlight, they will all disappear. If you get 'fisheye' somebody has waxed your varnish or gotten silicon caulk on it. If that happens, remove what you've put on and thoroughly clean the surface - several times with Comet, Ajax or similar and plenty of scrubbing and water.