Bubbles in Varnish?

[Little Rascal]

Has anyone got any tips to help avoid getting bubbles when I'm varnishing?

I'm doing hatch boards and getting toward the final coats but I can't seem to get rid of the last few tiny bubbles. I'm using International Original with about 20% thinners. (Using less thinners made it worse )

I'm sanding between coats but I would like the last coat to be bubble free.

Thanks...

 

[lw395]

Use a different brush.
Try something which is not so thick perhaps.
Keep trying, find a brush that works for you and look after it!
Try to do less brushing, too.
I'm not great with varnish, bt some of my best results have been with a brush that was supposed to be a throwaway for GRP work.
It has relatively coarse bristles, and tapers to fairly thin at the wet end.

 

[clyst]

Too hot !!

 

[lw395]

Too hot !!

Or too cold, too humid, planets not aligned etc.

 

[LittleShip]

Try using a Foam brush. The purists will tell you all about using badger hair brushes ect, I use foam brushes and throw them away.

If it is very warm then add a little Owatrol to the varnish as a retarder.

Tom

 

[oldsaltoz]

All you need is a heat gun or a decent hair dryer, give the bubbles a quick blast and your done.

Good luck and fair winds.

 

[Bobobolinsky]

Try using a Foam brush. The purists will tell you all about using badger hair brushes ect, I use foam brushes and throw them away.

If it is very warm then add a little Owatrol to the varnish as a retarder.

Tom

Spot on

Even cheap foamies are better than a brush

 

[johnalison]

Try using a Foam brush. The purists will tell you all about using badger hair brushes ect, I use foam brushes and throw them away.

If it is very warm then add a little Owatrol to the varnish as a retarder.

Tom

Second both foam brushes and Owatrol.

 

[VicS]

I dont seem to have trouble with bubbles.
I use relatively inexpensive brushes for varnish.
Dont know if there is any connection.

I use the varnish as it comes .. no thinning, no added snake oil.

 

[Amulet]

Has anyone got any tips to help avoid getting bubbles when I'm varnishing?

I'm doing hatch boards and getting toward the final coats but I can't seem to get rid of the last few tiny bubbles. I'm using International Original with about 20% thinners. (Using less thinners made it worse )

I'm sanding between coats but I would like the last coat to be bubble free.

Thanks...

If they are really TINY bubbles... then it's odds on that they are not bubbles. Most forumites who have complained of bubbles, including myself, have ended up realising that they are actually dust.

I may be wrong, but as I say, this has been the usual conclusion.

The only real reason for bubbles is outgassing, which occurs on a coat where the timber is not yet sealed and warms up while the varnish is wet. You wouldn't expect bubbles on later coats.

I cleaned up my act and my bubbles disappeared - they weren't bubbles. Best conditions for a final coat are outdoors, under cover when it's raining. The rain takes all the dust out of the air. I open the back and front garage doors during the rain and let the rain-cleaned air circulate.


Oh.. and the best tip ever on the forum for perfect varnishwork - don't look at it too closely, no-one else will.

 

[Little Rascal]

Thanks, I'll try the hot air gun trick.

They are definitely bubbles and they come from the brush (tried foam brushes years ago with paint and still got bubbles! so it must be me). There's a lot when I've been overbrushing but even when I'm careful there's still a few

 

[Amulet]

Thanks, I'll try the hot air gun trick.

They are definitely bubbles and they come from the brush (tried foam brushes years ago with paint and still got bubbles! so it must be me). There's a lot when I've been overbrushing but even when I'm careful there's still a few

Don't assume there's no dust on the brush, and if you're sanding between coats are you sure you're getting rid of all the dust? Vacuuming followed by dusting may not be enough, there are those who say you should wash it down too. For most of the varnish I use (Blakes, Epifanes and Skippers) there is an overcoat time before which no sanding is required.

I guess I must be wrong, but it really is hard to get bubbles, and in every other case of bubbles discussed in the forums (and there have been many), it has turned out to be dust.

OK - I'll stop trying to convince you now.

 

[LittleShip]

Thanks, I'll try the hot air gun trick.

They are definitely bubbles and they come from the brush (tried foam brushes years ago with paint and still got bubbles! Foam brushes are not very good with paint.so it must be me). There's a lot when I've been overbrushing but even when I'm careful there's still a few [/QUOTeE]

Never needed to try hot air gun and I have varnished in very poor conditions (cold, wet and damp conditions) but always used Owatrol.

Tom

 

[david_bagshaw]

As others have said dust is the enemy.

tak rags, varnish with minimal clothing.

dont thin, warm in a bain marie type pan.

dont over work, over brush etc

was told these tips by senior yard master some years ago.

 

[PuffTheMagicDragon]

Basic rules for varnish:

1. Stir gently, avoiding the entry of too much air into the liquid.
2. Strain the quantity that you need through old nylons (available for free from wife, partner or girlfriend) into a clean container and close the main can.
3. Let the varnish that you have poured out settle for five to ten minutes, placing it and the brush that you will use near the object that is to be varnished. This helps ensure that all three are at the same temperature. It also allows any micro bubbles to migrate to the surface and disappear.
4. First coat on bare or stripped wood is 2 parts thinner to 1 part varnish. Second coat 1 to 1 and third is 1 to 2, allowing ample time for each coat to cure.
5 Rub lightly with wet and dry paper, used wet and adding two or three drops of dishwashing liquid to a bucket of clean fresh water. Wipe dry with clean cotton cloth and then go over surface with a tack-rag.
6. Apply 5 full coats, rubbing down as above only after coat#2 and #4.
7. DO NOT overload the brush; 1/4" dip is sufficient. DO NOT overbrush. Pretend that the brush is an airplane that is landing, taxiing and taking off again.

Final tip: best brushes for ordinary brightwork are those recycled from a skip after being discarded by others. Stick them into a jar of fresh water with a handful of dishwasher powder; after a week or so they will be nice and soft, will have been tapered through previous use and any paint residue can be rinsed off.

I only use traditional Varnish. I do not use thinners to clean the brushes after use: I use diesel followed by warm soapy water and a final rinse before shaking dry. I then wrap the ferrule and the bristles tightly in three or four layers of newspaper and then fold the excess paper over backwards, holding it to the ferrule with a rubber band. This allows the bristles to dry in a chisel shape that I find gives the best results.

 

[Zagato]

Recently used Internationals Woodskin - brilliant stuff to use, slap it on, no bubbles, diificult to make drips/runs and dries well. So far holding up well Would never go back to the pains of using standard varnish!!