Bubbly varnish

jellyellie

jellyellie

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www.jellyellie.com
Hi all

In the process of sanding all exterior wood and varnishing it.

Just putting the 3rd coat on the door but it's going all bubbly. Tried a different paintbrush, tried varnish neat from the tin, but it's all bubbly.

Why?

Too thick? Too thin? Contaminated varnish? Dirty paintbrushes? Too cold?

There are small bits in the varnish tin which look like tiny bubbles, is this normal? Or are they bits of sawdust?

Please help...

jelly
 
The bubbles are most likely air, and can be caused by over-brushing. Might be worth a Google for tips and tricks to minimise them.

I used to get the same problem using International Original, and Schooner. Switching to a comparable Blakes product did make an improvement.
 
Last edited:
Hmm, definitely not over-brushing - bubbles appear with the first brush-on. I think bits of sawdust have got into the tin of varnish as it has been really windy lately. Have Googled and Googled.
 
Is it bubbles or dust?

There were a couple of threads about this a while ago.

Here's one: http://www.ybw.com/forums/showthread.php?t=229464

If it is dust in the tine I think you have a problem! If it is from the brush or surface make sure that you are cleaning both really well. If it is bubbles, I find this particularly bad with a wet brush (ie one that sat in white spirit from the previous day), although a decent brush and good brushing technique also help.
 
Just checked and they definitely are bubbles.

Interesting about your wet brush theory, Pye_End - the first two coats were fine as the first was with a new, dry brush, and we cleaned it and dried it before the second coat. This time it's just been sitting in cling film. So we're giving it a thorough wash, will leave it to dry and try again later.
 
Used to get bubbles in my varnish when I used Schooner but since changing to Epifanes have not had that problem or it may be that my technique has improved. Blisters that form after application are usually casued by trapped moisture or solvent that is heated to vapor by direct sunlight and exerts pressure behind the varnish film. If the blisters form during application this is caused by application onto a hot surfface or by moving the finishedpiece into direct sunlight after application.Make sure that if you are wiping down with white spirit that you give it plenty time to dry before your next coat.
 
Not clear if it's just as you are applying. Do the settle out as it hardens?
I stopped worrying about bubbles as they seem to dissipate before the varnish skins.
 
I think the bubble problem is directly related to temperature. I think when the tin is closed and you open it and dip the brush in and then apply to a surface the bubbles form on that surface for this reason.
I have found that skimming the painted surface with the tip of the brush at right angles helps to diminish them initially. Then when the varnish settles on the painted surface they disappear.
 
Filter the varnish first.
Only use the brand thinner not cheap white spirit.
Try to make sure that the temperature of the varnish and the surface you are putting it on are the same.
Clean off the surface with brand spray thinners or alcohol a bruler if you have it then tack rag it.
Buy a new Badger brush.
If it still goes wrong then buy a new tin of Epifanes.
Was silicon anywhere near this surface? If so that could be the problem.
Cheers,
Chris
 
varnish

never use varnish from a tin, always decant it into a yogut pot, that way you wont get bits in the new varnish, i found when having these problems i stood
the varnish tin in hot water to warm it thru, seemed to get a better finish this way
 
dunmor said:
never use varnish from a tin, always decant it into a yogut pot, that way you wont get bits in the new varnish, i found when having these problems i stood
the varnish tin in hot water to warm it thru, seemed to get a better finish this way
Click to expand...

And what exactically is a yogut pot ? Please elucidate. Thank you.
 
Probably similar to a yoghurt pot even...
Sometimes the air bubbles come from the pores of the wood - as xstiffer says try to have the varnish and the work at the same temperature. Thinning the varnish slightly will help the bubbles to dissipate before it skins over.
You can also filter the varnish through a pair of tights (assuming you have such things, don't wear them myself).
If it's as windy today where you are as it is here then it's not a day for varnishing!
 
I've had this experience too...a stream of bubbles forming at the tip of the brush and spreading onto whatever is being varnished. As mentioned above, I suspect it is linked to using a brush which has been stored overnight in a jar of water. I have also wondered if it resulted from not cleaning and drying a brush properly. Sometimes it can be so bad it resembles foam leaving the brush and drawing the brush across the top of the tin can leave a mass of foam in the tin. Infuriating.
My only suggestion is to try a fresh, clean brush. Clean the one you have been using, with spirits or brush cleaner, then wash it out again using washing up liquid and hot water. I was told a brush is only clean if you would drink the water running through it as you give it a final rinse!
Good luck, and persevere.
 
I second Donmor's suggestion of warming the varnish before applying to first or subsequent coats,The warmth will clear the air bubbles and 'thin' the varnish slightly giving a brushmark free finish for each coat,also helping the initial sealing/priming of bare wood,where often the bubbles are produced from the grain of the timber.
The water must not be too hot though, a meniscus will be formed when it is ready and will then disappear from the surface of the receptacle.(It helps if the wood surface is warm too).

ianat182
 
I've had this problem when epoxying wood in the heat of the day - the bubbles being caused by expanding air from the wood fibres. The solution (in my case, and maybe yours ?) is to apply the first coat in the evening, as the temperature begins to drop. The air in the wood fibres is then contracting, and the epoxy (or varnish) is actually pulled into the pores to seal them.
 
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