PDA

View Full Version : varnish problems


jbitzel
09-26-2004, 07:47 PM
I usually use gloss medium for varnish and today the paint peeled a little bit??? Was it because I used a bristle brush or because of the cheapness of the paint? I used generic paints that came with my sketchbox easel. :crying:

Lady Carol
09-26-2004, 10:09 PM
James,
I have no idea.

Is this the first time you varnished those paints? I suspect it is not the varnish as you have used it previously on presumably another brand of paint.

blumoon
09-26-2004, 10:23 PM
Do you happen to know what type of paints those were that came with the easel? I suspect they may have been oil based, and the gloss medium was water based. You can paint oil over acrylic, but not the other way around. Just a shot in the dark.

Richard Saylor
09-26-2004, 10:33 PM
Acrylic paint doesn't peel unless it is applied to an unsuitable ground. Gloss medium is just like acrylic paint without the pigment, so that shouldn't cause a problem. Maybe some oil or grease got on the painting surface at some stage. If it was the paints, they would have to be really bad, since it is unlikely that cheap pigments would cause peeling. :confused:

jbitzel
09-27-2004, 07:38 AM
The paint is so cheap they dont even have a name on them, they don't even have the color names on them. I am going to consider them as a last resort from now on. Heres the funny thing as far as them being oil based. They say acrylics on them but they have an odor that the liquitex paint I use do not have. In fact I have been painting at work on the weekends and my coworkers were complaining but they dry fast just like regular acrylics. But when I applied the varnish they seemed to soften and peel a little bit. I tried to rub the painting to get more off but the rest of the painting seems to be in pretty good condition. .... Thanks for the responses :wave:

mame
09-27-2004, 07:51 AM
Sounds like poster paints - because of drying time and "softening".

Futaba
09-27-2004, 09:18 AM
I wouldn't recommend using medium as a varnish, you should only be using products labelled as varnish. There are problems using a medium as a varnish; the coating will remian slightly tacky when dry and will actually attract and hold dust and it is not removable as a varnish should be.
I would also throw out paints of dubious origin. If you are spending the time trying to get a good painting, why take a chance on having it turn out poorly with low quality paint?

jbitzel
09-27-2004, 10:34 AM
What would you all suggest for a good varnish to go over medium. This way if it needs to be cleaned the varnish could be removed an reapplied?

Einion
09-27-2004, 02:55 PM
Hi James, your problem is an odd one and I'd guess it comes down to the cheap paints but I've never experienced lifting like this so I can only speculate.

I have some really cheap Hungarian acrylics too that have no colour names on them either, which I thought was unique :) Although they're pretty weak in the colour department strangely they're about the toughest acrylics I've ever used! Go figure.

As for the smell, different acrylics smell differently depending on the ingredients. Acrylic paint is a complex blend of ingredients that include anti-foaming agents, fungicide, humectant, stabiliser and matting agents, along with the pigment and acrylic polymer emulsion of course (sometimes made from more than one polymer). Sometimes you'll get a colour, like Ultramarine, that has a noticeable sulphur smell. Other colours can smell strongly of ammonia. Most acrylics are actually fairly odourless unless you put your nose right up to them, although some have a uniform brand odour that's a bit sweet.

There are a number of threads that cover varnishing issues if you want to do a quick search for them, including this one that was active only a few days ago:
http://www.wetcanvas.com/forums/showthread.php?t=218246

Einion

Richard Saylor
09-27-2004, 03:33 PM
I wouldn't recommend using medium as a varnish, you should only be using products labelled as varnish. There are problems using a medium as a varnish; the coating will remian slightly tacky when dry and will actually attract and hold dust and it is not removable as a varnish should be.
I would also throw out paints of dubious origin. If you are spending the time trying to get a good painting, why take a chance on having it turn out poorly with low quality paint?
Some special purpose mediums may do that, but ordinary mediums are essentially just acrylic polymer emulsion, and they are an excellent permanent varnish.

Richard Saylor
09-27-2004, 03:39 PM
What would you all suggest for a good varnish to go over medium. This way if it needs to be cleaned the varnish could be removed an reapplied?
I like Krylon Kamar. It can be removed with turpentine, mineral spirits, or naphtha.

eezacque
09-27-2004, 10:56 PM
Some special purpose mediums may do that, but ordinary mediums are essentially just acrylic polymer emulsion, and they are an excellent permanent varnish.

I beg to differ. The problem with acrylics is that it incorporates dust on its surface, like the dust was mixed through your paint when you applied. It's impossible to clean. The way to solve the problem is to 'seal' your painting with something different from acrylics: acrylics varnish.

eezacque
09-27-2004, 10:58 PM
I usually use gloss medium for varnish and today the paint peeled a little bit??? Was it because I used a bristle brush or because of the cheapness of the paint? I used generic paints that came with my sketchbox easel. :crying:

Maybe you over-diluted your paint with water or retarder?

Richard Saylor
09-27-2004, 11:23 PM
I beg to differ. The problem with acrylics is that it incorporates dust on its surface, like the dust was mixed through your paint when you applied. It's impossible to clean. The way to solve the problem is to 'seal' your painting with something different from acrylics: acrylics varnish.
I haven't had any problem with dust sticking to my unvarnished paintings, but I agree that it is a good idea to protect the paint film with a removable varnish.

jbitzel
09-28-2004, 07:55 AM
I beg to differ. The problem with acrylics is that it incorporates dust on its surface, like the dust was mixed through your paint when you applied. It's impossible to clean. The way to solve the problem is to 'seal' your painting with something different from acrylics: acrylics varnish.

How bad will the dust actually get? Is it worth worrying about? How many years of dust are we talking? :wave:

Richard Saylor
09-28-2004, 08:27 AM
I painted an acrylic portrait of Mother Goose for my daughter 30 years ago. It is hanging in her guest bedroom. Looks fine as far as I can tell. I'll examine it with a magnifying glass next time I visit.

jbitzel
09-28-2004, 08:29 AM
I painted an acrylic portrait of Mother Goose for my daughter 30 years ago. It is hanging in her guest bedroom. Looks fine as far as I can tell. I'll examine it with a magnifying glass next time I visit.
Maybe it has to do with the environment, if you had a wood burning stove it would probably be worst than central heat? I grew up burning wood in Indiana but now that I live in an apt. in florida I don't think I have dusted yet in the last 6 mo. :wave:

eezacque
09-28-2004, 08:30 AM
How bad will the dust actually get? Is it worth worrying about? How many years of dust are we talking? :wave:

Don't panic, as long as acrylics are kept in a relatively clean environment or framed behind glass, dust is nothing to worry about. However, I think it is fair to inform buyers of acrylics of the risk of leaving it unvarnished.

A good overview of the issue is http://www.si.edu/scmre/takingcare/acrylic_paintings.htm

jbitzel
09-28-2004, 10:29 AM
Great Link!!!

blumoon
09-28-2004, 10:46 AM
I use Golden Polymar varnish with UVLS, or Golden MSA Varnish with UVLS. Both are excellent, and removable. If you check Golden's Website (http://www.goldenpaints.com/) you will find a section on Varnish which is extensive and informative, including varnish removal. I previously did a lot of research on varnish, due to a problem I encountered some time ago. I am very happy with these varnishes. :D

piazzi
09-28-2004, 11:22 AM
How bad will the dust actually get? Is it worth worrying about? How many years of dust are we talking? :wave:

the polymer that bases acrylic paint as well as many acrylic mediums is porous plastic when dry. this is by design to allow drying of paint by evaporation (oil paint dries by oxidation -- thus the long time). So it's porous and over time small particles get in there. removable varnish like Liquitex Soluvar is not acrulic based, it does not dry porous and things cannot get in there, and your painting is protected. Some suggest one or two coats of Acrylic varnish on your paint film, and then a removable varnish on that. This will protect your painting when and if you try to remove the top layer with turpentine or such.

Hope this helped