Replies

1. 
   Alan | Aug 05, 2002 04:54pm | #1

   Wm,

   I don't know how much experience you have with artists' oils, so pardon me if I tell you things you already know.

   All the artists' oils I have ever used have linseed oil as a medium.  It's not unusual to add more linseed oil to thin the paint and extend the drying time.  Linseed oil was a deliberate choice because it takes so long to dry.  Painters often spend weeks or months on the same canvas.  The long drying time of linseed oil allows you several days or weeks before you can no longer move or blend the paints.  Perhaps you've discovered that you can return the next day and still be able to easily move the paint around.  IME six months would be a minimum for artists' oils to dry completely.  Keep sniffing it.  When you can no longer smell the linseed oil and the paint is hard everwhere, wait another month or two before you varnish it.

   Spar varnish would not be a good choice.  Spar varnish is much too soft for furniture or most any interior application:  when it's fully cured you can peel it up with a fingernail.  It's formulated specifically to remain soft so it can move with the seasonal movement of exterior wood.

   IMHO you'd be better served with a bar top varnish.  It is harder than ordinary varnish and is more resistant to damage and liquids.  The only drawback is that any oil varnish will have a definite amber cast to it that will change the look of the colors of your painting.  If that's not acceptable there are some polys (yuch!) that are clearer.

   The only finish I know of that isn't resistant to alcohol is shellac--for which alcohol is the solvent.  Alcohol will liquify shellac that completely dried centuries ago (not hyperbole).  But shellac does make an excellent sealer under varnish, or about anything else, so you might want to put a barrier of blonde (very clear) shellac between the oil painting and the varnish finish.  The shellac will keep the solvents in the varnish from your painting.

   Alan

1. 
   StanleyNiemiec | Aug 07, 2002 06:57am | #7

   "The only finish I know of that isn't resistant to alcohol is shellac--for which alcohol is the solvent. "

   Just to clarify your statement  --  nitrocellulose lacquers are also not resistant to alcohol.  Lacquer thinner is a mixture of various solvents which can include one or more alcohols.  While more resistant than shellac, spilled alcoholic drinks will damage a lacquer finish if left on the surface.

   And a point about varnish coatings over the artwork  --  spraying the top coat might be a good idea as thinner coats can be applied and there is little chance of dragging the painting as might happen with a brush.  An air brush might just be the perfect tool!

   Even if the paints have "dried" for an extended period of time, application of a top coat that uses solvents of the paint will soften it during application of a top coat.  If this happens, you might get some "crawling" or "alligatoring".  Thus a barrier coat as advocated by several wise individuals might be a necessity.

   There is no finish that will totally "waterproof" the surface.  All finishes are to a degree porous, some more so than others.  I would personally worry about using shellac as a barrier coat because I do not know what might happen to this layer when alcohol would penetrate the coating on top of it.  It might just go cloudy on you.

   What ever choice you make, this is one project that you should test a sample piece first just to be safe.

1. 
   Alan | Aug 08, 2002 05:38am | #8

   Niemiec1,

   Thanks for filling in the gaps in my limited knowledge.  (I did say "that I know of" and I know zilch about lacquer.  I've never used it--except from a spray can for some musical instruments I made.)  Thanks again (sincerely!).

   Shellac is perfectly safe over oil paints and under varnish (if that's what Wm. plans to use).  Oil paints have linseed oil as a medium and is most commonly thinned with turpentine--though some do use mineral spirits.  It will not react to shellac.  In addition to varnish (used only after the painting has thoroughly dried) shellac is often used as a sealer coat over oil paintings.

   Alan

2. 
   Gretchen | Aug 05, 2002 10:49pm | #2

   When your paint is dry (and it well may take a long time) I suggest you put on a layer of super blonde shellac to seal it followed by waterborne varnish to keep it crystal clear and prevent the amber color of other varnishes.    Several coats should give you ample protection.  A bar finish, in my opinion, would ruin the aesthetics of your piece that you have lovingly hand painted.  It would look like a coat of plastic had been put over it which is what it is basically.

   I won't even bother to comment on the erroneous spar varnish statement other than to say it is too amber for your application in my opinion. 

   Gretchen

   
   

   ---

   Edited 8/5/2002 3:55:56 PM ET by GRETCHEN50

3. 
   LarryPile | Aug 06, 2002 05:16am | #3

   Hi,

   I'd recommend Jeff Jewitt's website/forum.  Jeff's books, seminars and products are among the best..and I'm not affiliated in any way with him...just have learned a lot from him.

   The website is http://www.homesteadfinishing.com

   Ask him this question..it's a good one!

   lp

4. 
   Paul_Snyder | Aug 07, 2002 02:25am | #4

   Personnaly, I'd use a paint that dried in a day or two - but that's just my preference.

   Over the paint, a coat of blonde/super-blonde shellac is a good idea - it won't shift the color of the paint but will seal it so that the solvents in the following clear coats won't dissolve it.

   All good interior varnishes provide the level of protection you desire but have an amber color that you may not like over the paint. For maximum protection (alcohol, etc.) you'll want to apply 6-8 coats of the varnish and that will enhance the amber coloring.

   If you want to avoid the amber cast, use the water-base poly from Target Coatings (.com) - it's durable and as clear as glass.

   Paul

   F'burg, VA

1. 
   WilliamHF | Aug 07, 2002 03:59am | #5

   Thanks to each of you who have sent advice to me via "Knots."

   I have never painted anything before using artists' oil paints.

   The image I've painted is of a violin. The image is only 66 mm long and about 17-18 mm wide. I used only one coat of Winsor&Newton's Raw Sienna and same Co's "Lamp Black."

   I would much appreciate it if you'd tell me what brand of Superblonde or Blonde shellac I should use as a sealer.

   And I would much appreciate it if you'd NAME the brand and exactly which Varnish or Polyurethan you are suggesting I use over the shellac sealer.

   Sorry to be so dense. In this area of expertise, I'm an alien who doesn't even know where to go to register!

   Many thanks again

   William

   Florida

   I make something, sometimes twice, each year.

1. 
   Danford_C_ | Aug 07, 2002 05:46am | #6

   William,

   As Gretchen alluded to, spar varnish does have an amber tint.  That being said, I've been very pleased with the results of Epifanes and Interlux spar varnishes over the years.  When a piece calls for a varnish finish, I use their products exclusively regardless if it's a piece for indoors or out. 

   For a "traditional" spar varnish Epifanes Clear or Interlux Schooner Varnish 96.  When durability is a major concern I prefer Interlux Goldspar 95 which is a one part polyurethane varnish, it does not have that "plastic" look that your cheaper polyurethanes have.  Once cured, one can't tell one from the other.

   As I recall, you are somewhat familiar with marine spar varnishes, both are available through your chandlery.  As to the shellac, I use Behlen's flakes and would recommend that if you go that route, use their Behkol.  FWIW.

   Dano"Form and Function are One" - Frank L. Wright