Full Chisel Blog

December 15, 2009

Making Varnish

Filed under: Finishing,Historical Material,Of Interest,Uncategorized — Stephen Shepherd @ 12:33 am

As my favorite commercially made marine spar varnish [McCloskey’s Man of War] has gone up in price, I will probably be making most of my own varnish.  I have made varnish before, but as of late I have been doing research on varnish for an upcoming work.  I made up a batch from an old recipe and it works great, but I forgot to take any pictures.  Well I have rectified that and here is how it is done.

I took a couple of tablespoons of copal resin and carefully cleaned out any darker pieces and placed it in a crucible and put it over the alcohol lamp to heat it up.

I then used a small wooden stick to mix it around to insure that all of the resin was heated to the point that it started melting. It begins to ‘string’ as it is cooked or fused, many resins don’t solve with oil or turpentine or alcohol until they have been melted.

The upper pile is raw copal resin and the lower pile has been run or cooked.  There is a remarkable difference between the two at this point, the raw is hard and doesn’t crush easily, the resin that has been fused is very friable.

I then put it between paper and crushed it, first with the flat of a mallet face, then I used a round carvers mallet to roll and crush it even finer.

The other ingredients are sun thickened linseed oil on the left, I carefully poured out a couple ounces and heated it up in the glass jar.  The bottle on the right is straight linseed oil and turpentine [50/50] which I will add after the thick oil after the resin and thick oil has mixed.

This is how it looks as it is heating and incorporating in the mixture.

And this is how it looks after removing from the heat.

There is a bit of undissolved resin in the bottom, most will incorporate over the next few days.  I will add more linseed oil and turpentine as needed, but will wait and see how it ages.  I of course will not wait the recommended two weeks to give it a try but it is best after that period of time.  I will decant and strain the mixture before I use it on any serious projects.

Stephen

8 Comments »

  1. Stephen, it’s great fun making your own concoctions. I’ve had good success disolving the resin in turps before adding any oil. It seems to disolve quicker and more thoroughly than with oil.

    Comment by Jack — December 15, 2009 @ 1:52 am

  2. Very cool! Where do you get the resins from? Do art stores carry these? I hate to buy premixed finishes since they typically come in containers too big for me to use up before they go bad so the idea of making my own as needed is very appealing. I like dry shellac and powdered paints for these reasons as the dry stuff lasts almost indefinitely while I almost always end up throwing at least half of the premixed stuff away. Does the copal resin have a similar shelf life in it’s dry form?

    Comment by Bob Rozaieski — December 15, 2009 @ 7:23 am

  3. Jack,

    I have made varnish without fusing the resin first but there is always sediment in the bottom that doesn’t completely incorporate. This is the traditional method of making varnish and some resins will not solve until they are cooked, especially the hard resins.

    Bob,

    The only thing available in local art stores is Dammar in dry form. I order from sources on line here is one: http://www.woodfinishingenterprises.com/index.html they have a good selection, but shop around for the best price. In dry form it has indefinite shelf life, amber and some copal is of fossil origin, so age seems to improve some things.

    Stephen

    Comment by Stephen Shepherd — December 15, 2009 @ 10:10 am

  4. Hi Stephen,

    Great post, and I like the photos. I like your simple approach.

    Have you tried http://www.kremerpigments.com/ ? Too many cool things there to try. I have crushed madder root now and will try a madder lake for varnish pigment — one of these days! 🙂

    Ken

    Comment by Ken Pollard — December 15, 2009 @ 11:45 am

  5. Ken,

    Great web site and some of their prices are competitive, I can spend some money there.

    Stephen

    Comment by Stephen Shepherd — December 16, 2009 @ 10:00 am

  6. Folks,

    Just a word of warning, do not use glass jars that are not intended to be heated. Yesterday when warming up the varnish, I left it a bit too long on the heat, when I picked it up to test the temperature by putting my hand on the bottom of the jar, it immediately fractured. The jar stayed together and I quickly poured the varnish into a clean jar. I need to get some Pyrex beakers and glass funnels and take a couple more crucibles over to the shop.

    Stephen

    Comment by Stephen Shepherd — December 16, 2009 @ 10:04 am

  7. Great Article, Stephen! I double boil jars used for canning. This has so far done the trick for me.

    Bob

    Comment by Bob Strawn — December 23, 2009 @ 4:46 pm

  8. what is the ratio for the resin and the linseed oil?
    do you have any idea

    Comment by franki — September 5, 2010 @ 7:24 pm

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