Full Chisel Blog

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

The word ‘lintseed’ appears in the 1828 American Dictionary of the English Language by Noah Webster and gets the name from the fact that the process of making linen textiles, lint is produced.  Well I thought it was interesting.  Linseed oil as we call it today is one of the oldest finishes for furniture and other woodwork.

It is a drying oil that polymerizes on exposure to air, when properly applied to wood it will usually dry in 24 hours.  However if you put it on an expensive linen duster it can take a little longer.

I purchased this duster a couple of years ago and spent about $130.00 and had no intention of making it a slicker.  Then I got a great deal on a cotton/linen duster that looks the same but didn’t have pocket flaps.  So after much consideration I decided to make my linen duster into a linen slicker.

I weighed the duster before the process and it weighed 2 pounds.  I then put the duster in a bag and poured in a half a quart of linseed oil/ turpentine 50/50% with about a tablespoon of glycerin.  The glycerin keeps everything flexible.  I manipulated the bag until I got oil on all parts of the coat.  I took it out of the bag, re-rolled it put it back in the bag and stomped on it.  I kept this up for about an hour until all the fabric had got oil.  I weighed the slicker and it had gained a pound.

I then hung it up to dry in an airy place.  I was a bit worried that the coat might spontaneously combust and catch on fire.  If I had let it sit wadded up it certainly would have burned, but it was hanging properly and I kept an eye on things.  The first day the fumes were strong as it was the second, third…

Well it has been two weeks and I can still smell the mixture but the coat is almost dry.  It stiffened up but the glycerin keeps things flexible, so it didn’t harden up real hard.  I will give it a few more days before I wear it, but I am happy with the results.  The slicker is a bit darker than before the oil.

I also started using larger pieces of linen to apply oil to various projects.  When I am done I ‘dispose of oily rags properly’ by spreading it out flat to dry.  But instead of throwing it away I now have oil cloth, which I can use to wrap up food stuffs for reenactments, etc.

Making oil cloth has been around for centuries and used for painted floor coverings and even in lieu of window glass, oil cloth was placed in windows, kept out the cold but let in some light.  There are many other recipes for making cloth waterproof, but this is the easiest, just don’t oil anything you want to wear in the next month.

Now if I wanted something more heavy duty I would ‘tar’ up some ‘poplin’ and make tarred-poplin  or tarpaulin.

Stephen