Jamestown's home made varnish - Any worries? - UV?

[philcostello]

Hi all,

Jamestown has a home made recipe for Varnish, 1 Lind-seed oil, 1 Turpentine, 1/2 pine tar, 1/2 Japan drier.

Has anyone used this ?

Is UV a Worry ?

How does it work ?

[J.Madison]

Thats not varnish- Its boat soup. It'll turn black in the sun and takes a while to dry. I like it but many do not. It certainly isn't yacht quality stuff, but it is easy.

[BrianY]

Something I've wondered about for a while:

If you replaced the Linseed oil with Tung oil in this recipe, would it:

a) Be as effective?

b) Still turn black?

[David G]

http://forum.woodenboat.com/showthre...8972-Boat-Soup

[Bob Cleek]

Yep, it's the tung oil, rather than pine tar, that makes it varnish. Any of these basic recipes will produce as good a coating as they did 100 years ago. Problem is, there's a lot of other things that go into coatings, varnish included, that make modern varnish much better than they were 100 years ago (which is why varnish wasn't used much on anything but indoor furniture and interiors back then.) The key ingredient is the "ultraviolet inhibitor." These are additives that give the coating the ability to reflect the UV rays away from the varnish. There are many such additives. All are expensive. That's why good marine varnish costs more than tung oil, turpentine and Japan drier alone. Without effective UV inhibitors, no varnish will last more than a hot minute exposed to the sunlight.

[purri]

Raw Linseed Oil turns black because of the "neats" (fat content). The so called "boiled" variety has these components removed however the finish remains but a semi permeable barrier. There are quite a number of antique manuals on the subject but suffice to say modern finishes are much better but beware the VOC finishes incl those containing isocynates!

[philcostello]

Thanks everyone for the feedback.

I am curious then what would you recommend in terms of mixture for oiling the floor boards of the boat?

[lesharo]

Where's the resin?

I thought there were Egyptian caskets with varnish still intact.

Do these magical uv inhibiters actually exist or are they some form of sales hype? Are they "new and improved"? Varnish holds up outside for a very short time anyway with these uv inhibiters, so how short would be its longevity without them? A couple months? The only varnish that I know of that really does lasts is the two part urethane.