Oil and Varnish

Tony · Post by **Tony** » Wed Apr 16, 2008 11:29 pm

Hey Crew,
I have a conundrum.
I'm building a teak enclosure that will contain the bulk of my new electrical system. This enclosure will sit on the port side amidships, where I currently have a long teak trim piece (~7'). I'll shorten the trim piece to fit on either side of the enclosure. I generally oil all of my teak because I like the look better and it's really not that much work, however, I'm thinking I should probably varnish the enclosure because working oil in around the panels and switches would be a real pain. My conundrum is, should I continue oiling the trim pieces and put up with the difference in finishes, or should I varnish the trim as well.

Now the question: I just (as in a couple weeks ago) oiled all the trim pieces, can I varnish over the oil or do I need to sand it completely off (ouch)?

Any of you think mixing the oil and varnish would look bad?

Post by **Tim** » Thu Apr 17, 2008 5:55 am

Mixed varnish and oil in the same environs can look good--just as bare teak and varnished wood look good next to each other. It's perfectly acceptable to have one varnished component while the remaining areas are oiled, as long as you like the contrast in color and texture.

If you don't like the idea of the contrast, then either oil the new box (how often will you really have to oil it since it's on the interior and well away from the weather), or varnish all the trim.

bcooke · Post by **bcooke** » Thu Apr 17, 2008 6:41 am

Now the question: I just (as in a couple weeks ago) oiled all the trim pieces, can I varnish over the oil or do I need to sand it completely off (ouch)?

I have a chemist friend of mine that tells me oil and varnish are really quite similar and completely compatible. They are based on the same compounds. Rest easy and put the sander down. Repeat, put the sander down...

-Britton

Tony · Post by **Tony** » Thu Apr 17, 2008 1:51 pm

put the sander down...

GLADLY!

I think I'll go ahead and oil it. If I don't like it, I'll wait until next winter and take it apart to varnish then. I'm really more interested in getting out on the water than making more work for myself...thanks for the replies, guys.

feetup · Post by **feetup** » Thu Apr 17, 2008 4:45 pm

I used to be a gunsmith, and it was very common practice to mix oils and varnishes to achieve a tough, waterproof oiled surface. On a gunstock, water proofing the wood is essential, because if the wood picks up moisture, say on a rainy day, the wood will move and throw the accuracy off. Oils by them self, with the possible exception of tung oil are quite permiable to water, which is why linseed oil in particular makes such a good base for house paint. On the other hand, varnish alone on a gunstock will not feel good, especially when wet, and most folks like the oiled look on the expensive walnut of a custom stock. The technique was to oil the wood with a linseed based oil, using the soak-wipe-dry method for a couple of coats, then mix a 30% linseed oil, 30 % tung oil, and 30% varnish mix and apply it with 600 A wet and dry paper, sanding it in well, with lots of elbow grease to drive it in deep with the heat of friction, keeping the sandpaper wet with the mixture till the surface started to thicken with the sanding residue. Then carefully wipe in the direction of the grain so as not to pull the mix out of the open grain in the wood, but leaving only a thin layer on the surface. Do this for a few coats, or 3 or 4 for beauty and finally buff it with a little wax (carnuba/beeswax mix) and it will give you such a deep lustrous finish everyone who sees it will say "Aah!!"
My point is that oil and varnish mix very well, I have even used polyurethane that way. You can also get a very oil like look by using a thinned satin varnish and apply thin coats by wiping with a pad. Add a little oil, like watco or minwax, up to 50/50 and it will wipe very well, just like oil and it will look the same but not need the regular touch ups that oil does.
Also, varnish over oil works well as long as the oil has polymerised, or dryed. If the oil has not dryed properly, covering it with varnish will seal it from the oxygen and prevent polymerization pretty much for ever, and leave you with cured varnish over a jelled oil. Bad news, it will wrinkle and damage easily. If you can scrape oil up with your thumbnail it may not be ready yet.
One final note about the waxing part, both bees wax and carnuba wax are almost impervious to UV damage but each by itself isn't quite perfect. Bees wax is too soft, carnuba, which is the exudate of a south American tree, is too brittle. Mixed, 50/50 by melting in a double boiler, with a little natural turpentine stirred in when still liquid but not too hot makes a marvelous wax for everything from boats to musical instruments to fine furniture. Very water proof, very hard, doesn't even finger print if you don't apply it too thick. The turpentine makes it easy to apply, but evaporates quickly allowing you to buff to a gloss if you like. I learned this recipie from a book on gunstock finishing that was written by a paint chemist at the close of world war II. Wonderful book, full of little gems.

Feetup

Tony · Post by **Tony** » Thu Apr 17, 2008 7:05 pm

That's fascinating, feetup, thanks.

Rachel · Post by **Rachel** » Thu Apr 17, 2008 9:16 pm

I agree, feetup. Great post!

R.

Ceasar Choppy · Post by **Ceasar Choppy** » Mon Apr 21, 2008 11:16 am

feetup wrote:The technique was to oil the wood with a linseed based oil, using the soak-wipe-dry method for a couple of coats, then mix a 30% linseed oil, 30 % tung oil, and 30% varnish mix and apply it with 600 A wet and dry paper, sanding it in well, with lots of elbow grease to drive it in deep with the heat of friction, keeping the sandpaper wet with the mixture till the surface started to thicken with the sanding residue. Then carefully wipe in the direction of the grain so as not to pull the mix out of the open grain in the wood, but leaving only a thin layer on the surface. Do this for a few coats, or 3 or 4 for beauty and finally buff it with a little wax (carnuba/beeswax mix) and it will give you such a deep lustrous finish everyone who sees it will say "Aah!!"

I wonder if this is what they mean when they call a varnish "rubbed effect"?

Great little nuggets there!

feetup · Post by **feetup** » Mon Apr 21, 2008 2:56 pm

Ceasar;

The "rubbed effect" or "hand rubbed" finish is just that. You slop your oil or oil/varnish mix on the wood and then using your palm you rub and rub and rub till it begins to heat up from the friction, then you slop some more on it and rub some more. The oil seems to dissapear and since oil is very slow to dry, and you are not spilling it it must be getting driven into the pores of the wood. It is a lot of work, but a total delight to do if the wood has any amount of figure. It is difficult to describe how pleasant it is to see an ordinary looking piece of wood come to life, and how the figure in the grain becomes three dimensional to the eye, and smooth to the hand. No other finishing method will bring out the figure as well, except perhaps french polish, which involves about the same amount of sweat, but uses shellac which is VERY unresistant to water.

Feetup

Summersdawn · Post by **Summersdawn** » Tue Apr 22, 2008 12:29 pm

I did a hand rubbed finish on a highly figured piece of mahoghany for a coffee table, and feetup is right - the effect is very three dimensional. When you walk past the table looking at it, the rippling and ribbons change from dark to light, and shimmer, like a piece of folded silk. It is very appealing, however, you must be patient to do it, and it really is only suitable for certain pieces, where the eye will catch it just right, otherwise you are spending a lot of time for something your eye really just isn't going to see.