Thursday, February 17, 2011

Notes on oil finishes

Notes on oils

First up all Teak Oils are different. Manufacturers use names like Teak oil, Danish oil, and Tung oil however they want with no regards to the actual product or any type of standard. Know what you are using ahead of time. Read stuff from Bob Flexner on finishing before you try doing anything with oil finishes.


1st coat - Flood the piece:

The oil stays wet on the surface for about 15 minutes or so... depending on the temperature outside (if it starts to cure get it up) it was cold on this day and I think I left it wet for 20 minutes. What I try to do is watch the bubbles on Mahogany. When it stops bubbling you have enough penetration... on harder woods just wait until you are bored.

After 20 - 30 minutes:

Clean all the excess off and hang the guitar somewhere. Go in the house and eat some lunch... or build other guitars... don't start drinking yet though.

After another 30 minutes:

Clean up any places where the oil has bubbled out. Keep the guitar clean of oil bubbling from the pores for about 2 hours or until you notice that the little bit you left on the counter has started to cure.

After 24 - 48 hours:

Do a light coat of oil and wipe of the extra. It doesn't need to sit more than 5 minutes or so because at this point the piece should be sealed.


Behlen Teak oil takes a little longer to cure than Danish Oil (especially in the winter) so I wait a few days between coats (rather than the 60 minutes the can suggests). I will do another coat the next afternoon or day...and repeat the above process... then wait a few more days.

I am really not trying to build a film... you really can't do that with an oil mix. I am trying to make sure the wood is covered well.

After it stops smelling... about a week. I will take it in the house and leave it a day or two. Then when I am absolutely sure it is cured I hit it with BreeWax....

I used a relatively similar process for the 7_B with Danish oil and it still looks like the day I did it. Lets hope this one goes well.

Oil finishes offer very little protection... but with a bloodwood top the guitar really doesn't need much finish.

True Polymerized tung oil is tung oil that is cooked to accelerate the first stage (polymerization) of the two stage (polymerization and oxidation) drying process. However I wouldn't use it alone. Real tung oil takes forever to cure (I wouldn't use it straight). I have a bottle of the good stuff (pure tung oil) and use it for concocting home brews and non-guitar projects. IMHO the pure oils (tung or linseed) just don't provide enough protection.

The other problem is deciding what "Oil Finish" is best. That is a trial and error thing... so few "Tung Oil" finishes are pure tung oil. Most are varnish/tung oil/dryers mix. The two times I tried "Formby's Tung Oil Finish" one went great (Mahogany/Koa 6 string bass) and the other went south (gummy mess) really fast (a Pau Ferro stool). IMHO Tung Oil and oily woods is a risky combo that can be beautiful or ugly.

Tru-Oil is a BLO recipe finish. I believe it is Polymerized linseed oil and "Other oils" mix. I believe it contains Japan Dryer. I like it but... well I just don't know. I have used it several times and had good results. But just not what I wanted.

I am hoping that the Behlen "Teak Oil" which contains some tung oil and god knows what else produces a finish closer to what I want.

I want bare wood. Bare wood that is protected. I will find the best answer... just not sure when or how.

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