ronwalker49 - Posted - 05/12/2013:  07:31:17

Can anyone tell me what it is like, doing a hand rubbed finish with tung-oil..?

waynejo - Posted - 05/12/2013:  08:01:12

its not bad at all. i have used it on gun stocks a lot. it puts on a good finish as far as im concerned. i havent ever used it on anything else though.

The Old Timer - Posted - 05/12/2013:  08:05:19

VERY slow process however! And what you don't use up will harden into a solid lump of "varnish" in the bottom of the bottle. A luthier recommended it to me to darken a brand new banjo rosewood fingerboard.

ACFairbanks - Posted - 05/12/2013:  08:13:33

quote:

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Originally posted by The Old Timer

 

VERY slow process however! And what you don't use up will harden into a solid lump of "varnish" in the bottom of the bottle. A luthier recommended it to me to darken a brand new banjo rosewood fingerboard.

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Howdy,

The hardening problem is caused by oxygen in the container...

One trick is to put marbles, or some such, in the container, but there is an easier approach:

Just put water in the container:

The oil will "float" on the water, and virtually all the oxygen can be eliminated by adding enough water to allow the oil to fully fill the container before it is sealed.

All the best,

A.C.

Edited by - ACFairbanks on 05/12/2013 08:14:33

Oalbrets - Posted - 05/12/2013:  08:25:50

I use roasted walnut oil on my fretboard (La Tourangelle brand) and you can get it at Safeway. I only use it a couple times a year and it works great. I use Oz Cream Polish to clean everything else..

kmwaters - Posted - 05/12/2013:  08:36:41

I was advised to dilute it with some mineral spirits so the molecules can more easily penetrate the pores.  2 parts mineral spirits one part oil.  Any thoughts on this??

OldTimeGal - Posted - 05/12/2013:  09:29:05

My personal preference on wood is sesame oil, it's not a petroleum distillate product and doesn't go rancid like other vegetable/nut oils, also great for use on wood cooking utensils.  Works nicely with rotten stone for a final polish as well.

Mumble Peg - Posted - 05/12/2013:  09:58:58

I would like to recommend Tru-Oil, by Birchwood-Casey.  Lots of posts here on BHO about it. Just put Tru-Oil in the search box.

ACFairbanks - Posted - 05/12/2013:  12:06:18

quote:

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Originally posted by OldTimeGal

 

My personal preference on wood is sesame oil, it's not a petroleum distillate product and doesn't go rancid like other vegetable/nut oils, also great for use on wood cooking utensils.  Works nicely with rotten stone for a final polish as well.

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Howdy,

Everything I've read says that sesame oil does, indeed, go rancid, though somewhat more slowly than other seed oils.

All the best,

A.C.

rgoad - Posted - 05/12/2013:  13:03:29

I have used it cut 50-50 with linseed oil on oak and got a fabulous finish, hard as nails. takes a few applications, wipe it down, let dry and sand, etc. After maybe three or four you will have a little oil on the finish and it wipes off with no trouble. Be careful, though, it is toxic because of how it it produced. Arsenic, IIRC.

Ken LeVan - Posted - 05/12/2013:  14:05:32

I've used tung oil finishes for many years, and it is a great finish (especially if you make your own mix).

I've finished floors with it, kitchen counters, and furniture - used it on historic buildings as well as new construction - I have a cherry bathroom sink counter finished with tung oil and it is as waterproof as you can get.

Recently I finished an entire post-and-beam house with it, including the timber-frame itself, all the woodwork and trim, kitchen cabinets, and concrete floors - it took many many gallons.  It works on wood as well as masonry

Because it's an oil-based finish and has the dreaded VOCs, I couldn't buy the "ready-mix" in gallons in Pennslvania.  I had to order it from Texas along with a certificate from the supplier that said it had been manufactured before the VOC laws went into effect in PA. 

After I went through 4 gallons of that expensive stuff, I learned how to make it myself, and have been doing that ever since. I keep all the ingredients on hand and mix it as I need it in glass peanut butter or salsa jars.    It's a very versatile finish (I don't use it on banjos).

All the so called tung oil finishes on the market are composed of roughly the same ingredients, the tung oil itself being the most important "magic ingredient) and it's expensive, hence it's the thing they use the least of in the "store-bought" finishes.  You're really better off making it yourself in small batches, and you can alter the mix as the coats build up.  I will never buy a quart of "tru-oil, Minwax, etc etc again.

You have to start with pure tung oil, which you can buy in gallons, even in PA: grizzly.com/products/Tung-Oil-1-gal-/H3989  You can also get it in quarts and pints at Lowes, Home Depot, etc.  It has to be "pure tung oil"

Then you need:

mineral spirits to thin it woodcraft.com/PRODUCT/2084842/...godjAgAKQ

VM&P (varnish makers and painter's) naphtha to make it dry faster  amazon.com/Klean-Strip-VM-P-Na...001G9TGQI

Boiled linseed oil if you want the finish to get darker and more amber  woodcraft.com/PRODUCT/2020148/...godLkkAgw

and a smidgeon of some gloss oil based spar varnish to provide a "monster mash" of driers - don't use polyurethane - just down-and-dirty oill based spar varnish. A quart will last for many years.

A basic formula is something like this:

1  part    tung oil

2 parts   mineral spirits

1 part    naphtha

NOTE: the ratio of tung oil to thinner is 1:3  The ratio of mineral spirits to naphtha depends on how fast you want it to dry and how deeply you want it to penetrate. Naphtha penetrates more and dries faster, so you could use 2 parts naphtha - 1 part min spirits,  3 parts naphtha, 0 parts min spirits, 3 parts min spirits, 0 parts naphtha.

1/4 - 1/2 part linseed oil (if you want the finish to be darker and more amber)

1/4 part spar varnish.

This is going to work very well, although you should always test it on a piece of wood similar to what you are finishing.

The best system is to start thin - more naphtha, maybe 4:1 for the first coat, then reduce the thinner to tung oil ratio as the coats build up - "lean to fat" - eventually you get a very nice and durable finish.

WARNING!!! Rags saturated with this finish can and do spontaneously combust  I saw this happen with a Minwax floor refinish in a historic house where the guys left the rags on the stairway - they caught fire and it wasn't a good thing to say the least.  Put your wiping rags outside - don't leave them in the shop or put them into the wastebasket. When the finish hardens, the rags are no good, anyway, so get rid of them outside.

en.wikipedia.org/wiki/Tung_oil

Ken

OldTimeGal - Posted - 05/13/2013:  03:21:04

A.C. - With most vegetable oils, I'm sure that's the case.  I'm certainly no wood finishing expert, and there are many wood experts on BHO.  A major drying oil used in wood finishing is tung oil.  While the use of sesame oil is in all probability far less common, it is used as an additive to linseed and wood oil to retard the speed of hardening, and I do really like the way it works for my purposes on black ebony and maple. Here are some references I have found regarding the use of sesame oil as a wood finish: 

"I choose sesame oil as it has the longest shelf life of all the non-drying oils and does not become rancid easily. This is due to unique antioxidants found in sesame oil and not in other vegetable oils. I don’t recommend olive oil as it spoils very quickly and you get a tacky residue building up on the utensil. A food safe drying oil such as tung oil can also be used." - Edwards Smith Fine Woodworking

"Of the pure natural oils available I have used sesame oil for almost thirty years with great success." - Scott Zimmerman, Treating Fretboards, Banjo Newsletter 2003

"Sesame oil (tul kirum). Several coats of sesame oil were rubbed into the surface of the finished object." - Techniques used by Yi carpenters in finishing wood surface, from A Note on Yi Dynasty Furnituremaking, by Edward Reynolds Wright.

"We probably have a dozen different kinds of oil at home, but the ones used most for fretboard care are: lemon and orange for cleaning, sesame and walnut for replenishing." - fretboard finish, from Ukulele Luthier's Lounge, ukuleleunderground.com/forum/a...6174.html

There is a huge volume of wood finish formulas and opinions regarding wood finishing, even regarding the use of tung oil for fishing rods (bamboorodmaking.com/html/finis..._oil.html), - where someone does mention that sesame oil can go rancid.

Here's a handy clarification on oil finishes from Woodworking Magazine: popularwoodworking.com/techniq...y-and-use, and also at Best Oil for Wood?

Old Time Gal

quote:

---

Originally posted by ACFairbanks

 

quote:

---

Originally posted by OldTimeGal

 

My personal preference on wood is sesame oil, it's not a petroleum distillate product and doesn't go rancid like other vegetable/nut oils, also great for use on wood cooking utensils.  Works nicely with rotten stone for a final polish as well.

---

Howdy,

Everything I've read says that sesame oil does, indeed, go rancid, though somewhat more slowly than other seed oils.

All the best,

A.C.

---

Old Hickory - Posted - 05/13/2013:  09:15:32

quote:

---

Originally posted by Ken LeVan

I've used tung oil finishes for many years, and it is a great finish...

A basic formula is something like this: . . . 1/4 part spar varnish.

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Everybody, pay close attention to what Ken said, and what I emphasized.  Let me point it out:  He did not say "tung oil." He said "tung oil finishes." 

There's a big difference.

Pure tung oil, most oils for that matter, when wiped on wood is never going to dry, never create or build a protective film (which is, after all, the purpose of a finish). It will remain gooey.

"Tung oil finishes" have all those things Ken listed in his recipe, perhaps most importantly driers and solids (the spar varnish that he added).  The driers do just what their name says. The solids, or resins, create the film.  Ken is getting his resins from ready-made spar varnish (which itself has oil and probably mineral spirits in it).

Tung oil finish is simply a wiping varnish.  Its oil and solvent content is so high and its solids content so low that it wipes on easily and has a long enough working time that it can be smoothed out before getting tacky.

It can look great in just a few coats.  I use just two or three coats on interior door and window casings. But because the solids content is so low, it takes many coats to build up the kind of film that many people like on a banjo.  But it can be done.  It rubs out nicely after adequate curing. If you don't have a place to spray lacquer, a wiped-on tung oil finish is a good alternative for the do it yourselfer.  See pictures of a Tru-Oil finished resonator and neck in my profile. Tru-Oil is polymerized linseed oil, not tung. But the idea is the same.

I'm just emphasizing the underlying message of Ken's post and recipe:  Plain old tung oil with nothing added to it is not something you want to be putting on a banjo if you want a good finish.