Boiled Linseed or Tung Oil?

[DavidF]

And if Howard says it's so, then I believe him - he's the go to guy for finish info for sure.

[AndyBarnhart]

Originally Posted by DavidF

And if Howard says it's so, then I believe him - he's the go to guy for finish info for sure.

In this case, it just doesn't jive with the experiences and science of museums like this:

http://cameo.mfa.org/browse/record.asp?subkey=9527

or with my personal experience. There are better finishes, but I have not had it fail to provide decent protection when I have used it. Water will still bead on a surface that has been dry for years. I don't have adequate ventilation and can't use much else and for some historic stuff, anything other than an oil finish isn't accurate.

[DavidF]

I must admit that a piece of wood saturated with oil should be fairly waterproof shouldn't it. Maybe it's the degree of surface protection versus other film finishes? I'll be interested to know.

Have to say that link says "tough and waterproof"

[Gofor]

If you don't want fumes on the interior, rattle-can lacquer has served me well. give it a day to cure. Finish the outside with what ever you desire. There is nothing that says you must finish interior and exterior with the same finish.

Go

[AndyBarnhart]

Yes, it does. Sorry if I seem to take this argument a little personally, but even though I have only sold a handful of instruments over the last few years, the majority were oil finished. That will continue to be the case in the future and when I get my site out of the "construction phase" as I start doing more instruments, I will have a page with much the same information as the info in the link (from the Museum of Fine Art in Boston) or from the Waterlux site or other sources. I do agree there are modern finishes that are shinier, more durable and easier to apply. But when Howard says:

But to restate and clear up a couple of points, neither pure, 100% tung oil or boiled linseed oil is a good stand alone finish. Both are best considered colorants used to "pop" the grain in the wood. Neither provide protection or durability unless overcoated with a film finish.

I won't sit by quietly. It is his opinion, not factual information and I frankly don't see anything to back up that opinion. I consider it a good durable finish and have direct experience that I base that opinion on. I will continue using and continue telling people I apply a good finish to my instruments.

[AndyBarnhart]

This is what I use:



IMO, it is labeled accurately. I even use this stuff on the grab rails of my sail boat, which I sail in salt water and store outdoors.

[AndyBarnhart]

My last post debating the quality of tung oil; I won't beat the horse any further, but I found the data Howard refers to and I am providing a link and my opinion of why it fared poorly when applied improperly.

Originally Posted by Howard Acheson

My data comes from the US Forest Service Wood Products Lab Wood Handbook which classifies pure tung oil and linseed oil as providing no water or water vapor resistance. While pure tung oil is slightly more water resistant than linseed oil, neither have any real protective qualities.

That information is available online:
http://www.fpl.fs.fed.us/documnts/fp...tr113/ch15.pdf
The chart is on page 12. Tung oil didn't fare well in their test, but I am not surprised when you look closely. They tested 1, 2 and 3 coats and then checked them after 1 day, 7 days and 14 days. I am inferring that they put all 3 coats on the same day, but I could be wrong. I use more like 6 or 8 and don't apply them all in one day. My boat's brightwork has more like 10 or 12 and will get another coat or two in the spring. If you look at any datasheet on applying tung oil, like this one:
http://www.thewoodworks.com.au/site/...s/tungoil.html
you will find instructions like this:

Apply an initial wash coat, wipe off after a few minutes when the oil begins to tack and complete the process over several days with several light coats.

So the value of a test using 3 coats in one day is questionable at best, IMO. I don't know why they didn't follow the instructions; they did up to 6 coats for several other finishes.

A counterpoint from another recognizable name:

Pure Tung Oil provides a hard and tough surface finish that is absolutely waterproof; impervious to dust, alcohol, acetone, fruit and vegetable acids; and it doesn't darken with age like Linseed and other vegetable oils. - Russ Fairfield

http://www.woodcentral.com/russ/finish6.shtml

Tung oil is absolutely a pain to use if you are in a hurry and you won't get high gloss that will stay glossy. But saying it isn't a good finish and isn't water repellent is categorically incorrect, IMO.

OK, I'm done; we will now resume our regular programming...

[DavidF]

That's is all good information And would seem to confirm your opinion. I guess the old adage of "Once a day for a week, once a week for a month and once a year for life" has the truth in it. There is a furniture maker in England, Alan Peters, reputed to be the best in the country, and he swears by this method.

On a personal project note; I am undecided whether to go with this type of finish on a new dining table and live with the inevitable salt induced scratches, or go with a rock hard film finish sprayed on, with the accompanying risk of not such a perfect finish if I get the spraying even slightly wrong...... a constant dilemma

[AndyBarnhart]

Originally Posted by DavidF

That's is all good information And would seem to confirm your opinion. I guess the old adage of "Once a day for a week, once a week for a month and once a year for life" has the truth in it. There is a furniture maker in England, Alan Peters, reputed to be the best in the country, and he swears by this method.

On a personal project note; I am undecided whether to go with this type of finish on a new dining table and live with the inevitable salt induced scratches, or go with a rock hard film finish sprayed on, with the accompanying risk of not such a perfect finish if I get the spraying even slightly wrong...... a constant dilemma

When I said I was done, I meant with the debate. I will offer my possibly surprising opinion on your question. As a consumer, I would prefer the rock hard film finish on a dining table.

[Howard Acheson]

I'm not sure what you mean by "accurately". That product is a pure tung oil.

However, the marketing statements at the bottom are just puffery, not based on fact. Here's a test you can do. Apply a coat of your tung oil to a raw wood board. Wipe off the excess. Let it dry for a week and then apply it and wipe it again. Now let it dry for two weeks and then put a couple of drops of water on the surface. See if it is absorbed.

[merrill77]

Originally Posted by DavidF

On a personal project note; I am undecided whether to go with this type of finish on a new dining table and live with the inevitable salt induced scratches, or go with a rock hard film finish sprayed on, with the accompanying risk of not such a perfect finish if I get the spraying even slightly wrong...... a constant dilemma

I will assume that as a "dining room" table, this would be considered a piece of "fine" furniture that you've put a lot of work into. If this is something with _really_ nice grain that you really want to show off, you should consider Lacquer. It's not as tough as varnish, but better than everything else - most dining room tables don't see heavy use. Note that it is a much more repairable finish than varnish, as well. But IMO, the real value on a piece of very fine furniture is the clarity and non-yellowing properties. For these two properties, lacquer cannot be beat. You can build it to whatever thickness you desire and it polishes very nicely. If I was worried about my spray abilities, then I would either brush or practice spraying until I was confident it would be done right. If this isn't some throw-away piece of furniture - an heirloom - then it's worth it, IMO. :>

[merrill77]

Originally Posted by AndyBarnhart

In this case, it just doesn't jive with the experiences and science of museums like this

But Howard is in perfect agreement with the god of wood finishing knowledge - Bob Flexner. EVERY woodworker should have a copy of Flexner's book on their shelf. Read it. Learn it. Live it.

Seriously - Flexner is one of the most respected authorities on wood finishing in the industry. His book is fantastic. If you have any questions about any type of finish - that is the first place to look.

Here's what he has to say about pure Tung Oil:

"Tung oil can be made fairly water-resistant after five or six coats. But it is too soft and thin to resist scratching or water-vapor exchange, and is difficult to make the finish look nice. The first three or four topcoats appear flat and splotchy on the wood and feel rough to the touch. Only after five or six coats, sanding between each coat, can you get an even, satin sheen." <snip> "you need to wait several days between coats". "About the only advantage tung oil has over linseed oil, other than better water resistance after five or six coats, is that tung oil yellows less than linseed oil. This can be important on blond woods that you don't want to darken too much."

Note that I'm not trying to change the minds of anyone who has used Tung oil with good results and has a method that works for them. More power to you. This is simply more info for anyone thinking about trying it for the first time. Note that Flexner also notes problems with white coloration appearing in large-pored woods.

Hope this helps!
Chris

[AndyBarnhart]

Originally Posted by Howard Acheson

I'm not sure what you mean by "accurately". That product is a pure tung oil.

However, the marketing statements at the bottom are just puffery, not based on fact. Here's a test you can do. Apply a coat of your tung oil to a raw wood board. Wipe off the excess. Let it dry for a week and then apply it and wipe it again. Now let it dry for two weeks and then put a couple of drops of water on the surface. See if it is absorbed.

Well, I said I won't debate it anymore, but I will just reiterate two things I said earlier in response to your suggested test. I have wood that beads water after a long time after the last application, however 2 coats is barely getting started and the above test would be inconsistent with the recommended usage. It's a lot of trouble to do it right and there are mordern alternatives that are cheaper, easier to use (except that they generally require better ventilation, more equipment and/or carry substantial health risks) and provide as much or more protection . I don't claim it is the best; I just object to statements that it isn't a good finish and provides no protection against moisture. Those statements are true of an improper application of almost any finish, but I was referring to applying it as suggested by the manufacturers, not just two or three coats. I think the lab book on finishes may be slanted toward production shops; it is unsuitatable for dip-n-ship finishing IMO.

[DavidF]

Originally Posted by merrill77

I will assume that as a "dining room" table, this would be considered a piece of "fine" furniture that you've put a lot of work into. If this is something with _really_ nice grain that you really want to show off, you should consider Lacquer. It's not as tough as varnish, but better than everything else - most dining room tables don't see heavy use. Note that it is a much more repairable finish than varnish, as well. But IMO, the real value on a piece of very fine furniture is the clarity and non-yellowing properties. For these two properties, lacquer cannot be beat. You can build it to whatever thickness you desire and it polishes very nicely. If I was worried about my spray abilities, then I would either brush or practice spraying until I was confident it would be done right. If this isn't some throw-away piece of furniture - an heirloom - then it's worth it, IMO. :>

Thanks Chris, I agree I like lacquer a lot, I have sprayed Target Coatings WB lacquer with great success, just not on the scale of a dining table. They also do a conversion varnish called EM8000 that is a little more abrasion resistant, that I might try on a test piece.
The table is not started yet, in fact the design has only just been completed so I have time to experiment.

[Howard Acheson]

>> I must admit that a piece of wood saturated with oil should be fairly waterproof shouldn't it.

Sure, but I don't know of a way to "saturate" a piece of wood. Wood finishes penetrate only a couple of millimeters even on open pored woods. Naturally oily woods like teak, ipe, etc., allow almost no penetration.

The point is that no drying oil application will produce a truly waterproof finish. Oils may cause water to "bead" leading to an assumption that water or water vapor is being excluded. However, water vapor easily penetrates oil finishes.

Both pure tung oil and linseed oil will produce a sort of film layer if multiple applications are "rubbed" and allowed to polymerize. However, this process is a long time process requiring 6-10 applications with a couple of weeks between each. Then the finish must be reapplied at least annually to maintain its appearance. The resulting finish is very soft and easily damaged. But, it's relatively easy to repair.