Replies

1. 
   HowardAcheson | Jul 18, 2004 04:39am | #1

   Yes, anything that cures or polymerizes has a finite life.  In the case of pure tung oil, it would be measured in tens of years. 

   Tung oil is a very slow curing oil.  Even in the thin coats used on wood, it takes 3-5 months to cure.

   Howie.........
1. 
   Thunder1 | Jul 18, 2004 05:10am | #2

             Thanks Howie,

                  Any Idea why this gallon I got from woodcraft stays tacky.Ever had any defective 100% tung oil.This is what I thought,10s of years not 10s of months.I only used half a pint and the gallon plastic container shows clear amber with no curing.I want to return to woodcraft but my 1 year receipt is up but if defective it should not matter.8 months on walnut and mahogany and still tacky with one brush coat.

   Edited 7/17/2004 10:26 pm ET by Thunder1

1. 
   HowardAcheson | Jul 18, 2004 07:25pm | #3

   Tung oil must be applied in very thin coats. The process is to wipe on a coat, let it sit 20 minutes and then wipe the surface as dry as you can get it. You can apply a second coat the next day again wiping it completely dry. By completely dry, I mean that you should not get any transfer of the oil when you rub your finger on the surface.

   Now, the tung oil should be let to cure for a week. Then you can apply another coat. The old rule still applies. One coat per week for a month: once per month for a year: and annually thereafter.

   If it's tacky, it would seem to indicate that you put on too much. I would use mineral oil and 4/0 steel wool and go over the surface agressively to remove as much as possilbe. Let it fully dry for a week and apply another coat as above.

   All in all, pure oils--whether tung or boiled linseed--are poor finishes. I like to think of them as wood colorants rather than finishes.Howie.........

1. 
   Thunder1 | Jul 18, 2004 08:30pm | #5

            Thanks again Howie,

                       Problem solved.I tried to use pure tung oil the way I am  use to using tung oil finish,3 brush & rub coats in three days and then rub out to desire.

                          Will 1/3 pure tung oil,1/3 mineral spirits,1/3 varnish make a good tung oil finish similar to minwax tung oil finish or due you have a better brew.

                           Tung Oil on walnut enclosed....Rather minwax tung oil finish or whats in the can & walnut

   Edited 7/19/2004 12:53 pm ET by Thunder1

   
1. 
   HowardAcheson | Jul 19, 2004 06:33am | #7

   >>Will 1/3 pure tung oil,1/3 mineral spirits,1/3 varnish make a good tung oil finish similar to minwax tung oil finish or due you have a better brew.

   As it turns out, Minwax Tung Oil Finish contains no real tung oil. It's oil is boiled linseed oil.

   So, I would recommend substituting boiled linseed oil for the pure tung oil in your mixture. Boiled linseed oil will cure within 4-6 days so it is a better oil to use than the much slower drying pure tung oil.Howie.........

2. 
   nikkiwood | Jul 19, 2004 08:16am | #8

   Sorry, but I don't agree that tung oil dries appreciably slower than BLO. This fellow is using pure tung oil, and if he thins it out, it will apply and dry just fine.

   As for using it to make a wiping varnish, mixing tung oil with any kind of varnish will perform admirably as a wipe-on finish. But a 1/3 mixture may not be thin enough. I would say start there, and then add more paint thinner as your common sense dictates. The concoction ought to be about the same consistency as Watco Oil -- which is fairly thin.

3. 
   HowardAcheson | Jul 19, 2004 06:20pm | #9

   Try spreading some pure tung oil on glass and then spread some boiled linseed oil along side of it. See how long it takes to dry.

   Do the same thing with thinned tung oil 50%. It will take the same time to dry. All the thinner does is make the tung oil less viscous, it does not change the basic characteristic of the tung oil. Once the thinner evaporates, you are left with pure tung oil which is exactly the same as it was before it was thinned.

   Unless the tung oil is polymerized or chemical driers added, pure tung oil will take a long time to cure.Howie.........

4. 
   Thunder1 | Jul 19, 2004 11:53pm | #10

             My shop is open air. Temp 81F R.H. 82%

                            TEST

   Edited 7/19/2004 4:55 pm ET by Thunder1

   
5. 
   Thunder1 | Jul 20, 2004 09:48pm | #14

          The BLO is almost all dry while only the thinist parts of Pure tung oil and 50/50 mineral spirits  & tung oil is dry.Now the 50/50 is slightly ahead but remember that there is only half as much tung oil left to dry.

             In conclusion I am sticky.This is the subtropics they say and its like a sauna today in my shop. If  tung oil is put on thin enough drying times are similar but overall BLO dries faster.The thick and thin BLO is almost dry while the thick of both the others is wet wet.

   Edited 7/20/2004 2:52 pm ET by Thunder1

   
6. 
   Thunder1 | Jul 20, 2004 10:01pm | #15

   test

7. 
   Thunder1 | Jul 20, 2004 10:03pm | #16

   test

8. 
   Thunder1 | Jul 21, 2004 03:19am | #17

           27 hr latter and 50/50 pulls ahead of pure

   Edited 7/20/2004 8:20 pm ET by Thunder1

   Edited 7/20/2004 11:57 pm ET by Thunder1

   
9. 
   UncleDunc | Jul 21, 2004 03:21am | #18

   BLO dries faster because it's been modified. In the old days, they did heat it, thus the name boiled linseed oil. These days they add stuff to it, including but perhaps not limited to chemical dryers. The pure tung oil is probably raw oil. If you knew the right temperature, you could heat your own to make boiled tung oil, which would dry at about the same rate as BLO. Comparing the drying rate of polymerized linseed oil and raw tung oil is sure to give you a negative impression of the tung oil.

   Both oils dry by reacting with oxygen, not by solvent evaporation. Thinning the tung oil will help you apply it thin enough so that it can dry readily, but will do nothing to directly speed up the drying. Heat will speed up the reaction, as it does with almost all chemical reactions. Reducing the relative humidity isn't likely to have much effect on drying rate, because the solvent vapor pressure has little to do with the oxygen reaction. If you could think of a way to raise the oxygen content of the air, that would have a dramatic effect on drying, but would also increase the risk of burning your shop down.

   You can also purchase dryers from full service paint and finishing vendors. Google for "japan dryer". Follow the instructions carefully, because if you add more than the directions call for, the oil won't dry even faster. Too much dryer retards drying.

10. 
    Thunder1 | Jul 21, 2004 04:09am | #19

               Thanks for the info. I will  try combos of japan dryer,varnish,mineral spirits and pure tung oil.

11. 
    Dave10 | Jul 25, 2004 06:14am | #25

    My business is located on the SW coast of Florida. I know what you mean about the subtropcs. We found years ago that BLO and tung oil don't perform well under high humidy. We use pre-, post- and conventional lacqures in lieu. With a little fiddling, these finishes will produce the "close-to-the-wood" appearence of the oils.

12. 
    Thunder1 | Jul 25, 2004 08:45am | #26

         At least we get to see wood move right before are eyes,especially around tropical storms and cold fronts.

         You never see tung oil or BLO on woman's nails,just all lacquered up manicures, some with detailed art work.I always seem to feel a little off after spraying even in open air with the right mask and fans.Once again I think woman have something with this brush on type and maybe waterbase.Never brushed it yet or know pre from post.Its just the feel is missing,that soft texture.What brand do you use and is everybody still standing.

13. 
    bakesale1 | Jul 23, 2004 09:29pm | #20

    Howie:

    I saw in an earlier post that you called pure tung oil a lousy finish. Does this mean you never use it or that you think than anything that needs a "finish" shouldn't just get oil? I just built a tool box for my nephew and was about to use pure tung oil on it . Poor application in your mind?

14. 
    HowardAcheson | Jul 23, 2004 09:52pm | #21

    It depends what performance you want from a finish.  If it's only appearence, then pure tung oil will darken the wood(so will boiled linseed oil and it will dry faster).  But, it offers no water or watervapor protection and no abrasion resistance and it must be renewed periodically to maintain it's look.

    If  you want the same look and a little protection, use an oil/varnish mixture of tung oil(or BLO), varnish and mineral spirits.  The varnish adds some protection and durability but still not a finish for heavy abrasion.

    Next up the scale is two coats of a thinned wiping varnish.  Thin you favorite varnish 50/50 with mineral spirits and wipe it on with a cloth or non-embossed paper towel.  When it is dry to the touch apply a second coat the same way. 

    All three are "penetrating finishes and will give almost the same look and feel to the wood and grain texture.  The wiping varnish will give you the most long term protection of the three.  But, none offer the long term protection of film finishes.

    So, what do you want the finish to accomplish?  That will dictate which one is "best" for the application.Howie.........

15. 
    bakesale1 | Jul 23, 2004 10:02pm | #22

    It's just for looks. I read that tung oil darkens the wood less than linseed. I thought of starting with tung oil mixed with mineral spirits, then pure tung oil, tehn tung oil and japan dryer.

16. 
    nikkiwood | Jul 24, 2004 06:33am | #23

    I agree with all the counsel in Howie's posts in this thread -- except his contention that tung oil doesn't dry well and is not very durable.

    As long as the pure tung oil is diluted with mineral spirits, it will dry in 24 hours, unless you have murderous humidity -- in which case anything will take longer to dry.

    For me, the key to getting a durable finish with tung oil is multiple coats. I have done one coat a day (with a quick rub down) for as many as 6 to 10 days.

    The piece that was finished in this fashion, which is still in my life, is a stereo cabinet my daughter and I built more than 20 years ago. It got the 10 day treatment, went on to survive the rigors of dorm life, and is now enduring life with 3 young children. The finish is none the worse for all this wear and tear, and it still has that beautiful soft glow that comes from an oil finish.

    So, I would encourage you to experiment with the tung oil (just always dilute it). I have moved on to wiping varnishes, largely because I so admired the finish Sam Maloof was able to achieve with his chairs -- and that's what he used.

17. 
    HowardAcheson | Jul 24, 2004 09:51pm | #24

    Tung oil is tung oil. Tung oil mixed with a thinner is still tung oil, just thinner. Once the thinner evaporates, you are left with tung oil. Thinned tung oil appears to dry--actually oil polymerize, they don't really dry--but that's just because you have used less tung oil and, because it is thinner, it is absorbed more deeply into the wood. You can't change the chemistry.

    That said, I personally can't see any advantage to pure tung oil. I have side by side coated numerous walnut and cherry boards with multiple coats of both tung oil and boiled linseed oil. Both darkened the wood. In some cases--certainly not all--the boiled linseed oil added a small amount of amber color. But, in many cases, I could not see any appreciable difference in the samples. A customer I did the tests for actually liked the BLO better as the amber is what tends to "pop" the color.

    I have seen some museum quality finishes done with both tung oil and BLO. Both looked great but both required many coats, hand rubbed to get the patina that the items showed. This effort is just the reason the Maloof and others developed oil/varnish mixtures. They go on faster, dry more quickly and have more durability.

    Howie.........

2. 
   nikkiwood | Jul 18, 2004 08:12pm | #4

   I have bought Tung Oil from Woodcraft, and if we are talking about the same stuff, this is pure unadulterated tung oil. The product I am familiar with comes in a one gallon plastic jug,costs about $45, and is thick and gloppy -- about the consistency of motor oil.

   I always considered it a concentrate, and thinned it out with mineral spirits, enough so it wipes on easily.

   The material will gell if left in a partially used jug; I just squeeze the jug to remove any excess air. I have used it after it has sat around for 4-5 years, so shelf life does not seem to be an issue.

   I have not been able to find any other source for pure tung oil; all the stuff that is commonly available with a tung oil label has already been diluted. At least that's what I have been told by several knowlegeable dealers.

   I often mix it with a little varnish, and thin the mixture with mineral spirits to make my own wiping varnish.

1. 
   Thunder1 | Jul 18, 2004 09:35pm | #6

              Yes thats the same stuff I got. Now I am off to making my owen wiping varnish. Thanks for your input.

2. 
   Mackwood | Jul 20, 2004 02:49am | #11

   Shelf life is exactly one day less than the time between the project you bought it for and the next one.  (sorry, couldn't resist)

   "WISH IN ONE HAND, #### IN THE OTHER AND SEE WHICH FILLS UP FIRST"

   
   

   ---

   Edited 7/19/2004 8:42 pm ET by Mack

   
   

   ---

   Edited 7/19/2004 8:43 pm ET by Mack

1. 
   Thunder1 | Jul 20, 2004 03:46am | #12

              Its funny how I can apply that to my last few girlfriends.  Thanks alot.Now you got me worried about my 3 pounds of assorted colors dewaxed shellac flakes that are 2 years old at least that I am now ready for.They feel and look like solid lava rock.At least they are environ-mentally safe as long as I don't think of them.

    

                          The shelf-life of a relationship is one day less than the time between the day you met and the day you part....You know this shelf-life thing just might be a universal law we all try to wiggle out of. Look--- Life is one day less than the time between birth and death.

   Edited 7/19/2004 9:16 pm ET by Thunder1

1. 
   Mackwood | Jul 20, 2004 04:40am | #13

   Or the one resounding truth in the universe?!  Good luck with the shellac!

   Regards,

   Mack"WISH IN ONE HAND, #### IN THE OTHER AND SEE WHICH FILLS UP FIRST"