Replies

1. 
   HowardAcheson | Jun 10, 2006 09:30pm | #1

   >> Could it be the tung oil?  If so, should I thin it?  If so, with what?  Or should I just skip it entirely?

   Here is how you can answer those questions yourself.  First, prepare a board half of which you apply the tung oil to.  Let it fully dry--can take up to two weeks.  Then spray the board.  See what the effect is.  If the finish is materially different between the two areas, you have your answer.

   If there is a negative reaction, you can coat the tung oil with shellac.  Then spray the lacquer.

   Thinning tung oil has no affect except to allow it to penetrate a little deeper.  Once the thinner evaporates, you are still left with pure tung oil which takes the same amount of time to dry.

   Not sure what you mean by tung oil with driers.  I don't believe I have ever seen that.

   Howie.........
1. 
   forestgirl | Jun 10, 2006 11:26pm | #2

   "Not sure what you mean by tung oil with driers.  I don't believe I have ever seen that."  Cruisin' around the internet, you will see various references to using Japan drier with tung oil to decrease drying time.  Problem is, "Japan drier" is a generic term that doesn't tell you anything about exactly which driers are in the formula.  When I was investigating the issue a few months ago, the only info I was able to come up with that was even close to specific was from one of the oft-cited finishing experts, who indicated that cobalt drier is the one that works with tung oil.  Cobalt drier can be purchased via an artist's store that carries oil paints and such.

   I had hoped to find an industry article or something to back up the info, but never was able to.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

1. 
   HowardAcheson | Jun 11, 2006 06:31pm | #3

   Yeah Jamie, japan drier use needs to be very judicious.  It's not the cure-all that some think it to be.

   Personally, I'm not a fan of pure tung oil as a finish.  It may have a place as a treatment to color the wood but then you just have to deal with the long drying time.Howie.........

1. 
   Rich14 | Jun 11, 2006 08:20pm | #5

   Metallic driers don't accelerate tung oil polymerization. Heat accelerates tung polymerization, but tung oil that's been heat treated is simply called, heat treated. Most preparations that actually contain tung oil have heat treated tung in them.Pure tung oil can be obtained raw, or heat treated to various degrees.Preparations that have driers do so because they contain linseed oil. They may also contain some tung oil, but probably not. The driers accelerate the linseed and then it's called "boiled."Industry terms. Not logical.Neither tung nor linseed ever completely harden. Tung does to a greater degree than linseed, but it takes very long. No matter, they harden enough in most applications (all?) that it doesn't really matter.I also think the orange peel is a function of the lacquer itself and has nothing to do with the underlying tung oil. For whatever reason, the lacquer is not adequately flowing out before drying, despite past good performance. It's either in the application or the material. Retarder should take care of the problem.Rich

1. 
   forestgirl | Jun 11, 2006 11:39pm | #6

   Rich, apparently a cobalt drier will work with tung oil.  Japan driers have various metallic driers, and may have cobalt, but what percentage is anybody's guess.  I bought a small bottle of cobalt drier a couple of months ago,  Someday when I have the time, I'll run a test board with various amounts of cobalt drier in the tung oil and let y'all know what happens.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

2. 
   Rich14 | Jun 12, 2006 01:24am | #7

   That should be interesting. But cobalt is some nasty stuff. Be careful.

3. 
   forestgirl | Jun 12, 2006 04:35pm | #9

   It's used in pretty small amounts.  The bottle I bought probably is no more than 2 ounces? 

   The most serious effects seem to come from respiratory exposure, such as found in some industrial settings.  Next is oral exposure.  I think I'd have to work pretty hard to contaminate my body with the stuff when using a few drops in a pint of tung oil!  Fortunately it has it's positive aspects, according to the EPA:  It's "an essential element in humans and animals as a constituent of vitamin B12.  Cobalt has also been used as a treatment for anemia, because it stimulates red blood cell production."  Hmmmmmm.......forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

4. 
   Rich14 | Jun 12, 2006 05:15pm | #10

   Forestgirl,The fact that Cobalt is an element in some complex molecules in our bodies in no way makes the Cobalt you will be handling less dangerous. You have a form of Cobalt that is highly toxic.NaCl is common table salt, perfectly harmless in small quantities, actually essential to our bodies (within limits), and desireable to eat. But table salt's constituents, elemental Sodium and Chlorine themselves are deadly.

5. 
   forestgirl | Jun 12, 2006 06:02pm | #11

   I know Rich -- my educational (university) and most of my working experience is in the biological sciences to one degree or another.  I'm making light, just for fun.  Fact is, I'm not going to inhale or drink the stuff, and I use gloves when finishing.  Thanks for your concern!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

6. 
   HowardAcheson | Jun 13, 2006 04:39am | #12

   The amount of metal driers used in consumer finishes is deemed to be not harmful to humans but public health organizations.  The small amounts are considered non-toxic.

   That of course, is not to say that drinking a quart of boiled linseed oil is good for you.Howie.........

7. 
   Rich14 | Jun 13, 2006 04:49am | #13

   First they tell me I gotta stop the booze. Then the smokes. Now you say no more linseed erl?!Sheesh!

8. 
   SteveSchoene | Jun 12, 2006 06:28am | #8

   The main drier for BLO was lead based, and once upon a time was heated with the oil to encorporate it--hence "boiled".  I don't know when other methods began to be use to add the driers. (Which have not contained lead legally since 1978 stocks were exhausted.)

2. 
   joinerswork | Jun 11, 2006 07:11pm | #4

   Chair,

   My understanding of the primary cause of orange peel, is the too-fast drying of the lacquer, before it has time to completely flow out.  Could be, the lacquer you're using should be thinned a bit more, or needs a splash of retarder.

   Regards,

   Ray