Replies

1. 
   SteveSchoene | Jan 20, 2008 05:06pm | #1

   Yes, there is a controversy.  Some experts do take that position. Michael Dresdner is one.  However, the advice is also give by some manufacturers--Interlux recommends it before using its spar varnish and apparently believes that the oil migration will be slow enough that the varnish (or presumably the glue) can be applied and set before the oil interferes with adhesion.

2. 
   Don01 | Jan 20, 2008 08:30pm | #2

   I have been making some teak pieces for a friends sail boat and followed the practice of wiping the edges with acetone. I took my directions from the boating community.
   The teak I have is very oily almost greasy. I used Titebond III and did the assembly right after wiping. These joints seems strong but only time will tell.

   Will sanding remove surface oil?
   When I rub any of the waste (router/jointer waste or sanding dust) between my fingers it is very oily, so I suggest that only sanding would just reveal more oily wood. The acetone wipe has limited penetration so sanding afterwards would remove the "dry" wood and defeat the intent of the acetone wipe.
   As far as wicking more oil to the surface, this oil isn't found free flowing in the wood, it is trapped in the structure of the wood. The acetone evaporates so fast and cools the surface so much that any immediate migration is going to negligible if you are assembling right away.

   It may also be that modern adhesives are formulated to work well with all types of woods and wood compounds (MDF, particle board, etc). So a good sanding will produced more surface area for the bonding action of the adhesive. Recent articles are suggesting that new adhesives do not require the clamping pressures that the old glues did.

   We are always dealing with a mixture of old and new information. Sometimes more questions than answers.

   Don

3. 
   ted | Jan 21, 2008 03:21am | #3

   Firstly wood does not contain oil or oils. As proof of this set a piece of suspected "oily" wood and put it on a piece of paper overnite. Come back the next morning. Notice any oil stains on the paper? Wood does however contain reins. some have sticky resins like southern yellow pine and some have greasy feeling resins like Teak or Cocobollo.
   In reference to your question, I tend to scrape or plane before gluing. I've found that acetone brings it to the surface and just smears the resins around.

   
   

   ---

   Edited 1/21/2008 9:26 am ET by ted

1. 
   SteveSchoene | Jan 21, 2008 05:06am | #4

   Looking for the most authorative source I could find, I ran across an article that , suggests that the acetone wipe does improve bond strength for woods with "oily extractives", woods such as teak.  The article is from a conference on "Practical solutions for furniture and structural bonding."  The article is found among the Forest Product Laboratory on-line documents.   

   http://www.fpl.fs.fed.us/documnts/<!---->pdf2007/fpl_2007_frihart003.pdf

   It's a serious work, and I haven't digested it yet nor seen any comments on its findings, but it appears interesting on the general gluing process, not just gluing oily woods, which are basically mentioned in passing. 

1. 
   saschafer | Jan 21, 2008 05:27am | #5

   A Google search on "oily extractives" led me to this book:

   http://books.google.com/books?id=GGGkJdbnt4UC

   Click on "Preview this book" and look at pp. 98-101 for some interesting information on the effects of various surface treatments.

   -Steve

    

   Edited 1/20/2008 9:50 pm ET by saschafer

1. 
   SteveSchoene | Jan 21, 2008 05:59am | #6

   Thanks for the pointer to the Treatise on Adhesion and Adhesives.  Very interesting--so even the test results are mixed.  That looked like an interesting volume to struggle through--until I looked at the priced tag on Amazon at $320 for volume 7. I'll slake curiosity some other way. 

   I certainly haven't had problems with joints in Teak that have been acetone rinsed before gluing with epoxy.  Of course, I might have had no problem anyway.   

   Edited 1/20/2008 10:00 pm ET by SteveSchoene

2. 
   EricAnderson | Jan 21, 2008 03:37pm | #7

   Yes, this document is pretty clear on the subject:

   "Some wood species, such as teak (Tectonia grandis), are hard to bond because they have oily extractives that limit the ability of the

   adhesive to come into contact with the wood and therefore provide a chemically weak boundary layer. Solvent-wiping the surfaces of oily wood improves bond strength. "

   It also mentions that a freshly planed or hand sanded surface creates a better wetted glue surface. 

1. 
   Jfrostjr | Jan 21, 2008 04:58pm | #8

   I recently worked with some Cocobolo (my first time). Following the advice for tropical woods I wiped with acetone before gluing. Much to my amazement each 'wipe' produced more red stain. I would have had blond wood had I continued. The glue seems to be holding - but who knows?Frosty"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922

1. 
   saschafer | Jan 21, 2008 05:32pm | #9

   Cocobolo is supposed to be the worst of the worst in terms of gluability, although I'm sure there's a lot of variability from piece to piece. People have claimed to have glued it successfully, but I'm afraid to even try--I don't want something to fall apart ten years down the road. Cocobolo also coats all of your tools with a waxy, oily deposit, as I discovered after working on just a few small pieces. Fortunately, the gunk comes off pretty easily with alcohol.

   -Steve

    

2. 
   Jfrostjr | Jan 21, 2008 05:53pm | #10

   I am (was) working on a small bowl with a cocobolo accent stripe in maple. If it comes apart, the 'roof won't fall down'. I said 'was', as I ran into difficulty with the difference in hardness between the two materials - a real jolting turning process. I switched to my oval table for the time being.Frosty"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922

4. 
   Woodmaster1776 | Jan 21, 2008 08:50pm | #11

   I recently built some outdoor furniture using western red cedar. Since I'd heard this was an "oily" wood--and the furniture would need to withstand Chicago area winters and summers unprotected, I thought it best to go right to "the horse's mouth" for a glue recommendation. I e-mailed Tech Support at Titebond and they said to wipe the wood with acetone and then use Titebond III. Due to a mistake at one point in the construction process I needed to undo a joint--it wouldn't undo, so I remade the piece. Which made me feel comfortable that the Tech Support guy was correct.

   Bob

5. 
   RickL | Jan 25, 2008 06:58pm | #12

   Rule of thumb I've been using for 35 years is to mill just before gluing and wiping down with lacquer thinner for resinous woods like teak, ipe, etc. A jointed edge according to Forest Products Labs is better than a sanded surface. Certainly more work and steps to sand the surface after jointing.   Whatever works!!!