Replies

1. 
   Dave45 | Nov 22, 2004 06:14pm | #1

   My only experience with lignum vitae was in the Navy (almost 40 yrs ago) where it was used in the shaft seals where the propulsion shafts passed through the hull.  As I remember, it was used because it's hardness and "oiliness" made a perfect seal between the rotating shaft and the hull.  It must have worked because we never sank - lol.

   I would suspect that - like teak - you would need to wipe the surfaces down with acetone so the glue can penetrate the wood.

1. 
   Rich14 | Nov 22, 2004 06:59pm | #2

   Dave,Thanks. This business of wiping oily woods has as many naysayers as adherents (pun intended). The advice I've gotten with teak is that it MUST be freshly milled, but never wiped.Anyway, the natural oils of lignum are like those of no other wood. I wiped some samples with acetone and glued them to koa yesterday with Gorilla Glue (polyurethane). Wiping sure did result in a lot of "color" on the rag (olive green) and the freshly-planed, surfaces were much, much lighter after wiping.Everything looks good this morning, but who knows how long the bond will last? I have an email in to Gorilla Glue to ask for their advice.Rich

1. 
   Dave45 | Nov 22, 2004 10:55pm | #3

   I didn't know there was a controversy about wiping down oily woods.  I've never had to deal with it, but St. Normus NewYankeeus of Workshopicus always does when he works with teak. - lol

   Please post your answer from the Gorilla Glue folks - inquiring minds want to know.

1. 
   BG | Nov 23, 2004 01:22am | #5

   Dave,

   There was/is an article in FWW (#166) by Chris Minick that discusses how glue works.  What Rich said is exactly  the conclusion of the article...gluing up after milling is the best...waiting a couple of days can lead to contamination.  He did not test Lignum Vitae...but tested rosewood.  By comparasion using yellow glue on oak or walnut needs about 3500psi to break....on oily woods only about 1300psi is required...so he switched to epoxy adhesive and the failure psi was 2500 on oily woods....again, this was not tested on Lignum Vitae in the article. 

1. 
   Rich14 | Nov 23, 2004 05:49am | #6

   Thanks everyone, so far.No response from the Gorilla Glue folks yet . . .My glued samples are just 24 hours old now. I'll wait another day before trying to break them apart to see where the joint fractures.Uncle Dunc - yes I'm aware of the Primus plane design. I've used one. The "box joint" construction certainly must aid in the resisting of shear forces. I had thought of using that technique, but it caused too many problems in the throat area. Maybe another batch of planes to try that. My planes have pins through the sole into the body, so I'm not relying on the glue line alone.Strange that I've not been able to find one reference on the Internet to gluing lignum vitae. Lots of references to gluing "oily tropical woods."I'll post the results of my "test" and the answer from Gorilla Glue if I get it.Rich

2. 
   AlanWS | Nov 24, 2004 01:08am | #8

   I recall a short article, I think in FWW, where the author tested whether washing out the oil before gluing helped with oily wood. I don't recall the wood, but his conclusion was that washing helped a little bit, sanding just before gluing helped a lot more, and that gluing with epoxy (with or without rinsing or sanding the surface) worked much better than anything else for oily wood. I don't remember what other glue(s) he tried, but had stashed away the idea that epoxy works best in that case.Searching google for "lignum vitae glue" brought this up: http://www.rotdoctor.com/house/Htrop.html
   They claim their epoxy will glue lignum v. and: "Bond strength is comparable to the shear strength of lignum vitae."http://www.reellumber.com says
   "LIGNUM VITAE-
   Guaiacum officinale This hard, extremely heavy wood is known for its durability, waxiness and self-lubricating qualities. Works and turns well, but rejects most finishes and resists gluing. Common uses include industrial and marine bearings, clock bearings, gavels and mallets."My comments on gluing with epoxy: Make sure to measure out the two parts in the ratio specified for that type of epoxy, and to mix VERY thoroughly. Here's how I was taught to glue with epoxy in wooden boatbuilding. Boatbuilder's epoxy (West, System three, Raka, etc. are all good brands) is thinner stuff than epoxy glue, but it soaks into the wood well for a strong bond. Once as much has soaked in as possible, one then mixes some thickener into a bit more epoxy, applies that to the joint, and clamps. You don't need to clamp as tight as for other glues. Without the thickener (which is already present in epoxy glues) it will drip out of the joint and not hold as well. I don't know for sure, but I think this two step method is better than just using the glue, since the epoxy penetrates the wood. It may not be as helpful for a plane sole, but in boats one of the problems in gluing wood is that the joint itself won't swell, so wood that swells near the junction can put a lot of sideways force on the joint that can eventually lead to failure, so soaking epoxy into the wood may strengthen by keeping the swelling further from the joint.Note: If you do mix your own thickener into boatbuilding epoxy, you should be aware that silica gel (cabosil) works well, but will dull your tools more than the microfiber thickeners do.

   Edited 11/23/2004 5:11 pm ET by AlanS

3. 
   Rich14 | Nov 24, 2004 06:46am | #9

   Alan thanks.I didn't find that information in my Google search.Looks like that epoxy is a good way to go.Oh, well. This batch of planes is polyurethane glued. I haven't heard back from Gorilla Glue specifically about lignum vitae. But they're equally as enhusiastic about their product on "oily tropical wood."In another 24 hours I'll stress test my lignum v/koa joints.FWIW, the Gorilla Glue was very nice to use. Long open time. The cured glue line is not just thin, it's invisible. The wood was freshly planed before gluing. The cured, planed/sanded joint lines show a sharp demarcation between wood types and that is all. Lignum on one side of the joint, koa on the other and an infinitely thin, absolutely straight line where they meet and nothing else. Very nice.RichEdited 11/24/2004 1:18 am ET by Rich14

   Edited 11/24/2004 1:19 am ET by Rich14

4. 
   Rich14 | Nov 25, 2004 09:14pm | #10

   Now for my completely unscientific evaluation of gluing lignum vitae/koa with Gorilla Glue.First - understand that I have no means with which to measure the stress that I apply to the glue joint. As far as I'm concerned, if I can make a glue joint fail, and the fracture results in the wood's splitting, rather than the glue line, the joint is a success. Granted, such a method does not generate any numbers, but it confirms that the joint is as strong, or stronger than the wood, and there is nothing that can be done to improve that condition.That said, I glued up several lignum/koa samples (I don't know why I didn't think to bond lignum to lignum, but I didn't. Maybe because I needed to confirm the lignum to koa joint and I can't think of a use for gluing lignum to lignum).I wiped the lignum with acetone, scrubbing with a rag for about 30 seconds. I let the acetone evaporate for about five minutes. Then I moistened both surfaces as recommended by Gorilla Glue and let all visible surface moisture evaporate. I applied glue to one surface with my usual applicator method - a thin piece of maple, about 1-1/2" wide, notched on the end about 3/32" deep, every 3/32". I clamped the pieces firmly. Tiny glue beads oozed out all around the joint - no runs, no drips. Within minutes the beads "foamed" and expanded. I gave the joint 72 hours to cure before I removed the clamps. Gorilla Glue says a full cure occurs in 24 hours.I locked one end of each pair tight in a bench vise and hit the other member right at the joint with a 4 lb maul.In every case, I was surprised at the force with which I had to hit the wood to break the joint. I know I had to hit it much harder than if I had been breaking apart maple or oak. The first few times, it took two swipes.In every case, the result was the same. Part of the joint (about 1/3 to 1/5) separated cleanly right on the glue line, resulting in shiny (dry) glue-coated wood surfaces of both woods. The other half left ripped, shattered pieces of lignum, adhering to intact koa. The lignum shattered! in those parts of the joint, the strength of the lignum itself was the weak, limiting factor. In no instance did koa fibers fail - only lignum.In those parts of the joints where fractured remains of lignum were adherent to koa, I tried to fracture the glue line by driving a cold chisel directly through the glue line (parallel to and between the glued surfaces). I was really surprised at the continued pounding I had to apply to break the woods apart. It really was not easy and must have represented thousands of times the stress the joint could ever have been given in use. In every case, the joint finally separated on the glue line itself, but the lignum continued to shatter as I drove the chisel through as the glue seemed to adhere to it better than to the koa and to pull its fibers apart.Rich

2. 
   UncleDunc | Nov 22, 2004 11:04pm | #4

   I've seen European wooden planes with lignum vitae soles in catalogs. The plane bodies and soles are machined with interlocking grooves, like a box joint but all the way across the width of the plane. The advantage of this appears to be that the mechanical joint resists the shear stress and the glue is under no real load at all.

3. 
   douglas2cats | Nov 23, 2004 03:04pm | #7

   Somewhere in my Hiroshima filing system is a copy of Wood Magazine's glue review issue. I think it was maybe June or July of this year. They did a pretty thorough review and test of various kinds of glues - how good each worked at edge gluing, face gluing, open times, set times, how much load it took to break the joints, etc. They did a test with one of the oilier exotics (cant remember which species) and I remember being kind of surprised at the results. Since I cant find the issue I could be wrong but I think they ended up having the best results with a white PVA glue (??) Anybody else got that issue handy to double check?