Hardeners for Plant Resins

Good info, and I learned that tasting the rainbow is like licking a bugs behind...

GA, thanks

That is exactly the kind of nonsense I'm looking for!

I also appreciate that the site has another link discussing the depletion of Kauri trees..

GA, thanks

hairlesssimian -- We've engaged before on CR-4 and I've found you to be an interesting, pragmatic and creative fellow. So we meet again here.

Artsmith's comments and link to the formula for Kauri Varnish is fascinating and quite instructive. It seems to offer a more or less generic varnish formula albeit one that must be tuned by successive experiments for the resin selected. The concept of experimental varnish cooking is quite interesting in its own right.

Many years ago (44 to be exact) when I was having fun with oil painting (that's another somewhat sad story) I learned about cobalt dryers for the ordinary linseed oil/turpentine mix for oil colors. I was scheduled for an all night command duty watch in the Navy Advanced Training Command headquarters and decided to bring my oil color kit with me that night since things tended to be fairly quiet on such watches at the Air Training Command in Corpus Christi, TX. So wanting the paintings to be dry in the morning when I was done with the watch I added some cobalt dried to my oil/turps mix and fairly dashed off the two best (IMHO) paintings I ever did on 10x14 boards. To this day they hang in our living room showing no signs of deterioration or cracking. Of course being on a Navy pay schedule I was pretty cheap about how thick I laid the pigment on the surface.

That said, I wonder about the tendency of any drier added to a resin mix to produce a brittle cured state. I think in general the practice of adding fillers to resin mixes may be well employed where the cured strength of a raw resin mix may be so low as to invite cracking in thicker sections. A very appropriate filler to try initially would be the fine sawdust derived from cutting the mesquite wood itself. If that ultimately fails after trying several proportions of sawdust to liquid "varnish" another wood sawdust might be tried in hopes that it would not have the same chemical effect on the resin as the mesquite.

The fascinating part of the series of experiments I suggest is the search into a novel side of the trend toward doing things "green" that no one else has likely explored. Sorry I cannot begin to suggest varnish driers that are truly "green". This in itself would be a fascinating exploration.

Ed Weldon

Interesting you should mention brittleness. I was going to add a comment about the copal rough I bought a few years ago as "Colombian amber". It is certainly resin but whether a fossil resin (or how old) is in some doubt. One thing that surprised me was how brittle this stuff was - drop a piece and it may break. Maybe a fake, made with a drier? Not very durable, so hardly worth the trouble of working or polishing, although it might be well enough protected in a piece of wood, depending on the use it was intended for. Melting it with turps to make a varnish might be a better approach. But the heat and pressure applied stepwise in the other link to simulate aging seems to be necessary to make the material really tough (Baltic amber is much tougher than this stuff).

I often thought about our local resins - we have a ton of Balsam fir here (aka "snotty var") that blisters with sweet smelling sap in the summer. (Used to make turpentine, I believe, though not locally).

My dad tells about making rosin for his bow when he was a kid. They put fir sap in a tin can and set fire to it. The remaining product was the rosin they used.

Thank you for your kind compliment, and your well thought response.

Definitely brittleness is a major concern in this role. The final result should be that the void filler is at least comparable to the material around the void in terms of stability and structural integrity, while allowing the presentation of the natural state of the board prior to filling (in the NYW version the filler is dark (almost black) and opaque but it contrasts nicely with the wood and accentuates the form of the defect).

I am really surprised that filling with the same wood is not acceptable.......

DUUUUUHHHHHH???

For this post we are dealing with issues of aesthetics so reason has to take a backseat... These are the kind of ridiculous demands I deal with on a regular basis because I work in the arts, and the most important aspect of design in this world is the conceptual intent of the item not the practicality of it... In this case the concept is to use products that are natural and preferably derived from the same source as the lumber used to construct it; why... because I said so... (real artists make up better BS reasons for doing things, but ultimately their motivation usually can be attributed to some form of bragging right or to the communication of some sort of "Great Truth").

Since I am the idiot designer for this 'project' I'll allow that I'm an idiot and I should get over it... though should and will, those are different things...

hairlesssimian -- Being just a bit of an artist myself I think I understand where you are coming from. Certainly experimenting with a technique for converting whatever oil you can get out of the mesquite into a "glue" of sorts might provide a useful solution. I suspect the best source of the needed feedstock would be the dense burls around the base of the blant and top of the root bundle.

Some other ideas may come from the world of wood craftspeople, the folks who get a good bit of ink in Fine Woodworking magazine; College of the Redwoods types. These folks are a kind of artist that is very concerned with the practical engineering problems that must be faced in producing functional objects like furniture that at once demonstrate the art of great design as well as the epitome of wood craftsmanship.

One trick I've seen described there is the use of "butterflies" to stabilize a cross grain weakness that would otherwise cause a wood structural member to crack along the grain. They are also used as a form of joinery. While specialized for a specific woodworking problem the general concept of using specifically formed pieces of the same wood to overcome structural weakness is a useful idea. Granted such approaches demand a high level of skill in woodworking when producing professional level custom furniture.

But the very creative person may be able to conceive of a less skill demanding application of that concept that when executed well produces a fine result. Very often the crudness of a piece of are is it's most appealing attribute. An old weathered board is often far superior to any finely finished wood component in terms of it's artistic appeal.

Keep in mind that the objective is the final work. That level of the item has its own set of requirements for structural integrity. But as stated in the OP the component parts need to survive the building process. There is nothing wrong with the idea of adding reinforcements that facilitate the rough foming of the piece and then are removed prior to the finishing. The reinforcements can be machined/cut off or adhesive disolved/melted away when appropriate in the building process. If the reinforcements hide the weak area a digital photo or a photocopy image attached to the outer surface can guide work while the defect is hidden.

BTW, Fine Woodworking Magazine has been in publication some 35 years. Recently they started offering a CD or DVD (I forget which) containing images of all the back issues. IIRC it costs around $170. A lot of money for the amatuer who is not deep into this as a hobby or a career. But if your work requires extensive knowledge of what is being accomplished today in the world of woodworking at the professional level as well as an ability to understand the vernacular then the cost may well be justified.

Ed Weldon

excellent response!!!

I like where you went with the removable support pieces to get through the build process.

I do remember learning about butterflies once upon a time many moons ago, they wouldn't work in the final concept of my vision but are very useful and can be done with excellent visual effect.

I can tell you understand the art mind... at least as well as it can be understood.

Firstly, none of us think you are an idiot, way off the mark there.....

But, slavishly following the shape as I suggested won't hack it either....makes a fix difficult.....

I understand where you are coming from and at this point my only new suggestion is that the hole, as it is be scanned into a CAD system and then a clear plastic plug (so you can still see the hole) is made on a CNC machine, exactly that shape and inserted, so that nobody/nothing falls through.

That way you can have your hole and still see it, without causing accidents or leaks....

Me not being much of an "arty" person, thats probably the best (worst?) that I can think of........

I personally like wood to be flat with no unwanted holes at all.......knots are OK if they don't reduce the strength below what is required, irregular unwanted holes are anathema to me!!!!

I do like an interesting grain in/on wood and can understand that it adds character to a workpiece, like that a lot in fact......but the piece, if it is to be something useful, and not JUST a piece of art, sitting and doing otherwise nothing.....has to otherwise "conform" and the holes have to go.......unless of course you "needed" a hole at that point (to open a door or drawer for example), so that would be OK I guess.....

Hey Andy,

I was in no way offended by your post. My suggestion that I am an idiot is due to the fact that my design criteria ARE idiotic by their very nature, and my insistence that those criteria be met regardless of cost or difficulty is even more idiotic. I have chosen, for the purposes of this post, to take on the role of idiot.

My intention is two fold:

• To find out if anyone knows of a means to accomplish the desired effect (which I knew going in was unlikely)
• To exercise my brain and take as many along with me for the ride as I can

I am very satisified with my success on both counts as I got much closer to the thing I envisioned than I had expected, and, well, at least my mind feels a bit less rusty (there are some folks here I suspect never get rust on the brain; me, I need regular tune-ups).

You have my sincere thanks not only for your participation in helping me to achieve my goals, but also for taking the time to insure that I had not been unduly offended by your words.

Why not use the most natural thing? The wood itself. I was making a gunstock out of walnut. I had it almost finished but when I got closer to the finished piece a rotten piece or void showed up in the wood. I was using a branch from a walnut tree which was beautiful until I got to that spot. So I carved the hole out to good wood and carved a piece to fit into the hole. After a few trial fits I had it adjusted just right and I glued that puppy right in there. I used a piece that followed the grain somewhat and no one even notices it is there. Just takes a little more time. Since your wife wants to avoid epoxy let her carve out the plugs. ;-D You can just mix sawdust of the wood you're using with glue and cram it into the hole but I have never seen that take stain or whatever you're using to coat it with like natural wood. Many just use plastic wood and go on but I don't like that look as well either.

The holes and the voids are part of the beauty of the wood that is desired in it's use. To fill them in with wood what would be the use in using it. Cheap pine blank then would do.

You may find polyester resin and cabosil; a.k.a. Bondo has the properties desired:

http://scholar.google.com/scholar?q=Fumed+silica+colloidal+silica&hl=en&as_sdt=0&as_vis=1&oi=scholart

I was faced with having to sand and varnish a worn soft white pine floor. What was troublesome were the occasional areas where trauma had damaged the wood but the damage was such that gluing a fitted plug wouldn't work.

I did as others here suggested: I harvested the saw dust from the sanding machine, filtered it and then use Resorcinol as the binder. The void was built up, allowed to cure and is virtually invisible under the top coat of satin polyurethane.

Resorcinol is one remarkable glue. In spite of its age, it continues to compete successfully with modern adhesives that are approved for use by the FAA in building new planes or restoring classic or antique certificated aircraft.

Fabric covered aircraft from World War Two, whose wood parts were first joined 65 years ago, are still structurally sound and considered airworthy!

Weldwood Resorcinol is is but one powdered formulation. While I now use aircraft grade epoxy in much of my work, it's only because the number of parts made from wood have fallen as other materials have taken over.

Hope this helps some

Have fun!

L.J.

I know what I would do, I would make a shape to fit the hole in a CAD program, maybe a tad bigger. I would them place the plank with the hole in it in a CNC router and let it cut the hole so that the sides of the hole are perfectly vertical.

I would then use another piece of wood (Mesquite in this example) and cut a plug EXACTLY the size of the hole I had just made also on the CNC Router, and then glue it well and then gently, using a mallet, drive the plug into the hole and let it set.....

By careful observation of grain direction and color in both parts you can either make the grain run parallel, or even run at 90° to each other or whatever......

You could even make stars or squares or whatever your fancy was.....take all the knots out of a piece of Pine for example....

This I feel would be the best way and the hole shape, whatever it is can be followed almost exactly by photographing the hole and transferring it into a CAD program........

Or you could put dark woods into light colored ones or vice versa......freedom of choice....names, signs....the list is endless.....

I have never done this I hasten to add, but it should work just fine with good modern wood glues....

Some great info turning up here, thanks to all who have posted so far.

I need to clarify a couple points though:

This is not an actual project, it is merely an exercise in sating my curiosity.

The preference to use natural materials is aesthetic; meeting the aesthetic criteria is the primary goal of this post, regardless of cost, time required or convenience. The only additional goal is to meet the structural stability needs.

The voids in the wood are part of the beauty of the wood; however, the voids need to be filled in order to insure that the board is stable enough to endure passing through a variety of power tools and survive use as a structural component. Filling with more wood is defeating even though it clearly meets the natural material guideline because it typically requires the destruction of the natural form of the defect to be filled.

Assume the grain and structure of the wood will not only be plainly visible, but are in fact the principle aesthetic features of the 'project'.

I know I've done a bad thing, I've asked a bunch of engineers to think like 'artists' (I think real engineering is an art, though the art community may be skeptical). Well, you'll just have to get over that; besides, it's good for you

I've enjoyed this. Lots of good ideas. But, back to the original post.

I'd have to say that the person who is putting hand to wood should decide how to best arrive at the destination. Be that polymerized bug poop or marine epoxy.

That's being creative.

Cheers.

On a different note:

Here in the USA we are about to celebrate Memorial Day. That is the day on which we pause to honor all of the people who have made the ultimate sacrifice in the service of their country. So, on Monday, take a second to reflect about the meaning of sacrifice.

Lyn