I would like to build a table with a red top: Cocobolo, Bloodwood, Padauk or
Bubinga. I only want to invest the time and money if I can keep the color
of the wood (nearly) as red as when it is freshly finished. I presume that
the darkening that I have observed is due to UV exposure.
Will ordinary lacquer block the UV or is there a blocker that can be added?
Is there some other finish that will prolong the retention of the original
On Fri, 04 Apr 2008 08:11:33 +1300, Larry Spitz wrote:
Oxidation and UV exposure are a problem. Apply the finish ASAP after
cutting,sanding, or scraping. You can see a difference within 24hrs
without sunlight with some woods, within minutes in sunlight. That's not
to say that it won't change over time with a finish, but the less time
the wood is exposed to air or UV helps mitigate the fading and/or color
change. Usually re-surfacing and re-finishing every few years is required
for maximum color retention.
Yes, there are blockers you can add or finishes that contain UV blockers
or absorbers. Most UV products will be marketed for exterior use. I've
heard some references of good results with valspar/lily/guardsmen
products with uv blockers.
Ucecoat from cytec
Clariant interior wood finish uv additives
Many links recommend armorall, I didn't like the results.
Here's a book that has many ideas, (I don't agree will all of them,
armorall being one)
Methods of Work: The Best Tips from 25 Years of Fine Woodworking,
Finishing by Jim Richey
Another idea, is to produce a dye from the sawdust of the wood and dye
the wood that made the dye. Still fades, but the colors are often much
more intense to start. I only did this on a whim for pieces with color
variations, padauk and bloodwood, when making dyes from them for other
pieces, usually aspen or maple, sometimes cherry.
The new Nano tech blockers look good in theory, but I haven't personally
seen the results, other than the skin sunscreens. The theory, that seems
to be working in the sunscreens, is UV blockers can only block when the
particles block the UV rays. When the object is covered thick enough to
fully block all UV rays, the blocking agent is visible. This is only good
for opaque paints.(or white visible sunscreens) Using nano sized
particles it is now possible to fully coat the surface while remaining
translucent. We'll know better after a few more years of field testing.
Advertisers often exaggerate or even outright lie, so I wouldn't discount
the tech just because one product didn't live up to expectations. The
nano particle oxides can be purchased in raw form. If you have a
university near you that has a nanotech program, encourage them to mix up
a custom finish and do some testing for a school project.
A few new tech product links;
Nanotech gets a bad rap from the special "magic" qualities of a few
compounds and application processes. Simply put, companies didn't add
significant quantities of oxides for UV blockers until they were able to
be ground to small particles, mixed and bound to the paints or finishes.
Now we can grind and sift smaller particles and newer binding agents are
being used. Smaller particles should be more translucent in larger
quantities and no one can argue with the fact that higher concentrations
of oxides block UV better.
Good post, Joe.
I personally don't know if we will see widespread FULL use of nano
technology for a while. However, in line with your earlier comments,
it doesn't stop advertisers and manufacturers and their claims. In a
true sense of the word as originally used, nanotechnology used in the
application of coatings is baloney.
I don't believe that over the counter paint has a million tiny robots
working away for just $25 a gallon, and it cleans up with water.
I do believe that they have grabbed the term for their own use,
bending a partial definition of "nantechnology" as being one of
working with tiny particulates. However, this ISN'T on a molecular
level, and to me, that makes it no more than a marketing ploy.
I know that nano technology in coatings does exist and is being used
more and more and that it works.
But the application of a true nano technology coating is very
different as is the end product for the guy that buys "One Coat
Premium Sealer - Now With Nano Technology!" down at the local hardware
store THAT AIR DRIES.
Maybe Phil and Doug Nano were on the mixing line that day, and used
the current technology to add the stearates.
Or maybe they have a new micro grinder that added some crystalline
structure to the mix to increase UV or abrasion resistance, but to my
knowledge there are no time dry finishes that employ true
That depends on the constrained definition of nanotech, generally it
includes the subfields of study.
The term manufacturers should be using is nanomaterials or nanoparticles,
a sub-field of study in nanotechnology.
Hopefully as more people become aware of the advances in the underlying
science, the manufacturers will describe their products using more exact
terms. "Contains oxide nanoparticles" would be more correct for current
stains being marketed, although if nanomaterials are being used I don't
think nanotech is strictly incorrect. It just more like saying "There's
science in a can", a little broad and capitalizing on a buzzword and
therefore potentially confusing consumers. Confusion driving sales has
never been something marketing has shied away from.
Maybe. Certainly there are nanomaterials that need specific application
to achieve their desired functions. However, that does not discount
translucency and solvency of smaller particles of opaque materials
suspended in liquids. These should not need any special application to
achieve good results. I always grind pigments as fine as possible before
mixing dyes. If I don't there will be color blotches. It doesn't have to
be so high-tech of an application to equate to a newer, better product.
That's one reason why I put the idea out there. I, like many people, use
what has worked for me in the past. Often what I was taught the first
time. I'm looking for any experience from those who have the time and
money to experiment with the newer tech, whether high-tech or just new
I do quite a bit of glass work and the newer formulas being used have no
equivalence with old technology. COE stable glasses, thin film dichroics,
stable and predictable colors, many features not possible even 20yrs ago.
I'm looking forward to similar advances in wood technology. Sawstop blade
brakes, chainsaw brakes, NC and CNC tech, waterjets and variable focus
rotary lasers in the home shop price range, silver ion paints, ceramic
microsphere stain resistant paints and many other advances yet to be
Excerpts from wikipedia which imply characteristics of interest for
stains and finishes;
Materials reduced to the nanoscale can suddenly show very different
properties compared to what they exhibit on a macroscale, enabling unique
applications. For instance, opaque substances become transparent.
Suspensions of nanoparticles are possible because the interaction of the
particle surface with the solvent is strong enough to overcome
differences in density, which usually result in a material either sinking
or floating in a liquid.
Nanoparticles have a very high surface area to volume ratio. This
theoretically does not affect the density of the final product.
Reading your post, I agree with your premise of presentation.
However, there was an old comedy movie once that said in a fake ad
(imagine your radio advertiser's voice here):
"Now you can own this super ball made from the same material used in
tires of the B52 strategic bomber that safeguards our country. It is
simply amazing. You throw it down, it bounces up. You throw it up,
and it comes back down. All under its own power. No batteries
That's how the "nano ads" sound to me now. Anyway they can fit it in,
But in one strict sense, simply rendering the particulates to size
could include them in a valid definition of "nanotech" nomenclature.
This was one of the earliest attempts to define the technology and its
output I could find. This dates to the 80s, although the nano/concept
has been around since the 50s.
As nanotechnology became an accepted concept, the meaning of the word
shifted to encompass the simpler kinds of nanometer-scale technology.
The U.S. National Nanotechnology Initiative was created to fund this
kind of nanotech: their definition includes anything smaller than 100
nanometers with novel properties.
Much of the work being done today that carries the name
'nanotechnology' is not nanotechnology in the original meaning of the
word. Nanotechnology, in its traditional sense, means building things
from the bottom up, with atomic precision. This theoretical capability
was envisioned as early as 1959 by the renowned physicist Richard
You can see the shift in meaning. Now it seems to used for pretty
much anything on a microscopic level. But in fact on almost all
accounts rendered by the scientific community, "nanoXXX" is regarded
as a reference point on an atomic level if not at least the molecular
That being said, (and back to woodworking!) I am waiting to see if any
of these nano products make it to market soon. I have read about
paint that will block cell phone calls for about 5 years now. Never
seen it in use. Sure would be nice at the movies, eh? I have read
tales of sign companies that can power ad signs and change their
messages and colors with nanobots. There were claims of nano
technology breakthroughs that could block certain wavelengths of
radiation, and UV rays as well while remaining transparent.
It could be interesting days ahead for the coatings industry. Just
wish they would speed it up!
The rest of the applications for that technology in medicine, farming,
computing (remember the gel drives?), and on and on is just
staggering. Real nanotechnology will touch every part of our lives
High Performance Top Coat is the hardest, most durable consumer polyurethane
top coat on the market today. It contains all the consumer friendly
characteristics of PolyAcrylic Blend. In addition it contains a UV
Stabilizer to protect it from breaking down in sunlight and to protect the
underlying stains from fading. And with its pure polyurethane durability, it
can even be used on floors. This is the most durable product. Not
recommended for outdoor use.
The product is sold At Woodcraft of Rockler, it is made by General
Finishes. Non yellowing.
The problem as I have read is to have a finish that can actually block the
UV light from getting to the wood. Many of the UV protection additives are
there to make the finish last longer, not the keep the wood from changing
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