Translucent wood - experiences?

I came across this article recently: https://www.cbc.ca/radio/quirks/scientists-develop-transparent-wood-that-is-stronger-and-lighter-than-glass-1.5902739



A researcher holds up a square of transparent wood material against a green leaf. (USDA Forest Service)


Researchers at the University of Maryland have turned ordinary sheets of wood into transparent material that is nearly as clear as glass, but stronger and with better insulating properties. It could become an energy efficient building material in the future.

Wood is made of two basic ingredients: cellulose, which are tiny fibres, and lignin, which bonds those fibres together to give it strength

The process of removing the lignin, which gives wood its color, is apparently simple:

Starting with planks of wood a metre long and one millimetre thick, the scientists simply brushed on a solution of hydrogen peroxide using an ordinary paint brush. When left in the sun, or under a UV lamp for an hour or so, the peroxide bleached out the brown chromophores but left the lignin intact, so the wood turned white.







So, this may not be new, or news to anyone, but it sure does seem simple and interesting. The need for epoxy may negate any benefit of this process, but perhaps not.

Has anybody here attempted this process? Or worked with translucent wood material? Thoughts, ideas? I'm intrigued...

How'd they go from white to clear?

Mike Haasl wrote:How'd they go from white to clear?

I think they infused it with an epoxy.

It was in the linked article:

"Next, they infused the wood with a tough transparent epoxy designed for marine use, which filled in the spaces and pores in the wood and then hardened. This made the white wood transparent."

That's really fascinating to think about.

I'm assuming it's white because it's reflecting light. So they make it transparent by eliminating the surface fluctuations with epoxy, no more surface irregularities.

I don't know what to think about this... on the one hand using natural materials is good, but is epoxy better than glass?  It can be stronger, lighter, etc. but I don't think epoxy can be recycled in any way (although, wow, that carbon is SEQUESTERED BABY! Its NEVER getting out!). Glass is also essentially inert in the face of UV rays, while all (most??) plastics degrade with UV exposure.

Does it have a decent R-Value?
Wood is a better insulator than glass, but translucent treatment might change that.

William Bronson wrote: Does it have a decent R-Value?
Wood is a better insulator than glass, but translucent treatment might change that.

The article claims this will have a higher R-value than glass, but it may only be a marginal improvement.

I've been playing around with this a little bit.  So far I'm still working out the bugs.  To get good clarity you need a filler material that has a refractive index that matches the bleached wood vascular walls.  So the epoxy is one option, but we should be able to copy this with the correct natural material recipe.  I have this image in my head of large logs cut into cross sections that let the light stream through, but done so that you can still see the wood grain...using only natural materials.  Wish me luck :)

One note for folks looking at this.  The researchers used 30% hydrogen peroxide for this work.  The hydrogen peroxide at the store is typically 3%.  Not sure how much harder it would be to do with 3% solutions.  I'll pick up a bottle and give it a shot.  Maybe it will still work but just take longer?

Greg Martin wrote: I have this image in my head of large logs cut into cross sections that let the light stream through, but done so that you can still see the wood grain...using only natural materials.  Wish me luck :)

Yes, keep experimenting!

My plate is full at the moment.

Eliot Mason wrote:I don't know what to think about this... on the one hand using natural materials is good, but is epoxy better than glass?  It can be stronger, lighter, etc. but I don't think epoxy can be recycled in any way (although, wow, that carbon is SEQUESTERED BABY! Its NEVER getting out!). Glass is also essentially inert in the face of UV rays, while all (most??) plastics degrade with UV exposure.

There are ways to make resin out of tree sap, maybe that would work?

Or maybe treating the bleached wood with beeswax, linseed oil, or some other kind of natural water-resistant material would work? The result might be more translucent than transparent, but it would still be interesting to find out.

Greg:  Are you actually experimenting with thin slices?    If so, how thin are you going?  The source talks about 1mm , which I certainly can't produce!  I do like the idea of a stained-glass corollary with the image of a tree cross section!

Hydogen Peroxide in stores is indeed pretty weak.  It can be purchased at a 30% (or higher!) strength... but at a price (maybe $40/gallon in quantity).  that's still retail ... and mostly "Food Grade".  If you buy industrial grade stuff by the truckload then I'm sure the cost is lower!

I had to do some sniffing on R values (or equivalent) for glass vs plexi or polycarbonate.  Didn't find a table for it ... but the agreement seems to be that plexiglass itself has a lower R value than glass.  Of course the real energy/thermal improvements in glazing are in construction (double or triple walled, inert gas injection, eliminating thermal bridges) and in the fancy coatings that reflect certain wavelengths.  I'd think all of those techniques would apply here as well.  I'd going to accept the claim of a higher R value, but also not particularly care about that one factor as the marginal difference is probably low.

I've been thinking about the required fiber length ... if a 6' window required continuous 6' fibers (no knots?) then you're taking some of the most valuable (and expensive!) timber.  Mills and growers have switched to largely using smaller, younger trees - and the evil (IMHO...I'm being dramatic here) OSB which can be made from the poorest quality timber.  Anyway, applied to glazing ... there is an interesting potential here to make the equivalent of "transparent plywood" with bi- or tri-axial layers of wood fibers in the glass, or by laying all the fibers in one direction making the equivalent of bender board (yes, plywood that bends in one direction) and you'd have flexible glass?  I wonder if this is a corollary to laminated safety glass.  Further, following the OSB route... if really thin chips were treated and then tossed into the mix, would that work?

Eliot Mason wrote:Greg:  Are you actually experimenting with thin slices?    If so, how thin are you going?  The source talks about 1mm , which I certainly can't produce!  I do like the idea of a stained-glass corollary with the image of a tree cross section!

Hi Eliot, I've not gone thinner than 1/4" but I'm not happy with the results I've had so far.  I'm really just getting started and am still trying to figure things out.

Ellendra Nauriel wrote:
There are ways to make resin out of tree sap, maybe that would work?

Or maybe treating the bleached wood with beeswax, linseed oil, or some other kind of natural water-resistant material would work? The result might be more translucent than transparent, but it would still be interesting to find out.

I'm thinking the same Ellendra.  I have various tree resins and linseed oil sitting on my table right now.  I thought about wax too, but waxes tend to not be clear due to crystal formation I suspect.  Having said that, blending waxes with natural resins I believe can result in clarity.  May have yellowness.  It shouldn't be too difficult to come up with a blend that refracts light the same as cellulose and therefor produces a nice transparent window.  The only thing I'm wondering is will this darken over time.

Wonderful that you're playing with this.  I'm sure we'd all love to see progress when you're ready!

when i saw the thread title i immediately thought of cellulose clear rolling papers
which a google search for that turned up an article in stonerthings.c
not sure if it has any relevant info for you
they mention using eucalyptus tree and Asiatic cotton mallow as the source of cellulose

thanks for sharing that.

I think the method in the OP can be summarized as:
cut wood thin
place in sun, paint with strong hydrogen peroxide
eat a sandwich
collect wood

The video version ... is much more complicated!  But he also goes into a lot of experimentation with how to apply the epoxy.

What follows might belong in the Toxic Ick forum ... I've used some products from Rot Doctor.  They have VERY thin epoxies that are meant to penetrate wood ... like 18' (yes, feet).   I'm not sure about the optic qualities, but a thin epoxy might have some benefits.

I was surprised by the method used in the video to penetrate the epoxy.  I would think that you would want to drop the wood onto the epoxy so that you wouldn't be fighting surface tension but would rather be using surface tension to wick the epoxy up through the wood's vascular bundle.  Not sure though and won't be trying it as I don't ever plan to use synthetic resins.  Not sure when I'll next get into this, but I'll try and post some update photos.

Modern fabric + epoxy resin setting techniques sometimes use vacuum pressure to push the resin throughout the fabric. I mostly am aware of this from canoe building.

Essentially a plastic bag is placed over the resin coated fabric (kevlar, carbon fibre, etc), a vacuum is pulled on the bag.

I suggest using Sylgard rather than epoxy. Even high quality marine epoxy yellows over time. The Sylgard is used for making solar panels because it doesn't yellow. It's not cheap & very un-permie though.

Greg Martin wrote:

Ellendra Nauriel wrote:
There are ways to make resin out of tree sap, maybe that would work?

Or maybe treating the bleached wood with beeswax, linseed oil, or some other kind of natural water-resistant material would work? The result might be more translucent than transparent, but it would still be interesting to find out.

I'm thinking the same Ellendra.  I have various tree resins and linseed oil sitting on my table right now.  I thought about wax too, but waxes tend to not be clear due to crystal formation I suspect.  Having said that, blending waxes with natural resins I believe can result in clarity.  May have yellowness.  It shouldn't be too difficult to come up with a blend that refracts light the same as cellulose and therefor produces a nice transparent window.  The only thing I'm wondering is will this darken over time.

Even if the result was cloudy and yellowish, it would let light through better than most easily-growable materials. Assuming it works, that is.

Mike Barkley wrote:I suggest using Sylgard rather than epoxy. Even high quality marine epoxy yellows over time. The Sylgard is used for making solar panels because it doesn't yellow. It's not cheap & very un-permie though.

Agreed that Sylgard will last for a long time without yellowing.  My only concern would be that silicone has a lower refractive index than cellulose so I expect that the final result will exhibit a lot of refraction and therefore the amount of light transmitted will drop off.  Worth a try though.  184 has low viscosity for potting applications so it'll probably infiltrate nicely.

Just curious....does anyone know of any biological route to bleaching out the color bodies from the lignin?  I was just wondering if any fungal treatment, or anaerobic pickling approach, or really anything microbial might break down the color of wood and leave behind the whiteness.  Looking for a process that does create any strange waste products to deal with.  I suppose peroxide might fit that bill, but a biological route that doesn't require buying strong chemicals seems attractive if possible.

My other thought is that some woods are lighter to start with, like poplar.  Maybe they would be easier to bleach out or otherwise might not need it?  Living near the ocean, I've also noticed that driftwoods can sometimes look bleached out.  This gets me back to thinking about salting and fermenting wood, but driftwood lightness may be related to the salt water and sunlight combo???  No idea but fun to think about and perhaps experiment with.

Forgive my stream of consciousness posting.  If sun and wet salty wood does bleach out wood, I next wonder about filling the wood structure with salt....either NaCl followed by a sealing layer....perhaps something like the Sylgard mentioned earlier, or else perhaps filled with a salt that isn't water soluble, like CaCO2?  I'm also thinking about forming glass within the wood as it should produce a good refractive index match.

I was looking at her prices for raw wood veneer and they seem reasonable.
I think beauty supply stores deal in extra strength peroxide.
I wonder if waterglass could work in place of resins.

When I first saw this shared on another site a few days ago, I was tempted to try it right away, but I should probably stay focused on my current projects. Can't get distracted by the shiny! Glad to see someone else experimenting.

For source wood, hobby stores often have 0.8 mm balsa wood.

An idea that came to mind is: if you are going to use vacuum equipment anyway, could you vacuum the bleaching solution deeper into thicker wood, getting decent light transmission with greater strength and thermal resistance?

@Greg Martin - I'd be *very* curious how the bleached wood with nothing else done to it, affects plant growth. I *really* need some sort of greenhouse like shelter and the amount of plastic involved is something I'd *really* like to avoid. However, glass needs a much more substantial frame due to it's weight, and there's the added risk of breakage. If this "translucent wood" allowed enough of the spectrum through that plants like, that would be really great.

Then we'd have to determine how long it would last without rotting... mind you, much of the plastic last less than 5 years.

We get gallon jugs of "cleaning" hydrogen peroxide at a local garden/farm/horse store. We normally dilute it for our purposes, but it's not that hard to get and as chemicals go, it's kinder than many.

Jay, the few pieces I've made so far will let some light through when they are filled with water, but once the water dries out it becomes very white and would reflect away most light.  I was wondering if light might channel through if aligned with the wood's vascular bundles, but between the sieve plates and wall bumps it never really had a chance.