Effect of sunlight on different woods

[SVB]

Folks,

I saw this on the American association of Woodturners site but it has general validity.

Do we agree? Padauk change seems extreme. I also have heard purpleheart goes through a similar change ending up muddy brown but have not seen it to that extent myself on the purpleheart I have turned although has not ended up in direct sunlight.

Interesting when splashing out for some of the more brightly coloured timbers!

S

 

[Geoff_S]

I had an experience with a Maple kitchen. It looked fantastic when installed, a lovely light colour.

About 12 years later, I took down a wall to extend the kitchen and made matching units again in Maple. Now when I say matching, it turned
out in style only! The original units in comparison were orange, or if I were a designer, honeyed.

So a couple of options. The first I tried a powerful UV lamp for hours on end on the new Maple. H&S, protective glasses and no persons or animals allowed in while WIP. This did in fact have some effect and "honeyed" the new Maple a bit, but not enough.

So option 2 was to sand back the old kitchen to remove some of the colour. Now interestingly, the old kitchen was varnished and what I discovered was that although the old Maple had changed colour, it was in fact the varnish that had contributed to the orange effect. It still wasn't an exact match.

But it was all I could do and for another 7/8 years the kitchen stayed in place. But what I began to notice was that the kitchen units facing the window were now starting to match the old Maple, in other words were distinctly orange, whereas the units on the other side of the kitchen, away from the sunlight were still a definite Maple light colour.

Ultimately, it started to look a bloody mess, I'll never use Maple again for large areas like that.

As it happens, we had a burst pipe in the kitchen, major mess and the whole lot had to be ripped out and start again. And this time I chose American Black Walnut. 2 reasons. Reason 1, I really like it. Reason 2, it's so variable that the differences in the shades and colour tones are actually the beauty of it.

 

[custard]

Over the years I've done dozens, if not hundreds, of fade tests on different timbers with different finishes. And I'm in contact with many other furniture makers who have also run lots of these practical tests.

Here are four timbers that you'd commonly use in furniture making; clockwise from top left they are Oak, Sycamore, Black Walnut, and American Cherry. The right hand half of each sample has a UV resistant finish, the left hand side is unfinished. The bottom half of each sample was masked off, the top half was exposed in a south facing window, This shows the situation after two months of a British summer.

Couple of points. Firstly, not all timbers fade under these conditions. Most fruitwoods (look at the Cherry in the above photo) will actually darken, Laburnum is another timber that darkens in moderate sunlight. If you're picking a timber for a south facing room these are good candidates.

Secondly, American Black Walnut is probably the worst offender in terms of fading. However, even though almost all the ABW you'll find in the UK is steamed, there are some specialist timber yards (such as Tylers) that stock unsteamed ABW, this is worth tracking down as it is much more fade resistant. English Walnut is also much more fade resistant, yes it still fades, but instead of turning a flat muddy brown like steamed ABW it goes a delicate golden shade and retains a tonal range within the grain.

I could bang on for ages about finishing to resist fading, but the bottom line is forget it. There are some eye wateringly expensive, spray only finishes, that will buy you a few extra years, but no finish will secure the timber's original colour for very long.

 

[custard]

There's a wood finishing question that's related to fading, that's how pale on the pale to dark spectrum does a timber need to be in order for oil based yellowing to be an issue? This was touched on in a previous reply.

As with most of finishing it's fairly subjective. But my own personal view, after lots of practical testing, is that around about Oak or English Cherry is where I stop being concerned.

Incidentally, there's a popular view that water based poly will prevent any yellowing on pale timbers. But that's only partially correct, some brands are truly water white and won't yellow even the palest timber. But most brands of water based poly yellow to some extent, and some yellow almost as much as oil based finishes...as always the moral of the story is test first on scrap!

 

[sunnybob]

I've seen padauk and purpleheart that has been in direct sunlight long term.
Muddy brown is the best description.

 

[HJC1972]

The timbers that have a strong red tone are the worst for colour loss. Red is the most fugitive colour in the spectrum, thus rosewood and the other Dalbergia species, paduak, purple heart etc. will all undergo a quite dramatic change. My other half is a hairdresser and she tells me that the same is true in hair colouring. Red fades most. A more noticeable example of this can be seen with auto paints. Think of red Ford Escort from the early 80s and what colour the bonnet faded to after a few years. Pink. Thats the red doing the off. I think these days paints are better but my eleven year old vee dub Transporter in parika red is definitely fading quite a lot on the roof.