A question about prepared timber

[danfoto]

If I go to the local timber merchants and buy some of their prepared timber, it's really white wood.

The old secondhand prepared timber I've got in the shed tends to be much darker, and some of it's gone a lovely golden colour, although it's not been waxed or stained.

I assume that the colour change is down to oxidation of something in the wood (tannin?), but my question is - what causes that oxidation?

Is it just heat, or is their more to it?

 

[flecc]

It's light which has photo synthetic effects on softwoods, increasing the yellow tinge of these, some species such as certain pines yellowing more. There are various chemical treatments used by furniture and paper makers to prevent this happening. I've seen references to ortho-quinones being produced in the wood by light over time, but I'd guess the basis for these and the colour is the naturally high resin content of soft woods, resins tending to be yellowish anyway.

 

[danfoto]

Thanks for that, flecc. I was inclined to think it was heat tending to accelerate oxidation, so I guess if I want to mellow this new stuff down, I just leave it outside in the sun this summer?

 

[yselmike]

I recently got one of these rosewood sideboards not this one but exactly the same

Fristho sideboard R Glatzel rosewood 1960 | Mass Modern Design

Its gonna get a full blast of the sun during summer afternoons over about 50% of it, what will this do?
do I need to draw my curtains cheers

 

[hech]

Iron oxidises wood doesn't. The sun tends to bleach unprotected wood and turn it greyish, though this depends on the variety. White pine or deal is standard builders merchent stuff and again varies in colour depending on the preservative the timber mill uses. Most furniture is treated with ultra-violet resistant lacquers to stop discolouration so its always a good idea to varnish your wooden bike with at least 8 coats.

 

[flecc]

I recently got one of these rosewood sideboards not this one but exactly the same

Fristho sideboard R Glatzel rosewood 1960 | Mass Modern Design

Its gonna get a full blast of the sun during summer afternoons over about 50% of it, what will this do?
do I need to draw my curtains cheers

From my previous experience with similar furniture, sunlight will fade it, so curtains best drawn for protection. In my case a similar protection was more convenient, namely a venetian blind with 5 cm wide slats which interrupted the downward angle of the sunlight but left the room still well lit.

 

[danfoto]

White pine or deal is standard builders merchent stuff and again varies in colour depending on the preservative the timber mill uses.

I'm on about prepared timber, not stuff that's been Tanalised or whatever.

So you're saying that sunlight will turn white pine grey-ish?

 

[hech]

Pine, cedar, larch, oak, tropical hardwoods all will grey in the sun unless uv protected. Spruce is the cheapest and most commonly available softwood and is naturally very white. It is almost always treated with preservative as it rots so quickly when damp. Pine often will turn more yellow (mellow?)initially but will grey eventually if left exposed. Oiling the wood will improve the colour and help protect it.

 

[flecc]

Seems from what hech says that being in the shed out of direct sunlight UV has protected yours from greying yet danfoto.