Patina? color shift forming.

[Alf in Iowa]

Over the few weeks that I have been working and assembling all of the parts that male up the keel and deadwood I have had the sense that the wood was darkening. I consciously wondered it it was actually happening or if I was imagining it, not sure but also not really denying it. I shrugged it off as possibly skin oils from my hands along with the ongoing and ever present charcoal dust from laser cut edges being worked.

So tonight my curiosity got the best of me and I proved it to myself by laying out the keel assembly with some of the leftover wood that surrounded the keel pieces. There, side by side under the same light lies the proof of patina. I actually like it. It reminds me of how black cherry, my favorite cabinet wood, darkens as it ages. I wonder if this might be a feature of pear wood?, or is it merely external from my handling, skin oil and laser charcoal?

In any event, I like it.
alf in Iowa

 

[danielsje]

You may well be correct that the wood is “weathering” itself. I normally coat the wood parts with clear polyurethane matte sheen as I go which seals all the wood. I learned this trick from a professional master modeler years ago…all my wood models are now coated in poly as I build them. And yeah, it slows things down waiting for the poly to dry. However, understand that applying any coating to the wood, no matter how clear it claims to be, adds a patina to the wood…I have not found this to be a problem. Also, I have found that applying acrylic paint over the poly produces a smooth, rich painted part.

 

[bill36]

1. ALL wood darkens with age. The process is fundamental to the physics of chemistry.
2. The violet/ultraviolet range of frequencies in "light" reacts with some (perhaps all) of the chemicals in the wood resin
and decreases their ability to reflect 'light'. This reaction process causes the wood to gradually absorb more and more of (ultimately all)
the light frequencies and appear to be darker and darker (ultimately black). That is basically the scientific definition of darkening.
3. This light absorption process is the reason museums have low wattage red tinged (low flux density infra-red frequencies) lighting in their exhibit rooms (because everything absorbs light to some extent) and why they prohibit flash photography. Flash units on cameras produce a monumental burst of ultraviolet light that will eventually (given enough time and enough bursts) turn hardwood, cloth, string, glue, paint and any other physical substance known to man to dust.
4. Were it not for our electromagnetic shield (the Earth's physical process that runs our magnetic compasses which got Columbus to the New World),
this process would have been turned Earth into a dust comet bilions of years ago.

 

[jeep]

You may well be correct that the wood is “weathering” itself. I normally coat the wood parts with clear polyurethane matte sheen as I go which seals all the wood. I learned this trick from a professional master modeler years ago…all my wood models are now coated in poly as I build them. And yeah, it slows things down waiting for the poly to dry. However, understand that applying any coating to the wood, no matter how clear it claims to be, adds a patina to the wood…I have not found this to be a problem. Also, I have found that applying acrylic paint over the poly produces a smooth, rich painted part.

Great tip Dani, pre covering in a poly, will try. ( and I'm sure will make painting a lot easier.