Direct sunlight and its effect on the model

[Mike Y]

Trying to find a good spot to display my model. Unfortunately, the living room faces south and have a large windows. It is really great for all purposes except displaying the ship model

I understand that direct sunlight is not very good, but what are the effects exactly, if the model is exposed to the sunlight few hours per day, typically in the end of the day?

 

I have a pinnace model in that spot, it is in the plexiglas case, made out of basswood, stained and painted, finished with WOP, white PVA as a wood glue.

It is there for 2 years already, and no signs of any issues. If I compare the side that is always in the shade vs the one that is exposed to the sun - I can't spot any differences in colour or any problems with wood joints.

 

So how bad would it be if I keep my Cromwell model in that spot for few years? I am planning to upgrade the apartment in max 5 years time, so it is not forever.. 

I will use the gallery grade Plexiglas that blocks a bit of UV light, but then there is a temperature increase when sun shines on a dark pear, can it cause some deformations, oil discolouration or glue deterioration? In theory it is all bad, but in practice?

Would appreciate some experience! The model in question is primarily swiss pear with tung oil finish, anybody had experienced such combination being exposed to the sun for years?

Edited October 4, 2016 by Mike Y

[Landlubber Mike]

Many woods change when exposed to UV.  Some get bleached, others darken.  For some woods, the color change can be very dramatic.  Take a look at this article:

 

http://www.wood-database.com/wood-articles/preventing-color-changes-in-exotic-woods/

[mtaylor]

One way around the problem is either blinds on the window or a solid back (even temporary) on the display case.  Mike gave a good link and also paints will fade in direct sunlight.

[Jaager]

UV may also provide energy and a more efficient wave length of light to accelerate oxidation of organic compounds.

Cellulose can break down. That is wood - but given the thickness, that is likely a very long process.  Cotton or linen

rigging is much more vulnerable.  If you used a synthetic polymer as rigging material, the UV light can catalyze a

further crosslinking - the reaction that produced the polymer - and turn it from flexible to rigid and brittle.

If you are getting direct sun light, everything else in the room might be happier if the glass in the window contained

a UV blocker.  I think there are two types of blocker-  one to block the high frequency waves - that are mostly destructive -

and one for the lower frequency waves that house plants use and would not be good to block if you have plants.

 

Another factor is IR (heat) - factors in the glass of a case and the small enclosed space itself can allow micro areas of

heat that could be much higher than ambient temp.  The rule is: the rate of a chemical reaction doubles for every 10 degrees C. increase in temp.

[druxey]

Wood can also dry out with heat gain and crack: seams can open up.

[Maury S]

"Museum Glass" for the case is an alternative, but very expensive.  I think it blocks out a lot and certainly eliminates glare.  Providing some air holes for circulation is important as well.

 

Maury