On Friday, June 10, 2016 at 10:11:21 PM UTC-4, Don Y wrote:
On 6/10/2016 6:42 PM, Meanie wrote:
I have a fluorescent desk light which houses a small transformer with the
prongs and plugs into the wall. The original plastic shell/cover broke and
rendered the light unusable. I believe it broke due to the brittleness caused
by the heat from years of use. Anyway, I like this light and decided to make
another cover out of wood which came out pretty good. My only concern is that
heat again. I drilled little holes to help vent it but it's still a concern. I
used a small piece of black walnut I had laying around to make the shell. I
used my thermal imaging device (Flir adapter for phone) to read the temp of the
unit which reached over 100 degrees. Therefore, I'm wondering if this would be
too hot for the wood and can it cause a fire?

Wood starts to char at about 220F. Dry wood won't ignite until closer
to 400F.

But, I'm not sure how much cooler (than charring) you can safely operate.
I think even at ~200F for long enough time you'll see some discoloration
of the wood. Whether/when that poses a fire risk would be hard to say...

Note that you also have to consider what happens if the transformer fails
or degrades, over time.

you could add a thermal fuse to open the circuit if the temperature exceeds the combustion temp of the wood. this also protects from malfunction overheating.

why not convert to a LED bulb/s nearly zero heat that way