Steve Hill wrote:

Easy huh...pressure wash, tide wash, stripper on...scrape, pressure
wash...and dispose....then you need to Alodine 1200 the entire
surface...then use a good "metal etching" primer ( I prefer Montana
Products) and re-paint the whole thing and WHITE....is really the only
choice....

Years ago, I compared two nearly identical "Minden Fab" style aluminum
trailers, one painted white and the other without paint.

* for the skin in the direct sun, the unpainted aluminum did get
noticeably hotter to the touch than the painted skin

* out of the sun, both skins were the same temperature by touch

* The temperatures inside the trailers within 6" of the top were about
10-15 degrees F hotter in the unpainted trailer

* The temperatures at the gliders (inside the cockpit, near the major
fuselage and wing pieces) were essentially the same

* the top third of the fin was hotter in the unpainted trailer

These temperature comparisons didn't change significantly with the sun
directly overhead or from the side (with the sun at 10 am, for example).

My analysis:

* the hot air inside the trailer rises to the top, which forms an
insulating layer (that 6" of hotter air I measured)

* the sides of the trailer without sun (and the floor) conducted enough
heat away to keep most of the inside of the trailer only a few degrees
hotter than the outside air (both trailers)

I decided the effort and cost to paint the trailer would keep the glider
less than 5 degrees cooler, so I didn't do it.

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA