Anthony Watts reports on whitewash versus latex.
Since they mentioned paint, I thought I’d share this experiment with everyone. You may recall that I’m conducting an experiment measuring the differences in temperature imparted by different coatins on the Stevenson Screens. Early screens were spec’d to have whitewash. I made up a batch of whitewash based on a known historical formula and setup a test rig:
Here is one day’s worth of plotted data related to whitewash -vs- latex -vs-
bare wood I have three weeks of this logged data and they all look pretty
much the same. Russ Steele was kind enough to plot the data for me for a day, May 21st.
These are temps recorded in a 1/4″ borehole in the center of the wood slat
along with air temperature from an aspirated stacked plate IR shield. The
datalogger I used is NIST calibrated, and the probes are NIST calibrated.
Error is 0.1 degree F or less, and they are quite linear.
I have made it available on
http://www.surfacestations.org/downloads/paint_test1.zip These are all comma
demilited text files, suitable for import into R or Excel. This is three weeks worth of data.
The columnar format is:
date, time, Air Temperature, Bare Wood Temp(control), Latex Paint Temp, Whitewash Temp all in degrees F
I have my three new Stevenson Screens in, so I’m going to switch now from
wood borehole tests of the painted slats to actual air temperature tests in
three standard Stevenson screens. I expect the temperature differences to be
smaller, but still measureable.
I have aquired the exact formula for lime based whitewash and the exact
materials from a chemist at the National Lime Company. They are watching
closely too becuase whitewash appears to be a superior coating for buildings
to create energy savings for air conditioning.
Will advise when the new experiment is up and running, it will be live online.