I used a 2-foot diameter piece of hole- perforated metal (below); top painted white, bottom painted flat-black. Worked OK except at sunrise & sunset. A semi-circular (half dome) shape is probably better.
Did you use it in addition to the 7714, or instead of it?
How would you orientate the dome relative to your temperature gear? i.e. how high, and (if applicable) how far around? Fabricating a dome doesn't sound easy, but an arch out of that material might be easy.
Maybe a partial dome would be good enough? I must admit, though, a full dome does have a certain aesthetic appeal to it. As a conversation piece, it would certainly beat most other yard ornamentation I've seen.
Can you add a bit more color to "worked OK"?
I tried using it *with* the original OSI THGN801 sensor assembly as a radiation shield (of sort); positioned about 6-inches above the THGN801 unit on its own L-bracket.
It was a 2-ft square hunk of left-over metal in my garage that I sprayed one side (top) white and other side (bottom) flat-black, using Krylon spray paint (I believe).
That's a clever approach. I gather your idea was to absorb on the bottom and to emit and reflect on the top? Also, your approach uses the metal's thermal conductance to move the heat from the bottom to the top, where it could be directed away from THGN801. Very clever indeed. If all that worked efficiently, then doing it without the holes maybe would take it up a notch?
It looks as though Krylon flat black maybe isn't ideal, though, because although it does absorb it's also highly emissive: http://www.infrared-thermography.com/material-1.htm.
I guess if you were NASA, a good finish for the bottom would be GSFC Dark Mirror Coating (which absorbs 0.86 but emits only 0.04) http://www.dtic.mil/dtic/tr/fulltext/u2/a305864.pdf. Maybe it's possible to get some sheet metal with it already coated onto it? You wouldn't need much of it, so maybe the cost wouldn't be as bad as what you might be thinking. Then you could just cut to size and spray Krylon 1502 white paint onto the opposite side.
Or, maybe there's something else with similar properties. I didn't do an exhaustive search. Anyhow, if cost and convenience are dominant, the glossy black paint is probably less emissive than the flat black paint. It sounds like you're happy with your 7714 as it is, but if you still have your prior creation, maybe you'd want to try it out on the 7714 anyway? You might be so happy with it that you'll think you're in heaven.
