1. Low-E Coatings for HET Data & Conclusions 2 October 2002 John Good

2. Ambient 9ft.
Ambient 86ft.
Foil
LO/MIT
TiO2
Passing through
Louvers?

3. Ambient 9ft.
Foil
LO/MIT
TiO2
Ambient 86ft.

4. Ambient 9ft.
Ambient 86ft.
Foil
LO/MIT
TiO2
Passing through
Louvers?

5. Ambient 9ft.
Passing through
Louvers?
Ambient 86ft.
Foil
LO/MIT
TiO2

6. LO/MIT Durability Tests
Shoe Scuff
Finger Nail Scratch

7. LO/MIT Durability Tests

8. LO/MIT Durability Tests

9. LO/MIT Durability Tests
Shoe Scuff

10. LO/MIT Durability Tests

11. Conclusions ALUMINUM FOIL IS RECOMMENDED COATING: Performance - Foil
Al Foil stays 2-5 times closer to ambient temperature in 3 out of 4 measurements.
Installation – LO/MIT
Both coatings are easily prepped and applied.
Long Term - Foil
Foil will probably stay cleaner than the soft & rougher surface of LO/MIT.
Adhesion of foil is very good with no de-lamination problems reported by other Observatories.
Assuming the foil ever becomes “heavily oxidized”, it will perform as well as a fresh, clean coating of LO/MIT.
Maintenance - Foil
Recoating of LO/MIT will be a given every 5-7 years.
Multiple layers of gummy coatings.
LO/MIT is a permanent decision.
No other coating can be applied on top of LO/MIT.
Removable only with solvents – power wash won’t do the trick.
Al foil can be be re-laminated.
Much easier if the adhesive lasts since removal of old layer would be difficult.
No problems reported so far.
Aesthetics – Foil
Cost – LO/MIT (both costs are reasonable)
Aluminum Tape: $35-37k
$22k (tape & primer) + Labor (~6-8 man-weeks) + $7k (125ft. Man-lift) + $1.5k (Misc. Supplies).
LO/MIT: $19-21k
$5.5k (paint) + Labor (~6-8 man-weeks) + $7k (125ft. Man-lift) + $1,500 (Misc. Supplies).

12. DIMM Tower Foundation Poured last Friday. 15 tons of concrete.
Good work McDonald Physical Plant!