Brian,

I would go w/ the NP-1 urethane. Have used it for many years in the 
curtain wall environment. Paints over fine in my experience. Sealants 
that say they are paint overable are not all equally so. As to 
'reversible' sealants are temporary/sacraficial materials intended to 
have a limited durability -- though chemical science keeps extending out 
the durability and desired performance characteristics. I don't see 
reversability issues in the sealant question unless one is wanting to 
use heritage sealants for a specific reason of authenticity. As to the 
Sherwin-Williams product if they provide a full system warranty then 
consider it in the evaluation.

Now, other issues my consultant friends out of Dallas always spec 
silicones (and Chemrex-Sonneborn has a hybrid urethane-silicone sealant) 
because in their experience urethanes melt out of the joints. Problem w/ 
silicones is that they are not usually paintable.

As to SWI... got friends who are members but have never been inclined 
myself. John Bridges is both in APT and SWI.

][<en

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