[Public-List] Butyl and Polycarbonate

Greg Bover via Public-List public-list at lists.alberg30.org
Mon Oct 6 13:29:37 PDT 2014

When I redid my port lights a few years ago it wasn't because they leaked,
it was because I couldn't see out of them anymore because of fogging. When I
got the boat they were an unknown plastic and caulked with what appeared to
be butyl. I use polycarbonate in my business and I knew that it was subject
to embrittlement and fogging when exposed to certain chemicals. I did some
research and found lists like the ones at
www.palramhort.com/pdffiles/PC...Info/PC_Chemical_Resistance.pdf  and
As there are various sorts of butyl and butyl compounds on the lists of
chemicals to avoid in contact with polycarbonate I opted to use a Dow UV
resistant silicone. I had to do quite a bit of masking to make a neat job of
it, but so far, (two years) it has held up well with no sign of fogging.
It seemed to me that the best combination would have been safety glass with
butyl, but the estimate for just the glass for the four larger ports was
$250, whereas I could use off cuts from my shop for nothing. Ahh.life on a

Greg Bover
A-30 #114

Gregory R Bover
V.P. Operations, Project Manager
C. B. Fisk, Inc.
978 283 1909

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