If the old ones are not cracked, I'd use them as patterns for the new lenses. An evasive answer, I know, but I'd say in a typical small aluminum frame the dimension change due to heat would be negligible and leaving an 1/8" clearance all round should prevent cracking.
Rich Knowles Indigo. LF38 Halifax On 2012-10-17, at 21:43, Bob Moriarty <bobmo...@gmail.com> wrote: I am replacing the lenses on my portlights. They are in aluminum frames that are screwed into the cabintop. I understand that I need to take into account the expansion/contraction of the lens material. When the temperature increases does the inside circumference of the frame increase or decrease? Thx in advance, Bob M Ox 33-1 Jax, FL _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com
