firewall mounting with insulation

[philb]

For those that have utiilized insulation (ie Koolmat) on forward side of firewall, did you make cutouts in the insulation for the various structure attachments, or bolt things through and on-top of the insulation?

I've seen it both ways, but would think would be better to make cutouts, and have the structures bolted directly to the firewall, (rather than with the insulation sandwiched between the structure and the firewall), then use appropriate hi temp goopage sealing around the attached structure.

Thoughts?

Phil
KSLC
RV-10, finish kit, looking for a hangar...