says...
On Wed, 07 Oct 2015 16:10:52 -0500, Peabody
wrote:

I've got four large (4 x 16) fir beams and have repaired the rot with
epoxy.
But I wondered if if might be a good idea to drill holes in the beams for
borate rods in the hope of preventing the rot from continuing. Anyone here
have experience using them? Any idea of spacing?

What is a borate rod?

This tells all about it:

http://www.ewoodcare.com/Bor8-Rods_c_27.html

but basically, they're supposed to stop wood rot.