On Saturday, May 1, 2021 at 7:29:39 PM UTC-4, Martin Gregorie wrote:
On Sat, 01 May 2021 15:31:02 -0700, MMOORE wrote:

Standard 2-1/4" is ugly and screw holes to not line up.

What is the panel made of?

What, if anything do you plan to do with vacated instrument space (apart
from fitting a blanking plate)?

Solution ?

I've blanked holes in my Libelle's glassfibre panel with high (aeromodel-
building) quality plywood glued in with epoxy. and then finished the job
with fine close-woven 50gsm glass cloth overlapping the screwholes (also
filled, but with hard balsa) on both surfaces and wetted out with
laminating epoxy, and finally painted to match the panel.

The result has been durable enough to let me make holes for other
instruments that partly overlap the filled-in places and, a few years
later, show no signs of failure. Photos of my panel are he
https://www.gregorie.org/gliding/libelle/panel.html

All the materials (50 and/or 100 gsm glass cloth, Z-poxy laminating
epoxy, high quality 1/32, 1/16 and 1/8 plywood, and medium or hard balsa
are all best bought from model supply houses, either your local model
shop or online stores such as:

Midwest https://midwestproducts.com/ for (everything except glasscloth)

CST https://www.cstsales.com/ for glasscloth and epoxy glues and
laminating resins

I've not dealt with Midwest, but have used CST supplies and competed with
its owners at model flying competitions.

I'm also a model builder - can you tell?

HTH

--
Martin | martin at
Gregorie | gregorie dot org

Is an aluminum panel, I could put a back plate on it and a ram stick-on mount would just fill the hole (plan B here)