[AMRadio] Bondo

[Rick]

I haven't used auto Bondo in many years, so maybe someone on here can assist
me.  I have a few small holes where non standard controls have been added to
a cabinet and would like to fill and finish them.  They are no more than
3/8" in diameter.  Can I just fill them with Bondo or do I need to place
some kind of backing inside the cabinet first?

Is Bondo the best material to use?  I'll be painting it later.

Thanks for any and all assistance.

Rick/K5IAR