For the 2017 eclipse, I cobbled together some cardboard, tape, and eclipse glasses filters to put over the forward end of my Nikon 8252 Aculon A211 10-22 x 50 Zoom binoculars.  They worked great, but looked like trash.  

I wanted to do better for the April 8 2024 total solar eclipse, so I modeled these up.

I cut out about a ¼ inch around the paper/cardboard eclipse glasses and used aluminum foil tape to prevent unfiltered light from leaking into the binoculars.

The filter mounts are tapered and fit over the front of the binoculars.  This should be a snug fit.  You may need to tape them to your binoculars.   You do not want them to fall off, or bad things might happen.

I used black ABS for good light blockage and ruggedness.   PLA or PETG may work fine for you, but do NOT use translucent or transparent material.

I also used fuzzy skin in PrusaSlicer on outside walls with 0.1mm thickness and 0.1mm point distance, purely for aesthetics and feel.  The interior walls are smooth.

I also modeled up to other versions for binoculars in approximately the same aperture range.   One is “Universal” with a wide taper over approximately 62mm OD to ~74mm OD.

The other version is tailored for a friend's binoculars that are 62.2mm OD, so the internal taper is from 61mm to 65mm.

Pointing optics at the sun is hazardous and you are at your own risk in attempting to do so.