On Monday, August 26, 2019 at 10:54:32 AM UTC-7, Puckdropper wrote:
whit3rd wrote:

I've made some bins ...[with] tempered hardboard (like we used to call Masonite).

HOW can I make a clean slot in what is essentially just heavy paper?

Have you tried scoring the cut line with a knife first?

It's usually a problem on the long-dimension rip on a 4x8 foot sheet,
so the scoring would involve a modification to a table saw (possible, but
messy) or some really long straightedge for guidance.
I'm considering a narrow-kerf blade in a zero clearance throat plate (very thin material,
otherwise I'm uncomfortable with narrow-kerf solutions).

Really sharp tools will help a lot, but most edges are angled for
longevity and not ease of slicing. I wonder if an ATB blade will help?

Yes, a rip blade WOULD be a better (than combo) for this; currently, the plan is
to do those cuts with a track saw, and I'm not sure I have the rip-blade option
in my stack of small blades. It's worth looking into, thanks for the suggestion.
Zero-clearance throat plate in the track saw?

Aerosol shellac on the edges, and a lick with a hot iron, is the fallback solution.
For preference, don't try this with a good teflon surface iron: there's some abrasion.