Source for notched clear mica insulators

[dorkshoei]

Does anyone know where to purchase replacement mica insulators like these pictured (it looks like they originally came supplied with thermal paste on both sides).

They have notches which locate them onto the clip that secures the component to the heatsink.   There are at least 3 different sizes of insulator (3 different clip widths).   Not an attachment style I've seen before.

If I can't source the originals my plan was to buy a sheet of 0.1mm mica and cut my own using an xacto. Such as: https://www.mcmaster.com/8802K16   

I couldn't see sheets of mica on digikey/mouser but if anyone know a source please let me know.   I don't want to use AliE as I'm worried about getting fake plastic sheet or similar.

[Postal2]

Find some old mica capacitor and break it apart.

[jpanhalt]

My first impression is that a shearing action would be better than a knife for shaping mica sheets.  For the notches, look of what's called a nibbler.  I have never tried an abrasive cutoff wheel, and that might also work.

[thm_w]

Is there a specific reason you can't use a silicone thermal pad?

Mica is supposedly 0.6W/mK, you can get sil pads of better thermal transfer in similar thicknesses. But maybe double check the voltage withstanding capacity.

[dorkshoei]

My first impression is that a shearing action would be better than a knife for shaping mica sheets.  For the notches, look of what's called a nibbler.  I have never tried an abrasive cutoff wheel, and that might also work.

Found this where it's cut using a Stanley/utility knife: 

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Still be interested if anyone knows a source for exact replacement.

[jpanhalt]

Still be interested if anyone knows a source for exact replacement.

Unlikely anyone can answer that as they seem to have been made for a particular purpose.  The manufacturer of the device would be your best bet or its parts list, if available.

EDIT: Mica can be cut.  It can also be scored and broken like glass.  Shearing will probably cause less delamination.  As mentioned, I haven't tried abrasive cutting.

[squadchannel]

Does it have to be the exact same shape?
Mica sheets for TO packages with holes are available on digikey.

https://www.digikey.com/en/products/filter/thermal/pads-sheets/218?s=N4IgjCBcoOwAxVAYygMwIYBsDOBTANCAPZQDaIAzDAKwBMAHAJwgC6hADgC5QgDKnAJwCWAOwDmIAL7SgA