Hi, what do you use as sand blocks for fairing?
I watched some tutorials but they were all about wood working. Wonder if there is some adjustment specific for composites.
So...
Wood (btw, with or without pads)?
Foam? Xps would be ok
Commercial available? Ifound permagrit blocks fantastic but they only make the coarser grits.

Thanks

You can cast-in-place sanding blocks with some packing tape on your surface, some polyester filler (Bondo) to take the surface shape and a wood backer to hold on to...

I'm a big fan of the 3M yellow foam blocks and the Stickit paper too - the blocks are hard enough yet have some give.  Not cheap but a great system.

You can also glue acrylic sheet to softer foam to make a flexible-yet-hard block for curved surfaces.  You want to sand (fair) with something that takes the shape of the surface you want to achieve - but no more - so you hit the high spots but don't over-sand the low ones.