Being alone in a empty garage i turned my attention to my dash, like most unrestored dashes these days mine had cracks just the same.
First thing was too open up the cracks so they are level with the surrounding surface, I used a die grinder with a pine cone, overkill for this but worked perfectly at carving up the old foam.
Next was to place some tape on the inside of the cracks that penetrated all the way through, this stops the expanding foam from filling the areas where there not needed. Apply expanding foam, using a a paddle pop stick i would smear the foam onto the walls to help it adhere, sit and wait for a hour or so till its cured.
Once cured, quick lick with 120 on a orbital sander to remove excess foam, normal body filler was used to fill the small holes in the foam, this was repeated until I was happy with the overall shape and con tore of the dash. Block sanded / feather coat and more sanding till i was up to around 600 grit, a final lick of high build primer and a last block to get it smooth.
Here on i drove it out to a mob out in Kelmscott, H-Tek Ultimate Coating, here we are going to get the dash flocked in black. Turns out he would also repair a cracked dash prior to flocking. ........ ... .. ... sigh.
Last pics is another client's dash that was just flocked in charcoal.
While I was waiting for the foam to set i started attacking the rear lights, my lens where dull as you would expect for sitting around for so long, so a bit of wet sanding and going through the finer grades followed by a buffing wheel made them good as gold. I even removed the factory casting identification as polish would just get caught in the nooks and crannies of the lettering.