Cut a good number of small chips from a length of metal thread, they should be as long as they are wide.

This example shows bright check.

Use a length of machine sewing thread, waxed and folded double.  Bring the needle through to the front of the fabric from underneath, thread a chip onto the needle and gently manoeuvre it to the base of the thread.

Take your needle through the fabric, and stitch the purl in place.  Your stitch length should be long enough to allow the chip to lie flat without arching up but not too long so that the thread is visible at the end of the chip.

Use the tip of a mellor or laying tool to help direct the sewing thread into position and avoid catching the sharp end of surrounding chips

Continue to fill the shape with chips by varying the angle and stitching them close to one another so that no padding is visible.