[mlangsdorf]

Silk would be TL 0, WM 0.85, Cost $160, DR/in 8, Max DR 4, Notes CF*, Construction fabric.

Spider silk would be TL 0, WM 0.85, Cost $800, DR/in 8, Max DR 4, Notes CF**, Construction fabric.

* +1 DR versus cutting and impaling attacks, reduces effectiveness of barbs per Low-Tech p 104.
** +2 DR versus cutting and impaling attacks, reduces effectiveness of barbs per Low-Tech p 104.

This was a pretty simple conversion: silk armor costs 20x as much, but weighs the same, as cloth armor as the same DR. Spider silk armor is 5x as expensive but the same weight as cloth.

If you want a little more precision, you could say that every half inch of silk (round fractions up) gives +1 DR versus cutting and impaling attacks, and spidersilk has twice the bonus.