I recently started using Brodak (Randolph) butyrate dope after always using Sig. Let me say, I did not know that there could be that much difference between brands. Please do yourself a favor and try some Brodak dope (which is produced for him by Randolph). I really think you'll be very impressed. I still use Sig nitrate for attaching covering. I like to leave the lid cracked to let it thicken up, then two unthinned coats is all it takes to adhere silk, tissue, etc.