Nitrate dope comes in two flavors, taughtening and non taughtening. What I use (and have used for ever) on silk is taughtening, and Randolph Products Company is the only manufacturer in the US that makes it. Available from Aircraft Spruce.

Les

Now John,
You are not "sniffing" this stuff are you????
I remember silkspan.....and I would always come into the house a little dizzy....
Regards,
DOC