A couple of points from an old glass guy:
If you use boiled lindseed oil instead of soapy water it will turn to glue ones it's dried and aid sealing. Be sure your string is at least 3/16 thick or you will risk cutting the rubber with it. Put the rubber on the glass first, install the metal trim in the rubber (if there is any) and then tape it on useing many short lengths of masking tape. Your string will cut through them as you work it in. It usuially helps to have a partner push oh the glass (gently) on the outside while you work the string on the inside. Once it's in, slap the glass to seat it. If you do it so that it hurts your hand (slap, don't hit!) you won't break the glass(another reason why you should never wear a ring in the shop.
Leif (Owned a glass shop '76 to '88)
