Karen,

Most glazes are water based. The weather will eventually 'eat' them away. If you put Z Spar varnish (it contains linseed oil) directly over the door or wood, ( no added pigment) it shouldn't take long before it begins to discolor and look aged. However you won't be able to control just how aged it will look. Perhaps, you could try a test piece. Good luck.

Lav

I've aged doors with a crackle finish. I painted a base coat of one color, then a top coat of another color. Then I apply the crackle finish, and use a blow dryer to dry it quick. The top coat cracks as it dries, exposing some of the base coat. Then I used a varnish on top to protect.

The crackle finish is sold by Ralph Lauren Paints, or they have something at Pottery Barn also.

Hope this helps.