Urethane can and is used for this, just be sure to use a couple pieces of setting tape (I've even used the cardboard off a razor blade) to center the glass in the channel. If you use silicone, be sure it doesn't contain acetic acid (vinegar smell). This will cause rust as a lot of glass guys learned the hard way. Also, if you glue the channel on with the glass in the door, be careful not to roll it up and glue it to the cat whiskers. Don't ask how I know! Also, be careful rolling it down if the urethane or silicone isn't cured, you'll be starting over with a mess. If you ever have to take the channel off, you'll need to heat it with a propane torch, so I don't recommend this method for the vent glass. I've used this method many times over the years for door glasses, mostly by sliding the glass in with the channel and glass in the door, mainly because it's quicker and easier, and one shop I worked for claimed setting tape was obsolete. John
