GE Silicone rubber (RTV) and a caulking gun... OR.... I had problem where gas pipe came out of wall in garage for dryer and I made a two piece plate that was cut in half in center and has a hole centered on center line cut... Put each piece on one side of pipe and a few screws.... The amount "seal" around plate/pipe interface is just how accurate you wish to make it...
Similar to this escutcheon plate.... But home made out flat aluminum sheet (a little overlap at "joint" does not hurt)...

The really cool thing about silicone RTV is it can make a really good weather/dust/dirt/insect/insulating/flexible seal but its easy to remove with just a little tenacity....
Dale
Lives his life vicariously through his own self.
Any statement made by me are strictly my own opinion.
You are free to ignore anything I say if you do not agree.
