Vent gasket caulking

[BradB]

I'm hoping someone can clear up how to properly caulk (Vulkem) the stack vent gasket. I've seen some people who caulk the whole exterior and others who suggest all sides but the bottom.

I'm also wondering if I need to seal between the gasket and the pipe. The existing ones were not but that doesn't mean it was correct! I put the screen above the pipe and gasket thinking it would result in a better seal without the gasket sitting in the screen.

Anyone want to share their thoughts? Thanks!

[Mike Leary]

Did you buy a new gasket & screen? Caulking is not going to do any good without fresh rubber gaskets.

[Splitrock]

http://www.airforums.com/forums/f456...tml#post680585

[perryg114]

I am going to come up with a fix before long that will eliminate that gasket that lasts a short time then cracks. I put my vent stacks back together with a thick bead of Trempro-635 around the pipe. It is an experiment but I am working on a permanant fix. If you go back with a gasket you should caulk around the flange above and below the gasket. The gasket will crack in a short period of time.

Perry

[Tom Nugler]

Here is the method I’ve used on the Tradewind stacks. Did the same thing on my ’67 Globetrotter that uses a different type of cover.
Some may consider this blasphemy but I don’t use Vulkem, Tempro or Sika Flex. I use Ultra-Blue Silicone Gasket maker. This has been used in the automotive service field for 20+ years. It was designed for aluminum blocks, pans, valve covers, ect. it is non-corosive, very flexible, has a wide temperature range, gap fills, sticks to almost everything and appears to last forever. http://www.permatex.com/products/automotive/automotive_gasketing/gasket_makers/auto_Permatex_Ultra_Blue_Multipurpose_RTV_Silicone _Gasket_Maker.htm
The 3 vent covers on the TW had the screens corroded or broken out, with dirt and leaves collecting inside and water leaking down into the closets and floor.
Just putting the screen down over the pipe won’t stop junk from collecting inside the cover. There may be a small weep hole at the lower edge of the casting. IMHO this is fairly worthless. I filed out a ¼ inch grove at the bottom of the flange to drain out any water that gets in. I fit aluminum screen to the inside of the cover and secured it with the Ultra Blue and let it cure for a couple of days.
After cleaning the old sealer, gasket and crud from around the vent pipe I laid a generous bead of the sealer between the pipe and the shell and a dab around each screw hole. Then fit the gasket over the pipe. Then the cover went down on the gasket without any sealer. I secured the cap with new stainless screws.
My thought was since this stuff is pretty tenacious I don’t want to wreck anything taking off the cover if the screen is damaged or the vent plugs up.
After this repair the GT hadn’t leaked in the 5 years before I sold her and the TW is leak free after 3 seasons. As an aside, I have a "temporary" Ultra-Blue patch on a plastic wash tub at home that’s held for 18(?) years.

The purists may flame me for using a silicone but I can’t argue with success,
Tom

[noreen&sal]

Nice job. Sal.

[BradB]

Thanks everyone for the comments. I did use a new gasket, the old one was well past its best before date.

I like Tom's idea with the screen though, keep all the gunk outside and that will solve half the battle I think. I'll do mine this weekend and post some pics of how I make out!

Brad