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Building Tips and technical articles. => 1/2 A building. => Topic started by: Bill Heher on November 26, 2010, 09:17:43 AM

Title: Kavan Babe Bee tank extender
Post by: Bill Heher on November 26, 2010, 09:17:43 AM
I have a couple of these plastic ring extenders that increase a Std Babe Bee tank into an 8cc  tank. They always seem to leak, even when I use gasket sealer ( Perma-tex Red)).

Anybody know something that will seal the small groove between the extender and the tank body?  The rear cover seems to seal better= stiffer / more area to seal.
Title: Re: Kavan Babe Bee tank extender
Post by: Larry Renger on November 26, 2010, 06:38:39 PM
I would take a bit of Ajax or similar cleanser and lap the extender to the tank with some oil.  Just press in in firmly and rotate it around for a while.  Then clean it thoroughly with soap and water.  That should seat it in nicely.
Title: Re: Kavan Babe Bee tank extender
Post by: Wayne Collier on November 27, 2010, 09:18:25 AM
I've never used one of the Kavan tank extenders so I really can't offer much advice on that; however, I have been using Permatex blue RTV sealant in lieu of gaskets when assembling Cox engines.  I try to use enough without over doing it.  I usually let it sit for a couple of weeks before adding fuel.  I know that takes some patience, but I have one that hasn't been taken apart for over two years and is still performing well with no leaks.   
Title: Re: Kavan Babe Bee tank extender
Post by: Jim Thomerson on November 27, 2010, 09:57:49 AM
The bolt heads supplied with the extender did not seal on the tank backplate, and had major leaks. 
Title: Re: Kavan Babe Bee tank extender
Post by: Larry Renger on November 28, 2010, 01:49:35 PM
I haven't noticed any leaks, but just to be sure, just rubbed silicone seal into the bolt head recesses.  See my Tech Terror thread for where I am using the extender.  I need every drop of fuel I can get to get through the full AMA competition pattern.  I also re-tightened the bolts a couple of days after initial assembly, and did find some new slack to take up!  I guess the plastic "settles in" for a while.
Title: Re: Kavan Babe Bee tank extender
Post by: bob dickerson on December 05, 2010, 07:03:03 PM
first post

I always thought the screws supplied with the
Kavan extender were the weakest link.
Not crazy about the choice of metal used, and the
heads are kind of scrawny.
I ordered 2-56 allen cap screws from McMaster Carr
and had excellent results. I forget how much I paid, but
I remember they were a little pricey. They have them in lots if 12.
These were 1-1/2"ss for the
8cc stunt tank. The heads do flush with thre backplate
nicely and don't leak.
Hope this helps,
Bob

Title: Re: Kavan Babe Bee tank extender
Post by: kenneth cook on December 06, 2010, 03:04:22 AM
        Recently, I was going through some items my dad had in one of his infamous boxes. I came across a Kavan tank extension. This one though is all aluminum. The extender is as well. My first question is, are these a reliable aftermarket product? I just haven't had a chance to try it. I do have a plane that would benefit from the nose sticking out a little more though. Ken
Title: Re: Kavan Babe Bee tank extender
Post by: Paul Smith on December 06, 2010, 08:19:56 AM
I had one and sold it without ever trying to use it.

There are so many Golden Bee and Black Widow tanks around, why bother?  Also, the idea of drilling a big hole in the Babe Bee tank and hooking up an external tank works OK.