Mike, What are your tanks sitting on in the stub wings? Are they just sitting on the bottom skin? Does not sound like a good idea if they are. Those tanks carry a lot of weight and could over time or even with a hard landing or two, compromise the integrity of the bottom stub wing skin. My aluminum tanks are in the outer wing and rest on 90° aluminum tracks which are mounted from the front spar to the rear spar. The only place I used expanding foam was between the spar and the tank which securely holds the tanks in place. I then glued sheet foam on top and on bottom of the tanks to shape the airfoil from. Now 280 hours later I have no leaks and no compromised skins. Just something to think about.
In the first photo of this link you can see the foam glued to the top of the tank. Towards the bottom, you can see the tank mounted in the wing. http://www.flykr2s.com/wing.html Mark Jones (N886MJ) Stevens Point, WI E-mail: flyk...@charter.net Web: www.flykr2s.com ----- Original Message ----- From: "MICHAEL SYLVESTER" <shagste...@hotmail.com> To: "KRNET" <kr...@mylist.net> Sent: Sunday, November 08, 2009 8:49 PM Subject: KR> Foam expansion. Hey Guys, I will be mounting my aluminum stub wing tanks this week and am wondering if the x30 two part foam will pick the tank up ? I plan to weight it down just in case. I also just mixed up a batch to check expansion size and laid a 1 x 4 on the largest mass of it and I don't believe it lifted it much. To me it seems to be looking for the path of least resistance. Is there a precautionary warning out there ? Mike Sylvester kr2s builder Birmingham,AL. Cell no.205-966-3854