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#11
posted to rec.boats.cruising
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Fuel Tank Inspection Cover Leak
"Roger Long" wrote in
: Not enough for a proper inspection plate. Strictly speaking, the bolt holes should not penetrate the tank. Either blind holes in a thick ring or a flange that stands up above the tank like this: http://home.maine.rr.com/rlma/Stride...tem.htm#FOtank so that the holes don't open into the tank is the way to go. The lower flange on the tank in the picture was epoxied down and glass and epoxy run over the top of the flange when it was put into place. I'll confess to having some blind holes in the cover since the tank gauge is installed that way. Since the gauge is up in the raised cover, I decided I could live with it. I would have a ring (or square as the case may be) made to the outside dimensions of the cover and the inside dimensions of the opening. It should be 1 1/2 to 2 times the thickness of the bolt diameter. Drill and tap to fit the current bolt pattern and drill and tap in between for the cover machine screws. Fasten down over a gasket with short machine screws inserted from the bottom. You'll have to shorten the machine screws so they end up flush when taken up. The machine screws that hold the cover down will then be going into blind holes. The upper gasket will seal off any leakage up through the screws that hold the frame and the lower gasket will indent enough to let the cover screws compress the upper gasket. If you pick the right thickness for the ring material, allowing for gasket compression, you may be able to avoid cutting any screws. It's a day's work but aluminum is easy to work. It may not be necessary to go to these lengths with your particular tank installation but, if it is a tank that can have some head on it such as being over filled up into the vent and fill pipe, it may be the only way to be sure it will stay tight. Getting my tank gauge tight with the two or three feet of test head on it letting my upper tank siphon fill the lower brought me pretty close to stripping the threads. Diesel is runny stuff. I got my whole system tight and pressure tested in the cold weather and lots of things started leaking again as soon as it warmed up. -- Roger Long Roger, I think that you've got too much time on your hands. Spending a day+ resolving a minor seepage problem isn't worth my time. I realize that your fuel system is a labor of love, but it's not mine. Personally I think that just retapping the 2 holes for larger screws will solve the problem. The rest of the screws are just fine and have held for 10 years. I have plenty of other work to do and hope to get out cruising soon. -- Geoff www.GeoffSchultz.org |
#12
posted to rec.boats.cruising
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Fuel Tank Inspection Cover Leak
On Mon, 12 May 2008 19:48:06 -0500, Geoff Schultz
wrote: Goofball_star_dot_etal wrote in : On Mon, 12 May 2008 20:15:09 +0100, Goofball_star_dot_etal wrote: On Mon, 12 May 2008 14:00:47 -0500, Geoff Schultz wrote: I have an aluminum fuel tank which has about a 6-8" inspection cover made out of the same material. The cover screws through a rubber type gasket and the screws are threaded into the tank material. One or two of the screws have stripped the threads and the tank weeps diesel primarily when it's completely full. Basically I think that I have 2 options to repair this. 1) Redrill/tap with larger screws 2) JB Weld a nut on the inside. Any comments/suggestions? http://www.google.co.uk/search?hl=en...04-11%2CGGLD%3 Aen&q=cinch+nuts%2C++helicoils&btnG=Search&meta = -- or clinch nut.. or rivet nut http://www.google.co.uk/search?hl=en...1,GGLD:en&sa=X &oi=spell&resnum=1&ct=result&cd=1&q=clinch+nut&spe ll=1 for thinner panels. Heli-coils for thicker plate, typically 2x thread diameter. Both generally need a tool to fit. Considering that I only have 2 screws to repair, I really don't want to purchase a specialized tool. The helicoil is for much thicker material than I have. However, thanks for the suggestion. -- Geoff www.GeoffSchultz.org Perhaps oversize: http://www.google.co.uk/search?hl=en...G=Search&meta= Stronger than pre-tapped holes due to work hardening and tight fit. |
#13
posted to rec.boats.cruising
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Fuel Tank Inspection Cover Leak
On Mon, 12 May 2008 14:00:47 -0500, Geoff Schultz
wrote: I have an aluminum fuel tank which has about a 6-8" inspection cover made out of the same material. The cover screws through a rubber type gasket and the screws are threaded into the tank material. One or two of the screws have stripped the threads and the tank weeps diesel primarily when it's completely full. Basically I think that I have 2 options to repair this. 1) Redrill/tap with larger screws 2) JB Weld a nut on the inside. Any comments/suggestions? At the Boeing company they occasionally **** up a rivet. They drill it out and install an oversized one, they call a 'Lockheed Rivet' So put in 'Lockheed Screws' So how thick is the material? If it's thin, it might be a good idea to have more screws. Casady |
#14
posted to rec.boats.cruising
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Fuel Tank Inspection Cover Leak
On 2008-05-12 21:00:54 -0400, Geoff Schultz said:
Personally I think that just retapping the 2 holes for larger screws will solve the problem. Is it possible that they are self-tapping screws? (I believe mine are.) I had to jerry-rig our tank a few years and got a slight leak when full. I just slathered some 3M fuel-resistant "caulk". -- Jere Lull Xan-à-Deux -- Tanzer 28 #4 out of Tolchester, MD Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/ Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/ |
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