Sealer for fuel tank fittings?

[mcrowley]

Hello all, first time poster and new Savannah S builder. I could use some help... The ICP manual is a little less than detailed... I'm preparing my fuel tanks to install and the manual calls out Loctite 577 for the threads of the tank-to-hose fitting. Will that also seal the fitting to the tank? Is there something better? Thanks so much!

 

 

[Kyle Communications]

We just had this discussion on Lyndons thread...its a pain in the bum. I had leaks and fixed them by fitting a Oring groove and a Oring into the fitting...make sure the fitting when installed sits on the flat of the wall of the tank sump area and not on any curve at all. This means the tank fitting maybe slightly higher than in the dimensions

 

 

[mcrowley]

Thanks, I'll read up on Lyndon's thread.

 

 

[IBob]

We just had this discussion on Lyndons thread...its a pain in the bum. I had leaks and fixed them by fitting a Oring groove and a Oring into the fitting...make sure the fitting when installed sits on the flat of the wall of the tank sump area and not on any curve at all. This means the tank fitting maybe slightly higher than in the dimensions

Hi Mark, I'm now at the fuel tank part too.

 

The fittings look to be quite nicely made, with a smooth raised ridge round the flange face, presumably intended to seal against the inside of the tank (I mention this in case the fittings have changed since your build).

 

What I cannot understand is this: while the 8mm fitting goes into an 8mm hole in the tank, the manual calls for an 11mm hole for the 12mm fitting.

 

It is easy enough to wind the 12mm fitting through the 11mm hole, all it does is cut a thread in the plastic. But the fitting thread ends approx 1.5 mm short of the flange, so tightening pushes threaded plastic up onto this short 'shank'. We are then hoping to pull all this up sufficiently tight with the outside nut to bring the flange into the inner wall of the tank. And unless we do this by turning only the fitting and not the nut, we strip the plastic we just threaded in the wall. All of which may go some way towards explaining the difficulty in sealing these things.

 

This makes no sense to me. Surely this 12mm fitting should simply go into a 12mm hole, where the short (12mm) shank before the flange would centre it, and the nut could be turned to pull the flange tight? As per the 8mm fitting.

 

Do you have any thoughts on all this?

 

Thanks

 

BobI

 

 

[mcrowley]

I threaded mine through, then slipped an old piece of hose over the neck which allows me to hold it with pliers while I tightened up the outside nut...

 

 

[IBob]

I threaded mine through, then slipped an old piece of hose over the neck which allows me to hold it with pliers while I tightened up the outside nut...

Thanks, Mike, that is what I did too on my test fitting.

 

Nobody seems to have any thoughts on the hole size in the tank.

 

Right now I am looking at Loctite 577, as specified, and wondering why we are sealing the threads with that when the seal should be between the inner flange and the tank wall. The questions just keep coming, or maybe I should just stop thinking???

 

 

[rankamateur]

The questions just keep coming, or maybe I should just stop thinking???

That sounds like the easy way out!

 

If you just stop breathing all your problems will go away and become someone else's problems, doesn't mean it is a good way to go.

 

 

[IBob]

That sounds like the easy way out!If you just stop breathing all your problems will go away and become someone else's problems, doesn't mean it is a good way to go.

Wow. Okay, Steve, got that.

 

 

[mcrowley]

iBob, I also put the specified Loctite on the inside as well, so far it's passed the pressure test and the slosh test...

 

 

[IBob]

iBob, I also put the specified Loctite on the inside as well, so far it's passed the pressure test and the slosh test...

Thanks for that. I've been wondering whether to do the same thing. The manual says on the threads.....but the manual...well, you already know...

 

Very interested if you can give me any suggestions on the wingtips too.

 

 

[IBob]

iBob, I also put the specified Loctite on the inside as well, so far it's passed the pressure test and the slosh test...

Just a thought, Mike: have you completed all your tank fittings?

 

 

[mcrowley]

Just a thought, Mike: have you completed all your tank fittings?

All fittings are complete in the wings. I left the lines long to give me the option of adding valves if I decide too once I install the wings on the fuselage... Still can't decide the options of valves or the simplicity of straight plumbing...

 

 

[IBob]

All fittings are complete in the wings. I left the lines long to give me the option of adding valves if I decide too once I install the wings on the fuselage... Still can't decide the options of valves or the simplicity of straight plumbing...

Okay, main reason I asked is that I shifted where I put the fittings on the side of the tanks, rather than following the drilling pattern in the manual (which doesn't line up with existing holes in ribs etc).

 

As for valves, I have 4 tanks (it's an ex Australia kit and they have very big distances), and initially at least i'll be doing what they do: 2 inner tanks unvalved, 2 outer tanks individually valved.

 

 

[mcrowley]

Yes indeed.... do not follow the template in the manual, I did for the first one and pulled my hair out because it doesn't line up. I placed the tanks in the second wing and marked the place where the pre-existing holes in the ribs line up with the tank. Much better! I should have mentioned that before...