Microlighters

I wonder if anyone can assist me here. I am looking for a fuel friendly adhesive sealer for some auxiliary fuel tanks I have had fitted to my aircraft. A hole at the top of the plastic fuel tank accommodates a clear rubber tube running inside an aluminium sheath to suction the fuel, but I cannot find something sufficiently robust or fuel friendly to do the job. I've tried 'fuel friendly' gasket sealer and a white 2-part Pratley epoxy, but both have failed.

Could anyone give me any ideas?

Many thanks.

Mike

You need to sandwitch the plastic between two layers of aluminium with a layer of rubber/cork(preferably) between them. The top plate has the pickup tube and the vent tube(if neccessary) welded through it

Then you need a cork gasket, the same size and shape as the top plate

The bottom plate is designed to go into the tank and act as the other side of the clamping action. This plate has the holes threaded so you can thighten them up the squeeze the plastic and cork between them. In order to get this plate into the tank you need to shave two sides off the plate, and then cut a slot into the top of the tank to equal the size of this reduce plate width. Using wire or string to prevent the plate from falling into the bottom of the tank, insert it through the slot and then somehow retain it at the top of the tank (thread through the holes, tank upside down etc. Next the cork, then the top plate, and finaly the screws. Hopefully this is clear.

There are places in Montague Gardens who will weld the ali for you

http://www.aircraftspruce.com/search/se ... h&search=1

http://www.vansaircraft.com/cgi-bin/cat ... ct=proseal

Most helicopter AMO's carry stock of the Goop...

Thanks for the input guys, I appreciate it.

Greg, the tanks and suction system are already built and installed. In fact, I've used them on a few occasions (before it became apparent that the applications had failed). It is just a small aperture (about 1.5cm) through which the aluminium sheath passes which I am looking to 'glue' and seal. I made a few calls and was recommended ABE372 (a 2-part slow setting epoxy) which I yesterday bought and have applied. Once set, I will test it in my workshop and hopefully it will do the trick.

Thanks again

Alrenatively, rather make a little fitting that BOLTS onto the tank, with bolt through, and retainer nut and "O" ring top &bottom to keep petrol where it is supposed to be. NOT leaking! As most of these plastic tanks are made of polypropylene plastic, they are difficult or impossible to "glue". I have experimented a lot over the years, and found that the ONLY reliable means if attaching anything, is by mechanical means.

Thanks Boet

Mike, I'd support the direction of Morph's & Boet's advice. Using epoxy and other adhesives which will come into contact with your fuel is a recipe for disaster unless you are 100% certain that there are no long term compatability issues. Silicon, for instance, is an absolute nightmare when it comes into contact with fuel - disentigrates into individual fibrous strands which block the filters, pumps, carbs etc. :evil
I think their suggestions of finding a bolt-on "mechanical" solution rather than a "glue on" chemical one is good advice.

Learjet wrote:I think their suggestions of finding a bolt-on "mechanical" solution rather than a "glue on" chemical one is good advice.

........and so says all of us

Thanks for the advice guys - this is one of the reasons the forum is so valuable!

Go scratch for some ideas at a jacked up hydraulic shop. They stock all kinds of ferrules/ fasteners and should sort you out.