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Need a Gasoline-Proof sealant for Polyethylene

Need a Gasoline-Proof sealant for Polyethylene

Need a Gasoline-Proof sealant for Polyethylene

(OP)
I'm a Mechanical Engineer designing light hovercraft.  We are using Polyethylene fuel tanks and have a hard time finding anything that sticks to Polyethylene very well.

We have been experiencing leaks around our fuel sending units and need a sealant that can stand up to constant contact of gasoline/oil and fumes (2-stroke).  Most "fuel resistant" sealers just turn to mush or fall apart after a few days.  And if they do hold up against the fuel/oil they often lose adhesion with the Polyethylene.

Any recommendations?  
Thanks,

CS

RE: Need a Gasoline-Proof sealant for Polyethylene

You will not get anything to stick reliably. Use metal fittings and neoprene gaskets.

RE: Need a Gasoline-Proof sealant for Polyethylene

The old red Hermetite - if you can find it - and the newer Hylotyte Red are both fuel-resistant and semi-setting. They won't adhere but being semi-setting they may not need to. You'll need a reasonably accurate threaded fitting or flat sealing faces to achieve a good seal.
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: Need a Gasoline-Proof sealant for Polyethylene

1.  Put all penetrations through the top of the tank.
2.  Use a mechanical joint with a seal, e.g. an o-ring.

Spend a day in a junkyard.  Look for plastic fuel tanks.  Examine how they're mounted and how the connections are made.

 

Mike Halloran
Pembroke Pines, FL, USA

RE: Need a Gasoline-Proof sealant for Polyethylene

Another vote for a gasket or o-ring mechanical seal.

There are very few adhesives or sealants that stick to polyethylene.

If you can tolerate a "permenant" attachment, look at 3M DP-8500, although I'm not sure about its resistance to gas and oil.

If you need a removable-repairable attachment I doubt that you'll find anything suitable.

RE: Need a Gasoline-Proof sealant for Polyethylene

I agree with posts above that using a mechanical seal on the top side would be the ultimate goal.
If you have to go the way of using a sealant you might want to give Reltek a call for a specific recommendation

http://www.reltekllc.com/adhesives-for-polypropylene.htm

RE: Need a Gasoline-Proof sealant for Polyethylene

Mike...I like your advice about the junkyard.  It's amazing how much you can learn from such escapades.  Haven't done it in years...but should.

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