Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Need a Gasoline-Proof sealant for Polyethylene

Need a Gasoline-Proof sealant for Polyethylene

Need a Gasoline-Proof sealant for Polyethylene

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?  


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


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.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


eBook - The Future of Product Development is Here
Looking to make the design and manufacturing of your products more agile? For engineering and manufacturing organizations, the need for digital transformation of product development processes just became more urgent than ever so we wanted to share an eBook that will help you build a practical roadmap for your journey. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close