Repairing a crosslink poly (PEX) boat fuel tank

[max62]

I ended up pulling the plastic gas tank out of my project boat as there was a leak somewhere. Turns out a rodent, likely a squirrel, got to it and started gnawing on the vertical corner of the tank. There is a visible hole in that side corner that measures just shy of 3/4in long and about 1/8in at the widest.

It's a 30gal tank, The label on the tank says it's made out of crosslink poly, which I assume is same as PEX (aka XPE).

Not certain if and how it can be fixed. Never done plastic repairs. What product is safe to use on gasoline tanks to repair the hole? I have a heat gun but after doing some searching I get mixed information about being able to just melt some PE plastic strips over the spot as it won't make a proper chemical bond.

A friend suggested to build up the corner with some resin or PB mix. Then put a few layers of fiberglass mat.

Any thoughts on how this can be repaired?

 

[jbcurt00]

Its a gas tank, that holds a flammable liquid, in a boat...... I wouldn't repair it. I'd replace it. Not worth the risk, IMO....

 

[jigngrub]

Its a gas tank, that holds a flammable liquid, in a boat...... I wouldn't repair it. I'd replace it. Not worth the risk, IMO....

Yup!

 

[fishrdan]

^^^ YUP

Besides, there is no glue that will stick to cross-linked polyethylene and it can't be welded. A mechanical patch is an option, similar to the how the fuel sender is attached to the tank, but I wouldn't do it on a corner, too risky.

 

[max62]

No Title

I realize that I'm dealing with highly flammable material. I looked at finding a replacement tank. Cheapest replacement I can find will be over $650 after taxes and s/h. Just not in the budget. I have no faith in being able to find a similar-shaped used tank anywhere.

Just need a relatively quick fix that will hold up for a year or so, at which point I will saved up for a new tank.

After some research I found a product called G/flex from West Systems that can be used to fix PEX plastics according to this:
http://www.bdoutdoors.com/forums/thr...repair.197919/

I will give it a shot.

Oh and here's a pic of the hole.

http://imgur.com/KTrGQvp

 

[Woodonglass]

This might be of some interest to you...http://www.ifish.net/board/showthread.php?t=293881 If you filled your tank with water you could prolly do this technique!!

The G-Flex is some good stuff however the Plastic needs to be prepped properly. Make sure and do your research. I'd Highly recommend you call and talk to the West System Techs. They are some Really Helpful folks!!!!

 

[max62]

This might be of some interest to you...http://www.ifish.net/board/showthread.php?t=293881 If you filled your tank with water you could prolly do this technique!!

The G-Flex is some good stuff however the Plastic needs to be prepped properly. Make sure and do your research. I'd Highly recommend you call and talk to the West System Techs. They are some Really Helpful folks!!!!

It's the same writeup with same pics. Looks like coming from the same guy .

I guess first question is should I grind the spot out to make it a little smoother. Or leave it as is for irregular surface to allow epoxy to bond better?

I washed the tank inside and out. Will be using Acetone to clean the work area before applying epoxy. Q2: Should I heat the area before or after cleaning with acetone?

I will be building up the corner with the thickened version of the G/flex epoxy. Then patching it with 2, possibly 3 layers of patches that will get progressively bigger. Waiting for G/flex to arrive in the mail.

I wonder what weight of cloth that guy was using. Looks like a 2oz cloth to me. Q3: Do you think CSM would work just as well as I have plenty of it on hand?

 

[Woodonglass]

I have no actual experience with G-Flex or Cross Linked Plastic. That Article is all I've found. Like I said, I'd be calling West Systems for sure to find out about prep work. I do know for certain I'd be filling that tank with water before I put any flame to it!!! I'd say based on the pics that's 3oz E-glass. I would for sure not use CSM with Epoxy. You want a tight weave fabric for patch work.

 

[Bondo]

I have no actual experience with G-Flex or Cross Linked Plastic. That Article is all I've found. Like I said, I'd be calling West Systems for sure to find out about prep work. I do know for certain I'd be filling that tank with water before I put any flame to it!!! I'd say based on the pics that's 3oz E-glass. I would for sure not use CSM with Epoxy. You want a tight weave fabric for patch work.

First off, PEX is a low surface energy plastic, meaning that it essentially will not stick to anything, and nothing will stick to it. What Gougeon co. discovered is that by using specifically a propane torch, the non-polarized plastic surface, when contacted by the flame, oxidizes into a polarized surface. This allows materials to stick to it in a normal fashion. What was strange to me is that it doesn't require roughing with sandpaper. The following are direct instructions from Gougeon, included in their product packaging.

Ayuh,.... I've bonded several keel skid-plates onto Old Town canoes made of cross-linked,....

Donno 'bout acetone,...

I sanded lightly, touched the entire area with the blue of the flame, 'n epoxied the kevlar strips on,...
Done glass patches on other Old Town canoes,....
Only down-side is sunlight, 'n epoxy,...

 

[Woodonglass]

If that's the only down side then this should be ok since this is a below deck tank. Sunlight should not be an issue.