Glues Good with Polyethelyne and Gasoline

I would have thought JB Weld also. It's fantastic stuff.

This one claims to be gasoline resistant and good for most substrates. I've never tried it.

https://www.autozone.com/sealants-glues-adhesives-and-tape/sealant/eclectic-2-oz-tube-gas-and-oil-resistant-adhesive/417319_0_0

I have successfully used this product since I was a child. I tried it again this summer and it didn't work. I suspect something in the gas is no longer compatible with what used to be a great product.

Very likely the addition of ethyl alcohol (gasohol) rendered it susceptible to breakdown, just as it does to many types of rubber.

Yeah. That's what I suspected. Happened quickly. Overnight.

Hmm, funny you should mention that, I had been considering using my hot air (SMT) soldering rig to soften the seam and see if I could get it to seal.

If I can figure out whether it actually is Polyethylene, and what type, I will buy some and use that as a filler rod. Where's Lyn when you need him?! Hrummph!^%^$%*#

I'm pretty sure the standard hot-melt glue gun sticks are polyethylene. I have used my hot glue gun to repair other PE containers (such as special grow-boxes I use for gardening on my deck, which developed cracks in the bottom from the weight on the caster wheels).

Similarly, the plastic base material of snow skis was primarily PE, and was usually mended using sticks of what was brand named "P-Tex" that you melted into the scrapes and dings caused by rocks and debris, then scraped smooth and waxed afterwards. Ski shops instead kept electric melting pots of P-Tex that they could drip onto ski bottoms to fill the gouges. When I got working with my glue gun, I realized that this appeared to be the same stuff.

So you might go ahead and try that. Since the tank itself is PE, you can possibly heat and partially melt the edge of the cracked plastic with the tip of the glue gun, so that the new PE you squirt into the gap will weld with the old plastic to form a better seal.

From a search result on Quora:

What you are looking for is the Beilstein test. It determines the presence of PVC by detecting the presence of chlorine. You need a propane torch (or bunsen burner) and a copper wire. Copper wire by itself burns cleanly but when combined with a material containing chlorine (PVC) it burns green. Heat up a copper wire over a flame (use pliers to protect yourself and use a long wire) to remove unwanted residue. Press the hot wire against your plastic sample so that some of it melts onto the wire then replace the plastic covered wire onto the flame and look out for bright green. If it burns bright green you have PVC.
Finally, PE burns with smell like burning wax while PVC has a very pungent chemical smell and extinguishes itself immediately once taken off a flame.

Hot glue is no bueno with alcohol. Alcohol is the trick used to make it un-stick!

I'm with HTRN.

Hot melt glue is PE, with other plastics, depending on whose you buy.

I'd suggest picking a few and checking the MSDS (material safety sheet) on-line for ingredients.

Welding is good too. You can get PE rods, I'm sure. Or, if you have another old gas tank lying around, just cut some strips out of it.

Hey! I was just talkin' 'bout you!

Does the PE stamped on the tank mean polyethylene? Not my field.

That would be my guess. Probably not Professional Engineer or Protective Earth.

Well, probably, but it must be an older tank.

There's two different classes of PE, high and low density. My guess is that it is HDPE if it's a gas tank. It's, well, more dense and more resistant to gas.

Now there are triangles and such for recycling, which we must do more of.

Good luck.

Permatex Plastic Tank Repair Kit For Plastic 3.2 oz.

Permatex ® Plastic Tank Repair Kit - Permatex

(THIS PRODUCT IS NOT FOR USE ON PLASTIC FUEL TANKS).

Thanks Gents! I will get back to you in a few days. I will take all due precautions, but if you don't hear back from me in a week, send condolence thoughts to my widow!

I have 2 of these gens, so I am going to let the bad tank sit and air out for a few days, while I go camping with the other one. I will simply have to ration power so I don't overload the single generator. These 2 act as a set with a parallel cable, so they normally run at half speed, but can ramp up when something like the air con kicks on.

BTW: Just retired at the end of September, and I'm working harder than ever at home!

As it has very little chemistry, the material is poor at adhesion with adhesives. Polyethylene is better welded.

Soldering iron and a zip tie....haha

In the old days, PE was very common.

Not any more. Hot - melt adhesive - Wikipedia

Now, it could be

Ethylene-vinyl acetate

Ethylene-acrylate

Polyolefins (PO) (polyethylene (usually LDPE but also HDPE; HDPE has higher melting point and better temperature resistance), atactic polypropylene (PP or APP), polybutene-1, oxidized polyethylene, etc.), low-performance, for difficult-to-bond plastics.

Polybutene-1

And this is only a partial listing. Thus my advice to be sure of the material in the stick.

^{Confused yet?}

I couldn't stand waiting, so I tried the SMT hot air gun, and a Dremel propane soldering iron with a flat blade tip. softened it up with the SMT gun on either side of the seam, then took the flat tip and slowly moved some material toward the seam.

I had the cap on and sealed, and used a piece of spare fuel hose I had lying around to draw a small vacuum (cheeks only! not lungs) on the tank while smoothing the semi liquid material from one side of the seam then the other into the almost invisible fissure.

Worked like a champ! After that I did a full maintenance routine on both.

I think I will take a page from JWthetech - when I turn the gens off, I am going to leave the caps in the on position until they have had sufficient time to cool. I don't mind losing a little gas to evaporation if it keeps those seams from busting due to thermal expansion.

Thanks again to all!

there wont be any "busting from thermal expansion" since its all the same material.

the only way to repair HDPE is to melt it and add filler, which is what you did. J-B weld works great on many other materials, but does not adhere to the HDPE mostly due to the plasticizes in the polymer. any thermal plastic polymer will only work this way if it melts. this is how all the poly drain pipe sealant works. it has a solvent that melts the pipe and there is some melted polymer in the solvent which adds material to an uneven joint.

to bond acrylic, the only solvent that works is methylene chloride. take some chunks of acrylic and put them in a glass container with the methylene chloride, it takes a day or so to melt completly. then use this adhesive to bond acrylic. you can add straight methylene chloride to your joint but it has a low vapor pressure so it disappears quite rapidly. to slow down the evaporation of the methylene chloride, you can add some ethanol which will float on top and stop the evaporation (until your ethanol evaporates) since the two are not very missable.

thermal set materials can be sealed with J-B weld

there wont be any "busting from thermal expansion" since its all the same material.

I think you misunderstood me. When you turn the generator off there is no longer a cooling fan running, this leads to the internal temperature raising several degrees, which causes the gasoline in the tank to increase in volume, which is causing the seam to give way.

So, short answer, yes there is some thermal expansion happening, because it is definitively not all the same material.

Also, read my reply that states that JB Weld themselves state they won't bond well with polyethylene.

Did I understand that HDPE can be dissolved in Methylene Chloride?

I thought HDPE was impervious to just about all solvents at normal temperatures?

XPE (crosslinked Polyethylenes), which are used in some pipe and tubing products, won't dissolve but will soften and swell somewhat. Non crosslinked polyethylenes and polypropylenes will absorb quite a few solvents (softening and swelling), but most have to be heated to actually dissolve them. UHMWPE is more resistant.

No, methylene chloride dissolves acrylics, (Not PE/PP) which is what I understood him to say.

All polyolefins are pretty much solvent resistant.

Don't know of any "glue" that holds well on PE. I've had good success welding a kayak. I would suggest a little practice on something disposable before jumping on a tank. I would probably find a compatible piece of plastic to weld a patch over the crack after welding the crack. Plastic welding rigs are fairly reasonably priced. Good luck.

It is probably more cost effective to buy OEM tank from manufacturer or supplier. Glued joints are likely not preferred in designing a fuel tank since the glue could be subject to deterioration from the gasoline. The gas tank made of PE is autogenously fused together (PE auto adheses perfectly if it is cleaned, heated to correct temperature and pressed together). No glue was used to make the tank. The leak that your current tank has is likely a manufacturers discontinuity which propagated into a defect. If your adventurous and are not attached with the gas tank you can try;

Remove gas tank and ensure it is thoroughly cleaned free of gas (environmentally friendly). May have to use a steamer or take it to a shop to properly clean it.

1)If the gas tank wall is very thin and flimsy it will be difficult or impossible to proceed with the method the manufactuer used. I would not proceed. If the wall appears sturdy and thicker than 1/16"; Have the PE tank cut with a low heat process (such as bandsaw with pure water not oil coolant) along the fused joint "seam". It is important the cut is even and the tank is not damaged.The entire seam needs to be removed this may require two even cuts on each side of the seam if it is wide (cutting twice increases difficulty and decreases chance of success).

2)Find a local PE fuser shop. These shops are common for fusing HDPE pipe and there are a variety of machines available "HDPE fuser machines." The shop may do the rest for you for a small fee if they have workers and are not equipment renters/retailers. I am only aware of one PE fusing equipment reatailer in my part of the woods.

If the shop lets you use there equipment

3)clean the two cut surfaces with acetone (very important since the seams are generated by the use of temperature and force).

4)Heat the two pieces on the PE fuser pancakes (the pancakes also have to be cleaned with acetone)

5)press the two pieces together after reaching the desired temperature 110-130C (or heat until bead is created under light pressure). If you have a jig with some type of basic lever to increase pressure it is better. Press the heated pieces together quickly (within 10 seconds of removing from pancake) until fused joint appears like two small separate beads. If the gas tank walls are to thin it will be difficult or impossible to press the two pieces together.

6)allow to cool and test tank with water for leaks before reinstalling

Probably less expensive to just buy OEM replacement

Firstly, many thanks for all the great infos from all here, but it has only convinced me further that repairing such tanks is simply dangerous.

Petrol/Benzin/Gas is nothing short of being very dangerous, and has killed many over the years.......

If I was going to repair such a tank, I would simply buy copper or brass sheet and roll it into a new tank, riveted and either soft or hard (preferably) soldered. Copper or plastic piping, or similar, pipe completely unaffected by anything in the fluid of course....

I would even add a fuel filter (Model aircraft engine fuel filter is tiny and cheap)....and a fuel tap!!

The tank does not have to be placed exactly where the old one was either.....A couple of simple brackets would allow it to be mounted anywhere, or even separate like outboard motors are made and run!!

Such a separate outboard motor tank might even be a "quick-ER fix".....Also, they usually have a "bulb" to prime the carburettor!! See here:-

Problem solved!! And FAR safer than most of the ideas here!!

• http://reltekllc.com/adhesivesforpolyethylene.aspx

OR

• Joint it (thermoplastic) using a hot gun.

In my experience, JB weld is no good with gasoline/petro, or diesel. It might be good with PE. But I would just use heat, as it melt the seam with a "Hot knife" and press the edges together.

there may be an epoxy that works well with PE, and Gas, But I dont think JB is your answer. (I only use JB for low temp metal repair. Never on exhaust, or motors., or near solvents)