Aluminum gas tank filler neck repair

batrider said:
Will it work with ethanol gasoline? Says OK with jet fuel and avgas.
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Hi Batrider, I’m not a chemist but given the constitution of Jet A1 I would say yes. Ive used it on Vintage car fuel tanks witho issue.
Putting it bluntly: it sticks like S%#t to a blanket or anything else you care to mention in this well known phrase ! Don’t get it on your hands cos it’ll stick there too .
 
In the last week i have contacted two tank manufactures requesting information about the best sealant to seal my gas cap to the tank .. No response from either . I e-mailed JB Weld and received a very nice reply from their technical rep . He suggested looking to Gasoila for their " yellow labeled sealer " as JB Weld does not have an item for this .

Internet search came up with these two items .. Seal All has been around forever .. Permatex usually has good products so i bought both.

Cleaned both cans with wire brush .. Clean cloth with brake cleaner to remove all residue. Applied Seal All to can approx. 25mm in diameter x 3 mm deep .

Mixed up a piece of Permatex until an even light brown colour as per instruction . Pressed it firmly onto the bottom of the can ensuring edges were tight

48 hours after application i added enough ethanol gas to just cover the product . 12 hours later and added more gas to cover the product due to evaporation . 12 hours later this is what i can report ..

I was able to scrape away the Permatex product quite easily with a small screwdriver . While the top layer came apart , the bottom seemed quite hard and bonded to the can .. Possibly the gas had not enough time to soak all the way through ??

The Seal All remained the same . In a full cure it is still somewhat pliable and remained that way after being subject to gas for over 24 hours straight. Adhesion to the can seemed very good .

I was hoping the Permatex would work . The application would have been a bit easier . Mix the putty up and roll into a 6 mm dia . and length long enough to go around the inside . Press into place and Bob's Yer Uncle .

The Seal All will take longer to complete and most likely mean removing the tank .. 1st . option is to remove tank and with the tank on its side, add Seal All along the joint . Being as this is in liquid form ,only a bit can be done at at time .
2nd option .. use a small brush and try applying several light layers with tank in place as has been suggested by the manufacturer .

Decisions ... Decisions
 

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Ron Hulton said:
In the last week i have contacted two tank manufactures requesting information about the best sealant to seal my gas cap to the tank .. No response from either . I e-mailed JB Weld and received a very nice reply from their technical rep . He suggested looking to Gasoila for their " yellow labeled sealer " as JB Weld does not have an item for this .

Internet search came up with these two items .. Seal All has been around forever .. Permatex usually has good products so i bought both.

Cleaned both cans with wire brush .. Clean cloth with brake cleaner to remove all residue. Applied Seal All to can approx. 25mm in diameter x 3 mm deep .

Mixed up a piece of Permatex until an even light brown colour as per instruction . Pressed it firmly onto the bottom of the can ensuring edges were tight

48 hours after application i added enough ethanol gas to just cover the product . 12 hours later and added more gas to cover the product due to evaporation . 12 hours later this is what i can report ..

I was able to scrape away the Permatex product quite easily with a small screwdriver . While the top layer came apart , the bottom seemed quite hard and bonded to the can .. Possibly the gas had not enough time to soak all the way through ??

The Seal All remained the same . In a full cure it is still somewhat pliable and remained that way after being subject to gas for over 24 hours straight. Adhesion to the can seemed very good .

I was hoping the Permatex would work . The application would have been a bit easier . Mix the putty up and roll into a 6 mm dia . and length long enough to go around the inside . Press into place and Bob's Yer Uncle .

The Seal All will take longer to complete and most likely mean removing the tank .. 1st . option is to remove tank and with the tank on its side, add Seal All along the joint . Being as this is in liquid form ,only a bit can be done at at time .
2nd option .. use a small brush and try applying several light layers with tank in place as has been suggested by the manufacturer .

Decisions ... Decisions
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Curious result for the Permatex putty. That should be an epoxy based material. Could be related ot incomplete curing from under mixing (go well beyond just getting a solid colour from the two parts...you cannot mix too much), or perhaps it suffered from incomplete curing at the surface layer due to air exposure (oxygen inhibits the epoxy polymerization reaction).

You could try a test with a thinner layer to see if you still get a scrapable layer just at surface, or all the way through or solid all the way through.

Test both products for adhesive properties, trying to bond a can to another can with each of the two products. ///Maybe try pulling apart with a luggage scale or set of weights so you can obtain some actual numbers for comparison? Remember, epoxy to alu works best if you wire wheel the wet epoxy into the metal....the wire scraps away the oxidiation layer, and wet epoxy keeps it from reforming (takes only seconds) at alu surface, which would otherwise make a poor bond.
 
Scraped away all loose Permatex until all that was left was a thin layer which was solidly bonded to the can . Covered the Permatex with gas at 4 am this morning and at 2:30 this afternoon the Permatex had again broken down . I will go with the Seal All ..
 
Ethanol is a problem with sealers including JB weld. JB weld does hold up with race and AV gas but not Ethanol based fuels. The only thing I've found that holds up to Ethanol is "SEAL ALL"
There may be some tank sealers I haven't tried that work but I would test them first.

Aluminum gas tank filler neck repair
 
I got 13 years of leak-free repair from JBWeld, submerged in ethanol laced pump gas. (Didn't fail after that, I sold the bike)
YMMV
JMWO
😎🏁👍🏻
jseng1 said:
Ethanol is a problem with sealers including JB weld. JB weld does hold up with race and AV gas but not Ethanol based fuels. The only thing I've found that holds up to Ethanol is "SEAL ALL"
There may be some tank sealers I haven't tried that work but I would test them first.

Aluminum gas tank filler neck repair
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Last edited:
Yes - JB weld does hold up in ethanol. I've had it on the breather for my gas cap for 20 years. I forgot. But I've heard of it failing when used to build up and reshape intake ports. Mixed signals.
 
After much head scratching i decided to repair my tank using JB Weld Original . I could not find one product where everyone was in agreement .

Two tank manufacturers did contact me . One suggested JB Weld and the other said Araldite .

My intent was tonuse the Seal All however i decided that i probably would not get it to fill in evenly as it films up very quickly .

The JB Weld went on very easily with plenty of time to work the product in .
 

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TBW said:
Hi Batrider, I’m not a chemist but given the constitution of Jet A1 I would say yes. Ive used it on Vintage car fuel tanks witho issue.
Putting it bluntly: it sticks like S%#t to a blanket or anything else you care to mention in this well known phrase ! Don’t get it on your hands cos it’ll stick there too .
Click to expand...
 
I used JB Weld to repair a pulled-through mounting stud on a nylon Triumph tank that had itself been softened by ethanol fuel. That repair failed after about 3 years but was obviously a tough assignment. I have no doubt that JB would be fine for a filler neck repair that wasn't constantly submerged.
 
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