[tommytiger]

Some of you might recall me having a leaking fuel tank a couple of weeks ago.

I intended to get the fuel tank welded but welding chap couldn't do it for a while and I needed a quick fix as the weather looked really good for a couple of weeks. I did a little research and stumbled across a product called 'Pratley Putty' (£8 delivered) which was getting great reviews regarding patching fuel tanks. It's a south african product but it can be bought here in the uk in a couple of places. It's a two part putty which you knead together and has the consistancy of modeling clay, amazingly it's water soluble and can be smoothed with a wet finger.

I had a small crack in a weld, I cleaned the area, degreased it with some methanol, worked the putty into the crack and built a bead over it. I left it for 48hrs to fully cure ( I bought the slow curing ) and then pop a little zinc rich primer over the area. I've been riding the bike into work for 10 days now and not a sign of any fuel has appeared. It has set unbelievably hard, almost like a very hard ceramic.

I don't intend this to be a permanent fix but it appears to be doing the job until I can.

 

[Cybersausage]

You can also get the Araldite putty from Wilkinsons.

 

[tjwood]

Interesting to read about that putty. I have just done a fix to a small crack in a previous repair (not repaired by me) in the knee-grip area of my tank using 'ordinary' Araldite epoxy resin (two-tube stuff). Does anyone have any views on if this will be petrol-proof? I wasn't sure what to use because of the ethanol issue but went for Araldite because I needed something that would flow into the crack. I haven't tried filling up the tank with fuel yet as I only repaired it yesterday but I'd be interested to hear others opinions on whether it should work or not.
Thanks
Tony

 

[GrandPaulZ]

Sounds like JB Weld gas tank patch putty.

 

[Snakeoil]

I tested JB Weld with ethanol fuel and posted the results here. A glob of JB Weld that was fully cured and hard as a rock turned into a very rubbery glob of putty after soaking in a container of 10% Ethanol gasoline. It hardened back up when I took it out and left it on the bench to dry.

I left two globs, one in pure Ethanol and one in E10 for about a month, maybe longer. They never got any worse than getting rubbery. What I wonder is if the bonding strength is also compromised like the hardness is.

regards,
Rob

 

[triumpt120rv]

I no longer take chances with leaky 40 year old tanks. Patching it up with goop is risky. You never know when that patch is going to leak. You're riding around with what is essentially an "IED". Spend a bit of money and get it repaired properly or get a new tank with brand new metal. I think within the next ten years a lot Triumph original 40 - 50 year old tanks are just going to have to be scrapped or about 70% refurbished with new metal. "Rust Never Sleeps" (Neil Young).

 

[tommytiger]

I agree triumph120rv, rusty tanks are pretty much scrap, however my tank is rust free and only developed a tiny crack ( no rust ) on a weld. I bought this stuff just to buy me a couple more weeks riding, it is still absolutley rock hard. I will get the tank properly welded and will paint it over the winter.

I will from snakeoils experiment and get back, I've heard cheapo supermarket fuel has the highest cocentrations of ethanol and I can get pure ethanol from work so will soak it in both.

 

[tommytiger]

sorry that last sentence made no sense! I meant to say I will repeat snakeoils experiment and post the results.

 

[KADUTZ]

In the US both Loctite(part#988638) and Permatex (part #12020) market epoxy gas tank repair kits. I have no idea how they hold up to ethanol since that question was brought up.

Many many years ago Triumph had a problem with leaks around the filler neck crimp. Their repair was to solder the area with a soldering iron and solder.(I would assume acid core solder.) I would think this type or repair would work along a seam.

I am very sensitive to fuel tank leaks as a member of a club I belong to was killed due to a leaking petcock. After the explosion it too 48 hours to ID the remains.

As to fuel tank repairs if in doubt dont do it.

K

 

[Old Cafe Racer]

The only permanant way to go is with phenol novalac epoxy (that's what you will find in a Caswell repair kit)
It's the hardest most chemically resistant epoxy known to man with a binding strength second to non.
It's very similar to the epoxies commercially used to seal cold room floors.
Unlike other coatings it is permanent, becomes part of the tank and cannot be removed.
.

 

[Hypurone]

I use this exclusively. I even did my newly warranted plastic tank on my Ducati S4RS with this to guarantee no bulging/bubbling etc...

http://www.tptools.com/p/1856,167_POR-15%C2%AE-Fuel-Tank-Sealer.html

 

[Rookster]

Ever try using solder? Yes it sounds like BS but it will fill small cracks and holes. You can do it a few different ways: torch to heat the tank or a big soldering gun (not the pencil type). Either way you need to get the tank hot enought to melt the solder. Once you get it flowing it fills really nice. Obviously you shoulnd't apply a torch to a tank that has not been purged or mostly filled with something other than gas fumes. A big soldering gun works well.

Scott

 

[Snakeoil]

The only permanant way to go is with phenol novalac epoxy (that's what you will find in a Caswell repair kit)
It's the hardest most chemically resistant epoxy known to man with a binding strength second to non.
It's very similar to the epoxies commercially used to seal cold room floors.
Unlike other coatings it is permanent, becomes part of the tank and cannot be removed.
.

I used that Caswell kit on a Honda S90 tank. I know Steve Job uses it on all his fiberglass tank lining jobs when doing restorations. My only caution is it is thick as mud and flows like it. So the rule of thumb is to do it on a hot day, in the sun and have the tank warm. Yes, it speeds up the cure time, but from that I experienced at slightly below room temp in my basement, the cure time is a lot slower than they say it is. Others may have more than 1 experience with the stuff and can comment.

regards,
Rob

 

[Old Cafe Racer]

Rob, the easy way is to stand the mixed Caswell container in a tub of very hot water for a few minutes before pouring as that thins it down and accelerates the curing process.
I pour epoxies almost daily and that's the method I use when I have to pour thick mineral filled ones through small appertures.

.

 

[Snakeoil]

OCR,

Are you able to get two tanks out of a kit by doing them at the same time? By that I mean pour one, coat it, dump out the excess into the next tank and coat it.

I have to admit I panicked when I saw how slow it flowed and since they said 30 minutes to cure, I never thought I'd get both tanks done. So I caved and used it all for one tank only to find the cure time was much, much longer and I think I could have done both.

Caswell cautions against mixing small batches. What's your opinion on that? I was considering using it to fix float bowls that had been eaten up by bad gas.

regards,
Rob

 

[Old Cafe Racer]

Rob

You should get two normal tanks no worries, I last did a 5 gallon tank and had almost enough left to do a standard tank.

Should work fine inside float bowls, just brush a thin layer inside.
I'd be tempted to soda blast or bead blast inside first though.
Bead blast removes the corrosion better than soda.

David

 

[Snakeoil]

Thanks OCR. I'm a big fan of bead blasting in the right application. And brushing it was what I had intended.

Guy I know that paints tanks (says he's the K-mart of painters) uses Caswell all the time and when he did my two T140V tanks, he brushed Caswell's around the neck crimp joint, forced it into the joint with his finger like caulk and then wiped it clean. I think this might be a better solution to leaking neck crimps than soldering or similar. My '66 neck was brazed by somebody in the past and although you don't see it, when you take the cap off, it's ugly. Plus soldering those crimps is tough because it is very hard to get any contaminants out of the joint, which hinders the solder sealing it up. I had a professional welding shop try to silver solder a tank and they gave up and never charged me a cent.

Is that phenolic epoxy available elsewhere? Cannot believe that Caswell is the only supplier. I'm going to check with a local outfit that makes the epoxies we use in generators. Nice guys and always happy to help out. I'll report back on what I learn. I did get a sample pack from them a few years ago and ran the same test as I did on the JB Weld, at the same time actually. Their epoxy was not affected. Not sure what type it was.

regards,
Rob

 

[Old Cafe Racer]

Think I might have mentioned it before Rob but anyone who does cold room floors with have similar epoxy.

.

 

[Snakeoil]

Yes you did, OCR. I was just wondering about product vendors who might sell it. But that is a good tip. Thanks.

regards,
Rob

 

[ed_h]

The only permanant way to go is with phenol novalac epoxy
Unlike other coatings it is permanent, becomes part of the tank and cannot be removed.
.

That epoxy system is one of the best in terms of chemical resistance and durability, but saying it's part of the tank and cannot be removed might be overstating it a bit. It probably wouldn't survive welding or brazing, for example, like an uncoated tank would.