How to weld/glue/fix cracked outboard engine plastic fuel tank?

[delmarrey]

If your going to use something that might cause a flame, I'd suggest you pull the tank and flush it out a few times with soapy water. Other wise you may cause a nice little bomb.

And what caused the crack? You may need to support the tank better during the install.

[ErikFinn]

Originally Posted by delmarrey

If your going to use something that might cause a flame, I'd suggest you pull the tank and flush it out a few times with soapy water. Other wise you may cause a nice little bomb.

And what caused the crack? You may need to support the tank better during the install.

Yea that is common sense. At least to me. It was damaged after some waves made the dinghy and engine to bounce and the fuel tank cap got tangled to some wire or line. So I was told.

[ErikFinn]

Originally Posted by delmarrey

If your going to use something that might cause a flame, I'd suggest you pull the tank and flush it out a few times with soapy water. Other wise you may cause a nice little bomb.

And what caused the crack? You may need to support the tank better during the install.

And congrats for the 10Kth post

[Jmurray]

I had the same problem and just fixed my tank this weekend. I also went to buy new tank, did not think plastic would cost $140. After filling tank with water, I used a soldering iron and sealed the crack. The leak stopped, but since it has only been 2 days cannot give a warranty.

[Old Snipe]

I used to do a lot of kayak fishing and I was pretty abusive to my boats along the rocks, stanchions of the Chesapeake Bay Bridge and oyster beds. When I punched a hole, I would weld the plastic with acetone. Others would use a heat gun. Either way was effective. I'm not sure if I would trust doing it to a fuel tank though.

[bruce.cook2]

I fixed a major leak in my hard plastic 45 litre wáter tank many years ago while in the Azores? I used a hot-melt glue gun that I bought before leaving Canada...wondering if I would ever use it. The glue stick came with the gun. Anyway, over ten years later... the leak repair is still holding just fine.

[Sun and Moon]

... I would weld the plastic with acetone. Others would use a heat gun...

Originally Posted by bruce.cook2

I fixed a major leak in my hard plastic 45 litre wáter tank many years ago while in the Azores? I used a hot-melt glue gun...

It all depends on the type of plastic. If you can find out what you've got you can google to find out what will work. Also, some plastics get brittle with time, especially if UV exposed. If that has happened, the tank may just break again in a different place. But trying to weld sure beats spending $150 on a new one. If nothing else you get entertainment value.

[Cheechako]

No way to just order one? I know "we" don't like to use Silicone on boats, but I wonder if silicone would work until you get somewhere where you can buy a new tank? I know the auto parts stores sell it in various grades for use on engines. The stuff is flexible and tenacious for sure.....

[ssanzone]

You can also try A+B epoxy putty which sticks to everything.

Mix up equal parts, thoroughly kneed it together and apply.

In 24 hours it will have fully cured and a wide enough patch will reduce the amount of expansion but be careful not to over patch by too much as tanks expand for a reason.

gl

-steve

[a64pilot]

Silicone and fuel don't mix, the fuel rapidly deteriorates the silicone.

Being what the possible consequence is of leaking fuel on a running hot engine, maybe a repair isn't the best idea?

[Sun and Moon]

Originally Posted by a64pilot

Being what the possible consequence is of leaking fuel on a running hot engine, maybe a repair isn't the best idea?

+1 for uncommon sense

[Cheechako]

Originally Posted by a64pilot

Silicone and fuel don't mix, the fuel rapidly deteriorates the silicone.

Being what the possible consequence is of leaking fuel on a running hot engine, maybe a repair isn't the best idea?

Thanks, good to know, that's what I was wondering. Yeah, repairing that tank is a little iffy for sure... Unfortunately I looked on line and cant find any are available.. small bits are but not the tank that I could find...
convert to off motor tank?

[Hud3]

If welding doesn't seem feasible, try this...

Depending on the shape/length of the crack and access to the inside of the tank, another way to patch it is to drill a hole through the crack and install a bolt or machine screw with a washer on each side of the tank wall, each backed by a rubber washer or O-ring.

Access to the inside of the tank may very well be problematical. If you can't jury rig a way to install the nut/washer/gasket on the inside of the tank, say with bent needle nose pliers, try drilling a hole and inserting a self-tapping screw of proper diameter, with a washer and gasket just on the outside.

[a64pilot]

Originally Posted by Cheechako

convert to off motor tank?

Does it have a fuel pump? If so , then maybe.
Actually if you have the time go to aircraft spruce and order some B2 fuel tank sealer, think of it as silicone specifically made to seal fuel tanks, many aircraft fuel tanks are actually just sections of the wing, being as it's full of holes where the rivets go, this stuff is used to seal all of those leak areas, and lasts more than 20 yrs being constantly in fuel. It's a 2 part "liquid rubbber", the 2 is the working time, there is 1/2 too, and the A version is thin meant to run into corners and seams, that is not what you want.
Similar to 5200, just a lot thicker and you mix a black component with a white component and mix until uniform dark grey, and just like 5200, one drop will cover all your clothes, your car seats etc. Acetone will remove it until it cures, when cured Acetone, MEK etc won't even soften it.

[tbodine88]

I had the same problem, but living in the states with plastic credit card and Amazon, I fixed it the easy way I bought a new tank. I was thinking that maybe a heat gun and some heat shrink might fix it, but I didn't try it. Now that the old tank is empty (no fumes) perhaps I'll try it now.

Does it look like this? http://www.cactus.org/~tbodine/Saili...nkCoupling.JPG