Aluminium Fuel Tank Repair

[reel-em-in]

Discovered a small hole in the top of my inbuilt aluminium fuel tank that was caused by an incorrectly fitted stainless steel worm drive clamp that rubbed through the alumium.

I am looking to have someone price a welded repair but have not found too many interested parties given what they consider is an inherent risk of explosion. One of the main difficulties is that the tank is actually welded into place so removal is quite a pain.

My questions are:
Has anyone been through this exercise and if so who did the repairs (based around the Redlands if possible).

Has anyone tried an epoxy product rather than a weld and if so was it successful?

The hole is approx 6mm diameter.

Thanks in advance

[rowanda]

what about a fuel resistant silastic (or glue) and putting a small plate over the hole?

[samson]

Cracked my old boys tank years ago removed it emptied fuel filled with water and tig welded up emptied and dried worked a treat and no risk of explosion.

[Mr__Bean]

There are a couple of options if welding is out of the question.

Can you get access to the inside of the hole through the inlet or through the fuel guage sender unit hole? If so then the simplest repair is to install a stainless screw and locknut with 2 fibre washers. Inside won't corrode due to the fuel and outside should then be covered with sikaflex.

If no access to the rear, is the aluminum thick enought to hold a large self tapper? If so then same as above with a large self tapper and fibre washer and sika etc.

If no good, then there are very good fuel resistant sealants around, the best are 2 pack cured and are used to seal aircraft fuel tanks (rivetted wings). If this is your only way then give someone like Aviall a ring, they sell aviation fasteners and stuff. http://www.aviall.com/html/australia.html Ask them about fuel tank sealer in a "Semkit" The kits look like this http://secure.silmid.com/ENG/product/__01750AB015__/SEAA01/Sealants/PRC%20DeSoto%20Sealants/PRC%20Fuel%20Tank%20Sealants/PR1750A2%20150ML%20SEMKIT%20PPG-DTD900-6092A%20%20%20%20%20%20%20%20%201003

Good luck and let us know how you get on.

- Darren

[Chimo]

HI REM

What brand of boat welds their tank in? Maybe its an opportunity to take the tank out and check the rest of it over before reinstalling without the welder?

Cheers
Chimo

[billfisher]

If no good, then there are very good fuel resistant sealants around, the best are 2 pack cured and are used to seal aircraft fuel tanks (rivetted wings). If this is your only way then give someone like Aviall a ring, they sell aviation fasteners and stuff. http://www.aviall.com/html/australia.html Ask them about fuel tank sealer in a "Semkit" The kits look like this http://secure.silmid.com/ENG/product/__01750AB015__/SEAA01/Sealants/PRC%20DeSoto%20Sealants/PRC%20Fuel%20Tank%20Sealants/PR1750A2%20150ML%20SEMKIT%20PPG-DTD900-6092A%20%20%20%20%20%20%20%20%201003

Good luck and let us know how you get on.

- Darren

I have a similar problem. My tank is seeping fuel from where the fuel outlet is attached. I have tried some of that 'knead it' polymer repair product but the fuel still finds a way to seep out. It looks like the "semkit" might be suitable if brushed around the outlet.

[cormorant]

Fuel doesn't explode but fuel vapour does. We have welded car tanks before by having them totally full and the area very well force ventilated. Freaked the first time I saw it done. A old time welder will do this or as others have said fill with water but without a inspection hatch it may be a hard process to clean out remaining water and dry the tank.

Could fill with oil as it doesn't explode and can be flushed in situ easier with a kero air gun and then flush a bit of petrol through.

Have seen it on commercial tanks with a soft CO2 foam like what the fire guys use as a suspression foam as there is no way you can fill a 10,000l tank with water.

Speak with an industrial welder in the fuel sector.

Flooding teh tank with CO2 or inert gas sounds OK but since it is in a boat bilge you want to make sure the area outside the tank is very well ventilated so teh operator doesn't get sleeeeeeeeeeepy

[Mr__Bean]

I have a similar problem. My tank is seeping fuel from where the fuel outlet is attached. I have tried some of that 'knead it' polymer repair product but the fuel still finds a way to seep out. It looks like the "semkit" might be suitable if brushed around the outlet.

The last letters and numbers on the semkit tell you about its consistancy and working life.

If the semkits is a XXXXX-A1/2 then it is an applicator sealant with 1/2 hour working life

XXXXX-A2 is applicator with 2 hour work life

XXXXX- B1/2 is a brush on sealant with 1/2 hour wrok life

XXXXX- B2 is brush on sealant with 2 hour work life.

For the use here I would be going for A1/2 or if not avaialable then A2.

- Darren

[ThePinkPanther]

I had to recently install a new fuel spear into the top of my alu tank and, like you, was pretty twitchy about getting blown to pieces if welding was necessary.

Eventually I had a small square of 2 mm thick aluminium made up, drilled a hole in each corner and then after checking my Will was in order, very (very) tentatively used my battery drill as a hand drill by turning the chuck to get the holes going and voila, I am still here!

If you have an old fashioned hand drill you can do the same thing.

Use some STAG to glue the bits together before screwing it in and all to easy.

Of course, another way is to get a tube of aluminium KNEADIT from a hardware store and just fix it with that. Guarantee it will outlast you and never ever leak!

[billfisher]

The last letters and numbers on the semkit tell you about its consistancy and working life.

If the semkits is a XXXXX-A1/2 then it is an applicator sealant with 1/2 hour working life

XXXXX-A2 is applicator with 2 hour work life

XXXXX- B1/2 is a brush on sealant with 1/2 hour wrok life

XXXXX- B2 is brush on sealant with 2 hour work life.

For the use here I would be going for A1/2 or if not avaialable then A2.

- Darren

I rang Aviall at Bankstown airport they said the semkit is designed to be brushed on from the inside of the fuel tank and weren't sure that it would work from the outside in the application I am looking at. It costs $85 for a kit which is a bit to spend if there is doubt as to whether it will work.

[Noelm]

one of the problems you are up against is Aluminium is kind of porous and it has fuel kind of "soaked" into the Alloy, it is very hard to clean it properly to get anything to stick, when it is welded, the heat just burns away any impurities, but in your case i guess best/only option is a reapir from outside, maybe even as suggested, a screw or bolt that will thread into the hole and glued/silastic/sika/anything ,has got to be better than a hole!

[Moonlighter]

Quite a few years ago now I had a repair done to a underdeck alloy tank by Dave Claussen at Riptide.

I had the tank empty and disconnected ready to remove.

Dave lifted it out and he then drilled the hole out (it was in the corner) to about 10mm. Flushed the tank with water, then he hooked up a 2" hose to the exhaust of his car put the hose well into the empty fuel tank via the filler, and we left it running into the tank for 20 mins - so then it was full of CO from the exhaust.

Welded up no problems after that at all. Final job was to blast out as much water/condensation as we could with a compressor. Re-installed, filled with fuel (100 l) and added water absorber stuff (can't remember the name). All good.

Might be worth a call to Dave.

Cheers

ML