Aluminium Water Tank Repair

[Dino]

Hi,
A friend has a water tank that has 2 or 3 small holes in it. They are slightly bigger than pin holes. The tank has to be repaired in the boat as it won't fit out the cabin door. It has been removed from it's position under the bunk so we have good access to all parts.
It looks unlikely that we will be able to get anyone to weld it in place.
Can anyone recommend a chemical metal type product that has worked well for this purpose?

Thanks!

 

[RichardS]

JB Weld will fix it but good preparation by keying the surface will be essential to a good repair.

Richard

 

[VicS]

I agree JB Weld "original" ... A two pack metal filled epoxy.

clean off all oxide to bright metal surface.

Probably other epoxy repair putties will also work well ( eg Evostik Hard and Fast )

In the long term a new tank ( flexible ?????) may be the only solution

 

[PCUK]

The tank is basically scrap. It has corroded through in several places and any repair will be temporary as further pinholes will quickly appear. The only simple repair as the tank cannot be removed is to cut off the top and place a flexible tank inside. (From previous experience).

 

[lw395]

The tank is basically scrap. It has corroded through in several places and any repair will be temporary as further pinholes will quickly appear. The only simple repair as the tank cannot be removed is to cut off the top and place a flexible tank inside. (From previous experience).

Not necessarily so, the pinholes may be isolated as a result of inclusions in the welds or similar. Or small bits of other metal getting in. If it's a drinking water tank, then some sort of 'food grade' epoxy might work.
If it's just corroded because it's been sat in a puddle of salt water, I expect you are unfortunately correct.

 

[dod]

I repaired a leaking s/s tank a few years ago using normal car filler and then fibre glassing over the affected area. Still going strong to this day and no leaks.

 

[Dino]

Thanks folks,
It's the main water tank on the boat but is not used for drinking. We are going to try JB Weld Waterweld and see how we get on. He needs a temporary fix to get him through the season so hopefully it will be okay for a few months.
Thanks for all the info.

Dino

 

[vyv_cox]

If that is the only damage I would much prefer a reliable mechanical repair rather than take a chance on an adhesive. Drill the holes out and insert pop rivets, with an adhesive as well as a sealant.

 

[PCUK]

I can't see the point in this straw clutching. A flexible tank will do the job permanently and just as quickly as the various forlorn hopes suggested.

 

[vyv_cox]

I can't see the point in this straw clutching. A flexible tank will do the job permanently and just as quickly as the various forlorn hopes suggested.

You are making assumptions about the holes. They might be two of a thousand pits that are about to break through but they might be the only blemishes in an otherwise pristine tank. Unless the OP tells us we do not know either way.

 

[rotrax]

You are making assumptions about the holes. They might be two of a thousand pits that are about to break through but they might be the only blemishes in an otherwise pristine tank. Unless the OP tells us we do not know either way.

Exactly-PCUK's glass is half empty while Vyv's glass is half full..........................

Vyv's fix will cost a few pence and the success-or not-will be soon seen.

PCUK's fix will undoubtedly be successful, but at some considerable cost compared to a bit of two pack or pop rivits and sealer.

I know which way I would jump.

Some years ago at Pukakoe in NZ's North Island a motorcycle race competitor was stuffed-his aluminium fuel tank on his Norton has split-vibration failure-along a bottom seam.

He was loading up to go home as he could find no-one to weld it and two pack adhesives, applied I suspect without proper prep had not fixed it.

He subsequently completed two hard fought races, got in the final and on the second step after I used an old trick from my Grandfather's Brooklands days.

The cause of the vibration was removed-collapsed tank mountings-and new ones fitted.

I moulded half a bar of soap in my hands untill it was like plasticine, smeared and pressed it along the affected seam and covered it with bi-radial strips of gaffer tape.

Petrol does not dissolve soap.

 

[superheat6k]

I repaired the porous cast aluminium Vetus helm pump on my boat before last using aluminium brazing rods. The metal had to be completely clean and dry, which for a hydraulic tank meant several days soaking in a strong solution of fairy liquid, I then used my Dremel to lightly score and de-oxide the surface at least 1" from the intended braze site, with several cuts into surface at and close to the leak site , I then followed the instructions on the brazing rods, which melt way below the temperature the aluminium casting melts at.

The finish item never weeped at all after the repair, including fairing of the surface as the pump casing was visible at the helm position.

Another option here is to drill several holes in a square surrounding the porous area, insert Rivnuts with a sealant such as sikaflex 291, then make a cover plate and rubber gasket to cover the square, including the rivnut flat heads. Indeed you could cut an inspection hatch if this might be useful.