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Welding on top of fuel tank


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4 hours ago, Mike the Boilerman said:

If on the other hand the top of the tank is also the counter, it is probably 8 or 10mm, plenty to drill and tap. 

 

 

Its not a good idea, it breaches the tank, retest required and it is almost impossible to prevent fuel oozing out afterwards.

That's why rudder top bearings are bolted to a plate that is welded to the tank top.

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9 minutes ago, hider said:

Its not a good idea, it breaches the tank, retest required and it is almost impossible to prevent fuel oozing out afterwards.

That's why rudder top bearings are bolted to a plate that is welded to the tank top.

If this is the top of the tank, then why would fuel ooze out? Use of a suitable sealant should prevent a leak here, but if there is still a gap, it will just add marginally to the tank vent area.

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Even the so called experts cannot agree on the flammability of diesel fumes.

 

When I was working, I often designed and project managed standby generator installations with bulk and day diesel tanks.

 

In the Greater London area, the installation had to comply with Section 20 of the London Building Regulations, which are more onerous than any other part of the country and compliance was checked by the local authority fire officer.

 

In London, if the day tanks were in the same room as the generators, the fuel line between the bulk tank and day tank had to be fitted with a shut-off valve which closed in case of fire, along with a facility to drain the contents of the day tanks back to the bulk tanks.  Obviously this left the day tanks empty but full of diesel fumes.

 

In other parts of the country, some local authorities specifically forbade emptying the day tanks in the event of a fire, whilst others specifically required it.

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45 minutes ago, David Mack said:

If this is the top of the tank, then why would fuel ooze out? Use of a suitable sealant should prevent a leak here, but if there is still a gap, it will just add marginally to the tank vent area.

Slosh of the diesel as the boat moves and heels over as people move from side to side. Seen it on a car fuel tank sender in the top of the tank, where the petrol was oozing around a dodgy seal. With suitable sealant it would probably be OK, but my instinct would be to find a method that didn't involve drilling in to the tank. You would also end up with swarf in the bottom of the tank.

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Re Post #24:

 

"I was told exactly the same when a diesel bowser sank near Tower Bridge.  It  dragged down a tug which was moored alongside and caused, in my eyes, a massive stretch of polluted river.  Sure enough after a few tides it had all disappeared. "

 

River pollution doesn't 'just disappear', it moves elsewhere - until there's nowhere else to go and then it just gathers, stagnates and kills things.

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6 hours ago, dmr said:

Take the boat to any good boatyard with an experienced welder and they will weld it for you. If you are worried you could fill the top of the tank with inert gas, but the boatyard welder would not bother to do this.

 

.................Dave

 

What about taking the filler cap off and flushing the tank with a CO2 extinguisher?

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50 minutes ago, Mike the Boilerman said:

 

I'd have thought draining the diesel from the tank and filling it with water before commencing welding would mitigate most of the risk, and fairly simple to do too. 

But water contains both oxygen and hydrogen so is potentially even more dangerous than diesel. :)

 

...................Dave

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1 minute ago, dmr said:

But water contains both oxygen and hydrogen so is potentially even more dangerous than diesel. :)

 

...................Dave

 

WHAT????

 

Why does the canal not catch fire then????????????

 

 

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11 hours ago, Mike the Boilerman said:

 

 

Ha Ha Ha!

just replace the oxygen with CO2, problem solved. I would sooner weld on a full tank of fuel rather than an empty one.

Introducing water it  may be difficult to get it completely removed afterwards

When we were allowed to solder repair lorry diesel tanks (now banned) they had to have water run through for hours or even days otherwise they went bang when the torch went near them.

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I have brazed up cracks in lorry tanks many times. The tank would be full and you could hear the diesel boiling as you worked. I was young and bulletproof. Now I would pay someone to do it and  stand a bit further back.  Get it welded, a rivnut or couple of small bolts and a bit of strap holding my weed hatch down? no thanks.

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35 minutes ago, Narrowboat Nimrod said:

I have brazed up cracks in lorry tanks many times. The tank would be full and you could hear the diesel boiling as you worked. I was young and bulletproof. Now I would pay someone to do it and  stand a bit further back.  Get it welded, a rivnut or couple of small bolts and a bit of strap holding my weed hatch down? no thanks.

 

On the other hand, what if the OP used a suitable number of appropriately large, bolts..... ?

 

:P

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30 minutes ago, Narrowboat Nimrod said:

If you have arms like Mr tickle and can back a bolt up from inside the tank then thats fine. All other methods are just a bodge.

 

Dogmatism doesn't suit you....

 

 

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29 minutes ago, Mike the Boilerman said:

 

Dogmatism doesn't suit you....

 

 

Yes you are right, what I should have said is all methods mentioned by MIKE THE BODGERMAN are a bodge. Someone might come up with a real solution. I thought trolling was the sport of teenagers? My last post, don't waste your time replying.

On 21/12/2016 at 08:28, mross said:

There should be a page saying that if it were the case. Oddly the website checker www.downforeveryoneorjustme.com says it's up. you can ping the IP address but it is refusing http and https connections.

 

The domain 'keelblack.co.uk' is registered to Tony Brooks! and is still active.

 

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I really do not see the problem here.

 

There is a large (2" ?) high stub where the bracket has snapped.

Bend the bracket back down.

Weld a splice back in.

Little heat will get down to the fuel tank.

 

Simples !!

 

It looks like it has been like that for a very long time - the 'break' has even been painted over.

Inkedweed hatch lid_LI.jpg

  • Greenie 2
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I agree, it does seem like we are in mountain and molehill territory doesn't it? And another fragile ego cracks and flounces simply because I disagree with him!

 

Looking at the top bit, it appears to have thinned to near nothing with corrosion which suggests the bottom stub is not that substantial either.

 

 

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34 minutes ago, Mike the Boilerman said:

Looking at the top bit, it appears to have thinned to near nothing with corrosion which suggests the bottom stub is not that substantial either.

 

I am no welding 'spurt but would have thought welding a plate on the 'outside' of the loop onto good metal would do the job.

 

If the 'action' of a rifle can be welded without it losing its 'temper /hardness' (no - not that temper - I'd get a bit annoyed it someone heated me up with a welder) I'm sure that someone in the know could weld that up without any problem.

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On 02/06/2019 at 13:25, hider said:

Its not a good idea, it breaches the tank, retest required and it is almost impossible to prevent fuel oozing out afterwards.

That's why rudder top bearings are bolted to a plate that is welded to the tank top.

My rudder top bearing is bolted through the top of the fuel tank. I've removed it twice (once for painting and once to replace it.) and had no problem sealing it diesel-tight on re-fitting.

 

MP.

 

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5 hours ago, Alan de Enfield said:

 

I really do not see the problem here.

 

There is a large (2" ?) high stub where the bracket has snapped.

Bend the bracket back down.

Weld a splice back in.

Little heat will get down to the fuel tank.

 

Simples !!

 

It looks like it has been like that for a very long time - the 'break' has even been painted over.

Inkedweed hatch lid_LI.jpg

culdnt agree more ... plenty there to weld onto without any risk of heating the tank

 

Rick

 

 

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As above but I would 'belt and braces' and weld a bridging piece over the fracture. Whilst your at it you need to do the other side because that material is now necked (stretched) and will fail in the not too distant future. If you are truly concerned about heating the tank, pour water over the surface before you weld; it will act as a heat sink. When you have finished welding continue to pour water over the tank (not the welds). There is no way that sufficient heat would pass through to ignite the diesel.

As one of the others said " give it to an expert". I am sure they will knock that job off in less than half an hour!

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