Author Topic: petrol tank repairs and chromeing  (Read 4812 times)

Offline trevinoz

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Re: petrol tank repairs and chromeing
« Reply #15 on: 27.03. 2010 23:15 »
I have seen tanks which someone tried to repair with compressed air.
Too many P.S.I. and and the tank takes the shape of a pregnant whale!
             Trev.

Offline Stu55Flash

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Re: petrol tank repairs and chromeing
« Reply #16 on: 28.03. 2010 19:41 »
Quote


I've only seen the later tanks with a hole through fixing a rubber bung. I have the earlier tank with front and back fixing lugs. Does anyone know where these are available from?

Stu
"Keep a distance from lady "L" drivers in cars. Some are not mechanically minded, are slow to acquire road sense, an are apt to panic..." The Pitman Book of the BSA Twins.
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Offline MG

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Re: petrol tank repairs and chromeing
« Reply #17 on: 28.03. 2010 19:56 »
You might try Dean Hoare of D&G Motorcycles

D and G Motorcycles,
Clothallbury Farm,
Clothall,
Hertfordshire.
SG7 6RJ

Tel.  01462 790729

Email geoff@dandgmotorcycles.co.uk

He's the one that had my A10 tank reproduced, I'm pretty sure he offers plunger tanks, too.
Maybe you could as well supply him your old one as a template, like I did.



Trev, that's exactly what I meant when I said "with a bit of care and experience"  ;)
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1961 Matchless G12 CSR

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Richard

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Re: petrol tank repairs and chromeing
« Reply #18 on: 28.03. 2010 19:56 »
I take it yours is a plunger frame, take care when buying another tank as there are two types, I believe for the early type with bolt fixing front and rear there are replacement Indian made tanks, but for the type with the rubber sleeve type rear bolt fixing they are not making them, I have both types of tanks lounging about in the garage loft, however although not dented they require re-chroming
Richard

Offline Mosin

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Re: petrol tank repairs and chromeing
« Reply #19 on: 01.04. 2010 11:42 »
Hi I have a few dents in my petrol tank and i was wondering if any body could recomend some one ideally in the north west area as i live in cumbria, but if there is nobody in this area i am willing to go further afield p.s. sorry should have also said in uk thanks in anticipation Bob.

Alistair at Cumbria Plating services on Currock Road Industrial Estate in Carlisle did a great job on all the re-cromeing on my D3 Bantam. This also included the chrome tank strips which I was convinced were beyond repair. He also did all the paintwork for me and various other bits and pieces. I would definately recommend trying him first.
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Online BSA_54A10

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Re: petrol tank repairs and chromeing
« Reply #20 on: 01.04. 2010 22:26 »
Quote
Another nice way to get dents out of a tank is to pressurize it with compressed air and carefully heat the dented area with the oxy-acetylene kit. With a bit of care and practice this works very well.

If you want to live long enough to have grand children, never, never, never ever pump up a tank with a gas and then wack a torch on it.
The safe way to do it is to strap the front together with some thing like 1" square tube with a 2 mm wall thickness.
Make another strap for the back using flat iron at least 1/4" thick.
Now fill the tank with water, then pump in another 500 mls ( if you can ).
This will bump up the pressure inside the tank sufficiently enough to push any dent out but if the tank splits during the process only a quick low energy squirt of 500mls of high pressure water will be let loose in your garage.
Fill it up with air and then around 200 liters of extreamly high pressure air will send the tank flying around your work shop or send schrapnel flying in all directions and oft damage the tank beyond economic repair.

Once you have the tank pressureized run your oxy torch around the inside of the dent ,just below the rim, heating only the metal that was pushed in. The heat will release stresses in the dented metal which will yield to the pressure within and "roll" out and this will happen way, way before the metal gets to a red heat and softens.
Do not play the torch on the top of the tank or you will end up with a raised welt ( much like a wart on your nose) which will be very hard to shrink back in again.
Bike Beesa
Trevor

Online RichardL

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Re: petrol tank repairs and chromeing
« Reply #21 on: 01.04. 2010 22:49 »
Trevor,

Your water approach sounds like something I might try in the distant future, but as long as we're here it's a good time for me to gain the knowledge. How do you get the last pressurizing water pumped inot the tank?  Also, I would be surprised if the washer under my 1/2-turn butterfly-nut cap would hold the pressure, whether water or air.

Richard L
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Offline MG

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Re: petrol tank repairs and chromeing
« Reply #22 on: 02.04. 2010 07:42 »
Quote
If you want to live long enough to have grand children, never, never, never ever pump up a tank with a gas and then wack a torch on it.

Hey, I've done it several times and I'm still here to tell the story!  ;)

But you are right, the approach with the water definitely is an option, never thought of that.
It is indeed important to use an otherwise sound and solid tank and not to overdo with pressure (therefore apply more heat, we are talking about red heat and soft here!).
The pressures I had used so far never were sufficient make a tank fly through the workshop (Rocket tanks? *smile*).
And the chance of shrapnel flying around is zero ("yield before break" is one of the most important benefits of steel).

Nevertheless, thank you Trevor for a good word of warning. We wouldn't like to have people setting up bombs in their garage.

1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

www.histo-tech.at - Restoration, Repairs, Racing

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Online BSA_54A10

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Re: petrol tank repairs and chromeing
« Reply #23 on: 02.04. 2010 12:52 »
There are zillions of ways.
Easiest is a tyre valve in a plug in one of the fuel tap holes and a bicycle pump.
pour water down the handle then draw it up slowly.
Any oil pump will also work including those used for changing the oil.
Most drum pumps ( for pumping oil out of 5 Gallon drums etc ) will do the job.
The pump from an old floor jack

Place some heavy duty glad wrap over the cap hole then put the petrol cap back on to seal the hole and block off the vent hole.

This is how pressure vessels like LPG tanks are tested
Bike Beesa
Trevor