anyone tried ?

erik0905 · Post by **erik0905** » Mon Apr 10, 2006 9:33 am

hello all.

Has anyone to your knowlidge, ever tried to put liquid under pressure in a tank, to get it back in the right form.

Post by **charlesp** » Mon Apr 10, 2006 10:04 am

Hi

Yes I have. I have a hydraulic pump from a garage set. I managed to find an adapter at the local hydraulic hose suppliers which fits the petrol cock thread.

I fill the pump with hydraulic fluid, connect up the hose, and fill the tank with water - up to the brim to avoid any air pockets. I use a metal filler cap, which I screw on as tightly as I can.

I then pump away, making sure I can see the largest of the dents in the tank. Each stroke of the pump will reduce the dent - you can just see it happening if you watch carefully. Large dents in the straight areas will come out first, them the dents in end caps. Small dents and creases in the hemispherical surfaces don't respond all that well, and can be assisted by tapping the edges with a small hammer. Some recommend annealing those ares with a blowtorch first - I have yet to try this. Naturally anything to do with a blowtorch needs to be carried out before filling the tank with water, and should be conducted with immense care. The tank should be thoroughly cleaned out to ensure absolutely no petrol remains - not even fumes.

This works quite well on a 102 tank or even the little cylindrical one for the little model forty. But it is vital that you don't take it too far - brass is quite capable of stretching under this sort of pressure, and those last few strokes to get rid of a small crease could leave you with a barrel shaped tank, which is then no good at all. So be very careful.

Standard oval tanks are a bit of a problem. The natural tendency is for the flattened upper and lower surfaces to balloon out, and the flat or indented end caps to do the same. I have attempted (without great success) to construct a wooden jig or former which can be clamped in place to keep these surface the correct shape, I have problems with the end caps.

But for 102s it works well, leaving only small creases to be dealt with.
For these I recommend lead loading or even solder. Car bodywork filler is often used. In my experience the stuff chips off easily when you least want it to, but is the very devil to remove if you want it shifted.

Good luck, and my thanks to Ross Leger for he tip...

erik0905 · Post by **erik0905** » Mon Apr 10, 2006 2:28 pm

I have just tried. and it worked, I used an old greasepump, which had a hose that fitted the tank. I took out the piston and all and cleaned the rest, lucky for me I had a new hose. Water in the tank water in the pump, pump and the dents come out. ( before and after pictures taken ), but they can not be shown here, as far as I know. All done in Â½ hour.
It will come on my site when I get it running.

webmaster (BM) · Post by **webmaster (BM)** » Mon Apr 10, 2006 8:18 pm

Hi Eric

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If we wanted to have our own photo gallery that has the benifits of less spam and advertising then I could add that capability here but you would need to lobby John

Tim

erik0905 · Post by **erik0905** » Mon Apr 10, 2006 9:31 pm

my site is running and will be edited as time allows.

Ian_in_Oz · Post by **Ian_in_Oz** » Wed May 03, 2006 1:24 pm

I tried the water and greasegun trick but couldn't seal the cap or fuel tap thread properly. How do you get all of the air out when both of these threads go a little way into the tank?

Has anybody tried filling the tank with water and freezing it to let the natural expansion of the freezing water push the dents out?
Ian

erik0905 · Post by **erik0905** » Wed May 03, 2006 1:47 pm

Ian_in_Oz wrote:I tried the water and greasegun trick but couldn't seal the cap or fuel tap thread properly. How do you get all of the air out when both of these threads go a little way into the tank? Has anybody tried filling the tank with water and freezing it to let the natural expansion of the freezing water push the dents out?
Ian

I connected the pump directly to the tank in the little hole where the treads were the same as on the hose from the pump. i filled the tank with water, and the pump as well. First I let the air out , shaking it a bit with the cap upwards, and then I tightnend the cap and the little air one , with a tool that I don't know the name of, then I just pumped pressure. As the pressure rised more and more dents popped out, i all honesty some very small ones remained. I have been told by this forum , that ice has been tried, it was hard to control.

Post by **John@sos** » Sun May 07, 2006 10:33 pm

As a postscript to this I tried the freezer method. It did push out some dents slightly, but I imagine it is more difficult as the metal is so cold. It eventually started to bulge the flat sections so I gave up.

In the States there are specailist who insert hydraulic rams into feul tanks to remove dents... anyone had experience of this?

The only sure way does seem to be to cut off the ends and tap them out, then resolder...

It will come to this for all eventually, as we will run out of half reasonable tanks...

Regards,
john
SOS