Petrol tank construction

[No Signals]

I thought I would have known an obvious answer to this, ie 'welded'; but I've just obtained an old spare tank for my MW which is full of crud. To make it servicable I was considering cutting the end off, getting the inside bead blasted and then welding the end back on. Pretty straightforward I thought. However upon looking at the end, which is recessed in slightly, it does not appear to be an obvious weld joining the pieces together. Not gas, not electric nor some version of spot welding I'm not familiar with. Just a damn good fit. Removing the paint on a section hasn't made it any more obvious. Anyone know if these are soldered together, as this seems the only obvious method which wouldnt leave a trace of 'heated' metal? I would have thought brazing would have introduced too much heat and deformed the parts too much. So before I start cutting, anyone know if this might this unsolder?

[Marmite!!]

Could of been resistance welded..

[radiomike7]

I thought I would have known an obvious answer to this, ie 'welded'; but I've just obtained an old spare tank for my MW which is full of crud. To make it servicable I was considering cutting the end off, getting the inside bead blasted and then welding the end back on. Pretty straightforward I thought. However upon looking at the end, which is recessed in slightly, it does not appear to be an obvious weld joining the pieces together. Not gas, not electric nor some version of spot welding I'm not familiar with. Just a damn good fit. Removing the paint on a section hasn't made it any more obvious. Anyone know if these are soldered together, as this seems the only obvious method which wouldnt leave a trace of 'heated' metal? I would have thought brazing would have introduced too much heat and deformed the parts too much. So before I start cutting, anyone know if this might this unsolder?

 

Is the end recessed with a flange facing outwards? If so it may have been welded by passing the flanges between two copper wheels with a large current passing from one to the other. Think of it as a continuous spot weld, but there is no way you are going to take it apart without serious damage.

[Richard Farrant]

With this type of tank, the repairers normally cut circular access holes (about 4 inch or so) in it, might need several, because of baffles. Inside can then be inspected and cleaned. They do use dip tanks for cleaning rust, then once done, solder circular plates back over the holes.

[No Signals]

Thanks for the input fellas! What you have collectively suggested fits the bill. Got to admit I hadn't come across that technique before but it explains everything. I shall investigate further as to where to cut some suitable access. Thanks again.

[Simon Daymond]

I agree with Richard, every tank we've ever cleaned out, has had an access cut into the top of each compartment, which gives enough room to clean the crud out, we use a steam cleaner. Then we have cut patches slightly bigger than the holes and weld them back on. As they are at the very top, they are unlikely to leak, downside is, that if the tank is visible, you might have to do some titivating to make the patches invisible, i.e bit of grinding filing etc.

There are firms around who can coat the inside of the tank with a plastic coating, which can prolong their life and also takes care of any tanks that weep.

Hope you don't blow yourself up, like someone I heard of, who was repairing a petrol tank in his garage (at home), he had the door shut, the tank although empty of petrol still filled his small garage with fumes, the central heating boiler clicked on and, well you can guess the rest.

Not that it'll be much use to you as it's probaly too far away? - but there's a firm in Dewsbury, West Yorkshire, called Dewsbury Radiators, 01924 453382, who specialise in cleaning and repairing fuel tanks, chap called Alan, they can also re-core all manner of radiators.

[No Signals]

Thanks for that Simon. I travel to Dewsbury on a fairly regular basis so I shall sound them out to see what they can do.

[Simon Daymond]

ok, well Leeds ain't that far away if you need a brew, send me a PM if you're interested, you can come and hold something on the militant, extra hands are always useful.