Can anything be done with this
Depends entirely on what is behind those pinholes.
If its a large patch of rusty metal, then it may be time to look for another tank.
If its still solid metal, an experienced operator may be able to solder over those holes - I've seen this done
to the tank of a small Onda, and it was a permanent repair.
It will damage the paintwork though, although a paintstick may be able to cover over it.
If tanks are hard to find, it may be possible to weld in a patch panel of steel - a good operator can do this, although obviously it will need painting afterwards - and will not be cheap. Skillfully done, it will not be obvious that this has been done at all.
There are also available a number of types of tank sealing compound - you slosh them into a WELL CLEANED tank, and they seal over the steel surface and any pinholes. Applied carefully, they can work well. But if the rust is entrenched, ALL the rust must be stabilised/removed first, or it will work from underneath and more holes may soon appear.
Chewing gum also works, and soap - but only for short distances - maybe enough to get you home. !
Hope this helps.
