Thread: oil tank to water tank conversion

I certainly wouldn't spend much money doing it as 1500 litres is pretty small for a rainwater tank. It's amazing how quickly a tank that size can be filled.

Simon

We've got one of those that we're planning to use to recycle grey water. Still working on how to clean the oil out of it. Was thinking about trying some degreaser. Shame you can't just throw a match in it

The oil will have acheived penetration into the metal making it very difficult to acheive clean out, even to a standard for the garden.

Having seen several very nasty accidents from welding fuel tanks (and the bits and pieces of human scattered around) I know how difficult it can be. And this after caustic washes, steam cleaning etc.

Only way I know is to cut the end end off. Grit blast, paint with a surface tolerant paint and then preserve with two pack epoxy (tank liner) which will make the water toxic as well (for drinking anyway). Options limited!! Near new 44's are a better option than old steel tanks.

Some company's make polly tanks which could slide inside.

Sorry to be bearer of bad news. A "she'll be right" attitude may be OK for the garden so long as nobody can inadvertently drink the water.

Cheers

This is no help at all, however when we were in Albany, we went and visited Whale world

They have have three humungous tanks in which the refined whale oil was stored. As part of the revamp into a tourist attraction, they have converted them into mini theatres. My guess is they cleaned them pretty well, but you can still smell the oil in them.

My guess is your oil tank is in similar condition, it'd take a fair bit to get all the residue out. I did use a 1000L fuel tank for water, even that took a while for the residue to get away, despite beng constantly filled and emptied. Now it has a hole rusted in it.

Give it up, there is too much risk involved. There is the health issue and the safety issue you need to consider. The old saying that oil and water do not mix holds true.
Heating oil is nasty stuff and will not come out of the metal. This can lead to someone further down the track to belive it is ok to weld the tank for whatever reason and blow themselves up and injure others because they thought it was ok since it had water in it. Once you apply heat you create gas vapour which will blow up. It does not matter how long you have been usingh it for grey water etc.

I sort of agree with all of the above .... but....I think people can also be a tuch too alarmist.

If you REALLY want to use it, this is what you can do:

Cut the top open so that you now have an open vessel, with a big opening. Don't use a grinder nor an oxy-torch to cut it open.

Once open there are no more risks of explosions since the gas is not constrained. Lit a nice fire outside and get your tank on a side on top of it. Keep the fire all around it. You will get the tank to bare metal outside and inside, initialy with the occasional harmless flame inside. Once one side is burned flip it over.
To clean all the paint an oil residue you need to get the metal real hot and hopefully not too hot to twist the tank into a useless shape.
I have done this with a 200 litre drum used for oil with no problems.

Now paint it with killrust and top it up with some water tank paint, build a timber lid for it, fit a tap and Bob is you uncle.

PS
If you REALLY need to use a grinder to cut the tank open you can. The way to do it is to fit an air hose in the tank through the opening and keep a strong flow of air flowing in the tank whilst you cut. Any build up of flamable gas will be blown out and the concentration of gas remaining will not be enough to ignite.

If you are going to cut any fuel or gas tank with the oxy or grinder fill the thing with water, make sure the water level is below the cutting line. Then burn it as marc said.

Originally Posted by Nic0

If you are going to cut any fuel or gas tank with the oxy or grinder fill the thing with water, make sure the water level is below the cutting line. Then burn it as marc said.

Agreed, that is even better than the air hose.