Hi,
In rebuilding my Century Plus from 1965, CPCL, I've cleaned up the coat of black paint that a PO had afflicted the fuel tank and like its original brass/lacquer, and rather bashed-up, look. But I have persistent fine black powdery gunk visible in the fuel line that keeps coming back - see the pic. This is despite removing and flushing out the tank with fuel a couple of times, and replacing the fuel tap with a new brass one with a new mesh. The fuel cap looks good with the cork intact and not leaking, but I haven't taken it apart. Any suggestions of what may be causing this? Any any advice on the best way to clean the inside of the tank gratefully received.
Iain.
pic of the reappearing black powder/particles in my fuel line
Caustic soda. Gradually dissolve 200gr in two litres of water. Pour it in the tank and some more to fill it up to the fuel cap. Don't let the solution to come in contact with the fuel cap, paint or your hands. It will corrode everything. I also remove the fuel tap and seal the tank with a plug.
Let it overnight to react. That will remove everything. If necessary repeat or use 300gr of caustic soda granules.
Protect yourself. Eye wear, gloves and extra care. That stuff is nasty. In case it comes in contact with your skin you will feel a soapy effect. That means that you have started getting burnt. Vinegar would stop this. Pure water doesn't help. I have tried....
In addition dissolving caustic soda in water creates heat. If you throw a lot in you bucket it will form crystals that will take much longer to dissolve. You should stir the whole time. Heat can also reach boiling temperatures.
Thanks - I've found Caustic Soda in the US. You can get it at Tractor Supply as Roebic Heavy Duty Crystal Drain Opener, but it's a bit more rare here than in Europe.
What did you use as the plug for your tank?
Also, If I choose to dunk the whole tank in a bucket of Caustic Soda, will it remove the outside coat of paint and lacquer, and would that leave me with a rather attractive, if battered, brass tank?
Happy to help
The plugs I have and use have threads, 1/8x28 BSP. They are specially made to seal.. I don't know for what purpose were originally but I bought them from a shop with industrial stuff.
The caustic soda will kill everything that is on the tank as paint. I do it this way when I want to polish a tank. You may need to used grit papers afterwards to reach the healthy surface of the metal.
Caustic soda if the tank stays in the solution for two days it will loose some of the surface zinc this alloy has. When that happens it will get copper colored. But with the grit papers you can solve this issue.
The bucket you will use, should be made of plastic. Aluminum dissolves in caustic soda solution. I think iron stays unaffected.
There are other ways to clean it that are less dangerous. Caustic soda = Lye you can still get it at the food store here, comes in crystals.
For another method, remove fuel tap to protect filter on it. Remove fuel cap as well although can be left on. Put about a cup full of hard driveway gravel between 3/8" and 5/8" dia. In the tank, add about a pint of hot water with Dawn dish soap about a teaspoon full in the tank. Hold one of your fingers over the fuel tap hole or plug it with a rolled up rag or piece of rubber as a plug. Shake for a few minutes. Check with flash lite to see if it is nice and clean inside. If not repeat until it is clean, rinse out with very hot water, set in sun to dry.
The lye method works well but I prefer it for the bronze on the transom clamps where you can keep it in a pail and carefully brush the part with it. Most oven cleaners have lye or caustic soda as the major ingredient as well. Be sure to keep it away from aluminum, it eats through that pretty darn quick.
