High Pressure Washing and Neutral Detergent Pretreatment Greatly Increases the Efficiency of Rust Removal from Fuel Tanks!

One of the most effective ways to prevent a fuel tank from rusting in long-term storage is to completely drain the fuel from the tank. On the other hand, if you have a rusty tank in front of you, you will want to perform a perfect rust removal. There are many excellent rust removal chemicals available, but it is a waste of time to throw chemicals into a dirty gas tank. In fact, there are quite a few stains and rust that can be removed with just water. This is where a high-pressure washer and a mild detergent come in handy.

It would be a shame to let a rust removal chemical react with floating rust.

This is the gas tank I got for repainting, knowing the rust inside. I will remove the rust first, and repaint it when it is ready for use. It may happen that the rust is removed and a hole is opened, so the rust is removed first.

When I smell the smell of rotten gasoline from the tank cap vents, my restoring heart burns up because I'm a pretty serious motorcycle tinkerer. Even if you look at the motorcycle magazines of almost half a century ago from now, the maintenance and the restoration of the old motorcycle (at that time) always do the rust removal of the gasoline tank.

Furthermore, in the old days when 2-stroke engines were in full swing and before engine oil was separated for lubrication, there is a story that the engine oil in the gasoline tank acted as a coating and made it difficult for the engine to rust.

Since the gasoline tanks on today's motorcycles, including the two-stroke models that are becoming quite a minority, only hold gasoline, this can cause the tank to rust over time. To prevent rust in the tank when storing the motorcycle without riding it for a long period of time, you have two options: keep the tank full of gasoline or drain it completely.

It is difficult to fill the tank to the brim even when it is full, and in such cases, it is a good idea to add a stabilizer to prevent the gasoline from changing.

This is an example of my own experience, but when I completely drained the gasoline from the tank, including the inside of the fuel cock, and stored it in a marine container with the tank cap half-open, I was able to keep it dry and rust-free even after five years.

If you are unfortunate enough to have rusted your tank, or if you acquired your tank as a base for restoration knowing that it would be rusted, like the tank shown here, you will need to remove the rust. Rust = oxidation of iron, so in the past, rust removal required strong acid to remove the rust and then neutralization.

However, nowadays, many of the gasoline tank rust removal chemicals are neutral in nature. When considering how to post-treat highly concentrated acidic chemicals, the advantage of neutrality, which can be flushed down the drain, comes into focus.

The reason why iron oxide can be removed with neutrality is the surfactant.

Surfactant is an ingredient in soap and detergent, and it weakens the bond between water and oil. This works not only on the boundary between liquids but also between solids, and in the case of a rusty gasoline tank, it enters the boundary between the iron material and the iron oxide that has been eroded by the rust, and tries to separate the two.

Since it is neutral, it can be used without worrying about its effect on the environment. However, compared to strong acidic rust removers, the reaction is a little milder in terms of immediate effect.

Also, if the inside of the tank is dirty with gasoline and oil as well as rust, the surfactant has to work to remove that dirt. It's a waste of time to use it for extra work before the original rust removal.

Just a high-pressure wash from the oil feed port will remove a lot of the rust.

1) The inside of the tank, seen through the fueling port, is covered with red rust.
2) High-pressure washing is performed in a plastic container so that the stripped rust can be collected.
3) We were able to remove a large amount of rust, from large chunks to finely broken pieces, using only high-pressure washing.
4) Air blowing causes more rust to form. Trying to remove this rust with rust removal chemicals from the beginning is a waste of time and the chemicals will deteriorate.

This is where a home pressure washer comes in handy. The appeal of a washer that can easily wash away dirt-stained on concrete is the pressure. When you shove this high-pressure cleaner through the fueling port and spray it into the tank, you can clean the inside of the tank with much higher pressure than if you were to pick up the end of a standard water hose with your fingers and increase the force. It is natural because it is pressurized by the pump.

This pressure makes it surprisingly easy to remove the rust that has formed on the surface like scabs. Of course, depending on the location of the fueling port and the shape of the bottom plate of the gasoline tank, there will be areas where the high-pressure jet hits and areas where it is difficult to hit. However, the reaction efficiency of the rust removal chemical will be improved by blowing off the floating rust and residual gasoline stains that can be easily removed.

There is also the idea of utilizing sandblasting to remove rust from the inside of the tank. To use sandblasting, the person to whom the blasting is applied must be dry, so after cleaning with a high-pressure washer, the inside of the tank must be completely dry before use.

However, when the fine particles of aluminum oxide, the abrasive used in sandblasting, are sprayed into the gasoline tank, it is a difficult task to drain them all out. And the possibility that the abrasives left in the tank might somehow pass through the fuel cock or carburetor into the combustion chamber, or get caught in the fuel pump filter, makes it difficult to use sandblasting aggressively.

In such a situation, baking soda blasting has been attracting attention as a solid abrasive that does not affect the inside of the engine. Baking soda blasting, in which the fine powder of baking soda, which is also used for food, is sprayed by the high-pressure air of a compressor, has the advantage that it is water-soluble and does not leave residue, and that it is not as hard as metal, so it is difficult to scratch metal parts even when it enters areas with narrow clearances.

Baking soda blasting can also be used as wet blasting when used with tap water, which is quite effective in removing dirt and rust from gasoline tanks. Since baking soda blasting requires a blasting system and compressor, which are much more expensive than gasoline tank rust removal chemicals, it is not practical to install baking soda blasting for gasoline tanks. However, if you are attracted to baking soda blasting and introduce it, it will definitely be a powerful weapon for gasoline tank rust removal.

I digress, but compared to blasting, high-pressure washers, which are common household cleaning tools, are quite effective in removing dirt and rust from gasoline tanks because they utilize pressure.

1) The blue vertical tank uses baking soda as an abrasive, baking soda blasting with the product name EZ Blast. It removes rust from tanks that are clean on the outside but have rusted on the inside due to long-term storage.
2) When baking soda blasting is performed from the fueling port, a large amount of liquid mixed with red rust flows out from the fuel cock mounting area. The red rust ring on the ground shows how effective the rust removal is.
3) This is before the work. The tank has never been used, but it is rusted all over because it was stored in a humid place.
4) Only baking soda blasting is applied and before using rust removal chemicals, but most of the rust has already been removed. If it is in this condition, it will respond well to the rust removal chemical.
 

The surface-active power of neutral detergent is perfect for preparation.

Dilute a mild detergent for dishwashing with about 50°C water, put it in the tank, shake it well, and leave it there for about an hour.

Not only did the oil stains come off, but also the new rust powder that the high pressure washer couldn't remove.

Not to belabor the point, but the next best thing to using after high pressure washing is a mild detergent. Neutral dishwashing detergent is a surfactant, and it is the best item to remove the oil left by high pressure washing. In addition, as explained earlier, it has the same principle as neutral rust remover and has the ability to get in between the surface of the iron and the rust to lift the rust.

There are countless variations of surfactants depending on their ingredients and formulations, and the contents of a gasoline tank rust remover and a dishwashing detergent are different. However, the mechanism of getting in between the two different substances and separating them is the same, and in fact, when dishwashing detergent is injected into a rusty tank, it mixes with the dirt and the rust comes off.

Blowing off the floating rust by high-pressure washing and washing off the oil by degreasing are the best preparations for rust removal chemicals. When diluting the rust removal chemical, use hot water (about 50°C) instead of water to activate the reaction and greatly improve the rust removal efficiency. In addition, the rust removal chemical itself will be less contaminated by the pre-treatment, which will reduce the degradation of performance and improve cost performance when it is reused.

It's understandable that you might feel a little bummed when you see a rusty gas tank, but don't just throw in a rust removal chemical.

Finally, the rust-removing chemical was introduced. I diluted Hanasaka G tank cleaner, which has a good reputation as a neutral rust remover, with 50-60°C hot water, wrapped it in a blanket to keep the temperature from dropping, and let it react for 24 hours.

Drain the cleaner from the tank, rinse with water, and coat the inside with a separate tank cleaner beforehand. The bottom plate shines like new compared to before the work. If the rust gets too bad, it can cause a hole in the bottom weld, but fortunately, it didn't leak, so it can be used again.