Descending Simson Tank - what can you do?

If the tank has rust on the inside, that's not a big deal. As long as the tank is not rusted, there is still hope. Even rusted tanks can be repaired, but only by a specialist. But a simple rust removal can often be done by yourself.

Causes of rust in the tank

As with most metals, moisture is the root cause of rust, even with the Simson tank. Moisture can only be effective in the tank if the tank is left empty or half empty over a longer period of time. As long as the tank is filled, it can hardly rust (inside). Rust formation can only be found here after many years.

If you do not drive over the winter, the tank should definitely be completed beforehand. When standing over the winter with an empty tank, a lot of rust in the tank may have already formed in the spring.

Rust removal of the tank inside

There are various possiblities for that:

  • Rust removal from the professional, including subsequent sealing (cost about 150 EUR)
  • Self-de-rust with special de-rusting agents, self-seal
  • Self-de-rusting by other means

To have the rust removed by the professional has some advantages. The result will certainly be perfect, and even in the event of leaks or almost rusty spots, the tank will be completely repaired. Since you should not weld yourself a tank, a professional repair is practically inevitable in such cases.

For tank rusting, there are various "miracle drugs" - but it is better to rely on the proven. Again, there are a few options to choose from, depending on the degree of rust formation inside.

Different rust removal agents

Oxalic acid has long proven itself. It is also in the classic car industry a popular means to gently de-rust tanks, without attacking the material.

Often hydrochloric acid is also recommended for rust removal - but it is aggressive and can make the steel of the tank more susceptible to rusting.

Oxalic acid, on the other hand, does not damage the paint and does not attack it. Low concentrations (by 10 percent) of oxalic acid or of clover salt are also no problem in the dipping bath. In this case, the rust removal can take a little longer, depending on the degree of rusting.

Both acids are harmful and dangerous, so keep them out of reach of children, and wear sufficiently thick rubber gloves and, if necessary, protective clothing and eye protection. So you're safe from dangerous acid splashes.


After derusting you can also provide the tank with a suitable coating. Here there are finished coating agents in the trade (for example, POR 15, but also some others). A coating is usually not necessary if it is gently de-rusted. As long as the tank is always filled, there is no risk of rust.

Tips & Tricks

Sandblasting the tank inside is another option. But you should turn to a relevant specialist company, self-attempts are rather discouraged.

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