Service Tank Here are some examples of what can happen on and in a tank:
Unfortunately, the seam is always a problem area on fuel tanks. They usually consist of two deep-drawn sheet metal parts that have been welded together with a rolled seam. This type of production is used on most mass-produced tanks because it is very inexpensive to manufacture.
Since there is an air gap in the seam up to the roll seam (due to manufacturing), water enters the gap and starts to corrode.
The corroded metal becomes larger in volume due to oxygen absorption and pushes the roll seam apart.
That is why it is important to seal the gap during restoration.
We have had good experience with the product Owatrol. This is a penetrating oil that contains a synthetic resin. It penetrates the gap and seals the rust by curing. The material can be painted over after curing.
Once the rolled seam is open, there are two options. Unravel the seam, clean it and re-weld it. Or seal the tank from the inside, with an interior tank coating. However, I would only recommend a tank interior coating as a last resort. You can never get the coating out of the tank again.
We dispense with such constructions and tack weld the folded end bottoms of thin-walled tanks up to 2 mm by spot welding and weld the sheet edges tightly so that no water can penetrate from the outside.
Rust in the tank:
The most frequently asked question from our customers is, "how did that get in there"? There can be many ways. But one thing is a prerequisite. Water in the tank.
Fuels will always contain a certain percentage of water. This can come from a variety of sources. e.g. Water can be from incorrect refueling such as from canisters (old overstocked fuel) Leakage into the tank (rain, high pressure cleaning...) Ingress from the atmosphere (moisture) Human error (unprotected vents, fill ports, gaskets...) Or even from the supplier.
However, with correct refueling, the goal is to keep the water content within acceptable limits - well below the saturation point.
This is because the water molecules remain part of the fuel until there are too many of them. The point at which the fuel can no longer absorb water is called the saturation point. As long as the water remains below the saturation point as dissolved water, it is usually not too much of a problem. Significant problems arise when water separates from the fuel and becomes free or emulsified water. Emulsified water is another form of free water; in this case, the droplets are so small and so well mixed into the fuel that they float in it and do not settle to the bottom. There are no "droplets" when water is completely dissolved in the fuel. Until then, this is still acceptable for the tank. For the engine and injection pump, problems can already arise here.
However, if the water content becomes so high that the "droplets" combine to form drops and settle on the bottom, the water will react with the metal and rust will form. Temperature differences can also cause free water to condense on the top of the tank and form water droplets. Thus, the tank can completely rust in a short time.
In addition, water can be due to incorrect refueling such as from canisters (old overstocked fuel) Leakage into the tank (rain, high-pressure cleaning ...) Ingress from the atmosphere (moisture) Human error (unprotected vents, fill ports, gaskets ...) Or even from the supplier.
Unless the tank is damaged to the point that it looks like "Swiss cheese", we can weld a "patch" on leaks or solder them and derust the tank. After that we check it and treat it with anti-corrosion oil inside. This way it can be stored dry for up to a year. The tank can then be filled again without any problems. The corrosion protection oil washes out with the fuel and does not harm the engine.
We also offer tank sealing, but I would advise against this for the time being. Tank sealing is always the last resort to preserve a tank that can no longer be purchased. Because: we have a lot of customers who come to us with an old, sealed tank. The sealant or paint is peeling off the inside. Good. Of course, it must be said that these old coatings were not as good as today's.
Unfortunately, the interior coating cannot be completely removed again. If it comes off here, the fuel filter will always get clogged.
In most cases, a coating is not necessary. If the structure of the tank is still good and does not look like a "holey watering can" after derusting, everything is fine.
Slime and deposits in the tank:
In the presence of free water, the chemical molecules sometimes break away from the hydrocarbon chain of the additive and combine with water molecules to form a new substance. The new material is a soft solid that separates from the fuel and can quickly clog filters or form engine deposits.
Microbial Growth: Like most living organisms, bacteria and fungi (molds) need both food and water to survive. When free water is present, microbial growth can increase, creating slime that contaminates your fuel and acids that corrode your tank and fuel system.
Fuel Oxidation: Free water accelerates the oxidation process and promotes the formation of acids, gums and sediments commonly known as fuel degradation products.
After a chemical cleaning, many residues can be removed and the tank can resume its work.