Waxes, Oils and Fats: This Is How We Test Products For Cavity Protection

To further improve our products for cavity protection we test them in different scenarios. These tests and similar ones we conduct again and again over time. This way we test the performance of our materials in direct comparison with products of our competitors.

The test shown here is just one of many. It was started in the summer of 2014 and evaluated one year later.

The first tests of this kind were conducted by our boss Gerd Cordes in the mid-1980s. For a more detailed report on this see:

http://www.timemax.de/industry/en/history/gerd-cordes/

Tin-plated steel cans with screw-on lid: that is what our testing containers look like. For them to corrode faster we blasted their inside with corundum. The holes drilled later also are to accelerate the test. This way it is easier for the salt water to get into the cans.

These washers that have been welded together will later be screwed to the inside of the cans. Right now the washers are plated with tin, but soon…

The welded washers are to present special challenges to the corrosion protection sprays. During the test we want to check the crevice corrosion this way. Before the flat washers are screwed to the inside of the cans they have to be specially prepared. All in all the preparations shown here took several months. You see: it is a tremendous effort!

…the protective layer is removed. Just like the insides of the cans the washers are blasted with corundum.

One of our first climatic chambers for corroding: A plastic box containing some water. Before testing starts the testing washers have to be made to corrode.

The water level in the boxes is only a few inches. The grey holding sheet with the sand-blasted testing washers (visible on the left) is mounted on spacers and positioned just above the water level. Because the plastic box is closed the inside quickly turns into a “humid biotope”. To accelerate the process we placed the box on a radiator.

Just like inside a sauna directly after an infusion! The evaporated water cannot get out because of the lid. It condenses on the lid and drips back down.

For the testing washers this extremely high humidity is a kind of “oxidation stress”: corrosion attacks and sinks in its teeth!

As with all steel constructions here, too, the welded places corrode first. The remains of slag brought in during welding and the oxides accelerate the corrosion enormously.

Left Picture: after two months in the climatic chamber this is what the washers look like in January 2014. The slightly-out-of-focus picture on the right shows the testing washers in the summer, after almost six months in the climatic chamber.

The corrosion is the same all over. Thus, the same conditions for all products. Testing of the cavity protections can begin!

Now you see the purpose for which the testing washers were produced: The are screwed to the bottom. To take the picture we light the inside using an industrial light. Clearly to see in the picture on the right: the cans insides are rough, they were blasted with corundum.

As can be seen in the picture above the bottom washer is in direct contact with the sheet metal. Here, here is a narrow crevice. As mentioned earlier such crevices can be very important for corrosion testing. The capability of creep of a good product must be such that it creeps into the crevice and stays there.

As only a few materials are able to do this permanently this often is the place where the first perforation corrosion occurs.

Cavity protection from a spray can: now the inside of the cans is treated.

The testing construction shown here is meant for the North Sea island of Heligoland. On this island in the open sea frequent storms have to be expected. This is why the cans cannot be screwed to a massive sheet. The storm would rip everything away. Therefore we use a grate permeable to air as holding frame for the cans.

Our testing tower in Heligoland: it is positioned directly on the edge of the salty North Sea.

Half a year after testing began: already differences are visible! Again and again we go to Heligoland and check the condition of the cans. To look inside the cans we use an endoscope. We are curious: how well did the different agents prevent corrosion?

The corrosion-boosting conditions on Heligoland are so extreme that often tests show usable results after only a few months.

For further information about our test on Heligoland see chapter “Where We Conduct Test: Heligoland”.

http://www.timemax.de/industry/interne-pruefungen/hier-pruefen-wir/helgoland/

How We Test Products For Cavity Protection

Waxes, Oils and Fats: This Is How We Test Products For Cavity Protection

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