Penetrating oil
As Creep (corresponding to the respective market leaders in German-speaking colloquially called Caramba and in the USA as WD-40 hereinafter), a low-viscosity oil having low surface tension and water-repellent properties, respectively. It usually consists mainly of petroleum .
A solid lubricant such as MoS 2 or graphite is often added to the penetrating oil for a longer-term effect, especially at the higher temperatures in internal combustion engines . For the permanent lubrication of moving parts, creeping oils are unsuitable due to their low viscosity and relatively fast displacement.
properties
Creeping oils get their name from their property of penetrating into the finest cracks through capillary action, even against gravity, and infiltrating dirt, oxides and moisture in the process. Due to the rapid distribution as well as the lubricating and water-displacing effect, penetrating oil is able to e.g. B. to make rusted screws viable again in a short time. It also provides simple protection against corrosion .
Contact spray
Contact sprays belong to the group of penetrating oils and are used to displace moisture on parts of an ignition system, thereby increasing the current of the ignition spark. Contact sprays are also used for lubrication, corrosion protection, loosening tight connections and reducing the noise of squeaky connections. Contact sprays consist of low-viscosity mineral oils with corrosion-inhibiting and surface-active additives.
Rust remover
Rust removers are mostly penetrating oils, which are mainly used in repairs as an aid to loosen stuck screws and corroded metal connections. In addition, it can be assumed that every contact spray can also be used as a rust remover, but not the other way around. However, this does not result in a solution , but rather the rust particles are suspended in the penetrating oil . To dissolve rust, partially dilute acids such as dilute phosphoric acid or chelators are used over a short period of time and then rinsed off again under running water, otherwise increased corrosion occurs in the long term . This is usually followed by a renewed coating with a mineral oil in order to reduce oxidation .
Lubricant properties
The lubricating properties of penetrating oils are rather poor compared to substances that are optimized for lubrication. This is primarily due to the low surface tension and the creeping ability, which is desirable for other purposes. The creeping ability regularly leads to a migration of the oil from the lubrication point, also with the consequence that the creeping oil can be found "everywhere" and is then not available in sufficient quantity at one lubrication point for optimal lubrication. A bearing to be lubricated will run dry within a short time, also because any residues of the original lubrication have been washed out by the use of the penetrating oil. This is why the practice that is occasionally observed, for example using only penetrating oil spray in the home for door hinges or when repairing bicycles, is not a sustainable solution, but rather counterproductive in the long term.
Individual evidence
- ↑ a b c Wilfried J. Bartz, Hans-Jürgen Blanke: Expert Practice Lexicon Tribology Plus: 2010 Terms for studies and work. Expert Verlag, 2000. ISBN 9783816906919 . P. 416.