Hot bluing is the current standard in gun bluing, as both it and rust bluing provide the most permanent degree of rust-resistance and cosmetic protection of exposed gun metal, and hot bluing takes less time than rust bluing.Īfter eight rust, carding and oiling sessions Either of these two methods is called 'hot bluing'. Similarly, stainless steel parts may be immersed in a mixture of nitrates and chromates, similarly heated. Processes Hot bluing īluing may be applied by immersing steel parts in a solution of potassium nitrate, sodium hydroxide, and water heated to the boiling point, 275–310 ☏ (135–154 ☌) depending on the recipe. Blacksmith products to this day may occasionally be found made from blued steel by traditional craftsmen in cultures and segments of society who use that technology either by necessity or choice. īluing can also be done in a furnace, for example for a sword or other item traditionally made by a blacksmith or specialist such as a weapon-smith. The higher temperatures of the other processes as well as their caustic nature could weaken the soldered joints and make the gun hazardous to use. Many double-barreled shotguns are soft soldered (lead) or silver brazed together and many of the parts are attached by that method also. This process is also the only process safely used to re-blue vintage shotguns. Treating with an oiled coating enhances the protection offered by the bluing. "Rust bluing" and "fume bluing" provide the best rust and corrosion resistance as the process continually converts any metal that is capable of rusting into magnetite ( FeĤ). It does provide good rust resistance, which is improved with oil. This method was adopted by larger firearm companies for large scale, more economical bluing. The "hot" process is an alkali salt solution using potassium nitrite or sodium nitrate and sodium hydroxide, referred to as "traditional caustic black", that is typically done at an elevated temperature, 135 to 155 ☌ (275 to 311 ☏). It is a difficult product to apply evenly, offers minimal protection and is generally best used for small fast repair jobs and touch-ups. "Cold" bluing is generally a selenium dioxide based compound that colours steel black, or more often a very dark grey. Various processes are used for the oxidizing process. Both refer to the same chemical process for providing true gun bluing. In colloquial use, thin coatings of black oxide are often termed 'gun bluing', while heavier coatings are termed 'black oxide'. Black oxide provides minimal protection against corrosion, unless also treated with a water-displacing oil to reduce wetting and galvanic action. In comparison, rust, the red oxide of iron ( Feģ), undergoes an extremely large volume change upon hydration as a result, the oxide easily flakes off causing the typical reddish rusting away of iron. Bluing involves an electrochemical conversion coating resulting from an oxidizing chemical reaction with iron on the surface selectively forming magnetite ( FeĤ), the black oxide of iron. It is named after the blue-black appearance of the resulting protective finish. ( Learn how and when to remove this template message)īluing is a passivation process in which steel is partially protected against rust using a black oxide coating. ( September 2014) ( Learn how and when to remove this template message) Please help to improve this article by introducing more precise citations. This article includes a list of general references, but it lacks sufficient corresponding inline citations.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |