n past issues of The HobbyGunsmith we demonstratedways to use rust to blue agun at home. Rust was theoriginal method of browningor bluing a gun part, but it isvery slow for darkeningsmaller parts like screws orother small parts.

I this issue we look at aproduct from Caswell calledBlack Oxide kit that providesthe hobby gunsmith with theability to use a chemicalreaction to quickly darken apart.

Comparing the results ofthe new room-temperaturechemical bluing process tothe more extensive rustbluing appear to be verysimilar in appearance. However; it will be some timebefore we can determine howwell the chemical darkeningprocess holds up under hardusage.

For this project we aregoing to use the CaswellBlack Oxide process todarken the backing plate ofthe Dragoon cartridgeconversion project and to fixsome damaged screws.

Figure 3.

We began by cleaning thepart in either hot sodiumphosphate solution or othersuitable degreaser to removeany protective oils that mayhave gotten onto the steel partand might prevent theinteraction between the steeland the solution.

I usually dip the part in amild pickling solution madefrom hydrochloric acid, butthat is not really necessary. The etches any smoothsurfaces of the steel and givesthe chemicals some bite.

The parts are dipped intothe aqua colored solution andleft there for about fiveminutes. Figure 3 shows thebacking plate down in thesolution. The partimmediately begins to rustand then starts to darken intoa black oxide coat.

The part is ready to beremoved after about fiveminutes in the solution. Itshould be rinsed under

Figure 5

We decided to treat somerusted and defaced screws toillustrate how quickly a damagedscrew can be returned to a niceblack color.

The screws illustrated in Figure5 were polished using the samesandpaper method as thebacking plate for the cartridgeconversion.

Figure 6.

When they were bright andshiny, they were dipped into theblack oxide solution and thenwiped with steel wool. After oneor two applications of thesolution, the screws look as theydo in figure 6.

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Figure 1.

We begin the project byexamining the backing platefrom the dragoon project. Some rust had formed on thesurface and it needed a littlesanding with 220 grit wet ordry sandpaper that welubricated with unscentedmineral spirits.

Figure 2.

Figure 2 shows the backingplate after using thesandpaper to remove most ofthe surface scratches andpitting. The parts are readyto be dipped into the BlackOxide solution.

The solution comes as acouple of bottles of solutionthat is mixed with distilledwater to form the oxidizingsolution. The solutions mixquickly and are stored in aplastic bucket at roomtemperature. The kit comeswith a container of sealantsolution that is used tostabilize the finish.

running water and will have ablack coat that should beremoved for the mostappealing finish. I use 0000steel wool to burnish the partand bring up a nice shine thatis similar to a rust blue finish.

I generally repeat theprocess of dipping into theblack oxide solution aboutthree or four times. After thefirst dipping, I find a shoptowel can remove the surfacematerial and prepare the partfor either another dip in thesolution or to be dipped intothe sealing agent.

Figure 4.

Immerse the part into thesealing agent illustrated inFigure 4. Leave the part in forat least five minutes to allowthe solvent to soak into thefinish and help protect it. Remove the part and allow itto dry. I like to then add acoating of gun oil to parts asan extra precaution.

Figure 7.

Figure 7 illustrates the backingplate installed in the approximatelocation on the frame of theDragoon. The photograph doesnot do justice to the silkysmoothness of the new finish. The color of the new finish is ablue-grey that allows somereflection from base color of thesteel.

Those who have followed theHobby Gunsmith from its earliestdays will recognize the dragoonfrom the first issue, but may notethat it has been nickel plated. The Dragoon parts wereillustrated in the articles aboutelectroplating that appeared inearlier issues.

Makers of fine CartridgeConversion kits for:

Remington New Army1851 and 1861 ColtRuger Old Army

www.KirstKonverter.com

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