NRA NRA Firearm Finishing & Surface Treatments 1 — Questions and Answers
Question 1: What is 'cold bluing' and how does it differ from 'hot bluing'?
- Cold bluing uses an oven; hot bluing uses room-temperature chemicals
- Cold bluing uses selenium dioxide-based solutions applied at room temperature; hot bluing uses hot caustic salt baths for a more durable finish (Correct answer)
- Cold bluing is a type of Parkerizing; hot bluing is a polymer coating
- They are identical processes applied at different speeds
Correct answer: Cold bluing uses selenium dioxide-based solutions applied at room temperature; hot bluing uses hot caustic salt baths for a more durable finish
Cold bluing provides a quick but less durable finish using room-temperature chemicals, while hot bluing in caustic salt baths produces a harder, more corrosion-resistant oxide layer.
Question 2: What is 'Parkerizing' and on what type of metal is it typically applied?
- A chrome-plating process used on stainless steel
- A manganese or zinc phosphate coating applied to steel and iron for corrosion resistance (Correct answer)
- A polymer spray coating applied to aluminum frames
- An electroless nickel process applied to titanium
Correct answer: A manganese or zinc phosphate coating applied to steel and iron for corrosion resistance
Parkerizing is a phosphate conversion coating process that creates a matte gray-green surface on steel, used extensively on military firearms for corrosion resistance.
Question 3: What is 'Cerakote' and what are its primary advantages over traditional bluing?
- A hot-salt bluing process — advantage is lower cost
- A polymer-ceramic coating baked onto the metal — advantages include superior corrosion resistance, abrasion resistance, and wide color options (Correct answer)
- An electroplating process — advantage is extreme hardness
- A cold chemical treatment — advantage is no heat required
Correct answer: A polymer-ceramic coating baked onto the metal — advantages include superior corrosion resistance, abrasion resistance, and wide color options
Cerakote is a thermally cured polymer-ceramic finish that outperforms bluing in corrosion, chemical, and abrasion resistance while offering many color choices.
Question 4: Why must metal surfaces be thoroughly degreased before applying a bluing or Parkerizing finish?
- Oils increase chemical reactivity and cause uneven color
- Contaminants prevent the chemical conversion reaction from occurring uniformly, resulting in spotty or failed finish (Correct answer)
- Grease accelerates the process and causes over-bluing
- It is only required for hot bluing, not cold processes
Correct answer: Contaminants prevent the chemical conversion reaction from occurring uniformly, resulting in spotty or failed finish
Any oil, grease, or contamination blocks the chemical conversion coating from bonding with the metal, causing an inconsistent or failed finish.
Question 5: What is 'electroless nickel plating' and why is it used on firearms?
- A nickel coating applied using electrical current — used for high-gloss appearance only
- A nickel-phosphorus alloy deposited without electric current — valued for uniform coating, hardness, and corrosion resistance (Correct answer)
- A spray-applied nickel paint — used for budget builds
- A nickel salt bath similar to hot bluing — used for carbon steel only
Correct answer: A nickel-phosphorus alloy deposited without electric current — valued for uniform coating, hardness, and corrosion resistance
Electroless nickel uses a chemical reduction process (no electricity) to deposit a uniform nickel-phosphorus layer that is hard, corrosion-resistant, and compatible with complex shapes.
Question 6: What surface preparation step is essential before applying any coating to a firearm, and why?
- Polishing to a mirror finish — all coatings require a bright surface
- Proper metal preparation including cleaning, degreasing, and surface profiling to ensure adhesion (Correct answer)
- Heating the metal to 500°F — activates the substrate for coating
- Applying a primer coat of Parkerizing — required under all other finishes
Correct answer: Proper metal preparation including cleaning, degreasing, and surface profiling to ensure adhesion
Thorough cleaning, degreasing, and appropriate surface texture (blasted, polished, or phosphated) ensure the finish bonds properly and performs as intended.
NRA NRA Firearm Finishing & Surface Treatments 1
What is 'cold bluing' and how does it differ from 'hot bluing'?