This discussion focuses on restoring the surface finish of Atmos clock cases, including identifying original clear coatings, removing degraded finishes, and selecting modern products for refinishing brass and gold-plated components.
Understanding Atmos Case Finishes
Variations between models
Some Atmos models, such as the Atmos II, 519, and possibly 526, appear to have been produced without protective clear coatings, while the 528 series often shows evidence of a factory-applied coating.
Testing for clear coat
A continuity test using an ohmmeter helps determine whether a coating is present. Non-conductive readings indicate an intact clear coat, while conductive readings suggest exposed metal or worn plating.
Impact of coating condition
Cases with intact coatings may show dirt, cloudiness, or scratches, while worn coatings can expose brass or nickel beneath the gold layer.
Examples from restorers
Some cases cleaned with mild abrasives revealed nickel beneath thin gold plating, confirming that coatings and plating vary by model and age.
Practice cases
Extra cases from models 519 and 528 were used for testing stripping and refinishing techniques before working on primary clocks.
Removing Old Clear Coatings
Initial solvent attempts
Alcohol and acetone were ineffective at removing the original coating.
Paint strippers
Mild strippers had limited effect, while stronger strippers removed more of the degraded coating and improved appearance.
Multiple stripping cycles
Stubborn areas may require repeated applications to fully remove the coating.
Coating still present
Even after stripping, some areas remained non-conductive, indicating residual coating.
Alternative solvents
Lacquer thinner was suggested as another option for dissolving old coatings.
Choosing a New Clear Coat
Mohawk brass clear coat
Mohawk’s brass clear coat produced excellent results when applied to bare brass after polishing.
Polar Flawless Lacquer
This lacquer applied smoothly but shifted the brass color toward a more yellow, gold-like tone.
Thin commercial coatings
The original Atmos coatings were extremely thin and may not have modern equivalents.
Durability considerations
Modern lacquers may offer better protection but can alter the appearance compared to factory finishes.
Electroplating considerations
Brush electroplating was considered for restoring worn gold areas, though it requires significant preparation and skill.
Application Techniques
Spray vs. brush
Spray application generally produces a more even finish on large, flat brass surfaces.
Number of coats
Multiple thin coats are preferred over a single heavy coat to avoid runs and maintain clarity.
Surface preparation
Cases must be fully stripped, cleaned, and polished before applying any new coating.
Testing on practice cases
Using spare cases allows experimentation with products and techniques before refinishing a primary Atmos clock.
Color shift awareness
Some clear coats may subtly change the hue of brass or gold plating, requiring testing before full application.
Case Study: Refinishing a Damaged Atmos Case
Initial condition
The case appeared rusty, though gold cannot rust, indicating coating failure and contamination.
Continuity test results
The ohmmeter showed non-conductive readings, confirming the coating was still present despite the poor appearance.
Stripping attempts
Initial solvents failed; stronger stripper improved the surface significantly.
Remaining issues
Some areas still showed coating after stripping, requiring additional rounds.
Next steps
Further stripping and testing will continue before polishing and recoating.
FAQs
How do I know if my Atmos case has a clear coat?
A continuity test with an ohmmeter will reveal whether the surface is insulated by a coating.
What removes the original coating?
Stronger paint strippers or lacquer thinner may be required; mild solvents are often ineffective.
What clear coat should I use?
Mohawk brass clear coat is a strong option; other lacquers may alter the color.
Can I electroplate worn gold areas?
Yes, brush electroplating is possible but requires careful preparation.
Should I practice on spare cases?
Absolutely—testing products and techniques on extra cases prevents mistakes on primary clocks.
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