It didnt
claim to be full tungsten - it
was full tungsten. Given the molar masses of Tungsten and Gold, there is no way to achieve gen gold weight on a specific part without being near 100 percent tungsten (unless of course you add extra links - GMF QF THB ARF are all known to do this). Tungsten molar mass is 183.84 u and our 24k gold is 196.96657 u. Molar mass is the measurement of mass/volume
Let me share a bit of background in light of my experience.
Most precious metal watches in this hobby are steel-plated. Steel is an excellent material—it is easy to cast, machine, and finish (brushing, polishing, anglage, perlage, etc.), and it exhibits strong molecular adhesion for electroplating. However, its primary drawback is weight, which is significantly lower than gold.
Tungsten is an ideal substitute because it closely matches the density of 18k gold (~15.6 g/cm³ vs. 15.8 g/cm³). However, its physical properties make traditional watch manufacturing methods ineffective:
- Tungsten carbide cannot be CNC-machined or cast like steel. Instead, it must be sintered—where powdered tungsten is subjected to high heat and isostatic pressure to form a solid.
- Finishing limitations. Due to its extreme hardness (~9 on the Mohs scale), tungsten carbide is difficult to brush and polish using conventional methods. Diamond polishing compounds and high-RPM lapping processes are required.
- Structural weaknesses. Variations in sintering lead to porosity and grain boundary defects, making the material brittle and prone to chipping.
- Electroplating challenges. Tungsten has poor cathodic activity, leading to weak adhesion of plated layers, which can flake or darken over time.
To address these challenges, manufacturers have experimented with different methods:
1. Tungsten "Stuffed" (GMF/QF Day Dates, QF Daytona, THB/ARF Day Date Bracelet)
The most rudimentary and cost-effective approach. Tungsten blocks are inserted into steel cores and welded shut.
- GMF/QF Day Dates use tungsten weights in bracelet center links and a tungsten ring inside the movement (hence why they cannot fit 3255 clones).
- This approach is imprecise—weight distribution is inconsistent, and the tungsten components are not machined to high tolerances.
- Misalignment of the center links due to poor press-fit tolerances results in crooked bracelets, a common flaw in GMF/QF Day Dates.
2. Solid Tungsten Wrapped in Thin Steel Foil (THB/ARF Day Date Head, APSF Daytona Head)
This method involves wrapping solid tungsten in a thin leaf (~0.1mm) of steel.
- Achieves near-gen weight but introduces structural weaknesses.
- The outer steel layer is prone to de-lamination and intergranular corrosion, particularly in high-stress areas like the lug horns.
- Over time, microscopic cracks develop at the foil interface due to galvanic corrosion between the tungsten core and the steel shell.
3. Solid Tungsten with Steel Capping (David Chen & Xing Iterations)
This approach encapsulates tungsten within a precision-milled 316L steel shell (~1mm thick).
- Theoretically ideal but execution has been poor due to cost constraints and difficulty maintaining <10µm machining tolerances.
- Edge bonding failures occur due to differences in thermal expansion coefficients between tungsten carbide and 316L steel (~4.3 µm/m·K vs. ~16 µm/m·K), leading to eventual delamination under temperature fluctuations.
4. Direct Tungsten Electroplating (The Most Viable but Technically Challenging Approach)
This is, in my opinion, the only correct and long-term viable method. Instead of relying on structural encasement, tungsten cases and links are fully sintered, finished, and directly electroplated.
Electroplating tungsten is significantly more complex than plating steel or brass due to its low cathodic efficiency and high surface energy. Traditional electroplating techniques fail due to poor adhesion and rapid oxidation. However, speaking from personal experiences, advances in electrochemical deposition have made significant improvements:
1. Surface Preparation & Pretreatment:
- Tungsten is first subjected to a plasma etching process or electropolishing in a phosphoric acid bath to remove surface oxides.
- An activation layer (typically a nickel-cobalt diffusion barrier) is applied via a strike bath to enhance adhesion.
2. Electroplating Bath Composition:
- The plating bath typically consists of a cyanide-free gold or rhodium solution with an added complexing agent such as EDTA or citrate to enhance deposition uniformity.
- Pulse electrodeposition is used to improve layer integrity, alternating between high and low current densities to mitigate porosity.
3. Layer Bonding & Diffusion Barriers:
- To prevent intermetallic diffusion (which leads to darkening or peeling over time), manufacturers have started incorporating intermediate layers such as palladium-nickel or platinum-group metal alloys.
- This prevents the formation of tungsten oxides that degrade adhesion over time.
Early Issues & Recent Improvements
Previous Problems (First-Gen Tungsten Electroplating - JBL Daytonas, etc.):
- Rough finishing, as tungsten carbide required diamond-based lapping compounds to achieve a mirror polish.
- Plating adhesion failures due to incorrect electrolyte pH balance and lack of a proper diffusion barrier.
- Galvanic wear in high-friction areas (bracelets, lugs), where the plating would thin out, exposing the darker tungsten beneath.
Recent Solutions (Latest Gen Tungsten Daytonas):
Adoption of nano-particle-assisted electroplating to improve uniformity and reduce surface defects.
- Use of double-layer electroplating with a sacrificial nickel-palladium sub-layer to improve long-term adhesion.
- Better control of pulse current plating parameters to create a denser, more wear-resistant plated layer.
The New CBD Daytonas:
The new CBD Daytonas look promising in photos, and I have some on order with friends. However, long-term durability remains unknown. Without confirmation of their production method, it’s hard to determine if they are employing direct tungsten electroplating or using an inferior alternative.
In my experience, the only truly lasting and viable approach is direct electroplated tungsten with multi-layer adhesion barriers. If the CBD Daytonas have implemented the latest advancements, they may represent the best tungsten-based alternatives to gold watches to date.
