Every DSA anode reaches the same destination: the day its catalytic coating is too thin to hold voltage. What happens next is a purchasing decision most plants get wrong by default — they order new anodes, when the smarter economics usually point to recoating.
What recoating actually is
A DSA is a titanium substrate plus a few grams per square meter of precious-metal coating. The coating wears; the titanium — unless it’s been attacked by fluoride or run far past end-of-life — does not. Recoating means stripping the spent coating chemically, re-preparing the surface, and applying a fresh precious-metal layer to the original specification. The result is functionally a new anode, typically at 40–60% of replacement cost.
The math over a ten-year horizon
Take a plating line running 20 Pt mesh anodes with a 3-year bath life:
- All-new strategy: years 0, 3, 6, 9 → four purchases of 20 anodes.
- Recoat strategy: year 0 purchase, years 3 and 6 recoat, year 9 purchase → two purchases + two recoats. Total spend drops roughly 35–45%, and lead time on a recoat is usually shorter than a new fabrication.
On top of cash savings, recoating keeps your proven geometry: hangers, tabs and dimensions are exactly what your tank already fits — no re-qualification.
When recoating is NOT the answer
- Substrate damage — fluoride attack, severe pitting, or warped frames mean the titanium itself is spent. We inspect returned anodes and tell you honestly which pieces are recoatable and which aren’t.
- Process change — if your bath chemistry or current density changed, the old coating spec may be wrong for the new duty; that’s a re-engineering conversation, not just a recoat.
- Unknown coating history — anodes from an unknown supplier sometimes carry coatings that contaminate stripping baths; a first-time sample analysis settles it.
How to plan it
The plants that save the most treat recoating as a scheduled program, not an emergency: track operating hours and cell voltage trend, ship the set back when voltage rises ~10–15% over baseline, and rotate a spare set into the tank meanwhile. We hold coating records for every batch we ship, so a returned anode comes back with the identical formula — or an upgraded one, if your duty has grown harsher.
Have a set of anodes approaching end of life? Send us a photo and the count — we’ll quote recoat vs. replace side by side.