Basically UHDE BM2.7 can be directly recoated. It means without removing the anode louver or cathode mesh form the pans. Sometime the mesh/louver on old electrode deformed or corroded. We can repair them first.

For BM2.7 Gen.3 and Gen.4, it is better to do Zero Gap Retrofitting, since the gap between anode and cathode is too big. Zero Gap can obviously decrease the cell voltage.

BM2.7 Cathode mesh corrosion
Replace part of the mesh first

BM2.7 Cathode mesh deformation
Flatten it before coating

Flatten electrode after coating
make sure all dimensions are same as original

Zero Gap Retrofitting on BM2.7 Cathode
Nickel mattress and minimesh is used