A method of manufacturing a seal includes providing a seal arc segment defining first and second seal supports at circumferential ends. The seal arc segment further defining radially inner and outer sides. The radially outer side includes radially-extending sidewalls and a radially inner surface joining the radially-extending sidewalls. The radially-extending sidewalls and the radially inner surface define a pocket. The method includes machining the radially inner surface to have a higher surface roughness than the sidewalls.