Painting plastic has given me fits in the past. The solvents in the primer/paint melt the plastic. I am happy with the results I get now. The knobs were black with a round white dot. Most I have seen were dark maroon with a line. I cleaned them with a tooth brush then US cleaned them. All were scratch ,pitted and white powder forming a film over them. Even after all the cleaning.
I sand with 220 in and around pits holes to be filled with Evercoat metal glaze. Block sand with 320. Scuff the entire knob with 3M 07448 Scotch Brite Then spray Standox plastic primer. $25 a can. Let it dry over night. Scuff wash and repeat with standox. I really do not want the knobs to melt.
I scuff with 3M scotch brite, wash dry, then spray with Sikens color build primer. Best primer I have found so far. $500.00 a gallon. I use a 1/2 oz for all 5 knobs. Block sand and I mask the splines off so no primer gets in. Block sand with P800,scuff wash ,then water based amonia wash. Then PPG 320 wash. Tack,spray base,clear. enjoy for the rest of my life. Fingers crossed .
I sand with 220 in and around pits holes to be filled with Evercoat metal glaze. Block sand with 320. Scuff the entire knob with 3M 07448 Scotch Brite Then spray Standox plastic primer. $25 a can. Let it dry over night. Scuff wash and repeat with standox. I really do not want the knobs to melt.
I scuff with 3M scotch brite, wash dry, then spray with Sikens color build primer. Best primer I have found so far. $500.00 a gallon. I use a 1/2 oz for all 5 knobs. Block sand and I mask the splines off so no primer gets in. Block sand with P800,scuff wash ,then water based amonia wash. Then PPG 320 wash. Tack,spray base,clear. enjoy for the rest of my life. Fingers crossed .