A sealer coat is not necessary with the NP75. This surfacer can be finish-sanded with No. 600 paper and then topcoated directly. However, for this paint job, we wanted an intermediate primer coat before the topcoat color goes on. One of the main features we wanted in the sealer coat was a tinted product that will be close to our final orange basecoat color. Here the Sherwin-Williams Spectraprime Sealer System fits our needs exactly. This sealer is available in seven primary colors, which can be intermixed to create virtually any color desired. We selected the P30R, which is red, and the P30Y, which is yellow, to produce an orange sealer.
2 parts-P30 Spectaprime
1 part-S41 converter
2 parts-US4 reducer
1 part-H38 catalyst
SpectraSeal is made by mixing the Spectraprime P30 with the S41 Converter. Once the SpectraSeal is made, it is mixed in the ratio shown with the US4 Reducer and H38 Catalyst. The SpectraSeal is sprayed over finish-sanded primer surfacer and allowed to flash; then the basecoat application is sprayed directly over the top.
As mentioned earlier, the color we chose for our custom Corvette project is a high-impact orange hue from the Planet Color Muscle Tones line. It is exactly the high-energy tint of orange we were after for what will be a highly modified mid-'70s Vette. In a basecoat/clearcoat system, the basecoat contains all the color but none of the gloss or reflectivity of the final finish. The basecoat will appear dull once the solvents flash out of it, and the object is to lay down a smooth base with minimal texture, but obtain complete color coverage. We applied two medium coats to our Corvette, which covered beautifully over the orange-tinted sealer.
1 part-Planet Color basecoat
1 part-PCS-15/25/35/or 45 basecoat stabilizer
Here, again the solvent portion of the mix, the basecoat stabilizer is temperature dependent. Again, our preference is a little slower is better than too fast for the less surface texture and a smooth application of the basecoat. Do not use a fish-eye eliminator in the basecoat or adhesion problems with the clear may result. One-two ounces of UH100/900/904/or 924 clearcoat catalyst can be added to a quart of mixed basecoat for improved chip resistance.
The clearcoat in a basecoat/clearcoat system provides all the gloss, durability, chemical resistance, and reflectivity to the final finish. A high-quality clear is an essential ingredient when the goal is show-quality paint. We selected Planet Color's parent company, Sherwin-Williams Ultra 7000 clearcoat to finish our paint project. A good clear needs to go on smooth as glass-blend the edges of the spray pattern off the gun into a seamless coating, and then buff out to a mirror finish. We applied three coats of the Ultra 7000 clear over the basecoat after allowing sufficient time for the base to flash, or about 20 minutes, given our painting conditions and solvent mix.
3 parts-CC921 clearcoat
1 part-R24/26/or 28 reducer
1 part-UH924 catalyst
Ultra 7000 Clear should be mixed just prior to the intended application, and the pot-life of the mixed product is about one to two hours, depending upon the ambient temperature. The reducer selection is temperature dependent; again our preference tends to the slower side. Up to 1/2 ounce of V3K780 fisheye eliminator can be added per sprayable quart of the clearcoat.