Finishing Precision Board using FSC-88

1. Sand any saw marks, heavy texture, or roughness from surface to be primed. Use 120 grit sandpaper.
   
   
2. For deep cuts or abrasions, pretreat by spot priming with FSC-88, or in extreme cases FSC-360 WB knife grade filler. Allow to dry and lightly sand before continuing. To make FSC-88 a thicker consistency for use as putty, pour a small quantity on cardboard and let set until desired thickness occurs.
   
   
3. Apply liberal coat of FSC-88 by brush, roller, or spray gun. When applying by brush or roller, scrub in the first coat to wet out the cells. Allow to dry to tack free - about 15 minutes, recoat as soon as surface changes from gloss to flat matte. Spraying results in faster drying because of the higher solvent content and spray atomization. See FSC-88 Product Data Sheet for spraying details. If slower drying of FSC-88 is desired, especially when applying by roller, add about 2% to 3% mineral spirits. Do not sand between coats.
   
   
4. Apply a second medium heavy coat of FSC-88 by brush, roller, or spray gun. Do not allow it to run. Allow to dry to tack free - about 15 minutes. When a totally smooth surface is not required, skip step 5 and go on to step 6. Do not sand second coat if proceeding to third coat.
   
   
5. Apply a third medium heavy coat of FSC-88. Remember: All sanding must take place in the filler before getting back to the original PB surface. Since Precision Board is made of millions of tiny cells it is impossible to sand the Precision Board smooth.
   
   
6. When this final coat is tack free, usually about 15 minutes, carefully brush on a light coat of mineral spirits and allow it level out high spots of filler, fill in pin holes, and smooth the entire surface. Let dry over night.
   
    In areas of detail, i.e., relief cuts, vertical sides, and other hard to reach surfaces, allow the FSC-88 to dry a little longer. Use a brush wet with mineral spirits to gently smooth out the filler. With a little practice you can use this technique to eliminate all sanding of these hard to reach areas. Let dry over night.
   
   When using the mineral spirits process, if the FSC-88 starts to drag on the brush, it means the brush is too dry. Keep the brush as wet as possible with mineral spirits during this operation.
   
   
7. Sand smooth with 120 grit sandpaper or 120 grit Drywall & Plaster sanding screens. Allow it to dry 30 minutes before continuing. Faster sanding can be accomplished using 320 wet/dry sandpaper and a solution of 50% water and 50% mineral spirits. Use the solution to keep the surface totally wet and use minimal sanding pressure, as this method cuts quickly. Let dry minimum of 12 hours if wet sanding with mineral spirits/water mixture.
   
   
8. Lightly sand with 220 grit sandpaper. FSC-88 is totally dry when no balling up occurs on sandpaper. If it does, let dry until it does not occur.
   
   
9. For faster drying use a shop fan to blow across surface. Do not place it direct sunlight as the FSC-88 might dry to quickly causing blistering in the primer.
   
   
10. Wipe with tack rag and proceed with top coat system.
    
    
    NOTE: Clean up tools and equipment with mineral spirits of FSC-88 Reducer. It is always a good idea to prime and paint both sides of the sign to keep it from being warped by the drying paint.
    
    It will take a couple of times to become familiar with the approach, so don't get discouraged. Call us if you have any questions. Refer to FSC-88 Data Sheet and MSDS for additional information.