What are the benefits of using sanding sealer before applying topcoat?

There are four benefits to using sanding sealer as the first seal coat prior to topcoat

1. Faster production time. Sanding sealer is a softer finish designed for faster sanding and faster drying.
2. Save money - it costs less than topcoat if your project warrants purchasing a third product.
3. The film builds (thickness) faster because the particle size is larger.
4. It has strong adhesion properties. It does not stop tannin or dye bleed through, but it definitely improves adhesion.    

However, it only makes sense if your project is large enough to warrant the purchase of a third product or you are a professional volume user. 

Sanding sealer can be used over many surfaces:

• Raw wood: Use as the first coat when clear coating raw wood. 
• Painted Wood: Use as the first coat when clear coating painted surfaces. 
• Stained wood: Use as the first coat when clear coating a stained surface.
• Clean, prepped, existing surfaces: Use as the first clear coat if faster film build and improved adhesion are desired. 

Application

• We recommend no more than 1-2 coats, then finish with 1-2 coats of topcoat.
• Sanding sealer dries tack-free in 10-20 minutes. Drying Time: 1-2 hours under normal conditions. (70F -50% humidity)  
• Sanding sealer can be used with all of our water-based and oil-based finishes EXCEPT Endur-o-var.
• For more application notes, see our product page

HERE IS AN EXAMPLE OF HOW TO USE:

1. Apply one coat of sanding sealer.
2. Finish sand.
3. Apply two coats of topcoat, finish sanding in between coats.

Here is a video on finish sanding: https://www.youtube.com/watch?v=8lrOfipJZVk