If you wet down the areas were you can see thevweave you will soon know if it will be seen through varnish. I would reseal exposed timber with epoxy and carefully sand back to blend in. No need to apply more glass. I

If you do decide to replace the glass:

1. Mask off the repair are with 2-inch wide plastic packing tape. Leave at least 2 inches clear around the bald spot.

2. Cut a piece of glass that covers the area, including the packing tape.

3. Epoxy the glass onto the bald spot and onto about half the tape. You want to leave an outer perimeter of dry glass.

4. Once it's all cured to the green stage (not tacky but still flexible like stiff leather), gently peel it up from the tape until you get to the wood. Use a sharp razor blade to cut away the scrap glass. Remove the plastic tape. Push any loose bits of glass down onto the wood.

5. When it's completely cured, gently sand the edge to blend in with the rest of the deck. Fill the weave as usual.

This method will avoid glass snot and excessive sanding and should let you have a varnished finish if you want it. This page shows the same process being used to glass openings in a boat's bottom (down at the end of the page).

Have fun,

Laszlo

I have four layers of 8 pound fiberglass on the stem of my Chester Yawl for ramming speed.

Locally wet down the surface with a brush or roller four inches beyond the spot and apply a new piece of light fiberglass to cover the spot.  Wet down the new piece of fiberglass and apply 100% polyester (Dacron) dress lining over the area beyond the fiberglass.  Smoot with squeegee and let dry.  Dacron will tear off leaving surface smooth.  

photostream

Chenango Pete

Next time, try using a scraper instead of sanding. CLC carries them, but your local hardware store should carry them too. They are sometimes called furniture or cabinet scrapers.

scrapers / using scrapers / Wikipedia

Given that it could be a "high wear" area, I would be inclined to add a small patch of glass. You could feather the edge with epoxy and then scrape and (carefully!) sand it.

Keith

Big time second on using scrapers, especially for cleaning up drips, sags, and other surface irregularities.  Smooth control and very little dust. 

Just got to teach yourself how to keep 'em sharp.  I found this you tube video that shows a very simple method that worked great for me (many others show more complex methods)-

http://www.youtube.com/watch?v=d3sqDWFAA0s

In addition to a set of scrapers I bought, I also found that by breaking an old hack saw blade into quarters, I now had 4 scrapers that were very easy to use on my wherry (inside curves), after sharpening of course.

Hickory