Just because a blister or two develops on your boat it is not a serious issue and only a small number of boats develop a big problem with blisters.
Make sure blisters are drained and grind blister deep enough to remove damaged material beneath the gelcoat. Increase area as needed until all laminate around is sound. Clean area and allow to dry.
Hawk Filler goes on like putty to fill, patch, seal or rebuild aluminum, wood, concrete, fiberglass and steel. Hawk Filler can be drilled, tapped, or machined.
Mix on a non-porous surface. Do not mix on cardboard, paper-based and/or porous surface. Wear tight-fitting rubber gloves. Using equal parts of Part A and Part B, mix thoroughly to even uniform color. Mix using a putty knife, trowel or spatula. Apply immediately after mixing.
Apply using a putty knife, spatula or trowel. Spread smoothly on the surface in a 1/8″ – 1/4″ layer using heavy hand pressure to displace air bubbles/voids. If applying multiple coats, begin spreading away from the previously applied film so as not to trap air bubbles or leave an uncoated surface area. When using as a patch or grout, force material into hole or joint and smooth to the thickness needed.
Wear chemical resistant gloves. Mix leftover Part A and Part B, allow curing before disposing. Scrape up spilled material with a putty knife or cover material with an absorbent material and sweep into a container for disposal. For product already mixed, use acetone.
After repairs paint with Sea Hawk bottom paint or if redoing the hull apply Tuff Stuff primer, followed by bottom paint.
If the blister has damaged the fiberglass that will need to be repaired with fiberglass cloth cut to match damaged area.