I’ve been rolling unthickened epoxy on the hull. I’m having a hell of a time fighting runs. I’ve even come back and rolled it again. On top of that I don’t seem to get much coverage and can still feel the glass weave. Any pointers?
There are several possibilities. One is coat thickness. Use a short-nap foam roller - the red barber pole striped "adhesive rollers" or the yellow "adhesive rollers" from System III or Fiberglass Supply in Washington do a great job of applying epoxy and keeping the coat thin. Also, roll on as little as possible with each coat, re-rolling in opposing directions to get each new patch of epoxy to cover as much region as possible, then use a foam brush to tip off the coat (remove bubbles and smooth the epoxy). If that doesn't work, then viscosity of the epoxy may be the issue. Brand of epoxy and temperature are the main factors here. For example, I know System III works well in all temperatures, RAKA is a little thicker if I recall and may make a better choice ... Aero Marine is on the thin side and may tend to run. You may also experiment with mixing really well, letting the mixed epoxy sit in the cup for 3 or 4 minutes, then mix again and pour into your roller pan. This will allow the epoxy to just begin to set a bit while it's in the cup, then when it's poured into the roller pan it then has a lot of surface area and cools off. Hopefully the result is that after rolling it on the boat, it'll cure quicker and run less. Another factor with viscosity is the ambient temperature - if the weather is warm, the epoxy will be thinner and more likely to run. You may want to wait until it's dark outside and cooling off before you coat the boat much. Or get up early enough in the morning to get a coat on and curing to the sticky 'green' stage before the day starts warming up. FINALLY, the cure-all for runs is the use of a sharp carbide scraper - Don't try to fix them with sanding. The scraper will take the runs off flush with the remaining epoxy where sand paper will sand the thin epoxy around the run just as fast as the run, resulting in the removal of your epoxy coat around the runs .... bad juju....
Let us know how it goes....
Brian