Question about how Jimmy Lewis faired the overlap in this video...

[TallDude]

The bigger the fin, the more the force. I use an HD insert on all long boxes.

[magentawave]

The bigger the fin, the more the force. I use an HD insert on all long boxes.

Do you hide the area around the HD foam inserts with pigment or paint? Is there HD foam that's close to the same color as EPS?

[jrandy]

Late to this party for sure...
-grind laps are awesome on fiberglass cloth
-grind laps are miserable on carbon fiber (imagine black dust everywhere messing up the next hot coat)
-I generally do not conceal installs done with HD foam as they show an extra level of detail in the build.

[lazymodo]

Carbon wont puff up when sanded. Kevlar does that, carbon sands the same as glass. He uses the grinder first to take down the big chunks and strands then moves to the soft pads. If you start with a soft pad at the start you just end up ripping  the sand paper on all the rough stuff. Take the bulk down with the hard grinder , then go to paper.
Use two layers of tape and seal the lap area before you put the tape on. It will help with beads pulling out when you pull the tape. The longer the tape sits the more the glue holds so once you start finish it as soon  as the resin cures.