To seal my sump properly I want a one inch lip in 2ply of BID. This is usually done from underneath a box shaped like this one and I’ll do the strakes that way by having a fitted top that is removable and working from underneath. This log covers three days.

The solution for a structure like my sump is to use a ‘partial top’ so I can get inside and put in the BID corner tapes. All that I needed was a plank of wood with some release tape on the top edges of the sump. You can see in pic one I’ve done the long side layups and removed one of the planks for this photo opportunity.

The next pic shows that both long sides are done and I’m doing the fore and aft. This method also allows the tapes to cross over at the corners giving extra strength. I’ve use hot glue and little sticks to keep my top molds in place while doing the layup.

Pic 3 is after its all cured and I’ve gone in and trimmed the edges to a one inch over hang. This will be a great base to put the sump top onto and it should have no leaks at the edges.

First cure lip

Second cure lip

Full lip trimmed and good