Grinding & Bulkhead Work

February 8, 2019

I spent the better part of the day grinding fiberglass in preparation for various repairs that were required prior to fairing for primer paint.  The repairs ran the gamut - from areas requiring new core material, to filling old fastener and control box holes, to cracking gelcoat.  This is dirty and nasty job (as was grinding the interior), and so I wanted to get most of it out of the way.  

I began in the cockpit well.  I marked out the area of the cockpit settee, the old icebox that the owner requested to be removed and the access hatch be glassed over.  This area would become seating going forward, and so would require a more substantial construction.  I would prepare the area today for balsa core to come.  I marked the portions of the deck that I needed to grind out / remove, and did so with a combination of an oscillating tool and a small 1" belt sander for the tighter spaces.

I also went below, pushed my extremities into tights spaces along with a dangerous power tool, and prepared the underside to accept new fiberglass.  This new glass would be 1708 biaxial, and it would form the bottom skin of the balsa core 'sandwich'.  I laid out a test piece of 1/2" balsa core to confirm the material required.  I also tapered the surrounding surfaces to accept the new top skin fiberglass.

I moved to the cockpit well, and did a bit of tapering work on the area of the cockpit sole that required new balsa core.  In this area, I also went below and prepared the underside of the cockpit well for new fiberglass.  In removing the old core, I had inadvertently cut through an area where the core material ended, thus exposing the interior of the boat; there was also a hole here that held some component apparently not necessary for sailing, but was no doubt the reason for the core getting saturated.

I then moved up to the port cockpit seating and side deck to remove flaking and cracked gelcoat.  Gelcoat laid down too thick will suffer through the aging process, and this late '60's Allied 24 was showing her age.  I removed the gelcoat down to bare glass, and from here the repairs will be a layer of fiberglass and fairing work.

I moved over to the starboard side the cockpit and repeated the work.

I also moved along the starboard side deck, grinding away the worst of the gelcoat issues.

Finally, and after spending some time on the interior grinding the turn of the bilge below the cockpit well, I moved up to the coach roof and prepared two previous repairs for a couple layers of 1708 biaxial.

At this point, I switched gears and decided to address the open cockpit locker bulkhead.  With a 40-grit flap wheel, I prepped the surface the existing bulkhead, removing paint down to bare wood.  I also sanded the interior vertical surface of the cockpit well to accept new fiberglass.

After thoroughly vacuuming up the sanding and grinding detritus, I used a small piece of cardboard to template the bulkhead insert that would serve as the repair. 

On a 1/2" sheet of meranti, I traced out the template, and then removed it with a jigsaw.

The insert required only minor modification before it easily slipped into position.  I then removed it and sanded all edges to remove splintering and also to taper to soft edges.  As per usual, I got into focus mode and didn't get a shot of every step, but that's what my pulitzer-worthy prose is for...

I went back to the shop for a couple things: solvent and a rag, as well as a small pot of neat epoxy.  Back on the boat, I thoroughly wiped all surfaces with the solvent to remove any remaining contaminates, this included the new bulkhead insert.  I then painted on the neat epoxy to all surfaces that would be receiving new fiberglass, this also included the new bulkhead insert.

I made my way back to the shop to prepare strips of 1708 biaxial to serve as tabbing.  In my fiberglass work to date, I have collected a number of off-cuts, and so I now sifted through this collection of classic hits such as 5" x 8", or 6" x 5"...and cut them down to uniform size to use in tabbing in the repair.  I wet out the first few tabbing strips, and with the leftover epoxy resin mixed a small amount of thickened epoxy.  I brought the thickened epoxy to the boat, applied it to the bulkhead insert and set it into place.  With a squeegee, I spread the thickened epoxy squeeze out across the new and old seam.  I went back to the shop to fetch the tabbing strips, brought them to the boat and tabbed in the new bulkhead insert to the existing bulkhead.  Back to the shop I went to wet out additional tabbing strips and to mix another small pot of thickened epoxy.  With the thickened epoxy, I made fillets on the transition from bulkhead to interior vertical cockpit well surface, and did so to allow the fiberglass to lay down properly.  I then applied the balance of the tabbing strips to complete the repair, and finished it with a couple small sheets of peel ply fabric.  The peel ply did not cover all of the fiberglass work, so I will be water-washing and sanding prior to painting...or any other additional repair required.

Total Time Today: 6 hrs