Day 163, 8/17/24 Fuel tank part 5 (Tank lid build)

 Fuel tank

Building solid fiberglass lid to be able to make it solid glassed part of the tank to be sure it is hermetically bonded to fuel tank "bathtab", and no more leaks will happen any more there.

Thickness goal to have 5-6mm fiberglass thickness it be able to support itself.  

Main idea to have tank independent from plywood under sit board.  

Lid build.

As base to build I used original lid. covered it with mold release and built FG board. 

First step -laminated two layers of 1708 and two layers of copped mat to get initial 3mm board. using polyester resin (it is just cheaper).

Then, on  "bottom side" I glassed one layer 9oz Fiberglass Woven Mat using fuel safe epoxy. and covered with two "glassing" layers of epoxy to avoid any viods or bobbles in the surface allowing fuel to get to polyester resin board.  

Masking tape shows where must be edge of the lid.

Lid internal surface is nice and shiny. (still not fully cured to let chemical bonding to tank).

Lid cut in size and fitted.

To provide better support to fuel level sensors and review lid, 3 additional layers of 1708 added at the places where they will be mounted.

To make flat surface  at area of gasket contact i compressed plywood plates over the laminate.

Unfortunately I put too much of resin and it covered "border"masking tape.So aesthetically it comes not very nice.

Fuel cans sit on the top to provide good lid compression against  frame.

On the middle of the tank I added 3/4 height baffle plate with about 2x1" hole on the bottom to prevent fuel shake too much. Review hole made right over it to have access to both sides of the tank.

 

To be able make better compression on gaskets and use machine screws I designed backer plate with press inserted nuts and order them from sendcutsend.com service.

To mount lid permanently I thickened MAX GRP epoxy with Went system adhesive filler404 and made bead around and then put lid to it. In some places excessive thickened epoxy run out but it stick to walls inside and will be just visual imperfection nobody will see unless want to see.

however all perimeter get bonded.

To provide even more strength for this bond i added layer of the 9oz fiber strap glassed in between lid and edge of the "bath".

Looks not very "tasty" but likely will provide good bond.