DaveH6
Transom construction March 2010.
Laminating the transom proved easier than I expected. Working in my air conditioned workshop no doubt was a big help in terms of my comfort and extending the epoxy's working time in the Texas heat eventhough it was March.
First, I covered the jig with plastic food wrap. Next, I wetted out the plywood with a thin coat of epoxy on both sheets. I then used a grooved 1/8" tile setting trowel to spread thickened epoxy on the bottom sheet of plywood. The sheets were aligned then clamped together via drywall screws. I was concerned that the screws would be locked in by the epoxy but they all removed without incident.
* Edit- subsequent to this transom lamination, I learned of folks on various builds (none Bluejackets) drilling "weep" holes every 6" in the top sheet of plywood in a lamination to let excess epoxy and air escape. On my lamination I started installing the drywall screws at the top of the crown and worked downhill towards the port and starboard transom edges. Via this approach I was moving along a wave of excess epoxy and perhaps some air to eventually be expelled at the lamination's edges. One builder says that Devlin recommends the weep holes.
I followed a debate on a boat building forum on whether to put a sheet of fiberglass between sheets of plywood being laminated. Some say its needed to improve adhesion between the plywood sheets. Equal number of debaters say its a waste of materials and unwarranted weight.
When I cut out the transom opening for the outboard engine there were no epoxy voids in the edges. Today I am of the belief that with proper epoxy and clamping techniques, fiberglass between a lamination of plywood sheets is not necessary solely for the purpose of improving the bond.
Transom construction March 2010.
Laminating the transom proved easier than I expected. Working in my air conditioned workshop no doubt was a big help in terms of my comfort and extending the epoxy's working time in the Texas heat eventhough it was March.
First, I covered the jig with plastic food wrap. Next, I wetted out the plywood with a thin coat of epoxy on both sheets. I then used a grooved 1/8" tile setting trowel to spread thickened epoxy on the bottom sheet of plywood. The sheets were aligned then clamped together via drywall screws. I was concerned that the screws would be locked in by the epoxy but they all removed without incident.
* Edit- subsequent to this transom lamination, I learned of folks on various builds (none Bluejackets) drilling "weep" holes every 6" in the top sheet of plywood in a lamination to let excess epoxy and air escape. On my lamination I started installing the drywall screws at the top of the crown and worked downhill towards the port and starboard transom edges. Via this approach I was moving along a wave of excess epoxy and perhaps some air to eventually be expelled at the lamination's edges. One builder says that Devlin recommends the weep holes.
I followed a debate on a boat building forum on whether to put a sheet of fiberglass between sheets of plywood being laminated. Some say its needed to improve adhesion between the plywood sheets. Equal number of debaters say its a waste of materials and unwarranted weight.
When I cut out the transom opening for the outboard engine there were no epoxy voids in the edges. Today I am of the belief that with proper epoxy and clamping techniques, fiberglass between a lamination of plywood sheets is not necessary solely for the purpose of improving the bond.