Thread: Joining Ply to make a LARGE base

Assuming you want butt joints. If the ply was thick enough you could "hold it together" with biscuit joints. But that size area is going to require a sub frame to attach and support.

I have heard you can get ply skarf jointed.
Was also thinking rebate and laminate on aluminium in place of the removed ply
Or go a doubler underneath, and rebate with alloy on top
Or?

I'm hoping there are some tricks I don't know about.

The body walls and roof when closed will give it the stiffness overall, so I'm trying to avoid a subframe.

Thanx
Paul

Several ways to do it.

1 Scarf joint 6:1 glued with epoxy and high strength filler added.

2 Butt strap 20 times wider that thickness of ply ie. if 19mm then 380 x 19mm strap again glued with strengthened epoxy.

3 Rebated butt strap reinforced with biaxial glass.

Search the boat building forums for more details. Here is one thread I've found

I would think about a longer lasting plywood than formply one of the marine plys coated with epoxy will last especially on the floor sections where it will get wet and may stay damp.

How about 2 layers of thinner plywood, with panel joints offset both ways like brickwork. 20 x thickness should be adequate offset. Massage the layout for optimum use of material. I think upper and lower patterns could be the same, but rotated 180 degrees with respect to one another. For maximum strength and stiffness, place the long face grain in the direction of shorter span.

Cheers,
Joe