First gather up some heavy objects say cinder blocks or books or tools anything handy.
Gluing 2 sheets of plywood together.
Face the good sides.
It s better for us to get all done at a time to ensure the top surfaces in a board aligned.
It sounds like you re planning to stack two sheets together.
We recently glued together two 4x8 sheets of ply and then tried to pry them apart.
We can screw two pieces of plywood together at joints and hide screw inside the piece of wood.
Here s a tip that solves the problem.
This will give you tons of contact with long grain to create a really strong glue joint.
Lay two pieces of plywood out on two sawhorses.
Let the glue joint set for about 20 to 30 minutes then release the clamps and add another board.
Wet both sides with a water soaked rag then spread the glue all over.
In your case a half inch center with quarter inch glued to both faces might be safer than gluing 3 4 together with 1 4.
Showing you how i go about laminating glueing 2 plywood sheets together to make a very sturdy and thicker sheet of plywood.
Also each opposite laminate is of equal thickness to the other.
Put the second piece of plywood next to the first standing on edge.
Assuming there is a back side or a side unseen and damage will not be a problem.
Squirt glue all over one of the pieces of plywood.
Get as many cinderblocks as you need to apply the recommended pressure.
One could use screws to pull the pieces together and hold till the glue cures.
How to glue plywood together.
Rather than glue and clamp all the boards at once add one board at a time.
Lay one piece of plywood on a flat surface the floor would be best.
I ve glued plywood together with regular wood glue many times and it s not an issue.
Here again assuming full sheets of plywood as smaller could be clamped in a device.
Perfect to be used as a workben.
Gluing several sheets of plywood together is to make it thicker.
After job is done remove the screws leaving the two pieces laminated.
Plywood for instance is always glued up of an odd number of laminates for balance.
The only caveat is if you re trying to used pre finished plywood the finish would get in the way of the glue.
It may take a lot but they are cheap and reusable.
Inspect both sides of the plywood and choose the sides you like best.
If you want to bond them together to make a single sheet of 8ftx2ft x 1 1 5 inch thick plywood you need to do this.