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