The bars worked well when left 1 2 3 4 longer than the clear distance to the upper deck.
Go bar deck.
The go bar deck or the use of bent sticks between two solid surfaces is a very old method of applying clamping pressure while gluing two parts together.
Now you could just use lots and lots of expensive clamps with many cauls but most luthiers use what is called a go bar deck.
What you are looking at is a go bar deck sitting on the extension table of my table saw.
Go bar deck assembly from a sheet of 3 4 plywood cut six pieces each 2 feet x 2 feet.
Stack and glue two of the pieces together and stack and glue the other four together the extra thickness is required to give the go bar deck base sufficient stiffness.
The second part of the equation is to press it all into a disk with the correct radius but that s not todays problem.
3 8 threaded rods were used to make the deck easy to break down and store.
The deck consists of two double pieces of plywood a floor and a ceiling separated by four pipe nipples and flanges at the corners.
By bending fiberglass or wood rods between the upper and lower decks it is easy to put pressure just about anywhere you need it.
In the picture the upper transverse brace is being glued to the top of an acoustic bass guitar.
The deck is roughly 2 feet square and 2 feet tall.
After trying a couple of alternatives from the local big box store as well as my back yard i broke down and bought a set of 3 16 fiberglass rods for the go.