Part 1
Introduction
Welcome
Veneering Basics
14 Good Reasons
Vacuum Press Uses
Deciding on a Model
Overview
____________________
Part 2a (Option 1 of 2)
Project: V2 Venturi Press
About Project: V2
Parts List
Build the Manifold
Build the Reservoirs
Assemble the Venturi
Make the Carrier
Wire the Press
Testing and Adjusting
Mods and Options
____________________
Part 2b (Option 2 of 2)
Project: EVS Pump Press
About Project: EVS
Parts List
Pump Selection
Build the Manifold
Build the Sub-Manifold
Build the Reservoirs
Make the Carrier
Final Assembly
Wire the Press
Testing and Adjusting
Mods and Options
____________________
Part 3
Vacuum Bags
Vacuum Bag Basics
Polyurethane vs. Vinyl
DIY Vacuum Bags (A)
DIY Vacuum Bags (B)
DIY Vacuum Bags (C)
Connect the Bag
Bag Closures
Platens/Cauls
Breather Mesh
Maintenance
____________________
Part 4
Veneer Information
About Veneer
Backer Veneer
Veneer Glues
Veneering Tips
Substrate Materials
Flattening Veneers
Edgebanding Guide
A Sharp Veneer Saw
Jointing Veneers
Taping Veneers
Dealing with Defects
Curing Glued Panels
Veneering w/o Vacuum
Iron-On Veneering
Veneer Storage
Amazing Bookmatches
Copper Veneer Guide
Paperbacked Veneer ____________________
Part 5
Miscellaneous Info
Vacuum Frame Press
Vacuum Forming
Vacuum Chucking
Vacuum Clamping
Vacuum Clamp Matrix
Vacuum Infusing
DIY Vacuum Manifold
JWW Visitors' Vacs
Veneer Quality
HH-66 MSDS
Veneering FAQ
The Vac FAQ
Downloads (PDF's)

The platen system inside the vacuum bag is what keeps the panel flat while the press is in use. It also allows air to flow out of the vacuum bag to the vacuum source thereby creating evenly distributed pressure inside the bag.

I have seen numerous ways of sandwiching the veneer to the substrate with the use of cauls and platens. I truthfully do not know which is better, so I will limit the discussion to the method I use which has never failed to bring anything less than optimal results.

Platen Material

You'll need to make 2 platens from ¾" melamine. Or if you have plastic laminate available, you can also use plywood or MDF for the platens (be sure to adhere the laminate to one side of each platen). Either of these two types of platens is ideal for vacuum pressing because it will prevent the veneered panel and any excess adhesive from sticking to the platens. A coat of paste wax will ensure easy removal of the veneered panel from the press. The wax will last though many glue-ups.

The platens should be at least 6 inches smaller than the inside measurement of the vacuum bag. This will prevent the vacuum bag from stretching at the seams which will cause the bag to split. You can use a much smaller platen system if you do a lot of smaller panels. For my 2 x 4 bag, I have a 18" x 38" platen setup and a smaller platen setup that I used for drawer fronts which is 8" x 24".

The bottom platen should have a border (½" to ¾" thick and 1¾" wide) around the outside perimeter as shown in the picture below. This bordered platen will help keep the top platen in place while in the press.

The length and width of top platen should be 1/4" less than the bottom platen to allow easy removal after the pressing cycle is complete.

The sharp edges of the platen system will puncture the vacuum bag while under pressure. You can significantly increase the life of the vacuum bag by using a round-over bit in your router to ease the edges of the platens (and the frame).

Next, set your table saw blade to a height of 1/8", and cut grooves from the front to the back and side to side on the outside of each platen. The spacing is not critical but a 2 to 4 inch layout will work well. These grooves help channel the air to the stem, and are absolutely necessary. Remember, these grooves are on the outside when you place them in the vacuum bag.

If you are using a very large veneering setup, the "sandwich" of platens, substrate and veneer can be reduced in weight by replacing the top platen with a sheet of ¼" plywood with a laminate/melamine face. Cut the air channels (grooves) 1/16" deep.

The completed platens for a 2 x 4 vacuum bag

The Platen Concept: If you are veneering a substrate that is 2" (or more) smaller in length and/or width than the platen, the top platen will cave in around the edges of the substrate while under pressure. To remedy this, simply cut a few extra pieces of the substrate material and use them as spacers between the two platens. Be sure these spacers are the same thickness as the substrate being glued to the veneer.