JoeWoodworker Veneer
The Official Website of this Non-Professional Woodworker ™

Part 1

Veneering Basics
14 Good Reasons
Vacuum Press Uses
Vacuum Press Options
Questions & Answers
Part 2
DIY Vacuum Press Plans

Vacuum Press Chart
Project: EVS™
Project: EVS-2™
Project: V4™
Project: CRS™
Excel 1™
Excel 3™
Excel 5™
Part 3
Vacuum Bagging

Vacuum Bag Basics
Polyurethane vs. Vinyl
DIY Vacuum Bags
Connect the Bag
Bag Closures
Bag Platens
Breather Mesh 
DIY Frame Press
Part 4
Veneering Information

About Veneer
Veneering Glossary
Veneering Myths
Balancing a Panel
Veneer Glues
Veneering Tips
Substrate Materials
Flattening Veneers
A Sharp Veneer Saw
Jointing Veneers
Taping Veneers
Dealing with Defects
Curing Glued Panels
Veneering w/o Vacuum
Hammer Veneering
Iron-On Veneering
Veneer Storage
Amazing Bookmatches
Edgebanding Guide
Paper-Backed Veneer

Part 5
Miscellaneous Info

Vacuum Press FAQ
Veneering FAQ 
Veneer Glue FAQ
Vacuum Forming
Vacuum Clamping Pedal
Vacuum Clamping Jigs
Vacuum Clamp Matrix
DIY Vacuum Manifold
Vacuum Press Gallery 1
Vacuum Press Gallery 2


Vacuum Veneering - Tips, Tricks, and More!

Breather Mesh in Action!Breather mesh is a plastic fabric used in a vacuum bag to allow air to flow away from the project being pressed and towards the vacuum port or bag stem. It is used in place of a top platen/caul. Without it, the vacuum bag material will seal against itself or the veneer causing pockets of reduced vacuum.

Thse pockets of insufficient vacuum inside the bag, greatly reduce the clamping strength needed to press the veneer down onto the substrate. By using breather mesh, you allow the vacuum to evenly distribute throughout the bag and this is the key to successful vacuum pressing.

A bottom platen board (typically 3/4" melamine) is still required when breather mesh is used, but with this method there is no need to cut grooves in it or to apply the border strip as mentioned on the platens page of this site. To be very clear about this, only a single 3/4" melamine board without grooves is needed if you are using breather mesh. The platen board should be at least as large as you project panel but it can be larger. Some users prefer to have one platen board this is sized to fit their bag and they use that same set up for all projects large and small.

The life of the vacuum bag and the mesh can be significantly increased by easing all of the platen board edges using a 3/8" or 1/2" radius round-over router bit.

For flat veneer panels, the bottom platen is only used to provide a reference surface which keeps the veneer panel flat while the veneer adhesive is setting up. For flat and curved projects, the mesh acts as a flexible top platen that comforms to the shape of the project.

Some users set their vacuum bag and platen board over a pair of saw horses. This can be problematic since the platen board can bend under its own weight. It is better to place the vacuum bag and platen on a flat work bench surface instead.

You may be wondering if you can use window screen material as breather mesh. The answer is both yes and no. Window screen material can create a pathway for the flow of vacuum. Several users have sent messages saying they had no issues other than a moderate increase in the amount of time it took to draw full vacuum in the bag. It is important to know that a veneer that is not completely flat is not likely to flatten under window screen material; you can get lumps in the finished panel.

The other issue is that any adhesive that bleeds through the veneer will smear back onto the surface of the panel. The breather mesh offered at has a much wider and open weave than screen material so glue that comes through the veneer beads up and can be easily scraped off. I've also found that breather mesh is much easier to slide into the vacuum bag than screen material.

Breather Mesh Advantages

  • Light weight
  • Inexpensive
  • Re-usable
  • Allows you to see the veneer as it is being pressed
  • Does not fatigue the bag material
  • Reduces bleed-through artifacts
  • Easy to use, cut, and store
  • Will not stick to most veneer adhesives

It was once thought that breather mesh was only suitable for curved projects in which a standard caul would not be usable. However, you’ll find this material excellent for use with flat panel veneering as well. Here are some tips for using breather mesh on your next vacuum press project.

Breather mesh is typically cut to fit the size of the vacuum bag if most of the user's projects will be flat panels. Curved projects often require a piece of mesh cut to match the panel size.

Dont Forget!

Breather mesh can have sharp edges. Some readers have suggested covering the edges of the breather mesh with duct tape.

The Ideal Set-Up for Most Flat Panels
If you have a small project to veneer, you may not be using the full width or length of the vacuum bag. In this case, insert a platen and place your veneer and glued-up substrate on top. Then place the breather mesh over the entire veneer surface leaving a few inches of over-hang at the edge closest to the bag stem. Position the entire assembly so that the bag stem on the bag is above the overhanging breather mesh. This will allow you to evenly distribute vacuum over the veneered panel.

Note that the breather mesh and bottom platen
are larger than the project panel.


Optional Vacuum Mesh Bridging
If your breather mesh is just barely large enough to cover the project or if you want to keep the bag stem off the veneered panel, you can cut a small strip of breather mesh from any over-hanging side and place it between the main part of the mesh and the bag stem. The "bridge" piece should lay on top of the mesh that covers the project. I've done this with a strip that was only 2" x 12". This bridges the main mesh to the bag stem. Think of it as a pathway that allows air to move out of the bag.

But keep in mind that the vacuum bags offered at have a flush-mount stem. In other words, the bottom of the stem does not protrude into the bag. This means you can put the bag stem right on top of the mesh and directly over the veneer. That's why this section is titled "optional".

A breather mesh "bridge" makes a pathway
for air flow to the bag stem.

Veneer Positioning With Breather Mesh

Panel Type: Flat
w/ Very Flat Veneer
Panel Type: Flat
w/ Slightly Non-Flat Veneer
Panel: Contoured
w/ Very Flat Veneer
Face Veneer Up
(against the breather mesh)
Backer Veneer Up
(against the breather mesh)
Face Veneer Up
(against the breather mesh)
Backer Veneer Down
(against the platen)
Face Veneer Down
(against the platen)
Backer Veneer Down
(against the platen)
This position minimizes
bleed-through issues as
noted below.
The platen side provides the smoothest surface and most
even vacuum distribution.
This is the only way to veneer
a contoured panel with
breather mesh.

Additional Information
When vacuum is applied to the veneer, burl veneers will sometimes allow small amounts of glue to pull through the veneer face. This is often referred to as "bleed-through". One of the great aspects of breather mesh is that it reduces any adhesive bleed-through artifacts. With a standard platen or caul setup, the glue that bleeds through to the face of the veneer is forced to spread out on the surface and that can create a splotching effect.

The first key to preventing bleed-through is to use the right amount of adhesive with a dedicated veneer glue roller. The surface should be evenly and lightly coated with the veneer adhesive. When applied correctly, you should be able to see the substrate through the wet glue layer. To make this as easy as possible, I draw a few pencil lines on the substrate before applying the glue. Then I use the roller to spread to glue out so I can see the pencil lines through the glue layer. At that point, I know I've used the right amount of glue.

Even with the correct amount of adhesive, some bleed-through is possible. This is especially true with burl veneers. However with breather mesh, the glue stays in a tight bead on the surface of the veneer which is easily sanded or scraped off with a minimal amount of effort. After the excess adhesive is removed, the only glue on the face will be that which has filled any voids in the veneer. This is a great advantage and will give you a smoother finished panel.

veneer glue bleedthrough
Bleed-through with a platen or caul
veneer glue bleed-through
Bleed-through with breather mesh

  • Keep in mind that you can veneer the back side of the substrate at the same time as the face veneer. You do not need breather mesh on the back side of the panel. The platen itself will prevent any air pockets from forming.
  • Non-flat veneers over 1/32" in thickness may not flex enough to perfectly mate with the substrate surface when breather mesh is used. In this case, a 3/4" thick top platen is often a better choice. You can cut grooves in the top platen as shown on this page or use breather mesh on top of the top platen.
  • Breather mesh may leave small impressions in softer woods such as walnut, redwood, and pine which can typically be sanded off. Alternatively, you can eliminate the impressions with steam from a iron on the medium heat setting. Spritz the veneer face of the panel with water (after the glue is fully cured) and then iron lightly. Be sure to place a piece of cotton or flannel over the veneer surface to prevent scorching.

Breather mesh used to make a half-cylinder.

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