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
Project: EVS Vacuum 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 Bagging

Vacuum Bag Basics
Polyurethane vs. Vinyl
DIY Vacuum Bags (A)
DIY Vacuum Bags (B)
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
Copper Veneer Guide
Paperbacked Veneer

Edgebanding Guide

Part 5
Miscellaneous Info

Vacuum Press FAQ
Veneering FAQ
Veneer Glue FAQ
Copper Veneer FAQ

Vacuum Forming
Vacuum Chucking
Vacuum Clamping Pedal
Vacuum Clamping Jigs
Vacuum Clamp Matrix
DIY Vacuum Manifold
Vacuum Press Gallery 1
Vacuum Press Gallery 2

Downloads (PDF's)

Project V2 Vacuum System Information
Type: Adjustable Auto-Cycling
Vacuum: Air Powered Venturi
Page: 8 of 9
Venturi Press

Final Pneumatic Connections & System Testing

Congratulations! You're almost done. Within the next few minutes you'll be ready to run the vacuum press. Be sure to follow the rest of these instructions carefully.

Parts used in this section:
Tools Required:

Black tubing
Braided vacuum tube (10')
Brass barb fitting (1/4" NPT)
Lock-on connector

9/16" Wrench

  1. Cut the black vacuum tubing to fit from the vacuum controller to the brass barbed fitting on the lower end of the manifold assembly and attach it snugly.
  2. Now cut a piece of black tubing and connect it between the vacuum port on the venturi and the barbed fitting above the check valve on the manifold.
  3. Attach the braided vacuum tube to the vacuum valve on the manifold.
  4. Apply thread-sealing tape to the 3/8" barb to 1/4 NPT-male fitting.
  5. Lock On ConnectorAttach the barbed fitting to the lock-on connector. Be sure to hold the lock-on connector at the hexagon part of the casting when attaching the barbed fitting. If you hold the head of the lock-on connector and apply too much torque to the barb fitting, the connector will break.
  6. Slide on the lock-on vacuum connector to the open end of the vacuum tube.

The final assembly should appear as shown in the picture below.

Assembled Project V2 Vacuum Press

Testing and Adjustment

Do not plug in the V2 system power cord to your wall socket until instructed below. Set your air compressor to put out approximately 100 PSI. Higher pressure does not increase the CFM or maximum vacuum from the venturi unit. The V2 system can handle up to 120 PSI.

Close the vacuum valve by turning the handle to the left or right until it stops. Then attach your compressed air line to the quick connector on the Mac valve.

Vacuum Press Wiring ImageThere is a small plastic cap on the vacuum controller in front of the "common" tab. Under this cap is a plastic slotted set screw where the shut-off adjustment is made for vacuum system. Use a flat-head screwdriver to turn the set screw counter-clockwise until it is approximately 1/8" from the top edge of the vacuum controller body. In other words, there should be about 1/8" of the female threads visible when you look inside the adjustment area of the unit.

Be aware that particles in the air stream from the exhaust on the venturi can cause eye damage.

With the vacuum press power switch turned off, plug the electrical cord into your wall socket. Turn on the light switch and air should begin flowing through the venturi and the needle on the vacuum gauge should rise. The vacuum controller should shut off before it reaches 21" of Hg.

For the next stage of testing, you will want to carefully adjust the vacuum setting to 21". Using a small flat screwdriver, slowly turn the adjusting screw counter-clockwise until the unit creates 21" of vacuum and cycles off. Remember counterclockwise turns of the screw will increase the amount of vacuum required before the vacuum controller will turn off the air pressure at the Mac valve. I've found that most often, 21" of Hg is when there is about 1/16" of threads showing above the adjustment screw.

It will automatically cycle on again when the vacuum has decreased. You can test this by opening the vacuum valve and releasing a bit of vacuum from the system. The manufacturer of the vacuum controller claims that the controller will cycle back to the "on" mode within 4" of Hg decrease. This 4" amount of "differential" is not adjustable. In my opinion, this constant increase and decrease in vacuum inside the press bag allows for an even greater bond of the veneer to the substrate.

For venturi systems, the frequent on and off cycling is harmless. During normal operation of a tightly sealed unit, it is still common to have the unit cycle on every 10 minutes for 5 - 8 seconds.

Close the vacuum valve and allow the system to recharge. Watch the needle on the vacuum gauge to see if the system shows signs of a leak. It shouldn't leak if the brass fittings were correctly attached to the reservoir with thread-sealing tape. However, it's not uncommon to have a small leak show up. The fix for this is simple.

Got A Leak?  No Problem!

The typical auto-cycling vacuum press system recharges the vacuum every 15 minutes. This is just an average and it's based on the vacuum valve being closed so that no vacuum is directed to the vacuum bag. However, some people get a perfect seal and the system does not leak down for 24 hours or longer. How much fiddling you want to do to get a longer "off" time is up to you. Some people go nuts with it and others dont seem to worry about it at all.

Click here for leak troubleshooting tips.

Your Vacuum Press System is Ready to Use. Now What?
I've written this short but helpful article that explains what else you will need to begin using your vacuum press. The article also includes a step by step guide to using your system for veneering.

Yes, Joe is a practicing Catholic
The Vac FAQ
© 1998-2019
Terms & Conditions
Privacy Policy