Choosing a Vacuum Press Model
This page references the vacuum systems offered at VeneerSupplies.com. If you feel a bit overwhelmed with the options, click on the "Need Help" graphic on the right, and if that still doesn't help then feel free to contact me any time.
There are three types of vacuum presses for veneering. The information below refers to the systems offered at VeneerSupplies.com.
Auto-Cycling Venturi System
The Project: V4 kit creates vacuum using compressed air through a vacuum generator called a venturi. This system does not include an air compressor but you can buy one larger home improvement stores. The vacuum press is automatically controlled by a switching device that measures the vacuum level inside of the system and keeps it reasonably constant by opening the flow of compressed air to the venturi if the vacuum level decreases. The air compressor only runs if the air in the tank drops below level set by the manufacturer.
Auto-Cycling Electric Pump System
The Project: EVS kit also cycles on and off but achieves vacuum via an electric pump. Like the venturi system, it is automatically controlled by a switching device which measures vacuum inside of the system and keeps it reasonably constant by turning the pump on until the desired vacuum level is reached.
Continuous-Run Electric Pump System
A continuously running vacuum system such as the Excel 1, Excel 3, or Excel 5 uses an electric pump but does not cycle on and off. It run continuously, but don’t worry… most pumps are rated for continuous duty and some manufacturer suggest that these types of pumps can run for two years without stopping. These systems are less expensive and easy to assemble.
Maximum Vacuum: Each of these systems can pull more than enough vacuum for veneering and clamping most bent lamination projects. The maximum vacuum is 25.5" of Hg at sea level for all of the systems we offer. This equals roughly 1,800 lbs of pressure per square foot. See this chart for details. Keep in mind that approximately 1" of Hg is lost for every 1,000 feet above sea level. If a pump is capable of pulling 25.5" of Hg at sea level, it will only pull 20.5" at 5000' above sea level.
Cubic Feet per Minute: The most common performance measure is the flow rating at zero vacuum. This coincides with the amount of time it takes to draw full vacuum on a vacuum bag. Bags that have a large amount of air inside (such as those being used with a curved veneer project) will benefit from a high-CFM vacuum source. More information about this is provided in the chart in the next page. VeneerSupplies.com offers vacuum sources from 1 CFM to 9 CFM.
Keep in mind that a venturi will typically create full vacuum faster than a comparable electric pump. This is referred to as the "CFM Curve". It simply means that 3 CFM electric pump will draw vacuum slower than a 3 CFM venturi.
Project/Vacuum Bag Size
The CFM of the vacuum source typically determines the maximum bag size that can be used. Keep in mind, these are estimates.
*This largely depends on the porosity of the project.
|4'x4' or less vacuum bags
||1 CFM for flat panels
||3 CFM for curved panels
|4'x6' to 4'x8' vacuum bags
||3 CFM for flat panels
||5 CFM for curved panels
|4'x9' to 6'x15' vacuum bags
||5 CFM for flat panels
||9+ CFM for curved panels
||1 CFM for non-porous materials
||3+ CFM for porous materials
|Vacuum chucking on a lathe*
||1 CFM for very small projects
||5 CFM for medium projects
All of the systems described here are very reliable pieces of equipment with a focus on reduced complexity. Each component of every vacuum press kit uses vigorously tested components from trusted suppliers. Several of our vacuum press plans have been available and in use since 2002. A venturi-based model from 2003 is still the workhorse in my own shop! Consider posting a question on any of the online woodworking forums for more feedback on our vacuum press kits. We have very a helpful customer base.
Though the Project: EVS system is portable in the sense that electricity is easily obtainable, the system can weigh 30 lbs or more. Some users put casters on the bottom of the system to roll it around their shop. The 18 lb weight of the Project: V4 makes it very portable but compressed air is often not as easy to find outside of the workshop. The Excel 1 weighs approximately 14 lbs. The Excel 3 and Excel 5 weigh about 18 lbs and since they run on electricity alone, the Excel kits are the most portable systems we offer.
With the standard vacuum controller included with the Project: EVS and Project: V4 kits, the vacuum level can be adjusted from 10.5" to 25.5" of Hg. For most veneer projects, a setting between 18" and 21" is ideal. Setting the system to pull higher vacuum levels does not improve the bond of the veneer to the substrate. It only forces the vacuum source to work harder and risks glue-line starvation. The EVS and V4 kits can be upgraded with a special vacuum controller designed for accuracy at lower vacuum levels if needed for projects such foam core modeling. The Excel 1, 3, and 5 systems can be adjusted from 5" to 25.5" of Hg using the simple bleeder valve included with the kit.
Keep in mind that the acceptable decibel levels shown below can be impacted by pitch. A shrieking fire alarm may not produce the decibel level of a monster truck but it can be much more annoying. Electric vacuum pumps have a lower pitch making their noise levels somewhat more reasonable.
- Project: V4
These systems operate at 68 dB during the “on” cycle which is less than the sound of a running shower.
- Excel 1, 3, and 5
These systems operate at 63 dB which is slightly louder than conversational speech volume.
- Project: EVS
The 1, 3, and 5 CFM pumps offered at VeneerSupplies.com operate at 63dB. In an auto-cycling system the sound is only present when the unit is recharging the vacuum.
Project V4: less than 2 hours
Project EVS: 3 to 7 hours
Excel 1: 20 to 25 minutes
Excel 3 and Excel 5: 30 to 35 minutes
Benchtop Vacuum Clamping
The companion clamping kit allows you to use the massive holding power of vacuum to instantly hold work pieces to your bench top for sanding, routing, carving and more. The picture shown to the right is the version used for the EVS and V4 systems. A clamping add-on for the Excel 1, Excel 3, Excel 5, and CRS kits is also available.