14 Good Reasons
Vacuum Press Uses
Vacuum Press Options
Questions & Answers
Part 2a (Option 1 of 2)
Project: V2 Venturi Press
About Project: V2
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
Build the Manifold
Build the Sub-Manifold
Build the Reservoirs
Make the Carrier
Wire the Press
Testing and Adjusting
Mods and Options
Vacuum Bag Basics
Polyurethane vs. Vinyl
DIY Vacuum Bags (A)
DIY Vacuum Bags (B)
DIY Vacuum Bags (C)
Connect the Bag
DIY Frame Press
A Sharp Veneer Saw
Dealing with Defects
Curing Glued Panels
Veneering w/o Vacuum
Copper Veneer Guide
Vacuum Clamp Matrix
DIY Vacuum Manifold
JWW Visitors' Vacs
Veneer Glue FAQ
The Vac FAQ
Copper Veneer FAQ
Vacuum Infusing With A Vacuum Press
By Russ Garehan
Edited by Joe @ JoeWoodworker
This article was written a couple of years ago by Russ Garehan who kindly allowed me to post it on my website. Since then, Russ has moved on to other endeavors and is no longer offering support for this article. I have not used my vacuum system for infusing yet so I don't know much about this process other than what is shown here. If you build this system and wish to contribute to this article (or completely re-write it) let me know.
What it is...
This tutorial will show you how to make a pressure chamber for vacuum infusing which is a valuable and convenient means of dying wood veneers and stabilizing pen blanks for turning. The materials for this device can be found at most hardware stores at a reasonable price.
What it does...
Vacuum inside the chamber forces the fluid (dye for veneering or stabilizer for pen blanks) evenly into the fibers of the wood.
Do not heat the chamber. Heating the chamber could possibly cause catastrophic failure, sending steaming hot liquid and melted plastic flying upon failure. Do not use any solvents in the chambers without testing them first for compatibility with the PVC. Lacquer thinner and many other solvents will severely weaken the PVC.
Bill of Materials:
This chamber consists of several main sections: an outer PVC tube, an inner PVC tube to reduce the amount of solvent needed in the dying/stabilizing process, and a fluid level sight tube.
(1) approx. 3' of schedule 40/80 4" PVC
(1) approx. 3' of schedule 40/80 3" PVC
(1) 4" to 3" PVC reducer
(1) 3" PVC Test Caps
(1) 4" PVC Male to Male Coupling
(1) 4" PVC Cleanout fitting with Plug
(2) 1/8" ID Barb x 1/4" NPT fittings
(2) 1/4" FIP x 1/4" NPT elbows
(2) small hose clamps
| (1) approx 3' of 1/4" OD clear(it's actually only semi-transparent) polyethylene tubing(Avoid any other type of tubing as it may collapse under vacuum or dissolve when exposed to solvents)
(1) small can of PVC cleaner
(1) small can of PVC cement
(1) roll thread sealing tape
(1) valve stem assembly
- Hand drill or drill press and drill bits
- Bandsaw, hacksaw or other tool to cut PVC pipe
- Dremel tool with sanding drum or a spindle sander
- 1/4" NPT Tap
- First cut two pieces of PVC to length. In this example, the chamber is about 36" long, overall. You may want to make yours shorter or longer depending on the size of veneer or turning blanks. Remember that you can coil up the veneers inside the tube, so narrow, long veneers don't require long pressure chambers. Make the 3" pipe about 2.5" longer than the 4" pipe. The ends of the tubes should be smooth and even so sand them if necessary. This is particularly important for the 3" tube due to the nature of the test caps that will be fit to it later. The completed 3" diameter PVC assembly is used as a filler. The volume of air that is used by the 3" PVC simply eliminates the need for excessive solvent/dye in the vacuum chamber.
- Next, measure 2" away from each end of the 4" tube and mark the tube in each place. The 2" will accommodate the fittings that will go on either end of the 4" tube. Make sure both marks fall on a line parallel to the direction of the pipe. Drill a 27/64" diameter hole and tap it using a 1/4" NPT Tap. Only use one half the length of the tap as over tapping the hole will yield a loose fit.
- Wrap the male threaded portion of each of the 4 brass fittings with thread sealing tape. With the threaded portion facing you, wrap clockwise around the thread to avoid unraveling the tape when the pieces are screwed together.
- Screw each 1/8" ID Barb x 1/4" NPT fitting into a 1/4" NPT x 1/4" NPT elbow.
- Attach each barb/elbow assembly into the holes that were drilled and tapped in step 2 as seen in the picture. When installed, the two barb fittings should be pointing at one another. You may find that the male end of the elbow sticks out about 1/4" on the inside of the 4" pipe. To remedy this I sanded down the excess with a Dremel and sanding drum. However, you may wish to use a bench grinder or sander to remove the excess before installing. Leaving the extra threads protruding will make it difficult to put project material into the chamber, once assembled.
- Cut the polyethylene tubing to length. It should be able to be fitted onto both barb fittings while as straight as possible as shown in the picture. This tube will serve as a solvent "sight tube". It will show you how high your solvent is inside your chamber. Attach a small hose clamp to each end to ensure a positive seal on the barbed ends.
About the sight tube...
The site tube is merely there to check the fluid level. It's helpful in that if you know how wide (or tall) the veneer is, you can easily make sure you have enough fluid in the chamber. It should be noted that if there is not a good seal between the site tube and the brass nipples, the site tube will not function correctly when vacuum is applied. If air can get in, the fluid in the site tube will just constantly be "pumped" up the site tube while the vacuum is on. This isn't a big deal as long as you adjust the volume prior to turning on the pump, as it's not really practical to add dye after you start the dying process anyhow.
- Next, you will have to remove the lip inside of the 4" to 3" PVC reducer. I did this with a Dremel and a sanding drum. You can do this part however you see fit. Be careful not to sand the inside of the 3" portion of the reducer. This may prevent a good seal between the pipe and the fitting. Before and after pictures can be seen below.
- Clean the inside of the 4" side of the reducer and one end of the 4" pipe (about 2" is sufficient).
- In a well ventilated area, apply PVC cement to the two cleaned surfaces and fit the reducer to the 4" diameter PVC tubing.
- Next, clean the inside of the 3" section of the reducer and about 6" of one end of the 3" pipe.
- Apply PVC
cement (once again, in a well ventilated area) to the cleaned surfaces.
Slide the 3" pipe section into the 4" section, cleaned end first, and mate the two areas that just had cement applied. You'll likely need a rubber mallet to get these to fit together well. Pound the 3" section into the reducer until the 3" pipe is sticking out of the reducer by about 4", as shown in the picture.
- Clean the section of 3" pipe obtruding from the reducer and the inside of the 3" end cap.
- Apply PVC cement (once again, in a well ventilated area) to the cleaned surfaces. Mate the 3" end cap to the 3" pipe obtruding from the reducer, as shown in the picture.
- Clean the outside of the remaining end of the 4" pipe and the inside of one side of the 4" coupling.
- Apply cement to the cleaned surfaces and mate the coupling to the 4" pipe as shown.
- Clean the inside of the remaining end of the coupling and the outside of the cleanout fitting.
- Apply cement to the cleaned surfaces and mate the cleanout fitting to the coupling.
- Now, drill a 7/8" hole in the direct center of the cleanout plug. To get the inner washer to fit into the cleanout plug, you'll need to grind a bit off of the perimeter as seen in the first picture below. Install the male vacuum fitting as shown in the second picture.
- Wrap the threads on the cleanout plug with thread sealant tape. I found that the cleanout plug alone did not create a good enough seal to hold a vacuum. A few wraps of tape is enough to get a nearly perfect seal on the threads. I let the chamber sit with a vacuum on it for about half an hour and my vacuum pump did not need to cycle even once.
- Make a small metal rod to aid in removing the project materials from the chamber, as the gap between the 3" and 4" pipe is pretty small. I simply used a coat hanger that I straightened out. I bent one end of the coat hanger to fit between the two pipes.
- You'll now only need to make a stand or wall bracket to hold up the vessel since it has an end cap on the bottom.
You now have a pressure chamber that's perfectly suited to dying veneers and stabilizing turning blanks using the minimum amount of solvent necessary.
This pressure chamber is designed to be operated in the upright position. Operating the chamber on its side will result in liquid being sucked into your vacuum pump, thus destroying the pump. When operating the chamber, make certain that the chamber can not tip over or use a catch basin between the chamber and the pump to catch any fluid before it can get to the vacuum pump.
About Dying Veneers
I figured out that about 3 cups of solvent will give you about a foot of fluid height. The picture shown is curly maple. I used 3 cups of lacquer thinner, mixed with 10 parts Stewmac Cherry red, 10 parts Stewmac Vintage Amber, and 1 part Stewmac Black aniline dyes. Transtint liquid dyes can also be used.
It only takes about 5 minutes of vacuum to fully impregnate most veneers with dye.
I recommend using dyes with lacquer thinner or alcohol as these solvents will not warp the veneer and will dry very quickly.
Something to remember...
You can save the mixtures of dye in mason jars or any other solvent proof container if you want to use the same color again.
If you're having trouble fitting a large length of veneer into the vessel, first wrap the veneer around a spare piece of 3" PVC, then slide the veneer and pvc into the vessel, push the veneer down onto the vessel's inner tube and remove the spare section of pipe.
David Pruett recently built a vacuum infuser to dye small veneers for marquetry. He used the Excel 1 vacuum press to power the infuser. His website has more information including a nice video in which he explains the process.
"This bench top vacuum infuser is the perfect accessory for a woodshop vacuum pump. A vacuum infuser allows you to evenly dye veneer and small pieces of wood. You can also infuse wood stabilizing products such as acrylic resin, sanding sealer or Miniwax Wood Hardener.
The applications for a vacuum infusing are broad, ranging from colored veneer for marquetry to colored and stabilized pen turning blanks to colored and stabilized custom knife scales."