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

Part 1
Introduction

Welcome
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: V4™
Project: CRS™
Excel 1™
Excel 3™
Excel 5™
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Part 3
Vacuum Bagging

Vacuum Bag Basics
Polyurethane vs. Vinyl
DIY Vacuum Bags
Connect the Bag
Bag Closures
Bag Platens
Breather Mesh
Maintenance
DIY Frame Press

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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
   Guide

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Part 5
Miscellaneous Info

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

VeneerSupplies.com


 

Vacuum Veneering - Tips, Tricks, and More

Make Your Own Vacuum Bag

Vacuum Press for GuitarThe process of making an airtight bag had eluded me for many months. Time after time, I would make a decent sized bag and take all the necessary steps to prepare and seal it, only to notice a tiny leak somewhere. It was nothing but pure accident that led me to discover a solution that would seal the leaks on even my oldest bags. The secret? Well...read on.

The vinyl can be often purchased from companies that make boat covers or canvas awnings. Surprisingly, some fabric stores also offer it. If you have a difficult time finding vinyl for the bags, it can be purchased at VeneerSupplies.com. There are a few different thicknesses available in vinyl membrane sheeting. The most common are 20 mil, 27 mil, and 30 mil. Either will work with similar results but thicker is typically more durable.

Polyurethane bagging material is also available but, if you are building your first vacuum bag then consider building it from vinyl instead. Though the polyurethane will last longer, it is more expensive and can be more difficult to make a DIY bag.

One thing to keep in mind: the assembly process can be frustrating and time-consuming. If you are short on patience then a better option would be to buy a ready-to-run vacuum bag.

Dont Forget

  1. The vinyl cement is extremely flammable and will destroy your brain if you use it in a poorly ventilated area.
  2. The vinyl cement is very much like contact cement when used on vinyl sheeting. Once you touch the sides together, there is little hope for removal.
  3. Polyurethane sheeting has a different reaction to HH-66 cement. It takes a full 24 hours to cure.
  4. You will need a heavy-duty seam tool for this part.
  5. Any area that is to be cemented should be cleaned first with acetone or xylene. Synthetic steel wool or 'Scotch Brite' pads will help.

Tools and Parts

Getting Started
Though it is time-consuming, it is not difficult to construct a DIY vacuum bag for veneering. This is especially true for bags that are made from vinyl since polyurethane requires more prep work and clamping. When I make a custom size bag for a project, I prefer the seams to be as clean and even as possible. This is not always easy but there are some steps that can help remove some of the frustration.

For flat panels, start by determining the project size and adding 6" to the width and 12" to the length. Let's use an example project size that is 48" wide and 60" long. To make a custom bag for this panel, you will need two pieces of vinyl that are 54" wide and 72" long. The extra length allows room for the bag closure to be applied. As shown in the image below, the extra width allows the bag to pull together at the seam. If the bag is too small for the project (or the project is too big for the bag) then the seams will pull apart while under vacuum.

I think it's best to have about 1" of area where the vinyl will be bonded together to make the seam, so clean those areas with acetone or xylene. This must be done in a well-ventilated area. Don't forget that only three sides of each piece of vinyl need to be cleaned. The fourth side is left open so the project can be inserted. For a rectangular shaped bag, it makes the most sense for the open side to be one of the narrow ends of the rectangle. Don't bother to clean the side of each piece of vinyl material that will be the opening of the bag.

Set the second piece of vinyl over the first piece on a smooth flat surface. Align the edges around all four sides. It is critical that the vinyl is kept flat with no bubbles or raised areas at the edges or in the middle of the bag.

You'll want to start with a side of the bag that is closest to the opening and work your way around to the other side of the opening.

Carefully lift the top layer of vinyl away from the bottom layer in increments of roughly 12 inches. Apply a heavy coat of vinyl cement to the edge about 1" wide and let the top layer gently rest back down on the bottom layer as you go along. Have a helper follow behind you with the seam rolling tool as the you perform this process. That person should roll/press the two materials together using very firm pressure with the seam tool. Continue this process around the bag until you reach the other side of the bag opening.

Keep rolling the seam area for several minutes until the adhesive solvents flash off and the bond is made. Alternatively, some people have opted to use flat boards to clamp the seam for 30 to 60 minutes. If you are using polyurethane instead of vinyl, the seams will need to be very firmly clamped for 24 hours.

Making the Bag Air-Tight: The Secret
In the next section you will be adding the bag stem and making (or buying) a bag closure. Once you have done this, attach your bag to the vacuum press system. Place the platens or full-size piece of breather mesh in the bag. By "full-size", I mean a piece that fits inside the bag from edge to edge and end to end. Clamp the bag shut, and turn on the press.

When at least 18" of Hg is achieved, use the HH-66 vinyl cement to "paint" the outside edges of all previously sealed seams. Again, do this in a well-ventilated area. Vacuum will pull in the cement if any leaks exist. You might even hear the seam bubbling, and then just stop within seconds as the cement fills the void. Turn off the vacuum press and let the cement cure for another hour (or 24 hours if using polyurethane).

A second application of cement may be necessary.

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