Vacuum Veneering and Veneer Cutting

At this month's meeting, Jim Yates gave a demonstration/lesson on veneering using a vacuum veneering system; this included a demonstration/lesson on resawing veneers using the bandsaw.

If you have questions regarding the following procedures, contact Jim Yates at: jjyates4079@NOSPAMsbcglobal.net (remove NOSPAM from the email address before emailing).

Resawing Using the Bandsaw

Jim says that the selection of blades for your bandsaw is very important when resawing hardwoods for veneer. He recommends a skiptooth blade, which has teeth that repeat: left, straight, right, straight. Skiptooth blades help remove sawdust when cutting and are more efficient for resawing.

Carbide-tipped skiptooth blades are best, but VERY expensive. For a less pricey alternative, Jim recommends "Woodslicer" 1/2" blades from Highland Hardware (available online).

Tuning your bandsaw is also important when cutting veneers, but Jim did not go into this procedure. Information on tuning your bandsaw is readily available.

Unlike most veneer specialists, Jim prefers to cut his veneer towards the OUTSIDE of the bandsaw using a special fence of his own construction. Here's a picture of the fence:

The back fence straddles the band saw fence, as pictured; this back fence slides forward (towards the blade) after each veneer is cut from the board.

The front fence is divided into two parts, the bottom and the top. The bottom part is hooked into the track where a mitre gauge might reside; a thin piece of wood fits into this track, where two knobs (one visible in picture) turn bevel-headed screws which, as they tighten into the thin wood in the track, cause that wood to split, holding the front part of the fence in place solidly.

The top part of this front fence can be adjusted forward and back after loosening/tightening the two other knobs (visible in picture). The part of this fence pointing towards and nearest to the blade is sharpened into a V, with the point towards the blade; the distance of the tip of this "V" from the blade will be the thickness of the veneer to be cut. It's shaped like a "V" in order to allow the veneer to peel away from the board freely as it is being resawed (remember: the veneer will peel OUT, or to the right of this picture, as the board is resawed). The tip of the "V" is located right at the teeth of the blade.

NB: The far edges of these front and back fences (as seen in this picture) come ONLY to the back edge of the blade. Jim says that "the fence only extends to the back of the blade so that any curl in the veneer does not cause problems in cutting flat uniform veneers."

When setting this fence, place the stock to be resawn on edge with the end facing the blade; place the front face of the stock against the tip of the "V", then adjust the back fence to rest securely against the back face of the stock.

The cutting will start slowly, then go faster as the blade gets a firm foothold into the wood. Here is a picture of Jim resawing a sample piece of stock (look closely at these pictures, and you can see the veneer peeling from the FRONT of the stock):

Jim cut two pieces off of this piece of stock so that he could make a book-matched veneer.

Taping and Gluing

Veneers are glued to a substrate. A substrate is usually either a piece of plywood or a piece of MDF. Substrates used for veneering must be perfectly flat. Jim says that getting flat plywood has become extremely difficult, so he recommends using MDF.

A size of the substrate is determined by its final use in the project. You should always cut the substrate LARGER than you need for the final piece (so that the bad edges of the veneer can be cut away).

Veneer must be applied to BOTH the back and front of a substrate. Jim says that you don't have to apply the same material or the same thickness of material onto the back and front of a substrate. On the back of the substrate, you may choose to apply either an actual piece of veneer, or just a piece of doorskin. Choose what sort of material you will apply to the back of the substrate based on the final use of the piece.

Because Jim cut two pieces of veneer to be bookmatched, he needed to tape these pieces together. After figuring out which way they fit together best, Jim taped the two pieces together on their GOOD side, the one that's going to be on the outside of the piece. He used ordinary painter's tape (delicate hold):

Jim's favorite glue for veneering is Franklin brand extended open time glue for veneering. At the meeting, we weren't sure of the exact name of this glue. Jim says: "The Franklin company makes Titebond and the extended open time glue may have the Titebond name." He says that you can also use regular Elmer's white glue. Jim does not recommend ordinary Titebond glue as he says that it is has too much "grip" and doesn't allow for air bubbles to be extracted by the vacuum veneering system. He says that Titebond 3 might be OK as it has extended open time.

Jim says that extended open time for the glue is very important because it dries slowly, allowing the vacuum veneering system enough time to extract the air bubbles from the glued-up piece before everything dries up.

Using a glue roller, Jim applied glue to the back side of the substrate, then applied a piece of pre-made veneer (that he had cut earlier) onto the substrate. He pressed out as many of the bubbles as he could, then turned the piece over. After brushing off the dust from the FRONT side of the substrate, Jim applied glue using a glue roller:

Vacuum Veneering

Now, everything has to be assembled for insertion into the vacuum veneering system. Ultimately, our veneered workpiece will be sandwiched between two melamine platens inside a vinyl vacuum bag; vacuum will be applied, which will press the veneer onto the substrate without any bubbles or bumps. If you do it properly (which Jim did during the demonstration), that's how it works.

Let's talk about the platens before we go any further.

A platen is a perfectly flat board, set against the veneered face of your workpiece, which is squeezed from the outside to apply pressure to the veneered surface. The vacuum veneering system applies this pressure. It's really amazing how much pressure you can get just from a vinyl bag that's had all its air evacuated!

The "base platen" which presses against the BOTTOM (or non-show) side of our workpiece is that white gridded board that you see Jim using as a work surface in most of the above pictures. This "base platen" started as a melamine-coated piece of fiberboard that you can get at any store that sells wood or home improvement materials; Jim then routed straight grooves at regular intervals into the melamine surface. The grooves allow for the air to escape as the vacuum applies pressure to the piece in the vacuum system. This base platen also has a hole in it (at a junction of one of the grooves) which connects to the vacuum hose of the vacuum veneering system. When the entire assembly is placed into the vacuum bag, the vacuum hose is attached THROUGH the bag into the hole in the base platen.

Jim says: "Melamine is used because the glue will not stick to it - one could use wax paper in a pinch."

The "top platen" is a perfectly SMOOTH, FLAT piece of melamine-coated fiberboard. This platen presses against our GOOD, or SHOW side of the workpiece. It's smooth so that it won't make any marks on the veneer.

Jim taped the workpiece (good side up) to the top platen (melamine-side down) using painter's tape, one piece per edge. You can see the back side of the top platen in this picture:

Jim also uses this vacuum system to create, in Jim's words, "hardwood inlay blanks from which inlay strips may be cut." These hardwood inlay blanks consist of a hardwood substrate thickly veneered on front and back with a hardwood of a contrasting color. Here is a picture showing some of these hardwood inlay blanks, and the inlay strips which Jim ripped from the blanks:

Thanks again to Jim Yates for an exceptional class!

Jim Yates' Nesting Tables. The tops of these tables feature inlay made from inlay strips cut from hardwood inlay blanks.

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