Veneer tape

What veneer tape is

Veneer tape is a thin paper tape with an adhesive that is activated by water, often called gummed tape. You dampen it briefly, lay it over the joint between two pieces of veneer and let it dry. As it dries, the paper shrinks slightly and pulls the pieces together.

In intarsia the tape has a single job: it holds the cut pieces together as one veneer picture until it is pressed onto the substrate. Then it comes off again, and if it was done properly, nothing of it is left in the finished piece.

Why not ordinary tape

Ordinary tape, masking tape, painter's tape or clear tape, holds with a pressure-sensitive adhesive. For preparing the press that has three drawbacks:

• Residue. The adhesive can stay in the pores and show later as a mark under the finish.
• Tear-out. A strongly sticking tape easily tears fibres out of the thin veneer when peeled off, especially with open-pored woods such as oak.
• No pull. Plastic and crepe tapes stretch rather than pull. A joint that is not pulled together can open in the press.

Veneer tape, by contrast, dissolves with water, leaves no residue if removed in time and pulls the joint shut as it dries. Low-tack masking tape is still useful for the dry fit and for briefly holding a template (assembling an intarsia).

Perforated or plain

Veneer tape comes in two kinds. Plain tape is a closed paper surface and holds most strongly. Perforated tape has many small holes: you can see the joint through the tape while taping, and moisture escapes faster.

For intarsia with many small pieces and short joints, perforated tape is often the more pleasant choice, because you can still check every joint once the tape is on. For long, straight joints between larger areas, plain tape is enough. More important than the kind is that the tape is narrow enough for the pieces: a strip that is too wide over small pieces covers more surface than it needs to.

Applying veneer tape properly

Before the first piece of tape goes on, all the pieces lie in a dry fit and have been checked. What does not fit dry will not get better with tape. Then:

1. Show face up. The tape goes on the side that will be seen later. The back is glued and stays free.
2. Dampen sparingly. Just draw the tape briefly over a damp sponge. Too much water makes the veneer swell; as it dries it shrinks again, and the joint opens.
3. Along and across. One strip runs along the joint, short cross strips pull the pieces together. Spread the cross strips evenly so that no piece is pulled askew.
4. Press down and let dry. Press the tape down with a finger or a small roller and let it dry completely before moving the assembly.

With very thin or small pieces, less pull is better. If the tape pulls harder than the veneer is stiff, it lifts the edges slightly, which you only see in raking light (checking the quality).

Veneer tape on intarsia with many pieces

An intarsia often has dozens of pieces. Tape them all at once and you lose track, and small deviations add up across the whole pattern. It is better to work in sections: each section is fitted, taped and checked on its own, and only then are the sections joined at their transitions.

How to register pieces and avoid assembly drift is described in assembling an intarsia.

When gluing and pressing

The taped assembly goes into the press as a whole: glue on the substrate, the veneer picture on top with its free back down, tape on the outside. Because the tape is on the show face, it only touches glue where glue comes up through a joint, and exactly there you will see later whether too much glue was used (gluing and pressing).

Water-based glue and dampened tape both bring moisture into the veneer. So the tape should be completely dry before gluing, and the glue applied sparingly and evenly (glues for veneer).

Removing veneer tape without residue

As soon as the glue has cured, the tape comes off, and soon. A damp sponge softens it in a few minutes; then it can be peeled off along the grain or scraped off with a blunt blade. Use only as much water as needed, so that the veneer does not lift.

The first sanding takes the last traces of paper and glue (sanding veneer). If the tape stays on the surface for a long time, though, its glue sets harder and fibres tear out more easily when you peel it. Traces that are missed show under the finish as matt or light spots.

Photo: Reihax

Common mistakes with veneer tape

• Tape on the glue side. It is pressed in and stays in the glue line for good, weakening the bond at that spot.
• Applied too wet. The veneer swells, and the joint opens again once it dries.
• Removed too late. The glue has set hard, and fibres tear out when you peel it.
• The wrong tape. Pressure-sensitive adhesive leaves residue that only shows under the finish.
• Too much pull. Thin pieces are lifted or pulled askew.

Other sources of faults along the whole chain of work are collected in avoiding common mistakes.