THE GLUING OP WOOD 23 
When all the plies of a panel are glued together in one operation 
the tape used on cores or crossbands must be left in the panel. If 
a thin, open-mesh, cloth tape is used satisfactory results are obtained 
by this method. On the other hand, if a thick, solid, paper tape is 
used and the panel receives a finish later, the crossband tape often 
causes a raised area, which is objectionable in high-grade panels. 
The joint at the tape may also be appreciably weaker than elsewhere 
since its maximum strength is limited by the strength of the tape. 
Furthermore, the adhesive on the tape may be of relatively low 
strength. For high-grade work, where solid paper tape is used, it 
is therefore best to lay core and crossbands (taped side of crossbands 
out) in one operation, then, after the panels have dried, remove the 
tape from the crossbands and glue the faces on. Another method, 
which is sufficient for all but the best finishes, is to lay the taped side 
of the crossbands next to the core and glue the whole panel in one 
operation. It is possible for tape even under the crossbands to show 
through faces of thin veneer. If a panel has a face and a back side, 
a satisfactory procedure is to use one-piece crossbands under the face 
and taped crossbands under the back pry. 
For panels glued with a water-resistant glue, the glue on any 
tape which may be left in the panel should also be water-resistant. 
A perforated cloth tape is generally used for such work upon which a 
water-resistant glue is spread as the tape is applied to the veneer. 
The perforations reduce the area to be covered by the tape and thus 
allow frequent points of direct contact of the glue with the adjacent 
plies. 
Removal of the tape from the glued plies is best accomplished by 
sanding or machine scraping when the tape is d^. If the tape has 
been applied with nonwater-resistant glue, it is often moistened and 
then scraped off by hand. This, however, is liable to permit the 
joint between the edges of the veneer to open on subsequent drying 
and thus partially defeat the purpose for which the tape was used. 
If much water is used in moistening the tape, it may also cause 
checking in the face veneer. 
THE GLUING OPERATION 
SPREADING GLUE 
To make a satisfactory joint it is important to spread an adequate 
amount of glue evenly and quickly over the surfaces to be joined. 
Hand spreading with all but very thick glues is practicable on small 
or irregular surfaces or where the amount of gluing to be done is not 
great enough to justify the employment of labor-saving machinery. 
Machine spreading, on work adaptable to it, is quicker, more uni- 
form, cheaper, and more economical of glue than hand spreading, 
and for these reasons the greater proportion of all glue used on. wood 
is spread mechanically. 
Among the various types of mechanical glue spreaders in success- 
ful use are double-roll spreaders (pi. 4) for spreading both sides of 
flat pieces; single-roll spreaders for spreading one side or edge of 
flat pieces ; perforated plates which rise vertically out of the glue for 
spreading edge surfaces; machines for squirting glue into dowel 
