Sequoia Aircraft Corporation F.8L Falco, Construction Manual

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F.8L Falco Construction Manual D–7 Revision 4, March 1, 2002
total amount of adhesive used being evenly divided between the two surfaces. Double spreading is
recommended for dense species and where the time required for assembly approaches the
maximum permissible.
Table 2
Recommended Spreads in Pounds Per 1,000 Sq. Ft., Single Glue Line
Low Density Wood.......... 50 to 70
High Density Wood......... 50 to 60
The heavier spreads are required for rough surfaces or where long assembly periods are required
Assembly Time. The assembly period is the time elapsing between spreading a joint and
applying pressure. “Open Assembly” is the time between spreading and assemblying the spread
surfaces, while “Closed Assembly” is the time the spread surfaces are in intimate contact before
pressure is applied. It is generally desirable to permit the adhesive to penetrate into the wood for
15 to 45 minutes (when at room temperature) before applying pressure. For certain dense woods
and other non-porous material, it is advisable to allow part of the solvent to evaporate by
providing a short open assembly time.
Table 3
Recommended Assembly Times
Temperature of room, wood, glue: 70°F 80°F 90°F 100°F
Maximum Permissible Open Assembly Time: 10 mins. 5 mins. 1 min. 0 mins.
Maximum Permissible Closed Assembly Time: 60 mins. 45 mins. 30 mins. 15 mins.
The times in this table are based on using either “open” or “closed” assembly, not both. When a
combination of these two assemblies is desired, the maximum assembly times can be proportioned
from the table. For example, if one-third of the maximum “open” assembly time is used, then only
two-thirds of the maximum “closed” assembly time can be employed.
Curing Conditions
(a) Pressure—In general, sufficient pressure to reduce the glue line to a thickness of 0.002” to
0.007” is required. Thicker glue lines will result in an inferior bond. Pressures of 25-250 psi are
generally used. In thick assemblies, slight excess pressure is desirable to compensate for shrinkage.
(b) Temperature—Penacolite Adhesive G-1131 is adaptable to accelerated curing at intermediate
temperatures, as well as room temperature. Curing temperatures below 70°F should not be used.
For gluing flat stock at room temperature, minimum clamping pressure periods are shown in Table
4.
Table 4
Minimum Pressure Periods
Glue Line Temperature Low Density Woods Dense Woods
70°F 8 hours 10 hours
75°F 6 hours 8 hours
80°F 4 hours 6 hours
90°F 2-1/2 hours 3-1/2 hours
100°F 1-1/2 hours 2 hours
For curved stock the above times should be doubled.