WS20174A_SCN_2_FVLS-1990.pdf

WS20174A

15 JANUARY 1987

SCN 2

3. REQUIREMENTS

3.1 MATERIALS. THE MATERIAL USED FOR THE BONDING, COVERED BY

THIS SPECIFICATION SHALL BE A TWO-PART, NON-VOLATILE STRUCTURAL

ADHESIVE AND COMPATIBLE PRIMER. THIS MATERIAL IS IDENTIFIED AS WS20173

ADHESIVE AND WS20175 PRIMER.

3.2 PRODUCT

3.2.1 SHEAR REQUIREMENTS. FIVE LAP SHEAR TEST SPECIMENS SHALL

BE PREPARED CONCURRENTLY WITH PRODUCTION PARTS AND ASSEMBLIES,

DUPLICATING ALL PROCESSING CONDITIONS AND PROCEDURES USED FOR

PRODUCTION. BONDED ASSEMBLIES SHALL MEET THE SHEAR REQUIREMENTS

SPECIFIED BY THE APPLICABLE DRAWING(S). IN ADDITION, FIVE LAP SHEAR

TESTS SHALL BE PERFORMED FOR EACH NEW BATCH OF ADHESIVE AFTER

INSTALLATION TO AUTOMATIC DISPENSING EQUIPMENT (PREPARE LAP SHEARS IN

ACCORDANCE WITH PARAGRAPH 4.3.3 EXCEPT PRIMING NOT REQUIRED).

UNLESS OTHERWISE SPECIFIED ON THE DRAWING, THE MINIMUM TENSILE LAP

SHEAR STRENGTH VALUES LISTED IN TABLE 1 SHALL APPLY.

TABLE 1

LAP SHEAR STRENGTH

ADHERANDS MINIMUM AVERAGE STRENGTH (PSI)

STEEL TO STEEL

PHENOLIC LAMINATES TO STEEL

FIBER REINFORCED GRAPHITE

TO STEEL

3.2.2 CRACKING OR DELAMINATION. AFTER CURE, STRUCTURAL AND

NON-STRUCTURAL BONDS SHALL BE FREE OF CRACKING OR DELAMINATION OF

THE BOND LINE.

WS20174 A

I / I 3

DEPARTMENT OF THE NAVY

NAVAL SEA SYSTEMS COMMAND

WASHINGTON, D.C. 20362

DRAWN BY

ISSUED

SIZE CAGE CODE DWG. NO. REV

SCALE SHEET

A 53711

WS20174A

15 JANUARY 1987

SCN 2

3.3 FABRICATION CONTROL

3.3.1 BONDING AREA. BONDING OPERATIONS SHALL BE PERFORMED AT A

TEMPERATURE OF 77 ±10 DEGREES FAHRENHEIT (°F) AND A RELATIVE HUMIDITY NOT

TO EXCEED 60 PERCENT. THE BONDING AREA SHALL BE FREE OF DUST, DIRT AND

CONTAMINATION THAT WOULD AFFECT BOND STRENGTH.

3.3.2 SURFACE PREPARATION. UNLESS OTHERWISE SPECIFIED ON THE

DRAWING, SURFACE PREPARATION SHALL BE AS FOLLOWS:

3.3.2.1 NON-METALS. ALL NON-METALS SHALL BE CLEANED IN

ACCORDANCE WITH WS19170.

3.3.2.2 FERROUS ALLOYS. FERROUS ALLOYS, INCLUDING CORROSION

RESISTANT STEELS, SHALL BE CLEANED IN ACCORDANCE WITH WS19166. TYPES III,

IV, OR V OR AS SPECIFIED ON THE APPLICABLE ENGINEERING DRAWING.

3.3.3 HANDLING. CLEANED OR TREATED PARTS SHALL NOT BE HANDLED

WITH BARE HANDS, NOR SHALL ANY CONTAMINATION RESULT FROM CONTACT WITH

SUPPORTING FIXTURES OR MECHANICAL HANDLING EQUIPMENT.

3.3.4 PRIMER APPLICATION. UNLESS OTHERWISE SPECIFIED, ALL STEEL

SURFACES SHALL BE COATED WITH WS20175 PRIMER. ALLOW PRIMER TO WARM TO

ROOM TEMPERATURE PRIOR TO OPENING CONTAINER. THOROUGHLY MIX BEFORE

AND AGITATE DURING APPLICATION. SPRAY OR BRUSH COAT TO A DRY PRIMER

THICKNESS SPECIFIED PER THE PRIMER MANUFACTURER’S INSTRUCTIONS.

3.3.5 PRIMER CURE. AIR DRY AT 40 TO 66 F FOR NOT LESS THAN 60

MINUTES, OR 77 ±10 F FOR NOT LESS THAN 30 MINUTES, FOLLOWED BY 250 ±10 F FOR

30 ±5 MINUTES.

EXCEPTION: EC-3901 PRIMER CURE. AIR DRY AT 77 ±±±±10 F FOR NOT LESS

THAN 60 MINUTES FOLLOWED BY 190 ±±±±10 F FOR 30 ±±±±5 MINUTES, OR 77 ±±±±10 F FOR NOT

LESS THAN 120 MINUTES.

3.3.6 BONDING TIME LIMIT. PRIMER SHALL BE APPLIED TO STEEL AND

CURED WITHIN 8 HOURS FROM TIME OF SURFACE PREPARATION. STEEL SURFACES

SHALL PASS A WATER-BREAK-FREE TEST WITHIN 30 MINUTES PRIOR TO APPLICATION

OF THE PRIMER. IF NOT BONDED WITHIN 12 HOURS AFTER CURE OF PRIMER, STEEL

DETAILS SHALL BE SUITABLY PROTECTED TO PREVENT CONTAMINATION. ALL

BONDING OF PARTS SO COVERED SHALL BE COMPLETED WITHIN 180 DAYS. AT THE

END FO EACH SHIFT DURING BONDING OPERATION, PARTS SHALL BE SUITABLY

PROTECTED TO PREVENT CONTAMINATION.

WS20174 A

I / I 4

DEPARTMENT OF THE NAVY

NAVAL SEA SYSTEMS COMMAND

WASHINGTON, D.C. 20362

DRAWN BY

ISSUED

SIZE CAGE CODE DWG. NO. REV

SCALE SHEET

A 53711