--.----l--..ll- _ _-- .-... \" . .. - . . . -- .-.. ... .\" . . .- - - -- . - .- - - PURPOSE This BSS Standard describes the procedure and requirements for testing metal-to- metal peel strength of adhesive bonds. CLASSIFICATION a. - Class 2 - HodiEied Roller Class 1 Climbing Drum (1) Type I (2) The following Classes of metal-to-metal peel are covered in this standard. I b. The following types of specimens are covered in this standard. Acceptance Type I I Qualification XPPLICABLB DOCUMENTS Except where a specific issue is indicated, the current issue of the following references shall be a part of this Standard to the extent indicated. a. b, c. ASTM Dl781 ASTME4 Climbing Drum Peel Test for Adhesives Verification of Testing Mac'lines Aluminum Alloy Alclad 2024, Plate and Sheet 99-A-250/5 This section is not applicable to this specification. DEPINITIOUS This section is not applicable to this specification. TBST SPECIMEN REQUXREUENTS GENERAL a. Test Instructions The test instruction and methods provided by this standard are intended to be supplemented or amended by the referencing specification as necessary to suit diverse requirement6 and rnater ials. l (Continued) b. Supplemental In forma tion The following information specification. as applicable must be supplied by the referencing (1) The type(s) and numbers of panels and specimens to be prepared (2) Significant details of adhesive handling, preparation, application and open assembly time (3) The bond surface (a) con£ iguration and preparation for bonding (4) Cure pressure, nethod oE application, and cure time/temperature envelope (5) Cured bondline thickness (6) Environmental exposure time and conditions (7) Test temperature (s) (8) Test requirement (s) and criterion for acceptance 5.2 TEST PANELS Test panel assemblies consist of two standard panel blanks adhesively bonded toqe ther. a. Test Panel Blanks ft) blanks Except as otherwise specified, the material, thickness, and dimensions for shall be as shown in the respective figures for each Type of test ! panel. (2) Blanks shall more than 1 psi be capable of being pressed flat within 0.002 inch with no load. (3) The bond surface of blanks shall be free of corrosion, burrs, or other surface irregularities and shall have a surface finish of 125 RHR maximum. (4) The use of the part number designations given in this specification are optional. accordance with The flagnoted holes in Figures BSS 7206 designated part numbers only. 1 and 3 are required in b. Preparation ! The test surface(8) and method of surface preparation Eor bonding shall be specified. c. Assembly (1) Use Teflon, mylar, or suitable plastic film to simulate adhesive and leave about 2 inches unbonded at one end. (2) Except shall be assembled and cured 0.020-inch substrate down. as otherwise specified, the test panel blanks with adhesive applied (3) Use specimens with uniform bondlines. Bagging with an Auto a bonding fixture that prevents \"pinch-off\" at edges to yield test Vac device Zipper Closure for preventing \"pinch-of£\" in Type (available from Cogger Industries, Kent, Washington) is recommended I test panels. ORIGINAL ISSUE: 9-18-74 X-ZObOa REV. WW - 5.2 (Con t inucd) Cure 7 : d. (1) The cure time/te~perature/preseure envelope for the adhesive test assembly shall be specified. (2) The open assembly time of the adhesive from time of mixing or removal from refrigeration until cured shall be a8 specified. (3) Unless otherwise specified, all test assemblies shall be cured under fluid pressure, clamps, presses, weights, or other mechanical pressure means i.e., vacuum or autoclave blanket pressure. The use of spring is prohibited unless proven to provide functional and numerically similar test results. (4) The curing temperature and tine at temperature of the adhesive bond shall be as specified and shall be measured thermocouple (No. adjacent to the bond line. 30 maximum) embedded in the adhesive flash immediately by the use of a fine-wire 5.3 METAL-METAL PEEL TEST PANEL CONFIGURATIONS 5.3.1 TYPE I ACCEPTANCE a. Test Panel (1) Except as otherwise specified, the material for all blanks shall be 2024- T3 clad aluminum alloy in accordance with QQ-A-250/5. Standard thicknesses of the blanks shall be as noted in Figure 2. I (2) Blank dimensione shall be as shown in Figure 1. P ' '- t 5.50 f: -03 21 l(:.* - 1/ Holes, 4 places, 0.125 D centered approximately 0.25 inch from edges. - 2/ Test panels measuring corresponding trim discard edge of 0.5 inch are optional for Class 4.5 + 0.3 by 10.0 2 0.3 inches having a R modified roller peel. 2 Figure 1 TYPE I TEST BLANK T BSS 7 I Page 20 6 3 +. r ORIGINAL ISSUE: , 9-18-74 REVISED: \"En d-z2-86 i5.3.1 (Continued) b. Test Panel Assembly (1) Adhesive bonding material and instructions shall be designated in the referencing specification. (2) Two test panel blanks shall be bonded together as shown in Figure 2. (3) Identify each test panel assembly and specimen ae necessary. * ----- DISCARD- - - - - L - -i :;iL:;/-------- -------- L-- I -I---. I I - DISCARD 1-- 1.0 Typ. I 1 I_____ - I/ 14.05.03 2/ A4 - Unbonded :'\" t J- 3.1 - 1/ Trim discard edges shall be 1.00 inch minimum. Cut three specimens 1.00 0.03 inch wide. 2 - 2/ 0.020 inch I 3/ 0.040 inch 1 4/ Unbonded space 3.8 film. filled with Teflon, mylar, or other suitable plastic Figure 2 ! TYPE I METAL-METAL PEEL TEST ASSEMBLY AND SPECIMEN 5.3.2 TYPE I1 QUALIFICATION 1 a. Test Panel Except as otherwise specified, the material for all blanks shall be 2024-T3 clad dimensions of the blanks ehall aluminum alloy in accordance with QQ-A-250/5. Standard thicknesses and be as noted in Figure 3. , b. Test Panel Assembly (1) Adhesive bonding material and instructions shall be designated in the referencing specif ication. (2) Two test panel blanks shall be bonded together as shown in Figure 3. (3) Identify each test panel assembly and specimen as necessary. iPage 4 ORIGINAL x-m ISSUE: REVISED: 'En 4-22-@-. -\"... IEV. &/a -- 9-18-74 5.3.2 (Con tinuedl I ,,L0 lSCARO ,,@.A 1.0 I-I -7 ------- --- _+-- --.&I - -- ---+ I - Typical Saw Cut L-- I - / l/ 0.020 inch 7 r - 3/ 0.040 Holes, inch Unbonded g/ 4 places, 0.125 D centered approximately 0.25 inch from edges, optional. / For testing this dimension shall be euch that the required number BSS 7206 designated part numbers, this dimension shall be 12 inches. the assembly. Make a minimum of 10 specimens for qualification. of specimens can be made from For qualification - 5/ This optional dimension shall 0.03 inch wide from to reduce the discard be 1.00 inch minimum. For testing other than qualification, it shall be a 12-inch-wide panel assembly. edge width to 0.50 inch minimum to obtain 10 specimens 1.00 2 s/ Unbonded space is filled with Teflon, mylar, or other suitable plastic film. II Figure 3 TYPE IX METAL-METAL QUALIFICATION PEEL TEST ASSEMBLY AND SPECIMEN I TEST SPECIMENS a. Cut the test panel assembly as shown in Figures number of specimens. 2 and 3 to provide the required b. hll to the bond. cuts shall be accomplished so as to avoid overheating or mechanical damage c. Use of lubricants or liquid coolants during cutting is prohibited. 1 1 ORIGINAL ISSUE: 9-18-74 X-2O.m REV. lVIll a. The testing machine shall be verified in accordance with of + ASTM E4 to an accuracy 1 percent within the test loading range and have self-aligning grips. b. The Class 1, climbing drum peel apparatus shall consist of a flanged drum fitted with suitable clamps and flexible loading straps, or cables, such as shown in Figure 4 and ASTM 01781, together with a suitable testing machine and autograph recorder. c. The Class 2 modified roller peel apparatus shall consist of an open face three roller plate aa shown in Figures Figures 7 and 8, together with a suitable testing machine and autographic 5 and 6, constructed from components shown in recorder. I PRWEDURg CLIMBING DRUM PEEL TEST PROCEDURE - CLASS 1 a. The test specimen temperature shall be 75 t 10F. b. Clamp the specimen to a 1/4 specimen, with the 0.040-inch x 12-inch steel plate of the same width the testing machine. See Figure panel against the plate. Center the specimen in as the 4. c. Before testing, zero the machine with the drum, test specimen, and backup plate and clamps auspended from the upper load bar. d. Test according to the general instructions of load at a crosshead speed of ASTM Dl781 except apply a tensile 3.00 f 0.30 inches per minute. I e. Calculate the peel value as follows: P (Ro - Ri) (L - C) where r' I P a peel strength in pound-inches per inch of specimen width Ro radius of the flange, to the center of the strap Ri = radius of the drum L avCrage load, taken from the autographic recording corresponding to When the average load inches of peeling, after the first 5 second highest and the second lowest load shown on the autographic is in question, take one half of the sum of the 2 inches of facing have been peeled. reading. I C = correction for drum. the load in pounds required to overcome the weight of the place of the specimen, and measure the load required Determine by placing a strip of fabric of negligible stiffness in upward. Make the measurement with the backup plate and clamp in place. to roll the drum MODIFIED ROLLER PEEL TEST PROCEDURE - CLASS 2 a. Insert the test specimen into the peel test fixture as shown in Figure jaw. 5 with the unbonded end of the 0.020 adherend gripped in the test machine b, Before testing, zero the machine with the peel apparatus and test specimen suspended from the upper load jaw. c. Peel the specimen at 6 lnch/minute constant head speed. d. During the peel test make an autographic recording of load versus head movement (i. e., load versus distance peeled) . e. Record the load over at least first 1 inch of peel. 3 inches length of the bond line, disregarding the ORIGINAL ISSUE: 9-18-7 X-206W REV. 6/88 (Continued) f. Calculate the peel value as follows: Determine from the autographic curve of at least 3 inches of peeling (disregarding the first inch), the average peeling load in pounds-force, per inch of the specimen width, which is required to separate the adherends. a. b. Record material identity, testing conditions, and test results. Round off peel values to the nearest 0.5 pound-inch. Report all teat data for each specimen. e. 1 ORIGINAL ISSUE: X-loaoo REV.8lcrs 9-18-74 /-Self-tlghtent. Clamp \"A\" I/ - ST 6903 Equivalent testing or clamping devices may be used. All dimensions in inchee Figure 4 SCHEMATIC DIAGRAM METAL-TO-METAL CLIMBING DRUM PEEL TEST APPAFWTUS ORIGINAL ISSUE: X-MI)DO REV. En# 9-1.0-74 - - REVISED: 'En 4-22-86 -.-