SAE AS5127/1D pdf free download.(R) Aerospace Standard Test Methods for Aerospace Sealants Two-Component Synthetic Rubber Compounds.
This SAE Aerospace Standard (AS) describes test methods to determine the application and performance properties of two-component sealing compounds. It shall be used in conjunction with AS5127 and the applicable material specification. When modifications to these test methods are called out in material specifications the material specification shall take precede nce.
2. REFERENCES
The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other pubhcations shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.
3.1.4 CIassD
Sealing compound are typically used for application by extrusion gun or spatula but usage is not limited to these applications. Used for hole and void filling, or for other applications where a very thick sealant is required.
3.1.5 ClassE
Sealing compound are typically used for application by automatic riveting equipment, but usage is not limited to these applications.
3.2 Application Time or Work Life
Dash numbers following the sealing compound classification, e.g.. B-i shall be used to designate the maximum application time in hours for Classes A. B, D, and E. Class C dash numbers followed by a number in parenthesis represent application time in hours followed by the assembly time in hours in the parenthesis, e.g., C-12(48).
4. PREPARATION OF SEALING COMPOUND
The sealing compound must be mixed according to the manufacturer’s instructions.
NOTE: In order to achieve the expected cured sealant properties both curing agent and base compound must be mixed thoroughly to complete uniformity with no visible streaks or swirls of unmixed material. Both curing agent and base compound must be moved physically by the stirring instrument and the container walls. If mixed by hand the mixing blade shall be scraped frequently to ensure a complete blend. To minimize introduction of air into the sealant mixture (refer to A1R4069), no swirling motion should be used when stirring. To avoid risk of overheating the mixture and compromising application properties the sealant mixture should not be over-mixed or mixed too quickly.
4.1 Qualification Testing
Manufacturer’s instructions for mixer operation and mixing must be followed. Plastic disposable cartridges as shown in Figure 1 may be used, or a suitable manufacturer’s recommended alternative to hold the mixed sealant from which it can later be extruded from the cartridges for sealing application and specimen fabrication. If specified in the applicable material specification, sealing compound may be provided in cartridges for multiple component sealants as shown in Figure 2 and shall be mixed according to sealant manufacturer’s instructions.
The measured value shall be checked for conformance to the applicable material specification.
5.2 Air Content (Class B Sealant Base Compound Only)
NOTES: The AMS Committee G-9 is removing this requirement from the AMS sealing compound specifications based on historically high variability within the test method. It is not recommended to use this test for new material specifications. For low density (specific gravity <1.35) sealing compounds, this method was also inaccurate due to the potential inclusion of compressible filler materials.
The equipment used for the air content test shall be:
a. Sealant Cartridge, as shown in Figure 1.
b. Nozzle, 4.0 inches (102 mm) with 0.125 inch (3.18 mm) orifice shown in Figure 1.
c. Dasher rod with valve assembly and separate plug and ramrod from a 6-fluid ounce (177 mL) sectional cartridge as shown in Figures 2 and 3.
The test method shall conform to the following steps and shall refer to Figure 3 for the various steps:
1. When the sealant compound specifications requires air content to be tested, one test shall be performed at standard conditions in accordance with AS5127 (4).
2. Sealant base compound to be tested shall be stabilized at standard conditions in accordance with AS5127 (4) for at least 8 hours prior to the test. The test sample shall not be taken from the top of the sealant base container or drum.
3. Fill the cartridge with sealant base compound, being careful not to introduce air. Attach the nozzle with 0.125 inch (318 mm) orifice to the cartridge. Cut off the tip of the nozzle and extrude a minimum of 2 inches (51 mm) of sealing compound to remove entrapped air.
4. Prior to starting the test, the dasher rod should have the piston in contact with the dasher end and the valve should not be closed.
5. Insert the nozzle of the filled cartridge firmly into the handle of the dasher rod as shown in Figure 3 and deliver sealing compound slowly until dasher is about 314 full. The sealing compound, however, should be filled completely into the handle end of the dasher.
7. Measure the length of the sealing compound in the dasher rod in millimeters. The plug should be pushed forward until the whole plug clears the dasher rod handle. Measurements shall be between the interior bottom of the plug and the middle of the curved sealing compound bead at the other end of the dasher rod (length “X”, as shown in Figure 3).
8. Insert the ramrod into the dasher rod and push until the valve is in fully open position as shown in Figure 3.
9. Remove ramrod and clean off any remaining excess sealing compound at the handle end of the dasher ramrod.
10. Slowly push the valve body into the dasher, finally forcing a seal.
11. Lightly insert the ramrod again into the dasher until it just touches the top of the plug. Make a mark “B” on the ramrod at the handle end of the dasher.
12. Put firm hand pressure on the ramrod while the valve end of the dasher is held against a table edge. Make a second mark “C”.
13. Measure the distance between the two marks on the ramrod.
14. Calculate the percent air present in the sealing compound using Equation 2.
5.4 Viscosity of the Curing Agent
When the sealant compound specfications requires viscosity of the curing agent to be tested, one test shall be performed. The viscosity of the curing agent shall be determined using the same procedure as 5.3. Spindle size and speed of rotation to be used are defined in the applicable material specification for the class and application time of the sealing compound under test. The measured value shall be checked for conformance to the applicable material specification.
5.5 Flow (Classes B, C. and D)
5.5.1 Flow for Classes B and D
When the sealant compound specfications requires flow to be tested, one test shall be performed. A standard sealing compound gun cartridge, fitted with a 0,125 inch (3.18 mm) orifice nozzle per Figure 1. shall be filled with freshly mixed sealin9 compound. The sealing compound gun, cartridge and enough sealing compound to complete all required flow determinations shall be maintained at standard conditions in accordance with AS5127 (4). The test shall be conducted using a clean flow test jig as shown in Figure 4. The diameter and depth of the fixture plunger, the volume of the cavity, and the flushness of the plunger to the front face (±0.010 inch (±0.25 mm)) are critical and shall be controlled within the tolerance specified in Figure 4 during all flow testing. The plunger shall move freely over its entire range of travel without sticking or binding. Other dimensions of the flow jig are for reference only. The flow jig shall be placed on a table with the front face upward and the plunger depressed to the limit ot its travel. Within 15 minutes of the beginning of sealing compound mixing (5 minutes for B-116 and 10 minutes for B-114), enough of the mixed sealing compound shall be extruded using the application gun to fill the cavity created by the depressed plunger. On the flow jig’s back, the sealing compound shall be leveled with the front surface of the flow jig. Ten seconds after the leveling operation, the jig shall be placed upright on its base and the plunger immediately advanced to the limit of its forward travel. The flow measurement shall be taken at 30 minutes after the sealing compound has been applied to the flow test fixture. The test at this time interval will be considered the initial flow of the sealing compound. The flow shall be measured from the lower edge of the plunger to the furthest point to which flow has advanced. The measured flow distance shall be within the required limits of the applicable material specification.
If additional flow determinations are required according to the applicable material specification, the flow fixture shall be cleaned then refilled at the specified time with sealing compound from the same mix used in the determination of initial flow. The flow measurement shall be taken at 30 minutes after the sealing compound has been applied to the flow test fixture. For example. for 50 minutes flow, the fixture shall be refilled at 50 minutes after mixing 01 the sealing compound, and the flow measurement shall be taken 30 minutes subsequent to filling of the fixture. Typical flow test requirements, according to application rates, are shown in Table 1. All time intervals, other than initial flow, are measured from the end of the mixing period.