MOMENTIVE RTV511 2 Part Silicone Secondary IG Sealants User Guide
- August 20, 2024
- MOMENTIVE
Table of Contents
MOMENTIVE RTV511 2 Part Silicone Secondary IG Sealants
Product Information
Specifications
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Product Name: Silicones for Building
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Usage: Insulating Glass Quality Guide for use with 2-Part
Silicone Secondary IG Sealants -
Manufacturer: Momentive Performance Materials Inc.
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Website: www.siliconesforbuilding.com
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Contact Email : commercial.services@momentive.com
Product Usage Instructions
Test Procedures
Note: The test procedure may vary between operators. Ensure thorough stirring of the sample for uniform cure in the cup.
- Step 1 description
- Step 2 description
- Step 3 description (Refer to ASTM C1249 Appendix X2)
- Step 4 description
Butterfly Test
Note: Refer to ASTM C1249 Appendix X1 for detailed instructions.
- Pump sealant onto the center of the paper.
- Fold and flatten the paper to spread the sealant.
- Unfold the paper and check for streaks to determine mixing quality.
Record Keeping
Record the TFT (Test for Tack-Free Time) on the daily log for quality
control purposes.
Quality Control Information for use with 2-Part Silicone Secondary IG Sealants
Importance
The development and implementation of adequate quality control procedures are
important in maintaining product consistency. Effective implementation of
procedures and documentation is the responsibility of the user. The following
information, test procedures, and schedule of testing should be used as a
guideline. The importance of testing and record keeping can speed the
identification of material and equipment problems and provide workers with a
means to identify problems before producing units that may not meet the
standards needed for high quality.
Note: The ASTM C1249 Secondary Seal for Sealed Insulating Glass Units for
Structural Sealant Glazing Applications, which provides an overview of sealant
design topics for IG systems, should be used in conjunction with this manual.
Copies can be obtained at www.astm.org.
Receipt of Product
Receipt of products and usage of products from inventory should be conducted
in a first-in first-out method. Labeling containers with the date of receipt
can assist in tracking proper product flow throughout the production process.
Initial Quality Testing
Momentive performs rigorous quality testing on manufactured material before
release for sale or shipment. However, once material ships from our
manufacturing location, unforeseen circumstances can arise which could affect
the material; for example: prolonged exposure to high heat, dented or cracked
containers, exposure to moisture, etc..). Thus, it is a good practice to
quarantine material upon receipt until quality control tests the product. This
is minimally a snap test conducted with material taken directly from the newly
received containers. Once the product has passed the initial quality control
check it can be released to inventory.
Daily Production Quality Testing
It is recommended that a log is created to track daily production quality
testing. This log should minimally include Date, Time, Temperature, Humidity,
Mix ratio setting, Batch numbers and Container numbers, Snap time, Butterfly
results, and tack-free time. Maintaining such a test log gives users
familiarity with the normal behavior of the material and can allow some
forewarning of abnormal behavior should conditions arise.
Frequency of Testing
It is recommended to test whenever production equipment has been idle for an
extended period such as overnight, during lunch breaks, break times, or when
empty product containers are being changed out.
Test Procedures
Snap Test (Work Life)
Snap time is a measurement of the cure speed of 2-part silicone sealants. Cure
speed is affected primarily by the ratio of the A and B components, and to a
lesser extent by the temperature and humidity. The snap time is the time it
takes for catalyzed, mixed sealant to cure to a state where the mixture begins
to behave more like an elastomer than a liquid – that is, the material tears
within itself when the stick is removed from the sealant. Measurement and
control of snap time is critical to maintaining consistency of performance of
2 part sealants.
- Step 1 – Fill a small cup approximately half to 3/4ths full with freshly mixed 2-part sealant directly from the equipment and insert a tongue depressor. (Except for Initial Quality Testing, use the product directly from the packaging, weighing the appropriate ratio of the two components, and hand mix them).
- Step 2 – After approximately 25 minutes have passed, begin to monitor the cup at 5-minute intervals stirring the contents of the cup with a tongue depressor and withdraw the tongue depressor.
- Step 3 – Observe the material being pulled out of the cup by the tongue depressor. Initially, it will pull out to a thin “string”. As the material cures its viscosity will increase and become more difficult to pull.
- Step 4 – The snap time is the time when the material no longer “strings” when pulled out of the cup but snaps off.
- Step 5 – Record the time of the initial snap to the nearest minute.
Note: This test is subjective and subject to variation between operators. Stirring of the sample is necessary to ensure uniformity of cure in the cup. The appearance of the snap is subject to judgment; individual operators may obtain results that span up to several minutes. Agreement among operators on the appearance of the snap is suggested to minimize variation.
Note: If snap times deviate from expected, the Snap Test can be run by combining materials in a known weight ratio. Materials should be weighed, combined, and thoroughly mixed and tested as described above. This test can assist in the determination of potential equipment variation.
Note: This method is also depicted in ASTM C1249 Appendix X2:
Butterfly Test
The Butterfly Test is a measurement of the mix quality of 2-part silicone
sealants. Complete mixing as indicated by the uniform color of the mixed
sealant is necessary to ensure the proper performance of the mixed sealant.
Mix quality is affected primarily by the type and cleanliness of the mixer.
Pumping uniformity of the two components to be mixed, pressure variations in
the pumping equipment, sticking check valves, and other mechanical
malfunctions are potential causes of poor or incomplete mixing. The length of
the test paper should be long enough to accommodate the entire pump cycle.
- Step 1 – Fold the paper in half along the longer dimension, crease, and unfold.
- Step 2 – Purge the mixer to ensure fresh material is in the mixer.
- Step 3 – Dispense a ½” to 1” wide bead of freshly mixed material directly from the mixer onto the crease in the paper.
- Step 4 – Immediately fold the paper in half along the crease and press the sealant out by hand to a width of a few inches between the paper halves.
- Step 5 – Unfold the paper and inspect the appearance of the mixed sealant.
Note: This method is also depicted in ASTM C1249 Appendix X1.
Appearance Ratings:
- Uniform color and texture – Ideal appearance is a uniform color and smooth appearance to the naked eye.
- Longitudinal streaks – Faint longitudinal streaks (parallel to the paper crease) may be present. If the color contrast of the streaks increases with time mixer should be cleaned or replaced. Run Tack Free Time Test to ensure all material attains tack free state.
- Lateral band(s) – A lighter or darker color band may appear perpendicular to the paper crease.
- This can indicate a variation in mix ratio potentially caused by unequal pressures in the catalyst and base, check valve malfunction, or other mechanical causes. Run Tack Free Time Test to ensure all material attains tack free state.
- Large cured chunks of sealant – May appear when mixer has been used too long or insufficiently purged. Change the mixer.
- Coarse texture of sealant surface – Mixer not sufficiently purged. Purge the mixer and repeat the test.
Note: This test is subjective and subject to variation between operators. A smooth texture and uniform color provide assurance of a thorough mix and uniform mix ratio.
Tack Free Time (TFT) Test
The TFT is a relative measurement of the cure speed of 2-part silicone
sealants. Variations in the TFT can indicate variations in mix ratio, mix
quality, material quality, and other process variables, which may affect the
performance of the material. The TFT test can be performed on Butterfly Test
samples or actual production units.
Note: The material will typically become tack-free a half hour to an hour after the material has snapped. Refer to the daily test log for recorded snap time(s) and begin inspection for TFT as applicable.
- Step 1 – Lightly touch the surface and observe if the material is transferred. A tack-free condition exists when no material transfer occurs and with no visible disturbance to the material surface.
- Step 2 – If material transfer occurs or the material surface is disturbed, check again after 15 minutes. Repeat as necessary. Record the TFT on the daily log.
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commercial.services@momentive.com
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Frequently Asked Questions
- Q: What should I do if snap times deviate from expected in the Snap Test?
- A: If snap times deviate, run the Snap Test by combining materials in a known weight ratio, ensuring thorough mixing before testing.
- Q: How can I determine potential equipment variation using the Snap Test?
- A: The Snap Test can assist in identifying potential equipment variation by comparing expected and actual snap times when materials are combined and tested.
- Q: Where can I find full product and sales disclaimer information before using Momentive products?
- A: Visit www.siliconeforbuilding.com/LegalDisclaimer for the complete disclaimer before purchasing or using any Momentive products.