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An old sales adage says, "If you can't blind 'em with science, baffle 'em with BS." It's not uncommon for manufacturers to make scientific claims attributed to nebulous "specialists" or "lab people" who don't really exist--at least in-house. In the long run these thin attempts at expertise are exposed as phony and can affect an agent's reputation, if not their wallet. The Friday Fax has referred to the Polywater Laboratory and its claims repeatedly over the years, and so it begs the question: is it a real in-house entity with ovens, test tubes, beakers, and real college-edumacated people with degrees in chemistry? Answer: Yes. But don't take my word for it. The following excerpts are from an actual email narrative as the Polywater Lab responds to a large unnamed customer's technical questions about FST Foam Duct Sealant. The thread is too long for a single article and spills into the next issue. Read the dialogue and conclude for yourself the validity of our expertise. If you glean something useful about FST, great; but the real lesson here is that you and Polywater products are supported by people who know their ... stuff. Q: How does FST affect PILC? A: Attached is a lab report on FST Compatibility Testing with common electrical cable jackets. Note that PILC was not tested because it's more robust than the plastic jackets (PVC & XLPE) used in the testing. We may infer from this that there is no compatibility concern for FST use in ducts occupied by PILC cables. There has never been a known compatibility issue with any cable material with which FST contacts. Q: What is FST's movement tolerance with the heat produced by multiple cables in a duct? A: FST forms a solid seal. It does not soften at elevated temperatures. FST holds cables immobile in relation to the conduit at the point of the seal. This does not change with temperature or movement of the cables. If referring to dimensional changes in the cable materials due to temperature (expansion/contraction), because FST is a foam, it has just enough resilience to absorb the stresses without losing adhesion. Q: What is FST's shelf life once opened? A: The shelf life of opened material depends on many factors. Our standard answer is: if sealed and stored correctly, one month. Correct storage means out of direct sunlight, at approximately 20°C (68°F), with cap tightly placed on cartridge. Note that it's best not to leave spent mixing nozzles on FST cartridges as a cap for future re-use. Foam can back up into the cartridge orifice, hardening into a plug that makes re-use difficult at best. It's better to reuse the cartridge's original cap. This is in contrast to our non-foaming products (BonDuit or PowerPatch) where the used static mixer makes an excellent cap for future re-use. Q: How hard is it to remove FST from cable? A: There is no easy way to remove all of the FST from a cable. No solvent will work. Most FST will break or peel off, but there will be residue that would have to be scraped or sanded. Note that such residue is not problematic if an FST seal was removed to add another cable and then resealed with FST. Fresh FST sticks to old FST quite well. Q: Does the presence of water in a duct affect FST placement? A: FST's 2-part polyurethane foam does not require air or other compounds to complete its reaction. When water is present, the hydroxyl group (-OH) from the water molecule is incorporated and creates slightly larger cells in the cured foam by increasing the size of the gas bubbles forming. To reduce the number of larger cells in cured FST foam it's advisable to remove as much water as possible. Typically, pumping ducts and usage of an extra foam damming strip allows users to work with a dry 5" of duct length. Keeping the duct dry is not important after the sealant is placed and cured. Q: Is hydrogen released with FST use in wet conditions, and is this dangerous in the confined space of a vault with a portable heat source for splicing? A: The presence of water with and in FST generates carbon dioxide, not hydrogen: RNCO + H2O → RNH2 + CO2 where RNCO is the isocyanate side. All of the hydrogen stays with the newly made polymer. Water is already in the FST formula; it's what makes it foam in the first place. Too much water will put the reaction out of balance, cause larger bubbles, and can cause the foam to collapse on itself in extreme cases. Usually what we see is just the larger bubble phenomenon. The amount of carbon dioxide generated by FST is small and is contained in the foam. The water reaction is competing with the polyol reaction that is built into the product, so even if there is a great amount of water present, the amount of carbon dioxide that can be generated by a 250ml tube of FST is pretty small. Certainly too small to have an effect on air quality, even in a confined space. This is nothing so far. Stay tuned ... next week the dialogue really begins to "heat up." |
