Siless Sound Deadening Failure
In the submitted examples shown, Siless appears to show failure in two different
product types, their 3-in-1 CLD sound deadening material, and their closed cell foam
product. The failure modes are different, but both point to poor material quality and poor long-term reliability.
In the submitted 3-in-1 example, the butyl, according the the person who submitted
these photos, appears to have become soft, unstable, and non-elastic, while the foil
peels away far too easily from the butyl layer. That kind of behavior is a major problem for a CLD-based product. A constrained layer damper depends on the butyl maintaining stable viscoelastic behavior. When the butyl softens this much, loses elastic recovery, and the construction starts separating this easily, functional failure was already happening before the visible failure became obvious.
Siless also has a long enough history of complaints that these examples are not
surprising. Many people have mentioned similar issues over time, and Siless was also
the worst tested product in Chris’s independent testing. That lines up with what is shown here. The submitted foam example shows a different kind of failure. In that case, the adhesive appears to have broken down, separated from the foam, and stayed behind on the floor while the foam itself came apart. The remaining adhesive gets nasty and unstable. I am familiar with this type of behavior on this foam (it’s a common foam that is rebranded by many brands), and it is not what you want to see from a product meant to stay cleanly adhered and intact over time.
Taken together, these submitted examples show two different Siless products failing in two different ways. The 3-in-1 example points to a poor CLD construction with unstable butyl and weak layer integrity. The foam example points to adhesive breakdown and separation. Neither inspires much confidence from a performance or reliability standpoint.