Replies

1. GBA Editor
   Brian Pontolilo | Jun 20, 2019 09:16am | #1

   Kevin,

   I wrote a pretty extensive article about caulks and sealants for Fine Homebuilding and didn't come across these products, but I just realized that was now 15 years ago. How time flies. At a glance these two products have a lot of attractive characteristics. It'll be interesting to see if any GBA members are using them.

2. 
   Peter Yost | Jun 20, 2019 10:40am | #2

   Boy, it is really hard to find explicit and delimiting definitions of the terms caulk, sealant, mastic, etc.

   Here is my quick cut:

   1. adhesive: meant to be applied between two substrates to augment fastener connection of the two substrates. Adhesives are meant to be compressed/trapped.

   2. sealant - usually means liquid sealant and applied as a 3-D bead. These are meant connect two substrates, NOT compressed, and also installed with either backer rod or bond break tape to limit their attachment to the substrates to two unconnected planes, so that the sealant accommodates movement in connecting the two substrates.

   3. mastics: sticky stuff meant to seal surfaces, often left exposed

   4. PSA tapes: pressure-sensitive adhesive tapes meant to seal substrates and often accommodate some movement in the substrates regardless of whether or not the substrates are exposed or trapped by subsequent layers of the assembly.

   the most common chemical composition of many of these sticky materials include latex, modified bitumen, butyl, acrylic, silicone, and silyl/silane modified polymers. Each vary in their elasticity, accommodation of movement, environments they tolerate, strength of adhesion, outgassing, and cost.

   that clears things up, right?

   Peter

1. 
   kevinjm4 | Jun 21, 2019 07:34am | #3

   Peter appreciate the response. I just meant what is a sealant-adhesive technically speaking. I’ve seen sealants, and I’ve seen adhesives, but never sealant-adhesive. Just recently came across some when I was poking around looking at the polyether world. I can’t remember if the polyether was the sealant-adhesive, or if those manufacturers happened to make sealant-adhesives that I noticed on their website. Perhaps it’s just a way to say their sealant bonds/adheres really well, in general? Or they are flexible adhesives that are classified also as astm c920 class 50, which perhaps there is demand for somewhere...? I think it sounds cool

   Edit: here’s one-
   https://www.chemlink.com/Products/Multi-Purpose/SKU-8252-DuraLink-50-Super-Adhesion-Sealant

   And another-

   https://www.bestmaterials.com/detail.aspx?ID=10901&gclid=Cj0KCQjwgLLoBRDyARIsACRAZe5PzZ31UVFPLNz6G32uiDrLeOru_LAgmPjMcNLpZ4U0BMjfw_QOcsUaAtJUEALw_wcB

3. 
   Jon_R | Jun 21, 2019 10:40am | #4

   IMO, a good adhesive needs good adhesion, tensile strength and shear strength. This can be useful in some cases - if you prevent movement, then you need less movement capability.

   What specification of polyether do you consider superior to a polyurethane sealant like Demonic 100? Specs on the former look worse to me.