Question:I am trying to bond several rubber parts together. I would like to try a cyanoacrylate adhesive, but I hear they are very brittle when cured. Is that true?
Answer: Unfortunately, because some of the common cyanoacrylates tend to be somewhat brittle in comparison to other adhesives when used to bond rigid substrates, they are rarely considered for bonding rubbers. However, these adhesives have been widely used over the years for rubber bonding. For example, so-called “O-ring kits” are sold to make custom-sized O-rings from rubber cord stock, and some critical applications (like bonding rubber balloons on heart catheters) have always used cyanoacrylates. The rubber actually absorbs the stresses put on the bond, and the brittleness of the adhesive is not an important issue.