Page 155 - Handbook of Adhesives and Sealants
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124 Chapter Three
Figure 3.29 Compound butt joints: joint (a) has back-up material, which should be un-
der compression even at maximum joint volume. Sealant must withstand compression
and extension. A compound joint of similar materials (b) may cause sealant failure due
to expansion and contractions, if sealant is bonded to bottom layer (c). A release agent
either chemical or film, prevents sealant from bonding to bottom and allows materials
to stretch normally (d). 15
Figure 3.30 Design of corner sealant joints. 14
