Don...not saying 420 is bad just saying the 421 seems to have the characteristics needed in repair of bows to reach deep down into cracks in risers. Just something to think about.
Viscosity Medium
Components One part - requires no mixing
Cure Humidity
Application Bonding
Key Substrates Wood, Paper, Leather and Fabric
(LOCTITE® 421™ is designed for the assembly of difficult to- bond materials which require uniform stress distribution and
strong tension and/or shear strength. The product provides
rapid bonding of a wide range of materials, including metals,
plastics and elastomers. LOCTITE® 421™ is particularly
suited for bonding porous or absorbent materials such as
wood, paper, leather and fabric.)
(PRODUCT DESCRIPTION
LOCTITE® 420 provides the following product characteristics:
Components One part - requires no mixing
Viscosity Very low
Cure Humidity
Application Bonding Key Substrates Plastics, Rubbers and Metals