Bruce Albert: Yellowing of odorless acrylic is usually due to contamination. Here is a list of possible causes:
• Not letting the primer dry fully before applying the product (if the primer gets blended in with the main product, yellowing is the result).
• Using more than one coat of primer.
• Mixing systems — using one manufacturer’s powder with another manufacturer’s liquid, etc.
• Using the same brush on your odorless product and traditional liquids.
• Using a dirty brush, dirty dappen dish, or dirty anything else. Old product should not come into contact with fresh product.
• Pouring used monomer back in the original bottle.