Thank you for supporting us with your use of Dupli-Color products. Having taken a look at your pictures and the description of the product I believe the following could be the problem. The key ingredient in DupliColor Adhesion Promoter is M.E.K. (Methyl Ethyl Ketone) which will work to chemically etch plastics to help with adhesion of paint. Think about PVC pipe primer and how it etches the pipe – this is the same product. The second product that you are using, Dupli-Color Bed Armor also uses M.E.K. as a thinner. In certain cases, when these two products are combined, the concentration of M.E.K. will be too much and cause the plastic to “melt” or as you said “stay gummy.” That “melted” plastic is now under the bed liner which will cause it to shift when you touch it, not dry, and peel off. Some plastics are more susceptible to “melting” than others. From the pictures you provided of your motorcycle parts, it appears that the plastic is very shiny and has a scratch resistant glaze that has been applied. Despite the plastics composition, these protective glazes are almost always a mixture of styrene and acrylic – two plastic types that are not compatible with higher concentrations of M.E.K.
You are correct in stating that the marketing team states “safe for all plastics” on the front of the cans. This however is accompanied with an asterisk that refers you to our website where you can find a complete list of plastics that this product is safe to be used with. Styrene and acrylic are not on this list.
My advise to complete your product would be to not use the adhesion promoter. I believe that less M.E.K. will not cause this problem. Another possible option is to strip your plastics and use primer on them to seal the pores and then use the bed liner. This may keep the M.E.K. off the plastic and thus, stop the reaction.
