I am currently working on painting my locomotive fleet. One of the difficulties with custom painting a locomotive is getting the paint to stick to the handrails. Many manufacturers use a different type of plastic for the handrails, from acetyl to celcon, but they all have the same issue, the paint just does not stick well to the slippery plastic and easily flakes or chips off. Some modelers have found success with using Pactra Racing finish paint made for flexible model racing car bodies, but not all colors are available and the paint can be difficult to find. Fortunately, a friend of mine Steve that has done a great deal of custom locomotive painting, recommended a product that would help solve my problem.
The product is Automotive Primer Adhesion Promoter, sold at auto parts stores. I purchased the Dupli-Color brand at a local NAPA auto parts store. The product is a clear primer that improves paint adhesion to plastic, vinyl, and chrome. The instructions indicate to spray a couple of light coats and then follow up with the top coat within ten minutes of the last primer coat. I decided to give it a try and see if it worked.
I first cleaned the handrails with a light alcohol wipe and then allowed them to dry. Once dry, I placed them on a piece of cardboard, holding them in place with a piece of inverted painters tape. I sprayed the one side with the adhesion promoter and then quickly followed up within a few minutes with a light coat of Tamiya fine surface primer. The Tamiya paint is reported to be the best paint for handrails. Once the primer dried I followed up with a top coat of Tamiya spray paint for plastics TS-16 Yellow. Once the one side was dry, I flipped the handrails over and repeated the process.
One previous locomotive painting projects I did not use the adhesion promoter and had issues with the paint easily flaking off the handrails. With these handrails painted with the adhesion promoter I was able to handle them and attach them to the locomotive without any paint flaking off. Wow, what a difference.
Following Steve’s advice, I hope you give this product a try on your next locomotive handrail painting project, I highly recommend it.