The issue of shiny residue (the plasticizer mentioned in other responses) is an old problem. Back in the '60's and 70's, when dinosaurs walked the Earth, modelers who wanted to paint up the Airfix 1/32nd scale vinyl figures encountered this issue, and the solution at the time was to add a barrier coat of thinned PVA glue (white glue). This allowed them to paint the figures using Humbrol enamels, without the paint going shiny over time.
We also had the problem of vinyl and styrene reacting chemically. The 1/76th scale Airfix tank kits circa 1970 were known for their "rot-a-tracks" which would attack the styrene road wheels before turning into a sticky mess in short order. Airfix reformulated the vinyl after customer complaints, and the problem disappeared.
There have been frequent problems with Italeri's vinyl tires attacking styrene over the years, but again, the formulation problem appears intermittent, affecting some product runs while others are unaffected. The solution there was either a barrier coat, or a literal barrier, using Bare Metal adhesive aluminum foil on the tire rims to prevent the styrene and vinyl from touching. Curiously, the vinyl used on Italeri tank track was completely inert (at least in my experience).
I have never had a problem with the Tamiya vinyl track, though the glueable vinyl-styrene blend Tamiya introduced in 1997 is much less reliable, as it crumbles when exposed to enamels or lacquer thinner, and can break spontaneously where it has been bent (even in the box).
Dragon DS styrene hasn't degraded on any kits I've built or have in my stash, but the litany of problems seems to be increasing of late, and suggests a quality control issue with their suppliers, as others have mentioned. The only sure workaround would be after market styrene, resin or metal replacements.
|This message has been edited by GeraldOwens from IP address 126.96.36.199 on Sep 6, 2017 3:28 PM|