Guy Rixon wrote:Blu-tac will be fine provided that you can remove it all afterwards. Anything left may stop the suspension from sliding freely.
A few vehicles ago, I was painting one with BB axleguards already fitted and not removable. (These days I use Carr's blackening solution on the brass and leave out the paint.) I wanted to keep the paint off the sliding surfaces, so I masked up with rubber masking fluid, sprayed primer and then, a day later, spayed black enamel. I was then restrained from even looking at the work while the Four Horsemen ran a gymkhana through my life. Two weeks later, I came back to the model, sitting in full sun on the bench where I'd left it. The rubber stuff had melted and run over everything, then apparently mutated like something out of the Alien movies. The rubber/paint/ick mixture would not shift out of the crevices cleanly, paint that I wanted to keep was abandoning ship all over, and the suspension wouldn't go because the "protected" sliding surfaces were clagged up. I ended up stripping the whole model with Nitromors.
Ouch, not good. I will check out the carr's stuff if all goes well. I will make sure to keep the blu-tack off the important bits and hopefully all will be good. I hate to imagine what it's like trying to spring a steam loco