I am going to strip the paint off of a Classic's Sunstreaker, and I was wondering how long I should soak the painted parts in 91% Isopropyl Alcohol. Last thing I want to do is ruin the parts.
I wouldn't soak it. It seems to make some plastic brittle. For example, my animated deluxe bumblebee's arm broke just pushing the balljoint back on. Just keep rubbing the parts you want to take the paint off. Eventually it will rub off. Even if you soaked it for days it still needs some friction to get it off.
The only problem I've had from soaking is the occaison fogged clear part, but future seems to take care of that. With that said, I never soak in alcohol for more than 24 hours, usually I can get away with 3 or 4 hours. If its not coming off by then, then alcohol is probably not going to take it off, there are a few parts like that, Classic Jetfire's red comes to mind. I usually have a jar of alcohol sitting on my workbench for random brush cleaning or parts cleaning. I use a cheap toothbrush to help clean my parts and I left the toothbrush in the alcohol for a long time, weeks. Well the alcohol is always evaporating away, but the toothbrush stayed covered. After a few weeks away from my bench I pull the toothbrush out and it was warped all to hell. I wish I had taken a picture of it. The plastic had also become very soft. That is an extreme case, but it happened.
I second that; the only real problem I've had is with leaving clear parts overnight; Classic Bumblebee and ROTF Sideswipes windows crumbled into pieces...mind you, once they were left to dry thoroughly, the clear parts that survived seem to get stronger again... I've never had any problems with non-clear sections though...
