Removing paint

[Canadian Atlantic Railway]

I have several Walthers two bay aggregate hoppers that I stripped awhile ago but some paint was left on the outside on both ends of the cars. It is hard to get anything in there to scrape and I came across a grit blaster I had bought and there was some unknown grit with it. What would be a good medium to use with the blaster that will take paint off but not eat into the plastic?

[doctorwayne]

You could try ordinary baking soda - I've used it to etch the surface of Delrin truck sideframes to improve paint adhesion. You might want to wear a paper dust mask, but I also suggest that you work outdoors. You should be able to create a temporary blasting booth in the nearest available snow bank.

Wayne

[Canadian Atlantic Railway]

Thanks Doc! I figured it would be a job best done outside. What is a good psi to start at?

[doctorwayne]

Hmmm....good question. I used a regular sandblasting outfit, with a grit cup about the size of the container used for spray painting (not airbrushing). I wore a leather work glove to hold the trucks, and worked at about 60-75psi, I think. For styrene, which is softer than Delrin, try starting at about 50psi and and then crank it up as necessary. At least with something the size of a freight car, there's no need to get your hand too close to the work area.
I've since purchased a Paasche Air Eraser, but have yet to use it. I got some aluminum oxide grit to use with it, but, obviously, can't comment on its effectiveness - probably too much for paint removal.

Wayne