I kind of skimmed the replies, but I wanted to touch on one term I saw the OP use.
Rubbery
If you are using an acrylic paint that is designed for clothing, or lexan, or any other flexible surface, you are buying a paint that i will cure "rubbery" because it needs to cure flexible in those applications. I can't say for sure your paint is like this, but when I hear "craft store acrylic" and "cured rubbery" I have a feeling this might be what is going on.
Strip the paint and start over. For acrylic paints I use LA's Totally Awesome. That stuff works great and will strip acrylic paint in minutes.
After you strip the paint wash the parts in soapy water to remove any leftover Totally Awesome.
Then I recommend a paint that might be better suited to the application. If you want to stick with low odor, try Tamiya X or XF line of acrylic paints. They have some solvent in them so there is a little odor, but they can be used inside.
To thin the X or XF paints, you can use Tamiya acrylic thinner. If you can use something with odor, like you have a way to ventillate, then get some Mr Leveling Thinner from Mr Hobby. Tamiya paints love that stuff.
I will get bad remarks about this, but you can thin X and XF Tamiya paints with water. People will disagree, but it works. This will keep the odors down if you don't have ventillation.
Another option for low odor acrylic paints is the Createx line. They are available in craft stores, art supply stores, and Hobby Lobby. They are acrylic and low odor and have a nice gloss clear to put over your paint.
I appreciate the thoughtful reply. Gone are the days when we had only one source of paint in the little carboard box with the variety of enamels. i know they are still available but im a little more choosy now. Thinning for airbrushing is something i am tackling now im looking for a pdf i can print as a handy source for hobby paint and thinning. I am leaning toward Craftex and Model Master since i have quit a large collection of MM from my other hobbie.