Gauge bezels

One of the jobs I have is to make some bezels for the gauges. I can't find any online for a decent price, but I also can't machine them. I'm heading for 3D printing, but I have trouble with the material and with the output. The prints are the right shape but usually a very uneven texture. For example, here is a raw PLA print;

The front face is as rough as it looks. This is also PLA which will melt and distort in a car. The latter is easy to fix, I have to print with ABS. I did have to do some messing around with bed adhesion, but managed to do an ABS print with no distortion;

So it won't distort in the car, but the surface is just as bad. 

To fix the surface, there are two options. One is to sand and paint, the other is to use acetone vapours to 'melt' the surface. This is a sand and paint;

And this is an ABS print after 5 hours of a vapour chamber;

It's quite clear to me that acetone wins by a country mile. It's nice and glossy, easy to do (just leave it alone for half a day!!), and repeatable. So I just need to adjust the print and then do the work. I did have high hopes for the sand and paint, but it's still just too rough to be able to sit in my line of vision every time I go for a drive.

I did note that even with the acetone, the surface isn't perfectly smooth. I think I'm going to have to adjust the print to get the front edge domed slightly, but also sand it a little bit. The sanding marks should disappear after the acetone does its job, but sanding will give it a head start and give me the best result. 

So I need to leave this one to solidify so I can inspect it a bit more, then print a few. Oh, and the vapour chamber I'm using is an opaque tub so I have to open it whenever I want to check it. And of course, every time I open it I release the vapour that had built up. I think for the final version I'm going to use a glass lid so I can watch it. 

(Update) after an hour or so, here's the acetone polished one in place on the rev counter;

I'm very happy with the result, just the profile to sort as it needs to host a plastic or glass face. Probably plastic to be honest, it's easier to get plastic of that size rather than glass.