Painting Sedition Wars bases?

[Predatorpt]

Yesterday I started painting a random figure I had here at home, just to get away from all the GW stuff I've been doing. It was mounted in a plastic Sedition Wars base and primed with my primer of choice (Tamiya Grey Primer), the one I use when I don't want to break out my airbrush.

All was well until I noticed that the primer in the base was scrapping away with the touch of my fingers while I painted.

I checked and the same didn't happen with the mini, just the base, so I'm wondering if the problem isn't with the base itself. Is it really plastic or some kind of plastic resin that needs to be washed like real resin? 

[Major_Gilbear]

The plastic is different, any may be more resistant to the solvent in the spray primer (which is usually strong enough to etch the plastic's surface and therefore bond the primer).

It's also possible that it may exude very small amounts of oil, or still have release agent on it from moulding.

I would suggest scrubbing the bases with a stiff brush and some ethanol, and then using some extremely fine sandpaper (or an emery board for ladies' nails) to provide a key around the base rim for the spray primer to form a good bond on.

[Predatorpt]

The plastic is different, any may be more resistant to the solvent in the spray primer (which is usually strong enough to etch the plastic's surface and therefore bond the primer).

It's also possible that it may exude very small amounts of oil, or still have release agent on it from moulding.

I would suggest scrubbing the bases with a stiff brush and some ethanol, and then using some extremely fine sandpaper (or an emery board for ladies' nails) to provide a key around the base rim for the spray primer to form a good bond on.

Yeah, I'll drop them in my sonic cleaner for starters and then they'll get the sandpaper treatment. The plastic really feels strange. Thanks!

[Major_Gilbear]

Another thing to try perhaps is putting some acetone on a lint-free rag, and rubbing the base edges smooth and clean before priming. That should work quite well as long as you're not soaking the bases in the acetone!

[rumacara]

Rodrigo, some plastics still have remnants of the solvent to remove  from the moulds (Miniart plastics are a real nasty example) so they need to be washed first with hot water and if you have blue soap use it.
Or the tips already given.
Tamiya primer is one of the best i know and it addheres literal in almost every material (i use it on my plastic and metal miniatures).

[Predatorpt]

Thanks for all the input! The bases have been taken for a ride in my sonic scrubber, I'll try and paint them this Thursday and update the thread.