I've heard rave reviews about the Vallejo primer, so tonight I finally tried some out. Sprayed like a dream! No thinning, went on wonderfully.

I noticed a few blemishes I'd missed and so I went to scrape them off with a knife...only to discover that the paint simply peeled off like it was a sticker, stuck on with loose adhesive... The figured I'd sprayed were cleaned, so there shouldn't have been a bunch of oil or gunk that caused this. Certainly the "can't fix problems after priming" isn't the downside to this great spraying primer??

Paints like Vallejo Model Air and Lifecolor are "vinyl" acrylics. They dry is a rubber like sheet, almost like a skin. It is very possible that the primers dry the same way.

The ones in the large bottles are marked Polyurethane....

I've had similar adhesion probs with certain plastics, so have used Future as a thinner witch had the effect of 'hardening' it, making it more 'sticky' & a bonus of making it far more amenable to being reworked & sanded, etc.

As ever your mileage may vary & test it on a hulk first.

When I tested Vallejo Primer on different materials I came to these conclusions.

Spraying on Polystyrene. Sits well after about 8 hours.
On resin, leave to dry at least for 24 hours preferably 48 hours.
White Metal. Give it a week to dry.
Photoetched brass. Two thin coats, the second after the first one has dried. Then give it 3-4 Days.

Given this, Vallejo Primer sits very well. You cant scrape it with our Nails. I had to use a screwdriver when testing. And of course you can also sand it.

Its also a good idea to warm the bottle in warm water and remember to have higher airpressure, 50-60PSI, than normal.

Vallejo Primer is also brushable and shrinks when drying. So dont worry to much if it comes on a Little bit too much.

It is very similar to Citadel Primer, except in drying time and smell.

Cheers