Issue with Liquid Mask

[Wacker 2]

Hi guys, I hope somebody may be able to help...

A while back I got myself an airbrush to have a play around at spraying some shells... I got myself some liquid mask and all was great. But I wasn't doing any 'fading' with paint so only using solid colours with a nice clean design... as a result I sold the airbrush and have been painting with Liquid Mask and normal spray can paint.

The problem I'm having is that the paint doesn't seem to be sticking to the liquid mask very well... as a result, when you try and peel a peice of liquid mask off it doesn't break along the paint line and the liquid mask pulls out from underneath the paint. Starting to get on my tits as its causing a lot of inperfections in the end result.

I've tried Tamiya paint, and Fast Finish paint... tried applying thin coats and thick coats... tried drying with hair dryer, leaving on a radiator or just air drying between coats but nothing seems to work.

I've done a shell this evening and at one point I was able to peel a chunk of the paint off whilst leaving the liquid mask on the shell.

I've tried RCS Liquid Mask and Bitty Design Liquid Mask and both do the same.

Hoping somebody else out there has had a similar issue... any suggestions on what I'm doing wrong... or if its the paint I'm using is there any suggestions on which spray can paint is best to use... or a prefered Liquid Mask to use?

Many thanks for any help
Jon.