Paint not sticking

[Guest]

Hello

Can one of you experts please advise me. I airbrushed with Vallejo primer yesterday and, as always, it gave a good coat. I masked part of the surface with Tamiya tape as usual. I sprayed an acrylic colour onto the unmasked area and this was fine. But when I removed the tape, some of the primer came away too. I've not had this before, that I can recall anyway. What could be the cause please?

Thanks, as always.

[Alan 45]

I would say a finger print , the skin has oils and sometimes it can stop a pain from sticking , other reasons are humidity and heat can also do the same.

[Guest]

Thanks for replying Alan. It won't be finger prints. I always clean the surface with isopropyl and I always wear a glove on the hand I use to hold the model while spraying. I suppose it could one of the other two factors you suggest.

[Alan 45]

Glad I could help , I have had another thought , could the primer been a little thick on the masking tape? If so it could just have dried to the tape and pulled off when you removed the tape , I've done that a few times when I've masked up , I remove the tape as soon as I've painted now

[BarryW]

How long did you leave the primer to cure before masking? ideally I leave it 24 hours but a bit longer when humid.

[Ian M]

Barry beat me to it. I too would of said that a "good coat" of primer would need a couple of days to cure.

Been there done that. Its a pain init

[Guest]

I left it 24 hours gentlemen, I suppose I must be more patient though 'patience is for the dead'

Thanks for all of your input. I've stripped it and will re-prime and leave it for 48 hours.

[Andy2035]

Hi Adrian,

I had a similar problem a while back when I was trying to paint one of my die-cast cars, I tried leaving it for just over a week and yet it still did the same thing, finally the only way I managed was to build the coats up slowly, each one was a mist coat and I left it for a good couple of days between each one...

Another thing, how long have you had the primer, you could try dropping Vallejo an e-mail via here...: - http://www.acrylicosvallejo.com/en_US/contact

Explain to then what you have done/tried etc and see if they can come up with anything, they are really helpful and friendly...

Andy...

[Guest]

How did you prepare the surface Aidan ? I always wet & dry with 1200 or 1500 before applying any paint to a plastic surface so that the primer can bite.

Also you say you gave it a good coat. I first, with primer, apply a mist coat well diluted say 60 30. Then I apply a full coat of primer but still say 10% thinners.

Leave about 12 hours mist coat & full coat then a good 24 hours drying. I have never masked primer. I put the main finishing colour on first overlapping the area of demarcation for the adjoining colour. When that is dry then I mask over the finishing coat.

Thinking about it not a good idea to mask over priemer at all as it is not such a fine coat as the top coats. I would also think you can get creep under tape as you will not get such a good seal with primer.

Laurie

[Guest]

I prepared the surface in my normal way Laurie. I think masking it was the problem. I had not masked primer before. Still a learning curve.Thanks to all who have offered suggestions.