Is it me or is it the occasional kit?

[Danny]

A wee bit of advice needed please....Ive completed 6 planes since my return to the hobby, a couple of 1/:72 scale being used only to increase my airbrush skills.

What Ive noticed though is this... Different kits hold paint better than others. Ive tried halfords spray primer and valejo primer and the effect on 2 of the models

has been the same, the paint is very easy to scrape back off !.. I wash the kits with water and washing up liquid, let it air dry, prime then paint. This is the same

process I used on the first 2 kits but I brush painted them and didnt have this problem. Is there a trick to keeping a well earned paint finish or is it hit and miss?

I dont have long nails, leave each coat 24 hours and 1 of the problem kits shed paint after a coat of pledge....any suggestions most welcome..

Thanks and regards Danny

 

[BarryW]

Danny, try wiping the models over with alcohol ( ipa ) instead of the soapy water. Some people also run over the model with a very fine sanding sponge as well, before the alcohol wash. I don't do the latter and never have the problem you describe after curing for 24 hours. Could it be that your humidity means a longer curing time is needed?

 

[CDW]

I don't know much about differing kit manufacturing processes but i would imagine that theres a difference in the plastic they use and any chemicles they use in the moulding process so this would give the issue you are having.

On the subject of painting and preparing which i know a little more about......

A lot of people thing that if they prime a surface it'll be fine for the paint, this isn't true as the primer will not stick to a dodgy surface either, primer also needs a keyed surface to stick to.

True Primer (not this cheap grey paint you get) is technically only a thin filler to be sanded down to give a very smooth surface for the paint to lay on.

To get a good surface for the primer to stick you'll need to have a keyed surface, as Barry says above this really needs to be in the form of some delicate sanding procedure as just washing the oil off sometimes isn't quite enough as the plastic surface could be holding back some oil/releasing agents.

My method (which is in no way definitive but works for me) is to give each of the parts a good shake in some bird grit in a jar (Laurie calls this the Grit-Colin method and there's a thread in the tips section ) this will cover the whole surface with minute scratches and eradicate any oils on the surface, it doesn't get rid of any detail if you don't go too mad with the shaking.

I never use primer but use a slightly thinner version of the colour i'm using (acrylics) as the first primed coat, it seems to work the same as primer and i can see any issues with the surface that need addressing.

Thats my 2p's worth, for what it's worth

 

[Danny]

Thanks for taking the time to respond guys...appreciated. To be frank, I never thought about the fact that primer would need a keyed surface, but instead that primer would add a keyed surface for the first coat of paint.. !!!!

Love this forum, advice on the simple processes and correction to your own thoughts is priceless..

Danny