GW Primer eats Plastic!

[Oxygenthief]

I have been painting for a long time and using GW primer for awhile now and I have noticed that GW primer eats the older plastic on GW models. I had some of the original Plastic SM bikes I finally got around to painting and when I got through vigorously shaking the can I sprayed the models only to find the platic melting under the primer. I have also noticed the melt on a land raider I painted. Originally I thought it was a chemical reaction with the plastic coating that is barely visable on the surface of the model so I cleaned the thing in a mild detergent. That doesn\'t solve the problem it still eats the plastic. Does anyone know how to stop this from happening? Or has anyone experienced this besides me?

 

[finn17]

Plastic eating primer

I haven\'t come across this before personally. I believe the GW blurb states that their primer has a \'keying\' effect which all good primers should have, but that doesn\'t mean that it should eat plastic!
It wont be the paint which is doing the damage but the solvent carrier. This leads me to ask: Are you possibly spraying too thickly or from too-close a distance? Ideally, most of the solvent should have virtually evaporated away by the time the paint hits the mini.
If spraying thinner and from a greater distance does not solve your problem, it does indeed look like the primer is incompatible with older plastics.

 

[Oxygenthief]

I don\'t think its the distance or the coat.. a thin layer started the melting on a different bike model all togethor. In addition I haven\'t had any trouble with the new marines or other plastics except small sections on a Land raider and it actually vanished with a little sanding and some regular paint. So it probably is the solvent carrier. Thank you for the imput.

 

[AntonA]

Yeah something like that happened to me. One time I had the smart idea of priming a squad of plastic terminators while it was raining. To make a story short, the humidity did something and the primer ate away at at all the detail. Perhaps it was raining or just very humid in your case as well?

 

[mountie]

I\'ve had the exact same problem,
:flame: as have many of the painters in my area. Finn is right on when he mentions the solvent carrier.

But I\'ve used it on some other styrene, tamyia model kits etc, and the plastic hasn\'t \"krinkled\" like GW\'s. This has led me to the conclusion that GW is using a really low grade of styrene.
This plastic appears to have been selected to make it easier for the kiddies to cut than to be durable or even resist the solvent in thier own brand of primer.

My solution-buy rackham-

 

[Ebonbuddha]

Amen.

The samething happened to me. I bought six new Vypers and primed two of them. The samething happened. It started to bubble. I washed two more and let them dry overnight. The samething happened. This has never happened before. They could be using a lower grade styrene it to make it easier for the younger hobbyist. Or they could just be using a really low grade syrene to cut cost to make more money.

Originally posted by mountie
But I\'ve used it on some other styrene, tamyia model kits etc, and the plastic hasn\'t \"krinkled\" like GW\'s. This has led me to the conclusion that GW is using a really low grade of styrene.
This plastic appears to have been selected to make it easier for the kiddies to cut than to be durable or even resist the solvent in thier own brand of primer.

My solution-buy rackham-

 

[JakeTwoTonCommon]

Yuuup

Could be worse I live in the swaps of Florida so for me I have to base everything by hand, its always to humid outside :|~

 

[MaestroOfMayhem]

Try an enamel primer, I like testors but it is a little more expensive. I would use it anyways for space marines. Enamel primers are often smoother, they have less grit and fit tighter around the models. You cannot reverse the melt, but you can complain to GW, I\'m sure someone there will help you (eventually).