Chaos Black undercoat melting plastic?

[Brother_Ovis]

In short - I had two Land Speeders, undercoated them with Chaos Black primer. One turned out fine, the other one got a very fine grain on most surfaces, kind of like the plastic 'curdled'. I thought that maybe it's some fault of the model itself, or maybe it got that way when I tried to heat it up with a hair dryer to bend it to shape, but today I got a Predator tank I bought used online and it's got exactly the same grain on some surfaces, and it's undercoated black. I don't suppose that previous owner was also trying to heat it up for some reason, which made me think it's some fault of the primer. Propellant, maybe? What do you think? Have you ever had similar problems?

[daveclark890]

It does happen some times, it has something to do, I believe with humidity and the mixture in the can at the time of spraying. You could always strip it off and reapply.

 

What exactly were you trying to do with the hair dryer and trying to bend the speeder? (just curious)

[Brother_Ovis]

It does happen some times, it has something to do, I believe with humidity and the mixture in the can at the time of spraying. You could always strip it off and reapply.

 

I tried stripping the paint, but it's not that. It's the plastic - it's obviously damaged.

 

What exactly were you trying to do with the hair dryer and trying to bend the speeder? (just curious)

 

It was the previous version with the top part not really aligned with the bottom part, which resulted in two gaping holes on the sides (you can see it on some LS photos in the SM codex). I figured that if I heat the plastic a little it will become softer and will bend to shape, like it works with resin casts. For the record - it didn't :wacko:

[RebG]

It's much more likely to be the way you've sprayed it than a fault with the spray paint. As you can see one Speeder has come out fine so if it was 'melting' the plastic due to a fault it'd happen to both.

I've had a slight graining before. It's annoying but I believe it's usually down to atmospheric conditions like humidity or air temperature or the fact that you are too close or too far away. Something along the lines of; too close and you get too much paint causing it to dry unevenly, too far and the paint, especially if it's a bit warm, can start to dry before it hits the model, I believe that's what usually causes the rough effect.

Also, you can try stripping it but I've tried 4 different cleaning products so far and never got black primer off plastic properly.

[puck]

There's a tutorial up on fromthewarp about how to prime modals. In it he mentions this exact problem is caused by holding the can too far away from the model while spraying. After some google-fu the best scientific reason I could find was that this results from the spray paint partially drying/separating mid flight to the model.

[Brother_Ovis]

Thanks for your replys, but you all are missing a point: the grain isn't in the paint, it's a surface damage to the plastic.

 

Of course it doesn't have to be the primer's fault at all, I just can't see any other culprit.

[madscuzzy]

Yes what they are saying it not what you are intending. Your is the result of the thinner in the spray eating away at the plastic. This happens when the model is sprayed too closely or when there is too much thinner in the spray paint. This happens when using some cheap industrial spraycans or if the thinner and paint do not mix properly in the can. While it is some work you can try to get the surface back with some fine sandpaper.

[Elric the Silvercoat]

Yea I have had this same problem with one of my Jump Packs I sprayed all of five Jump Packs and was getting to the end of the spray's propellant on the last Packs and now the Jump Pack looks like I baked it. Its like what madscuzzy said, its the thinner in the spray that eats the plastic.

[Brother Immolator]

To the OP:Propably you sprayed it too close.All the guys i buy primers have the habit of telling not to spray to close and i guess they are right.

 

TO RebG:Use white spirit it gets the paint to somehow 'unbind' from the mini.Just keep it outside or in a well aired room cause the stuff really stinks and it cant be good to breath it.