Static Paint Problem !?

[norscout]

What happened here? How best to fix this? How to ensure this does not happen again?

I primed this model yesterday and got the ugly result seen in these close up photos, about 3" of surface.
I've seen this happen once before. It appears to be static electricity on the surface messing up primer layer.

After sanding I swatted and wiped surface with an old t shirt rag. Then I wiped clean the surface with odorless mineral spirits, also on an old cotton t-shirt rag. I let dry completely before spraying rattle can auto primer. Model was sitting directly on folded up cardboard on my truck tailgate. The cardboard has been used many times for spray painting and has accumulated paint on it.

I'm thinking I got static electricity on the model surface. Perhaps using the cotton cloth rags caused it, or do you have ideas or answers to this mess?

Thanks for any suggestions or advice.

 

[joberg]

Happened to me...once I used a damp rag (those micro ones for detailing your car) and the problem was solved.

 

[norscout]

Know of any good videos or tutorials on model prep best practices for painting?

 

[joberg]

Know of any good videos or tutorials on model prep best practices for painting?

Depends on the medium and the context. As prep/painting 101 is concerned, cardboard will have to be dusted very carefully before painting.
No need to say that any paint booth or others have to be clean (not hospital clean): no dust flying while you're spraying.
Do be careful, also, with platform/bases used on which you put on your model. These can be generating dust as well.
Plastics also have to be dusted/or damp rag trick before painting. Last, but not least; if you don't have a proper spray booth, the overspray can also leave paint dust on your painted or unpainted surface.

 

[norscout]

I wet sanded it and it's all good now, but I'm puzzled at how so much static got on the model. I guess it was the cotton cloth.
I like spray painting outside and often just throw cardboard on my tailgate and spray no problem. The tailgate has a spray on liner, but I wonder if somehow the truck battery can cause static charge on a plastic model on the tailgate.

 

[Sluis Van Shipyards]

I had luck with wet sanding then wiping it with a wet cloth. When I built my SW Chiss fighter years ago, I had dust where the wings angle out at the base. I Googled it and figured out certain areas can cause little vortices that cause the paint to dry before it hits. I've never ever seen that happen ever. I'm not saying it's that, but it's another weird thing that can happen.

 

[JediMichael]

That happened to a star destroyer I built out of cardboard years ago.
I figured it had to do with the fact that I bought super cheap walmart spray paint onto the cardboard. That was probably part of it, but I never actually thought of static being an issue.
Figured it was more dust, also probably true. As back in 2007, I wasn't nearly as experienced as I've become now.

 

[joberg]

That happened to a star destroyer I built out of cardboard years ago.
I figured it had to do with the fact that I bought super cheap walmart spray paint onto the cardboard. That was probably part of it, but I never actually thought of static being an issue.
Figured it was more dust, also probably true. As back in 2007, I wasn't nearly as experienced as I've become now.

High quality cardboard is the key for sure. It can be painted with your regular spray-cans or airbrush (acrylic/oil paint).

 

[JediMichael]

High quality cardboard is the key for sure. It can be painted with your regular spray-cans or airbrush (acrylic/oil paint).

Yeah. All the cardboard was random pieces from around the house. Some from the neighbors who was throwing ot out. That was back in 1995. I was just excited to be making it.

 

[norscout]

Do we think old cardboard with lots of accumulated spray paint can cause static buildup that gets on the model?

 

[srspicer]

As stated above, wet sanding is the key. I have found that wet sanding and then letting it air dry before priming works best. Prime it, wet sand it and let dry over night or all day. Then prime again. Most of my static issues were gone using this method.

 

[JediMichael]

I've actually never tried wet sanding but have heard of it.

 

[Captain Dunsel]

Lightly blasting the model with an air-hose or even an air-can goes a long way towards removing particles and achieving a good finish before you paint.

Tack cloth is also your friend, in terms of removing any cloth/dirt/cardboard remnants, etc. before you paint.

 

[joberg]

Do we think old cardboard with lots of accumulated spray paint can cause static buildup that gets on the model?

Never happened to me

 

[joberg]

As stated above, wet sanding is the key. I have found that wet sanding and then letting it air dry before priming works best. Prime it, wet sand it and let dry over night or all day. Then prime again. Most of my static issues were gone using this method.

I wouldn't try wet sanding on cardboard...even with many coats of primer/paint.

 

[srspicer]

Looks like here is plenty of primer over the cardboard. You don't have to soak it, just a small amount with the sandpaper and mop up any extra before it get to the back side.