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Every now and again I run into this issue with particular models: As I paint them a fine particulate seems to emerge on flat surfaces and in corners. By the time I'm done painting, it's like there are no smooth surfaces left on the model. This is becomes especially apparent when models are photographed, but it is still quite apparent to the naked eye. It's like the model is dusty, sandy, or... crumbly?

My first instinct is using reconstituted paints, and I definitely do see more of this when a a paint jar is particularly haggard. But it's certainly not unique to old paint. It could be that there are multiple causes; I'd like to isolate and treat all of them.

Could it be old primer?

Could I be applying primer incorrectly?

Could it be actual dust? Either getting locked in when I prime or as I paint each layer over the course of a few days?

Does building process play a role? If I file something down should I be spending more effort polishing afterwards?

Could it be paint drying out on my palette as I use it? I find GW paints tend to dry out faster than I remember them drying out when I was a teenager. I used to brush paint onto a palette and combine it with water to varying degrees as needed depending on what I'm doing. I find now that this is almost impossible and by the third time my brush goes to the palette the paint I left there is useless. I now pretty much draw paint straight from the can.

That's everything I can come up with. Any and all insight would be appreciated.

I have no idea what you're trying to describe my friend. Maybe some photos with examples would make diagnosing the problem easier?

you seem to know a lot of places it could be coming from, you just need to start eliminating/changing one step at a time to figure out where it is be coming from.

id guess maybe its primer drying before it hits he model from spraying too far back.
id start a wet palette too and clean brushes and water pot

 DaRealJDB wrote:
Every now and again I run into this issue with particular models: As I paint them a fine particulate seems to emerge on flat surfaces and in corners. By the time I'm done painting, it's like there are no smooth surfaces left on the model. This is becomes especially apparent when models are photographed, but it is still quite apparent to the naked eye. It's like the model is dusty, sandy, or... crumbly?

My first instinct is using reconstituted paints, and I definitely do see more of this when a a paint jar is particularly haggard. But it's certainly not unique to old paint. It could be that there are multiple causes; I'd like to isolate and treat all of them.

Could it be old primer?

Could I be applying primer incorrectly?

Could it be actual dust? Either getting locked in when I prime or as I paint each layer over the course of a few days?

Does building process play a role? If I file something down should I be spending more effort polishing afterwards?

Could it be paint drying out on my palette as I use it? I find GW paints tend to dry out faster than I remember them drying out when I was a teenager. I used to brush paint onto a palette and combine it with water to varying degrees as needed depending on what I'm doing. I find now that this is almost impossible and by the third time my brush goes to the palette the paint I left there is useless. I now pretty much draw paint straight from the can.

That's everything I can come up with. Any and all insight would be appreciated.

Right. Acrylic paint is plastic. It does not dissipate static electricity very well.

The act of swiping a brush across a surface creates static electricity. Particles from the air will be drawn to the surface of a model as you paint. The most common one is dust, it sounds like you have a lot floating around in the air. Dust is weird, it globs onto other particles and fibers to create larger particles. This is probably what you are seeing, will look like tiny bumps in irregular patterns on the surface of every model.

You can't avoid dust unless you work in a clean room, but you can control the amount in the air. To diminish it:

1) Do not use nylon brushes, use sable. Nylon is probably the best plastic insulator, which means it's going to create the most amount of static.

2) Get a hepafilter to clean the air.

3) Recirculate air. Keep a window open, run a fan, do anything that moves air out of the room.

4) Change your air filters on your HVAC and get your ducts cleaned. If you live in a place that's 20+ years old and you have not cleaned the ducts, your AC and heating is probably pushing a ton of dust into the air.

5) Suspend a couple pairs of socks in the air. Old art school trick, you can rub them against plastic and to pull dust from the air.

6) If you have shag carpet, cover it with an area rug. Carpet fibers degrade over time and will get into the air.

7) Run a humidifier. Humidity can weight down dust particles and keep them from ruining your models.

8) If all else fails, build yourself a clean room. Put up some walls in a corner of your basement, build in a fan / air filter, and seal the thing. Some places simply have too many environmental factors to control.

 techsoldaten wrote:

 DaRealJDB wrote:
Every now and again I run into this issue with particular models: As I paint them a fine particulate seems to emerge on flat surfaces and in corners. By the time I'm done painting, it's like there are no smooth surfaces left on the model. This is becomes especially apparent when models are photographed, but it is still quite apparent to the naked eye. It's like the model is dusty, sandy, or... crumbly?

My first instinct is using reconstituted paints, and I definitely do see more of this when a a paint jar is particularly haggard. But it's certainly not unique to old paint. It could be that there are multiple causes; I'd like to isolate and treat all of them.

Could it be old primer?

Could I be applying primer incorrectly?

Could it be actual dust? Either getting locked in when I prime or as I paint each layer over the course of a few days?

Does building process play a role? If I file something down should I be spending more effort polishing afterwards?

Could it be paint drying out on my palette as I use it? I find GW paints tend to dry out faster than I remember them drying out when I was a teenager. I used to brush paint onto a palette and combine it with water to varying degrees as needed depending on what I'm doing. I find now that this is almost impossible and by the third time my brush goes to the palette the paint I left there is useless. I now pretty much draw paint straight from the can.

That's everything I can come up with. Any and all insight would be appreciated.

Right. Acrylic paint is plastic. It does not dissipate static electricity very well.

The act of swiping a brush across a surface creates static electricity. Particles from the air will be drawn to the surface of a model as you paint. The most common one is dust, it sounds like you have a lot floating around in the air. Dust is weird, it globs onto other particles and fibers to create larger particles. This is probably what you are seeing, will look like tiny bumps in irregular patterns on the surface of every model.

DUDE!! THANK YOU.

I have witnessed exactly what you describe. I couldn't even put words to the behavior because my brain didn't even know that was physically a possibility.

Amazing suggestions. I will be implementing them.


Automatically Appended Next Post:

 queen_annes_revenge wrote:
I have no idea what you're trying to describe my friend. Maybe some photos with examples would make diagnosing the problem easier?

It can be seen really clearly in the full-size gallery photo from my current WIP:

https://www.dakkadakka.com/gallery/1056511-.html

That does not look like dust that's landed on the painted surface, but the paint itself that's going bad.

 Agamemnon2 wrote:
That does not look like dust that's landed on the painted surface, but the paint itself that's going bad.

Understood. I just got another batch of paints in. I'll keep my eye out for the performance of the older ones vs the new ones.

I had this problem a lot using Citadel Zandri Dust spray. It was brand new. Don't prime in dry air and make sure the can isn't too far away. Hope this helps!