I have problems with certain 3D printed models never seeming to want to dry--the paint stays tacky for weeks.

I have tried washing the model off first; that didn't seem to help. And it's not every model, just some of them.

It does seem like if I let the model "rest"/"breathe" for a couple of weeks after shipment before I start painting, it is less of an issue, like something is sublimating off.

Anyone else with this problem or tips? Is it a part if the 3-D plastic, or part of the process (a lubricant or wash)?

I have no idea why that's happening, but out of curiosity what brand paints are you using? Acrylic I presume--and are they any colors in particular? Metallic? Matte or gloss?

23 minutes ago, Force Majeure said:

I have no idea why that's happening, but out of curiosity what brand paints are you using? Acrylic I presume--and are they any colors in particular? Metallic? Matte or gloss?

Testors enamel, actually. And some by Model Masters. I use them on FFG models with no issues.

There was one that I had spray painted, and I thought it might have been something in the paint to aerosolize it. But all the latest has been brushwork. And it is a very inconsistent side-effect model-to-model. . .

Enamel paints have lots of weird stuff in them, it's possible that the paints are eating away at the 3D print plastic, since that plastic is pretty fragile.

Shapeways uses a powder-bed based printing method, so there may be chemicals in the plastic that the paints are reacting with. Perhaps the binders in the plastic (the glue that holds the prints together)?

I used Testors enamels for a bit and I was noticing that they ate away at the glue on models and took hours to dry, not to mention smelling terrible, so I switched over to acrylics.

IDK. I hate to be that guy whose advice is "buy different paints", but from my experience trying to make enamels work I'm thinking that might be your best option...

I had this problem in the past. It was with Modelmasters metallic paints. After many thoughts the only reason I could find was that I didn't use the correct thinner to dilute the paint. Never had the problem anymore when I used the Modelmasters thinner. And this was only the case with brushed on paints. When using the airbrush I've never seen this problem before.

It seems that you preparation is good. Wash the model in soapy water, then wash off the soap using plenty of tap water and leave it to dry. Preferably by air.

Then prime your model and put on small layers of paint.

In my teens, I used to use Testors enamels on my model kits. Clean up was smelly and noxious, plus it took hours to dry, especially when painting with glossy paints--I had so many fingerprints on my model cars from touching the paint to see if it was dry...

All that aside, I did have similar issues with tacky paint on certain models that came from Japan. In retrospect, it must have been a different kind of plastic than the Revel kits I was using.

When I switched to acrylics (Testors has some decent ones) I could get more done faster and was able to paint indoors.

Look into it. They aren't too pricey. You may just have to buy a few key colors for your 3d printed projects after all.

39 minutes ago, Kieransi said:

Enamel paints have lots of weird stuff in them, it's possible that the paints are eating away at the 3D print plastic, since that plastic is pretty fragile.

Shapeways uses a powder-bed based printing method, so there may be chemicals in the plastic that the paints are reacting with. Perhaps the binders in the plastic (the glue that holds the prints together)?

I used Testors enamels for a bit and I was noticing that they ate away at the glue on models and took hours to dry, not to mention smelling terrible, so I switched over to acrylics.

IDK. I hate to be that guy whose advice is "buy different paints", but from my experience trying to make enamels work I'm thinking that might be your best option...

Hmm. This has almost seemed like that on a couple of models. But then, only in 1-2 spot on that model--the rest of the model was fine. Never a smell issue, though.

There has got to be some sort of chemical interaction going on. . .

Yeah, I guess could buy different paints. Don't know why, but I've always been a fan of enamel over acrylic for handling and coverage. And you don't have to seal enamel with a finish, so I guess it always seemed more durable.

After painting a lot of different resins/plastics, my number one rule is to wash any unknown/new material throughly. I will wash it with warm water and dish soap, soak it in the soapy water in a minimum of overnight, then use an old toothbrush to scrub, then rinse. This process tends to remove any mold release agents that may be present.

Are you using a primer or undercoat at all? I know that some plastics, like Reaper's Bones plastics, seem to have an issue with spray primer curing and constantly feel tacky until moe painting is done.

4 hours ago, Ikka said:

Are you using a primer or undercoat at all? I know that some plastics, like Reaper's Bones plastics, seem to have an issue with spray primer curing and constantly feel tacky until moe painting is done.

No. I usually don't prime stuff, and 99% of the time it is not an issue.

I had considered that this might be one solution, but then wondered if chemicals were chemicals, and it wouldn't matter.

Secondly, I live on the 6th floor with no good place for spraying paints. And I'm worried brush priming will only cause inconsistencies and loss of detail.

I have also had similar issues. For me it was a spray can primer on reaper bones miniatures.

They are still sticky after 3 years.

On 12/6/2018 at 3:08 PM, Velvetelvis said:

I have also had similar issues. For me it was a spray can primer on reaper bones miniatures.

They are still sticky after 3 years.

This is a known issue with the Bones material specifically, it shouldn't affect x wing minis,

a lot of plastics and resins have a "cure time" during which they are more chemically active, but its hard to say if thats part of it without knowing the type of printer and whatnot. some resins the cure time is many days, but they also set reaaally slow so probably not what youve got in those models

its more likely testors paint just sucks.

I used testors for over a decade for work and my Doctor thinks it might have caused the chronic health issues im having now. theyre not only a carcinogen but the fumes can cause blindness and other organ damage.

also, i ruined my first IG2000 using testor enamel paints so im a little salty. switched to acrlics and havent looked back!

On 12/14/2018 at 8:59 PM, Vontoothskie said:

a lot of plastics and resins have a "cure time" during which they are more chemically active , but its hard to say if thats part of it without knowing the type of printer and whatnot. some resins the cure time is many days, but they also set reaaally slow so probably not what youve got in those models

Yeah, I strongly suspect this is the problem. I might just buy stuff and let it sit a couple weeks before painting, and see what that does.

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also, i ruined my first IG2000 using testor enamel paints so im a little salty. switched to acrlics and havent looked back!

Odd. I haven't had any issues on FFG models at all.