"Washing 3D printed models before priming????" Topic

So this just came across my radar on Google AI.

As of 2025, my general practice for modeling is to wash metal and resin models always. Mild soap/detergent and warm water.

I don't wash plastic models as a general rule, be they like fantasy models like Warhammer or military models. Never had a problem with adhesion.

With the advent of 3D printed models, which I began to purchase and paint around 2020-2021, I have never as a general rule washed 3D printed models as they don't come out of a mold, since they don't use a mold process! And therefore don't use mold release agents since there's nothing to be released, etc.

Which begs the question, what exactly would be the reason to wash a 3D printed model before priming?

The AI, along with a number of modeling forums, mention washing RESIN 3D printed models but not washing FILAMENT 3D printed models.

To be honest I never even bothered to find out the difference. All I know is, some 3D printed stuff seems to be sturdier and feels somewhat like toy or styrene plastic when handling it. Others seem more brittle, and thinner parts are sometimes almost as fragile as dry spaghetti strands.

But in either case, I never washed either type, and never had any adhesion issues with primer or paint. In fact, in ten years of priming, I had ONE model that had a true adhesion issue. It was a set of resin historical A frame tens, I believe they were actual resin cast and even after washing, they heavily resisted primer and it fell off without any provocation.

But that was the only instance.

So, the question is, do you wash 3D printed models before priming? And if so, why?

I've primed without washing and clear-coated (usually satin and then matte) afterward. No problems so far, but they haven't experienced the generation of play which some of the metals have--and won't in my lifetime.

No, never.

The only figures I ever wash are soft plastic ones.

Ive had the odd resin building which needs a wash though, or the paint doesn't stick.

Since a resin model would have been cleaned and cured: I don't know what washing would do.

@Louis XIV

Perhaps AI has confused washing resin with IPA to clean off surplus resin with the detergent/vinegar wash folks suggested for soft plastic/metal miniatures back in the mists of time :-)

I printed a bunch of scenery with Elegoo ABS-like, prints were sticky after washing/curing. Had the daft idea to wash them again with detergent.

Made zero difference 😆

Kodiakblair – That was my thought too. You do wash resin as part of the printing process either with IPA, water or some combination.

But if you buy 3d printed models there is no need to wash them as they would already have been washed and cured. My process is 2 IPA baths let dry and then UV cure. (Sometimes I put the models in warm water to help separate the supports.) Once cured then it is straight to priming.

The only models I have ever washed were the old soft plastic type.

Zero need to wash filament printed resin models. Prime and paint. Resin UV cured printed models need to be washed as an overall part of the printing process. Depending on the resin, different washing agents may be used such as water, alcohol, and others. This removes the slime on the outside of the print that would ruin the details should the print be cured with it remaining. Whether properly cleaned while being made, or not, there is zero need to wash a model again as once its cured, it is what it is and it is hard. Prime and paint.

As above, no need to wash FDM miniatures. they're pure plastic (or whatever) and there's nothing on them.

Resin minis come out of the vat coated in resin. If you cure them immediately you'll lose a lot of detail, cause there's gobs of extra resin on there. They go into alcohol or detergent and get washed. I put mine through a second, water-only wash to get the detergent off. Then they get cured. Everything should be off them my now. There's really nothing to wash off. But they have been washed, as a necessary part of creation.

Never wash FDM printed or Commecial resin/Lazer sintered. Some are 10 years old and no problems. Lasted far better than metal where the pant flakes due to mechanical truma.

Print and prime is my method too.