3D-printed Gray Resin

Frequently asked questions.

Model Monkey products can pose a choking hazard to young children and pets. 


3D-printed models are recommended only for very experienced modelers, age 12 and up.

Model Monkey products ordered through this catalog are 3D-printed by Model Monkey in North Carolina, USA, in opaque, gray resin plastic capturing very fine detail.  Surfaces are very smooth. 


What is 3D-printed resin?  Gray resin is an acrylate-based plastic chemically similar to Plexiglas.  Gray resin is not nylon.  Grey resin models are produced using a different technology than that used by other 3D-printing companies like Shapeways.  Gray resin is chemically different than polystyrene plastic found in injection-molded plastic kits.   Gray resin is also more brittle than polystyrene.  Thin features are more fragile than polystyrene.  Here are some Model Monkey products 3D-printed in gray resin:

When will you print my models?  We print models after an order is placed, on a "first come, first served" basis.  We will print your models as soon as any orders received previously are complete.  3D-printed models are not cast inside a mold.  3D-printed models are created in very thin layers one layer at a time.  This makes 3D-printing a very slow process.  Typically, it takes several hours to print a single model.  Thank you for your patience!

Why does the model have so many supports?  Each gray resin model will come to you with several supports attached to it.  These supports look like "sprues" found in injection-molded plastic model kits.  Since 3D-printed models are not made inside a mold like injection-molded plastic kits or other resin models, there is no mold to provide support to overhanging features during printing.  Without a mold, overhanging features must be supported in some other way.  The 3D printers we use create supporting sprues which rise up from a tray called a "printing raft" to support overhanging features during printing.  The models cannot be 3D-printed without the sprues and printing raft.  Sprues and the printing raft also provide strength to the model during shipping.  Sprues and the printing raft must be removed by the modeler.  Sprue removal is normally difficult.  That's why 3D-printed models are recommended only for advanced modelers, not beginners.    


Why do you print models at an angle?  Printing larger models at an angle helps prevent sag from occurring between supporting sprues during printing and makes sprue removal easier.

How should I cut away the supports? 

  1. Most importantly, work slowly.  Rushed efforts can damage models. 

  2. Attachment points are smaller in diameter than the sprue.  The attachment points' diameter varies between 0.3 mm and 0.6 mm.  Attachment points are normally weak. 

  3. Use a very sharp cutting tool like a new cuticle clipper or new sprue cutter.  Your cutting tool must be very sharp so that you don't have to force the cut. The old saying, "let the tool do the work" applies.

  4. Try not to twist, push or pull when cutting.  For small models, place the tool in a good position to cut nearest the part, not the tray.  Try to make the cut so that you do not have to move the tool or the model when cutting.

  5. Large models like big, hollow turrets, boxy fire control directors and pilot houses will have many internal supports that are difficult to reach.  Cut the supports nearest the tray first.  Start at the outside, working your way around the model.  Work inwards, carefully cutting away the tray.  Then cut the supports from the model.  

  6. Make final cuts near the attachment point.  Try not to twist, pull or push when cutting.

  7. Gently trim or sand away any remaining "nubs" just like you would on models made from injection-molded polystyrene plastic.

If you accidentally break off a piece of your model, you can probably re-attach it using CA glue.  Gray resin is brittle.  Resin does not bend, so the break itself is not likely to be deformed.

How should I clean the model?  If you need to clean your 3D-printed model, isopropyl alcohol is recommended.  You can also use warm water with mild dishwashing liquid like "Dawn", "Fairy", "Joy", "Simple Green" or baby shampoo (no conditioner). 
3D-printed gray resin plastic is chemically related to Plexiglas.  Cleaners that harm Plexiglas can damage gray resin, too.  Do NOT use acetone or acetate (fingernail polish remover) to clean your models.  Acetone and acetate can melt 3D-printed plastic.

Does your 3D printing process use waxy support material or oil?  Our 3D printers do not use waxy support material during printing.  No oil or other mold release agent is used.  No cleaning away any wax, oil or mold release agent is necessary. 

Do the models come fully hardened?  Normally, yes.  No additional exposure to ultraviolet (UV) light, called "post-curing", is needed.  Your model is created when ultraviolet light emitted from a laser chemically hardens liquid resin.  After printing and cleaning, we place your gray resin model in a UV light booth to fully harden the resin before we ship your model to you.  If you find a spot on your model that feels a bit rubbery, place the model in direct sunlight for a half hour or so, exposing that spot to the sun's UV light.  The sun's UV light should finish hardening that spot.

Do you send assembly instructions with the model?  No assembly instructions come with your model.  Please study photos and renderings on the product webpage.  Most models are direct replacements for plastic kit parts so your plastic kit's instructions are applicable.

What kind of glue should I use?  Cyanoacrylate (CA) "super glue" works best.  For larger parts, epoxy can be used.  Liquid glues intended for injection-molded polystyrene plastic models, such as "Testors Liquid Cement" or "Tamiya Cement", do not work with gray resin.  Superglue remover containing acetone may harm the plastic.


What kind of paint should I use?  Gray resin plastic is compatible with many common acrylic, enamel, and metallic (Alclad 2) hobby paints without the need for primer.  Gray resin also accepts Molotow marker paint for painting tiny details.  Click here for an enamel paint demonstration by James Duff, owner of Sovereign Hobbies, manufacturer of "Colourcoats" enamel paint.

To determine how your paint will behave with 3D-printed resin, test your paint on the 3D-printed resin tray that your models come attached to,  Remove your models from the tray and paint the smooth tray bottom without primer.  Check your results and proceed accordingly.  Do not use methyl ethyl ketone "MEK" as an airbrush paint thinner.  MEK is known to chemically react with 3D-printed plastics and produces a powdery residue on top of the paint that is difficult to remove.

Are your models printed by Shapeways?  Our gray resin models are not printed by Shapeways.  Some Model Monkey designs, like metal and plastic nameplates and models too big for our printers, are not suitable for gray resin printing.  Those models can be ordered from Shapeways.  Models and nameplates ordered from Shapeways are sold, printed and shipped by Shapeways from their factories in New York and The Netherlands, not Model Monkey.   Click here to see Shapeways' website and learn more about Shapeways' materials and their cost. 


Shapeways' white acrylic "Smooth Detail" plastic is chemically different than Model Monkey gray resin.  Shapeways' acrylic plastic models are printed using a different process than our gray resin models.  Unlike gray resin, Shapeways' 3D-printing process uses wax and oil.  Clean Shapeways' plastic with isopropyl alcohol or warm water with mild dishwashing liquid like "Dawn", "Fairy", "Joy", "Simple Green" or baby shampoo (no conditioner).  Place your Shapeways models in direct sunlight or under another ultra violet light source for an hour or so to ensure all of the plastic is fully hardened.  If not fully hardened, enamel paint may not harden on Shapeways' acrylic plastic.  Cyanoacrylate "CA" glue works best with Shapeways' acrylic plastic.

Will you send me a free sample?   Model Monkey does not honor requests for free models.

Will you research and design a model for me?  Model Monkey is not able to provide research and design services for individual modelers.  You can hire professional 3D designers from sites like Shapeways (click here).

Will you alter the design of an existing model for me?   Model Monkey is not able to provide custom alterations to existing designs for individual modelers.

How are your models designed?  All Model Monkey designs are original and proprietary, created one line and shape at a time using sophisticated CAD software on a powerful computer.  Our models are not scanned copies of any plastic, resin, wood or paper models' kit parts.  Nor do we steal files from computer games, such as "World of Warships" and "World of Tanks", and adapt the stolen files for 3D-printing in order to create our models.

Can I buy your CAD files?  No.  The computer aided design "CAD" files used to create Model Monkey products are proprietary and not for sale.

Will you send me the references you used to design your models like high-resolution photos and 2D plans?  No.

Can I buy one of your models and make copies of it, even if it's just for my own use?  Legally, no.  Model Monkey-designed models are legally considered "creative works" and are fully protected by US and international copyright laws.  Making copies of our models, even for your own use, infringes upon our copyright and is illegal.  Our "creative works" include:

  • Model Monkey-designed models and nameplates

  • Model Monkey-designed models and nameplates 3D-printed by others, e.g., Shapeways

  • CAD files used to print our models and nameplates

  • this catalog

  • photographs we made of our models

  • computer generated renderings we made of our models


Can I buy one of your models, modify it and sell copies?  Legally, no.  Modifying our models then selling copies does not meet the legal requirements associated with "derivative work" or "fair use" under US and international copyright laws.

Material Safety Data Sheet for liquid gray resin (click here).


Except for custom nameplate text, we do not accept requests for new models or alterations to existing models.

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