How to Finish 3D Prints and Props for Cosplays
Tutorial Contents
Important!
Make sure you wear proper protective gear – protect your eyes, lungs, hands and skin, etc.!
Protect your workspace – cover surfaces with a protective barrier as needed
Tips and Tricks
- Use a scrap piece of EVA Foam to apply putties to 3D prints – it acts like a squeegee. This method reduces the need for sanding and reduces the amount of putty needed to finish the prop.
- Add a dab of glue into any slots that dowels are inserted into before inserting the dowel. This adds a deeper layer of adhesion between the parts.
- Before applying glue, roughly sand any surfaces that will be glued with a 120 grit sandpaper
- Clamp pieces firmly in place when joining the parts together (pressure is key! Make sure they’re pressed together firmly to ensure a strong bond, and make sure they don’t shift during setting or you’ll end up with a crooked prop)
- Super glue accelerator is a great product for impatient people (like myself)
Assembling Props
Due to machine constraints, props are often printed in multiple parts and need to be assembled – sometimes they have spaces for dowels, other times they are just flat surfaces. Regardless of what kind of setup you have, sometimes you have to assemble 3D printed parts.
Make sure your prop is aligned exactly as you want it to be – pressure is key, so using clamps or similar tools to press the parts together can help ensure a solid, seamless finish. Place it in a spot where it will not be disturbed while the adhesive is curing.
Adhesives
The adhesives I recommend using are…
- Super glue (any kind of cyanoacrylate glue)
- Gorilla Glue
- PVC Cement
- 3D Gloop!
- Contact cement
Finishing Methods
Option 1: Wood Filler
Materials and Tools
- Wood Filler Paste
- Rustoleum Filler Primer
- 120, 240, and 400 grit sandpapers
- Your paints of choice
Steps
- Sand the surface thoroughly with 120 grit to eliminate the more aggressive layer lines.
- Prime it with the Rustoleum Filler Primer, allow primer to dry. This will allow you to better see any remaining layer lines better. Sand aggressive layer lines again as needed.
- Using either the wood filler, brush the putty over any gaps or holes. Dilute with water if/as needed. Allow this to dry completely
- Sand again with 120 grit.
- Prime again with the Rustoleum Filler Primer, allow primer to dry.
- Sand with 240 grit
- Filler paste any gaps/holes as needed.
- Sand with 240 grit
- Prime again with the Rustoleum Filler Primer, allow primer to dry.
- Sand again with 400 grit.
- Prime again if desired and allow to dry.
- Paint to your heart’s content!
Option 2: Glazing/Spot Putty
Materials and Tools
- 3M or Bondo glazing putty/scratch filler paste
- Dupli-color Sandable Primer
- Rustoleum Filler Primer
- 120, 240, 320, and 400 grit sandpapers
- Your paints of choice
Steps
- Sand the surface thoroughly with 120 grit to eliminate the more aggressive layer lines.
- Prime it with the Duplicolor Primer, allow primer to dry. This will allow you to better see any remaining layer lines better. Sand aggressive layer lines again as needed.
- Apply your preferred putty to any gaps/holes, allow to dry completely.
- Sand with 240 grit sandpaper.
- Prime it with the Duplicolor Primer again where needed, allow primer to dry.
- Sand with 240 grit.
- Filler paste any remaining gaps/holes, allow to dry completely.
- Sand with 320 grit (wet sand optional).
- Prime with the Rustoleum Filler Primer, allow primer to dry completely.
- Sand again with 400 grit (wet sand optional).
- Paint to your heart’s content!
Option 3: Molding Paste
Materials and Tools
- Plain ol’ Molding Paste OR 70% Molding Paste to 30% Gesso mixture
- Dupli-color Sandable Primer
- Rustoleum Filler Primer
- 120, 240, 320, and 400 grit sandpapers
- Your paints of choice
Steps
- Sand the surface thoroughly with 120 grit to eliminate the more aggressive layer lines.
- Prime it with the Duplicolor Primer, allow primer to dry. This will allow you to better see any remaining layer lines better. Sand aggressive layer lines again as needed.
- Apply your putty to any gaps/holes, allow to dry completely.
- Sand with 240 grit sandpaper.
- Prime it with the Duplicolor Primer again where needed, allow primer to dry.
- Sand with 240 grit.
- Filler paste any remaining gaps/holes, allow to dry completely.
- Sand with 320 grit (wet sand optional).
- Prime with the Rustoleum Filler Primer, allow primer to dry completely.
- Sand again with 400 grit (wet sand optional).
- Paint to your heart’s content!
Option 4: Filler/Putty and Epoxy/Resin
Materials and Tools
- Pourable clear cast epoxy (like this one from Alumilite) or UV cure resin – this choice will depend on the size and intricacy of your prop.
- If your prop is something similar to a sword, with mostly flat surfaces and simple shapes – clear cast epoxy may be the best route to go. This is a very thin resin and is used by pouring then spreading it across the surface of the prop.
- If your prop is smaller and has many nooks and crannies, UV resin may be the better option for you. This is a more viscous option and can be applied using a small brush to coat delicate areas without losing detail.
- Bondo Filler Putty or Molding Paste (and Gesso if desired) or Wood Filler
- Dupli-color Sandable Primer and/or Rustoleum Fillter Primer
- 120, 240, 320, and 400 grit sandpapers
- Your paints of choice
Steps
This method is a bit more flexible with the preliminary sanding. I personally did not do any sanding prior to applying the epoxy to my 3D print, but I would recommend if your prints have severe layer lines or z-axis banding.
You may need to work in small sections and allow each section to cure before moving on to the next area when working with either option. These are liquids and will run if moved around/tipped/placed at an angle.
Please note that both epoxy and resin are toxic – please be sure you are wearing proper PPE when working with either of these materials, follow good housekeeping measures, and be mindful of your environment. Lay down protective barriers as necessary.
- Sand the surface where needed with 120 grit to eliminate the any aggressive layer lines.
- (Epoxy) Mix your clear cast epoxy according to the instructions it came with and pour it carefully and sparingly across the surface of your prop. While wearing proper PPE and gloves, use your finger(s) to spread the epoxy evenly on your prop.
(UV Resin) For flat surfaces, apply a generous amount of UV resin to your prop and spread evenly using gloved hands. For more intricate details, apply a sparing amount of resin and work it into spaces using a brush (do not use a brush that you want to keep – you will not be able to wash the resin out thoroughly and it will not be safe to use for anything except resin after this). Do this in a semi-shaded or shaded area, away from direct sunlight. - (Epoxy) Allow your epoxy to cure completely based on the cure time information on the package.
(UV Resin) Cure your resin with a UV light or in strong, direct sunlight according to the directions on the package. - Once your choice of resin/epoxy has fully cured – sand any rough areas with 120/240 grit and fill any gaps/missed areas with more of your material of choice and allow to cure again. Repeat until desired smoothness is achieved.
- Prime it and allow primer to dry. This will allow you to better see any remaining layer lines better. Sand layer lines as needed.
- (As needed) Apply your epoxy/resin to any remaining gaps/holes, allow to cure completely.
- Sand with 240 grit sandpaper.
- Prime it again where needed, allow primer to dry.
- Sand with 320 grit (wet sand optional).
- Sand with 400 grit (wet sand optional).
- Paint to your heart’s content!
Painting, Paints, and Pigments
Top Paint Picks
- Acrylic paints (Plaid FX, Artist’s Loft, etc.) for base coats
- Spray paints (Rustoleum, Krylon, etc.) for base coats
- Automotive paints (Duplicolor, etc) for base coats
- Airbrush paints (i.e. MasterBrush, MagicFly, etc. Or make your own with acrylic paints and hi-flo mixing medium) for weathering and shading
- Paint pens (i.e. Posca, Sharpie, etc) for fine details or exaggerated shading
Proceed with Caution
- Oil paints – they take forever dry, so they should not be used for base coats. They can be used as an apply and wipe for weathering and different color effects, but use sparingly.
- Rub-n-Buff should be used very sparingly if at all, it’s prone to transferring and is hard to seal and preserve the desired finish
Sealing
- Acrylic Sealants – such as MrSuper or Mod Podge spray – are my go to. I do a minimum of 2 coats of sealant on my 3D prints just to help preserve the finish.
