Week 4: Finishes


The finish can often make or break a piece.  It can give a toy it’s personality and tell its story.

Artists to Watch

Amanda Louise Spayd
Cracked Hatchet


Color can tell a lot about your toy.  Bright primary colors scream playful toy.  Dark dirty colors have a dark dirty tale to tell.  You should experiment with different color pallets to find the right feel for your piece.


Whether it is with a brush or a spray can, a simple paint job can transform a piece.  But remember, always use PRIMER first.  In fact, use a material specific primer, plastic primer for plastic, metal primer for metal…

When the paint job is done, it’s a good idea to add a clear coat.

Spray Paint Finish Process

Always start every paint job with a layer of primer.  For 3D prints it’s a good idea to use Filler Primer.


Use painters tape or the vinyl cutter to create intricate masks for painting.

Painting Tips

Crisp Lines on Round Objects

If the object is round, you can use the lathe or drill press to get clean even lines.

Parts on Sticks

Put your unpainted pieces on sticks.  Shove those sticks into a foam base.  This makes spray painting much easier.

Or use alligator clips on sticks to grab hold of small parts when painting.


Sanding is the secret to success.  Start with low number grits and work your way up.  Nail files and emery boards are convenient for small intricate parts.

You can wet sand plastic and metal parts (never wood).

Wet sanding an aluminum part

Wood Burning (do not use soldering irons)

Laser etch wood

Engraving lighter species of wood on the laser creates repeatable precise results.  The parts must be flat.
Laser etched wooden gorilla toy

Adding Texture


Red flocked toy

Flocking is adding tiny pieces of fiber to a surface.  It gives a soft texture.

Texturing and Painting

A technique to add texture and color contrast.  Crinkle up tin foil, spay mount adhesive to it, add to a solid form, paint it in a contrasting color, lightly sand after drying.

Dying Plastic

Some plastics, like delrin and nylon, can be dyed.  Rit and Jacquard iDye are popular dyes.

Jacquard iDye Poly Orange

Polishing Metal

Metal polish and the fabric buffing wheel on the grinder.

Polishing Acrylic

Just a few minutes, using only the Tripoli Polishing Buffing Compound, leaves an amazing glass like finish.  It also has the added benefit of softening all of the sharp edges of the acrylic.


Electric tumbler

Tumblers give a smooth, polished finish to rocks, glass, plastic,   metals, and 3D printed parts.  The “medium” you use determines the finish you get.


Use off the shelf water transfer decals or create your own.

Mega Hobby Car Decals
Transfer Stickers

Metal Inlay Powder

Metal inlay powder on wood

Powder Coating

Powder coating is an incredibly durable paint job.  The main difference between traditional paint and powder coating, the pigment is in powder form and applied electrostatically and baked on using an oven.  Only materials that can hold a charge and withstand 400 degrees can be powder coated (basically metal only).

Powder Coating Video Tutorial

Re-machining Powder Coating

A powder coated finish can be milled, etched, or turned off giving great results.

Powder coated aluminum tube before re-machining

A powder coated tube after re-machining, some of the finish has been removed

It can also be laser etched away.

Laser etched powder coated metal tags

In Class Demo


Vinyl Cutter

Laser Etching Painted Metal

Metal Polishing

Signing Your Work

Always sign your work.  It can be sculpted into the figure.  It can be part of the paint job.  It can be the very last thing you do.  But please, sign your work.

Signed toys on the bottom of shoes

Midway Survey

Please take a few minutes to fill out this quick survey and let me know how you think the class is going so far.


A fully finished prototype is due.  That means have a finish on it.  If you want to experiment with finishes you can make multiples.   If your final 4 pieces are going to have different finishes, you can get started on them this week.

Related Reading/Viewing

How to Apply Flocking

Intro to Fab Finishes

MyDipKit – Water Transfer Printing

Spray Paint Finish Process

Metal Inlay

How to Smooth and Finish Your PLA Prints

Ultimate Guide to Finishing 3D Printed Parts