Week 7: Finishes

Overview

In this class we will review final projects and cover various quick and reliable finishes to add a high level of polish to your projects.

 

“Don’t make something unless it is both necessary and useful;
but if it is both necessary and useful,
don’t hesitate to make it beautiful.” — Shaker dictum

Various wood stain samples

 

Show and Tell

We’ll review and discuss final assignments.  What processes/techniques/tools did we use?  Any tips?  What would we change if we could do it all over again?

 

Tool of the Week

Branding Iron
An artist signs it on the front, a craftsman signs it on the back.

Always sign your work.  It’s a snap with a custom Branding Iron.

 

Tip(s) of the Week

“When you think you’re done sanding, you’re almost half way there.”

Sanding is such a big part of a great finish, but it is by far the most boring part.  The trick is to start with the lower number grit sandpaper (the rougher stuff) and work your way up to higher and higher grit (the smoother stuff).  It’s important not to jump right to the smoother paper.  You can’t go wrong if you start with a rough 150 grit, go to 220, then 400, and finish with 600.

Pieces of sandpaper

 

Keep extra scrap material to test your finishes.

Always test your intended finish on excess material.  You never know what it will look like until you do.

Wood stain testing

 

Finishes

Finishes are typically the last thing you do, but they have the ability to make or break a project.  Sometimes a great finish can take days if not weeks to apply.  We don’t usually have that kind of time around here.  Below are a few quick and reliable techniques.

 

Random-orbit Sander

Random orbital sander

 

All good wood finishes start with sanding.  Taking the time to sand something properly is always a good idea.  A way to speed things up is to use the random-orbit sander.  The sander has replaceable sanding discs and can make short work of projects.

Sanding disks for orbital sander

 

Wet Sanding

Plastic buckle being wet sanded

Wet sanding is a process that’s often used on car paint jobs, guitars, and even 3D prints to give them a mirror-smooth look.  Typically, on plastics, metals, or stone.  Never wood.

Wet sanding is typically done after dry sanding to get an even finish. Unlike dry sanding, wet sanding is done not to shape a surface, but to remove the large scratches left by dry sanding. Water is added throughout the sanding process to the paper and part. Only use wet/dry sandpaper when wet sanding.

 

Furniture Wax/Paste Wax

Can of furniture wax

Furniture wax, or paste wax, is an easy finish to add to wood.  With a clean rag, rub the wax onto the wood.  Let it sit for a few minutes, then buff out with a fresh clean rag.  The piece is ready to use about 30-60 minutes afterwards.

 

3 Part Wax Finish

Get a beautiful and a durable wax finish with this lathe-mounted polishing system. Buffing passes are made with a Tripoli buff (linen wheel), White Diamond buff (linen/flannel wheel), then Carnauba wax (flannel wheel). The final finish is very similar to multiple coats of lacquer but is softer and much deeper.  This finish can be applied in minutes.

3 Stage Wax Buffing Wheel Video Tutorial

 

Stains and Oils

A great wood finish can take weeks, if not months.  We don’t typically have that kind of time around here.  A nice “quick” wood finish is tung oil.

Can of tung oil

 

Apply tung oil using a clean rag — wear disposable gloves.  Follow the manufacturer’s directions on how to apply (usually liberally), how long to wait in between coats (usually 8 hours or over night), and how to dispose of used rags (carefully, they have been known to spontaneously combust, seriously).  When the tung oil gets tacky, use another clean rag to polish the wood and remove excess oil.

When the first layer of tung oil is dry, a second coat can be applied following the same steps above.  When the second coat is dry, a third coat can be applied.  And so on, and so on.  2 to 3 coats usually does the job.

When the tung oil is dry, a furniture wax can be applied on top of it.  Again, follow the manufacture’s instructions, but usually apply with a clean rag, wait 10-20 minutes (or until cloudy), and then buff it out using another clean rag.

 

Plastic Polish and Scratch Remover

3 part plastic polish

Polishes can be used to clean, repel dust, eliminate static, remove fine scratches and abrasions, restore faded colors, and remove heavy scratches from plastics.

 

Easily Remove Laser Engraving Residue from Wood

Cleaning a laser cut etch, before and after

If you’ve ever run your laser at low speed and high power, you’ve seen the results – sticky sap and varnish covering the areas you’ve already engraved. Using a common and easily accessible hand soap, you can quickly and easily remove wood residue from any project. Additionally, the product we’re using for this project is a biodegradable, waterless, petroleum solvent-free hand cleaner that contains neither harsh chemicals, mineral oils nor ammonia. – via

 

Priming and Painting

Two plastic figures, one primed one painted

Preparing your project with primer before you paint is the best way to ensure a lasting finish. Priming not only adds to the durability of the paint job it also saves you time, especially if you have the primer tinted the same color as the finish coat.

 

Spray Paint for Plastic

Painted plastic bookends

When painting plastic, it is a good idea to use spray paints made specifically for painting plastic.  These paints coat better and form a stronger bond to the material than ordinary paints.

 

Plasti Dip

Is a multipurpose rubber coating that come in both a spray and dip form.

Various spray cans of Plasti-Dip

Dipping objects in Plasti-Dip

 

Dying Plastic

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

Jacquard iDye Poly Orange

A photo posted by Karve Machine (@karvemachine) on

A photo posted by Karve Machine (@karvemachine) on

 

Tumbling

Electric tumbler

Tumblers give a smooth, polished finish to rocks, glass, plastic, and  metals. Tumblers run quietly at a low speeds.  The “medium” you use determines the finish you get.

 

Polishing Aluminum

Polished aluminum video jewelry

Using a polishing wheel and compound, metals can be taken from a brushed to mirror finish.

 

Powder Coating

Powder coated tin can robots

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).

Unfinished cans

Powdered cans

Powdered cans after baking

Powder Coating Video Tutorial

 

Note

ALWAYS use the spray booth when using spray paint, powder coating, Plasti Dip spray, or anything that gives off fumes.

 

Glow in the Dark Powder

Glow Inc, glow in the dark powder.

 

In Class Demo

We will go over our 3 Part Buffing System that attaches to the lathe.  It is quick, easy, and gives great results.

If there is time, we’ll cover the basics of powder coating.

 

What you Should Try

3 Part Buffing System

 

What You Should Buy

When you find a finish that you like and is reliable, buy all of the components necessary (stains, oils, rags, brushes, cleansers, etc.).  Put your name on them and store them in the fire-proof cabinet in the shop.

 


 

Related Reading/Viewing

How to Use 3 Stage Wax Buffing Wheel

Make Magazine Powder Coating

Powder Coating at ITP

Aging Wood with Baking Soda

Sanding Tips

Sanding Efficiency

Wrinkle Texture Paint

Making 3D Printed Parts Look Like Metal (primarily the Rub & Buff sections)

Mirror Finish on Milled Aluminum

LumiLor Electroluminescent Coating

Swirl Painting a Guitar Body

MyDipKit – Water Transfer Printing

Reviving the Art of Crushed-Eggshell Lacquer

An Easy-to-Apply Two-Tone Painting Technique That Still Shows Wood Grain

Electro Plating

Tips on Applying Wax