How to finish your CNC Plasma project (tips & tricks)

So you cut out your part, using all the Cut Quality Tips & Tricks, the part came out great. Then you removed all of the left over Dross using the Dross Removal Tips & Tricks. Now you’re ready to finish your piece!

You have a million options and counting. From rattle can, to automotive grade paint finishes, to powder coating and specialty patina finishes, or just let it naturally rust.. The options are unlimited.

Many times these decisions are driven by what the customer wants, or the finish the customer can afford. More likely what they are willing to pay for. The three most popular options are Rattle Can, Powder Coat, and custom patinas.

Rattle Can (Spray Paint) – This tends to be the most popular finish option for a few reasons. Very inexpensive, few if any equipment costs, huge color pallet to choose from, easy, quick drying. A lot of my customers start off using Rustolem, Krylon, and many others. The Ace Hardware brand line seems to be one of the best in my opinion. Everything from the way they spray to how fast they dry is better with the Ace brand spray paint. Not sure who is making this line for them, but it’s really good stuff. I highly recommend this as a finishing option.

After some practice, you can get results very close to that of paint sprayed out of an expensive gun. One of my local customers (Desert Fabworks) has the best results by having a nice, clean, lint free surface. He doesn’t use primers, unless he’s doing a yellow. When spraying, he has the piece horizontal and sprays a medium coat, going back and forth across the piece, keeping a wet edge as a spray. Then when one pass is complete, he sprays a second pass.. 90 degrees to the first pass.

He get really good results with this method. The Ace brand spray paint tends to also be the least expensive as well. They have regular sales where you get it for $3.00 a can. If he has a really large run of pieces that are the same color, he will sometimes use a spray gun, auto grade paint, and clear. But most of the projects that he paints himself are small runs with 20 or less of a particular design or color.

Powder Coating – If I could have a full powder coating operation in my shop, I would likely do much more of this and less of the painting. Currently, most things that I want powder coated I send out, right up the road. As far as durability goes, powder coating is the best. It’s what I use on my plasma tables.

If I want something to have a great long lasting finish I have it powder coated or recommend it to my customers. Color selection and options are limitless, and the durability is the best you can get. It’s going to be one of the most expensive finish options, but also one of the best.

Building your own oven and spray booth are pretty easy and inexpensive, and with guns available from Harbor Freight and Eastwood, it can make getting into it pretty inexpensive. Like any finish option, your prep and the tools you use make a big difference in the final product. Don’t expect to be having your parts featured on the cover of a magazine when you use the Harbor Freight gun and an old oven, but it is an option. If you have a powder coater near your shop, make friends, trade work, and make use of this as an option.

Rusting – I’m in AZ and the rusted look is very popular. Getting that natural patina and letting it be is big business. To achieve this look, you can hand off a bare shiny piece to the customer and let mother nature and time do its thing.. or you can speed up this process. One of my customers has a secret for speeding up the rusting. He takes a level spot in pea gravel, sets his piece on this level bed, then sprays it with Regular household bleach out of a garden sprayer. Then he spreads a thin even layer of pea gravel over the piece. Afterwards, he mists it with water and bleach, alternating every hour or so, and in about 5 to 6 hours he has a piece that looks like it has been outside for years.

The pea gravel adds a pattern and a bit of texture to the piece due to the way it holds water and touches the piece. If you have your piece vertical, you will get streaking.. which can be good or bad, depending on the look your going for. If your piece is not level, or has a very uneven surface, puddle areas can develop and create a different look. Each piece is unique, and looks can be varied pretty easily.

When he achieves the level of rust that he wants, he takes the piece and carefully knocks the pea gravel off without disturbing the rusted surface. He leaves like this or applies a clear coat When it comes to clear coating this, it goes against all the prep rules. It’s definitely not a clean rust free surface, but it works. The most durable option is to have it clear powder coated. This process involves heating up the piece in the powder coat oven, then pulling it out while it’s hot, and spraying on the clear powder coat while its still hot. Afterwards, you put it back into the oven to complete the cure.

My customer did this process for an entire restaurant that wanted its walls clad in rusted steel. The rust had to be contained, and never flak,e because of the restaurant environment. This was successful, and after years this finish is still perfect and flake free. Doing this will dramatically darken the piece and add gloss to the finish, instead of the lighter matte finish with natural rust.  

Bare steel –  Bare steel with a clear coat is also very popular. You can have a polished or textured look to the metal with sanding, then clear coat the entire piece to keep it shiny. My customer’s favorite clear coat to use is Ace Hardware brand spray paint. It’s his go to option for clear coat. It’s indoor / outdoor, does not yellow, dries super quick, and is very inexpensive. The quality is top notch.

Patinas –  This is the last option I will talk about, but one of the finishing options Desert Fabworks uses the most. Patinas Cover a broad category. They can be finishes that are sprayed, brushed, dabbed, rubbed. Most of the time they are translucent to some degree and are rarely completely opaque. He gets all of my patina’s from A company called Steel F/X, they have a ton of options. With most of the patina options you can blend multiple to achieve some amazing results.   

Steel F/X has a huge website dedicated to all of the options, photos, and videos to show you and guide you through the use and application of this, so I’m not going to go into every option here. Click on the links and check them out. The two that I will show you here are the two Desert Fabworks uses the most. The first one being called Copper F/X.  This turns plain steel into looking like real copper. The spray has real copper in it that binds to the metal. The pieces, if not clear coated, will weather and age just like real copper. The next most popular item for him is the Metal Solvent Dye. There is a full palette of colors to basically stain metal with color. All of these finishes work best on plain mild steel with no mill scale / bright sanded finish.  

All of this is just scratching the surface of what you can do as far as finishing your pieces. A good portion of my customer’s business is made up of just parts that are never finished or they are welded into structures, vehicles, furniture or other components and then powder coated or painted.   

Check our Desert Fabworks Instagram page for more examples of some of the work he’s done and some of the different finish options that are out there.

More From Westcott Plasma

  • All
  • CNC Plasma Projects (Tips & Tricks)
  • How to start a CNC Plasma Cutting Business
  • The basics of CNC Plasma Cutters
  • The Basics of CNC Plasma Cutting
  • The Basics of CNC Plasma Software
  • The basics of Plasma Tables

Key Terms: CNC Plasma Terminology

What does “blow-back” mean? What are “lag lines”? The plasma cutting industry is full of unique words and phrases. Fortunately, …

What is CAD / ART Software in CNC Plasma Cutting?

There are hundreds of options out there when it comes to software. I’m going to cover adobe illustrator and Design2Cut, …

Design2Cut CNC Software in Machine Control Screen

The basics CNC Plasma Cutting Software (Complete Guide)

When it comes to Software for CNC Plasma Cutting, you can break things up into 3 distinct categories: CAD or …

sign up for our newsletter

Learn everything there is to know about plasma cutting! We’ll email you twice a week with a new article to read.