Introduction: Three Ways to Make a Chalkboard Sign
Chalkboard signs are pretty awesome. They are often used to display menus or special items in restaurants with a really creative artistic and stylized flare. My wife and I really wanted to incorporate some decorative chalkboard signs into the decor of our wedding, but we needed them to be permanent so the writing would not rub off and our designs were well out of my skillset for me to draw them by hand.
As a result, I began playing around with different ways to design and produce painted, permanent, and decorative chalkboard signs that are permanent and manufactured using CNC machinery. I found similar methods that worked with cutting plotters, lasers, and mills, each with their own sets of strengths and weaknesses. Through this Instructable, I will share my methods for making high-quality painted chalkboard signs on three different machines that fit a wide variety of designs, needs, skills, and budgets.
Step 1: Choosing Your Materials
Depending on which production method you choose, materials and tools may vary. For each production method, I used the following materials for the chalkboard paint, sign material, and design:
For each production method, I used Rust-Oleum chalked paint applied with a high density foam roller. I like this paint because it covers evenly with a single coat, and many of these methods rely on single coats to avoid bleeds. The biggest negative I have about this paint is that it scratches easily, as you can see from some of my photos. Touch ups were also rather difficult to blend.
For each production method, I started with a white sheet as the base of my sign. You could use a lot of different materials for the white sign board, each with their own pros and cons or benefits for different production methods. Here's a few I tested:
- Painted Wood- The cheapest option is to lay a base coat of white paint onto a piece of wood or MDF to use. This material would work with the Laser or Plotter, but is the most difficult to work with as it is not very sticky for masks.
- Melamine White Panel Board - This Melamine board with white panel outer shells is another cost effective option. With smooth surfaces, the white panels work excellent with masks but aren't thick enough for mills. These boards are also often thick and heavy in comparison to other options
- PVC Composite Boards - This is my favorite option because the boards are light and white through out with smooth surfaces. This material works with all methods, but there are precautions discussed in the laser method that must be considered.
Depending on which method you choose, you will need to use some sort of CAM software to actually produce your design using a CNC machine. Many machines have their own unique CAM applications that often provide some design capabilities, but I prefer to design in a vector program and then import my design into the machine specific software for production. Vector design applications can be exported as a svg or other vector file format that is compatible with most CNC production machines like plotters, lasers, mills, routers, and 3D printers. By using a vector design program, I was able to make a single design and produce it on three different machines using three different CAM applications. You'll see my "MJS" test design throughout many of these photos as I was experimenting with different production methods.
I talk a lot more about vector images and software in this Instructable, but in general I prefer to use Adobe Illustrator as my primary design application. Illustrator is not free, and its pricing is pretty steep. Gravit Designer is a powerful alternative to Illustrator that is free and works on any device. I have a collection of beginner and student-friendly Gravit Designer tutorial videos on my classroom YouTube Channel here.
Step 2: Using a CNC Cutting Plotter
A CNC Cutting Plotter is often referred to as a vinyl cutter and can be used to make signs, decals, and apparel. These machines have recently become easily accessible through brands like the Silhouette or Cricut available in many craft stores. I personally use a more industrial Graphtec unit in my makerspace, but they all use a blade to cut vinyl (an adhesive sticker material) that can be used to make a mask.
First, I cut my sign board to the needed size for my sign on a table saw. I then imported my vector design into Graphtec's controller software to manufacture the design using the cutting plotter. The cutting plotter cut my design onto a sheet of green vinyl.
After the design was cut onto the vinyl, I needed to weed out all the excess vinyl so all that was left was my design. I then applied transfer tape to the vinyl decal so it could be lifted and placed onto the PVC sheet using a squeegee. This can take some practice to evenly lift a decal and apply onto a material without getting bubbles. A good tip is to do everything low and slow. Don't try to rip up the vinyl straight up into the air or apply a lot of pressure quickly with the squeegee. Just work slowly and at a low angle as you go.
Once the decal was applied to the white sign board, I removed the transfer tape using the same low and slow technique used to apply the decal.I then applied the chalkboard paint using a roller in a single even coat. I first painted the sides, then back, then front. I used a peg board made out of plywood and brad nails to keep the sign in the air to dry evenly.
Wait until the paint is dry before peeling off the vinyl mask. This is unusual as most paints work better with a wet peel. However, I found that the chalkboard paint worked excellently with dry peeling as long as a single even coat was applied. this makes peeling easy as you don't need to worry about drips or smudging. I used pointed tweezers to carefully peel the vinyl mask off using the same low and slow method as before.
Step 3: Using a CNC Laser Cutter / Engraver
A CNC Laser Cutter / Engraver is a machine that uses a beam of light to cut or engrave material. There are lots of different types of lasers out there that range from low-power diodes, to CO2, to fiber. The type of laser you need really depends on the type or thickness of material you are going to cut. For this method, we are only cutting through painters tape so any method laser would work well.
Personally, I use a 40 Watt Universal CO2 laser engraver in my makerspace. Universals are a higher-end brand that are geared more towards industry like Epilog. There are lots of cheaper alternatives by GlowForge, Dremel, Full Spectrum, Boss, and more. All lasers have a handful of safety requirements that must be considered like proper ventilation, cooling, and a constant stream of compressed air.
In the first step, I mentioned that PVC boards are my material of choice but extra precautions must be considered for using a laser. PVC-based materials cannot be cut or engraved on a laser. Cutting or engraving PVC material release toxic (and deadly) gases. In this tutorial, I do not cut into the PVC materials, I am only scoring the painters tape to create a mask.
First, I cut my sign boards to the needed size for my sign on a table saw. I then covered the whole sheet with blue painters tape using a squeegee. Ideally, try to find a super wide roll of painters tape to reduce the number of seams across your sign. The fewer the seams the better as they provide areas for bleeding as you'll see in some of my photos.
I then inserted the the masked sheets into the laser and sent my vector design to the laser through Universals CAM software. With the power set to only score the painters tape, I cut my design into the signs. I then weeded out all the excess tape so all that was left was my design using tweezers and the same low and slow method described in my previous step.
After weeding, I applied the chalkboard paint using a roller in a single even coat. I first painted the sides, then back, then front. I used a peg board made out of plywood and brad nails to keep the sign in the air to dry evenly. Wait until the paint is dry before peeling off the tape mask. This is unusual as most paints work better with a wet peel. However, I found that the chalkboard paint worked excellently with dry peeling as long as a single even coat was applied. this makes peeling easy as you don't need to worry about drips or smudging. I used pointed tweezers to carefully peel the tape mask off using the same low and slow method as before.
Step 4: Using a CNC Mill
A CNC Mill is a machine that carves material using a high speed cutting bit attached to a motor. Mills are extremely similar to CNC routers with the primary difference being the type of motor used to turn the cutting bit. Mills / routers are used to produce countless products as they can cut through virtually any material with ease depending on their size.
There are tons of great brands out there to get DIY hobby mills or routers, but my personal favorite is Inventables. Inventables provides excellent resources and guides for beginners through products that compete with higher-end machines. I used the Inventables Carvey CNC Mill to produce the chalkboard sign in this step.
Unlike the first two methods, no mask is required and as a result the mill requires the least amount of prep work. The first step is to cut the sign material to size, then paint it using the chalkboard paint. Once dry, I mounted the sign into my machine using a series of clamps carefully placed to secure it in place without scratching the paint.
The next step is choosing a carving bit (AKA end mill) to actually carve the design into the sign material. There are dozens, perhaps even hundreds of different end mills out there. Each one has its own materials, surfaces, or finishes that it specializes in carving. I chose to use a 1/8th Spiral Upcut bit which is great for carving soft materials with clean finishes.
Once loading the material and bit, I sent my design through the Easel CAM software to manufacture my sign. After carving, it was clear that the bit cut into my outline more than I had intended. To fix this, I could have used a 1/16th bit for the outer path, or the entire design if I could spare the additional manufacturing time. I am no bit choosing expert and I rely on Inventables' Carving Bits 101 resource when trying to figure out which to choose. These resource isn't necessarily specific to Inventables-only machines and I recommend it to all who are looking to learn more about bit selection.
I also set my carving depth far more than necessary. To remove the blackboard paint, I really only needed to carve 1/64th or so into the material rather than 1/16th. The carved area remained white because I used PVC boards, but if it had been painted wood I would have carved right through the base coat as well.
Step 5: Choosing Your Method
So which method should you choose? Each method produced chalkboard signs that all looked very similar, but there were some differences in production techniques. I've listed a few things you should consider in order to best choose a machine and method.
The first thing to consider is which one of these machines do you have access to. It's nice to know that all three can be used, but it's likely you don't have access to all three to do a simple project like this. In general, cutting plotters are cheaper and easier to obtain.
Another thing to consider is the size of your sign. Even if you have access to more than one of these machines, you may not be able to fit the entire sign into your mill or laser to carve / cut your design into it. From this perspective, the cutting plotter is the best option because you can apply a vinyl mask in sections to virtually any size sign.
Detail / Complexity:
How detailed is your sign? In general, a laser can cut with higher precision than a mill or plotter. For the bar sign, I cut cursive words that were less than 1/16th in diameter. Both my mill and plotter would have made a mess of the mask for these sections.
The mill had the least amount of setup / prep as there was no mask to weed. However, the mill also has the longest manufacturing time. From a pure time perspective, the laser method took the least amount of time as the mask did not have to be transferred, only weeded after cutting and before painting.
All of these methods were very similar, as were the material cost when removing machine expenses from the equation. The mill was the cheapest as no mask was required. The laser was the second cheapest, and the cutting plotter was the most expensive due to the cost of vinyl and transfer tape in comparison to painters tape.
Step 6: Conclusion
This little project turned into a great comparison between three machines and production methods. As mentioned before, the biggest factor in choosing which method comes down to which machine do you have access to. But I had a lot of fun experimenting and seeing how the plotter, laser, and mill compared in a similar test.
In the end, I used the laser for all my wedding signs but one that was too large to fit in its bed. The laser signs came out a little cleaner as the larger sign was made with a vinyl mask on painted wood rather than PVC and bled a little more due to poorer adhesion between the paint and vinyl. For touch ups, I had a lot of success with these POSCA Fine tip Paint Markers.
I will still always marvel at all the hand drawn chalkboard signs I see in restaurants, but if you're like me and better with a mouse than a brush, I hope this Instructable helps you!
Thanks for reading, happy making!
Participated in the
CNC Contest 2020