How to Make a Carved Stadium Sign on a CNC
With the start of football season, I wanted to create signs for a few friends of their college stadiums. This is the process I used to stain, paint and carve them out on my Inventables X-Carve CNC.
Step 1: Stain the Wood
These signs are built with 3/4 in poplar cut to roughly 12x12 in. After cutting them to size, I stain them with Minwax Dark Walnut that really helps make the white paint POP later!
Step 2: Shellac
After stain, I apply a coat of Shellac. I've found this helps with the masking removal process later in addition to making it easier to clean up any overspray with mineral spirits.
I've enjoyed using the spray shellac, it lets you apply a smooth coat and dries in only 30 minutes (even in the 90 degree heat and 80% humidity here in the South).
Step 3: Mask With Oramask
This stuff is a lifesaver. I first learned about it from @gotwoodworkshop. Oramask is a long sheet of painters tape but a little more sticky and plasticky (that's a word right?).
I cover the entire surface and then use a piece of wood to get all the air bubbles out. Since this is a pretty detailed cut, you want to have the mask stuck entirely down to keep paint from bleeding over once it is cut out.
Step 4: CAM Setup
I created my stadium designs in Adobe Illustrator. Once I had a vector, I saved it as a .svg file to import into Inventables Easel. Easel is an online CAM software that interfaces directly with my CNC. It doesn't have all the bells and whistles as some of the higher end software, but its ease of use and cost (FREE!) make it my go-to solution in most cases.
The cut happens in 3 different stages with three different bits:
1. Rough pocket removal (1/8 Compression bit)
This stage removes the bulk of the material. In Easel, you can set up a 2 stage cut which I have done in the second artboard which appears at the bottom of the screen. I have removed the football field and geographic coordinates from the design since it is cut at a later stage.
2. V Carve Detail (60 Degree V-Bit)
This stage adds the detail to the larger stadium and gives all the walls a slight 60-degree taper.
3. V Carve Super Detail (18 Degree V-Bit)
The coordinates at the very bottom of the image, as well as the football field, required a bit with a lower taper than the earlier 60 degree. By using an 18 Degree bit, I'm able to get a deeper cut at higher detail. You could probably use the 60 degree bit for everything, but you would need to make the coordinates larger than what I have done.
Step 5: CNC Carve
Get to work little robot helper!
One thing to keep in mind is that you will need to change bits 2 different times, be sure not to move the router when loosening or tightening the collet. If you do, then the next stage will be slightly off, and any change will show up in the final product.
I typically cut each stage twice, with the second cut functioning as a finishing cut. While this takes longer on the front end, it saves a ton of clean up time with sandpaper!
Overall these signs take roughly 2 hours to cut entirely.
Step 6: Spray Paint and Peel Mask
Once the sign is carved, I will spray the exposed wood with one coat of spray lacquer. This helps to seal the wood for a more even paint application.
Speaking of paint, my go-to spray can is Montana Gold. This produces a finer, slower spray which gives you a much smoother covering versus what you would typically get at the big box stores.
Plus you'll feel like a graffiti artist ;)
After the paint dries peel off the mask. This has always been the part I enjoy most!
Step 7: Shellac and Sand
Each sign is finished with two-three coats of shellac with sanding in between each coat.
Step 8: Finished!
Finally, a hanger is attached to the back, and the sign is wrapped up to be sent out!
These have been a blast to make and if your interested in seeing the ones I've done so far I've got them up at my Etsy store.
I tried my best to take the best tips I've found in cutting/painting/finishing signs from around the web, but I'm no expert. If there is something you've found helpful make sure and let everyone know in the comments!
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