“Kick the tyres & light the fires” is a blog by [Ruscool Electronics] that is focused on building a cockpit simulator from scratch, and while the blog is loaded with all sorts of nifty information, reader [Brian] pointed out one entry which explains how to make back-lit control panels out of acrylic sheet, and a CNC machine.
The parts start off as clear acrylic, and cut to shape and size. Next up is a thick, but uniform coat of paint so the panels are opaque , then its back off into the CNC machine for engraving. What is engraved is now a frosty white, ready for leds behind.
The end result looks fantastic and professional, though, we are left thinking of how to pull off the same look, sans CNC.
Ideas?
use a stencil while applying paint?
I’ve had some success on some mock ups using a laser printer onto tape. you can then use a second piece of tape to lift off the graphics and layer it onto whatever surface you want.
you end up with a piece of tape on whatever it is you are modifying, but if you trim correctly this isn’t noticeable and in terms of mock ups it is great because you can peel off and put a new one on.
Oh, and obviously if you got it, a laser cutter could work even better than a CNC, depending on your material and your paint.
Would using something like petroleum jelly work as a mask? Once the paint is dry, a quick wipe would remove any painted jelly leaving the rest of the painted surface intact.
Now, for a slightly biased opinion, the “Best” solution, is to call up a shop like mine to have the CNC work done. CNC routers do a fine job on most plastics.
If you simply can’t get access to a CNC then:
I’m in agreement with “dirtyoldman”, stencil. This method is often used my sign makers, use a piece of cut vinyl to mask off a surface before painting or sandblasting. So, using suitable masking, one could take either approach, mask then paint, or paint then mask then sandblast.
I just don’t see how a laser will be an effective solution to removing paint without cutting through the plastics. But I’m a Router guy, not a laser guy.
How about print the art on transparency sheet in a laser printer, text is ‘white’ and lettering reversed. Then glue it to a sheet of opaque plexiglass. Add another layer of plexi for durability.
“I just don’t see how a laser will be an effective solution to removing paint without cutting through the plastics.”
Raster mode.
Materially simple. Do it like industry would do it — reverse mask silk screen.
1/ Make a mock up of your panel in the graphics software of choice.
2/ Output a positive to to acetate, place on the back of your plastic cover. Downside is it may not look right if switches need to be torqued down. Continue…
3/ Output a photo reverse to a sheet of acetate.
4/ Build a cheap frame for a silk screen. See Instructables.
5/ Use the reverse, flipped, to expose a photo resist mask for the screen.
6/ Lay down several coats of your paint on the back of the panel.
The hardest part to source will probably be a very fine polyester silk screen fabric needed and photo resist film. The rest, wood, staples, squeeqe, tape and paint can be found in any hardware store.
Sand and mask off the areas on the acrylic before painting. Then you just need to remove the mask and you are ready to go. I have done this in Theater for signage and for controll panels for the last 15 years.
GE Lexan is the standard for industrial control panels. Back printing with multiple layers of ink using silkscreening is the traditional way and in volume still the best. Screen layers for graphics as needed, one strike for each color and then screen on the background color. Leave areas in background open for LCD panels, LEDs and displays. Screen the front with frost and clear in two strikes and then UV cure. Emboss using a die set to raise edges on buttons or add stainless steel domes to provide a snap action to each key. Die cut to size or use a rotary paper cutter for straight edges. Use 3M sheet adhesive to stick the finished overlay to the panel structure. The panel can be made to carry the electronics on a circuit board mounted behind spaced out with standoffs. LED shine thru graphics for active display or clear openings in the background as indicator lamps. Layered construction like this allows the overlay to be changed at any time without altering the panel or circuit board.
this is excellent!
ive taken my dremmeling skill as far as i can and i never get that perfect look when im done. cnc and automated engraving machines seem too expensive for the average consumer or hobbyist. where or how does one get started in machining?
I just painted some backlit buttons last night. Cut them out with the laser, then etched the mirrored version of the design I needed. Paint the buttons opaque, then peel off the protective paper from the plexi. The paint is on the back of the buttons this way, but it looks cool. Plus you can use some vellum to diffuse the light.
I agree with all the laser guys here, using a laser to selectively remove the paint and cut out the button holes is a very effective use. The only downside is you cannot route recesses, but that can be dealt with two layers of thinner material.
Using a router is cumbersome, most likely because the toolchain is much harder to use. A (good) laser just acts as a printer.
Very professional look, impressive. Thumbs up.
how about old school engraving with a pantagraph rig? fairly easily made with a dremel or arbor cutter.
Doing this with a cnc is just like making cnc circuit boards using a pointy 90 degree pcb bit to just barely take enough paint off the top. The trouble is getting your plexi piece completely level.
I’ve used clea perspex and laser printed labels to get the same effect. you need to black out one lable with a felt tip pen then stick another label on top of it, lining up the printing. A bit tricky but the effect is pretty good.
http://www.flickr.com/photos/protostack/2940562655/in/set-72157616598111186/