Step 4: Paint the Plexiglas

Edit: If you want to make life easier you can start with opaque white Plexiglas but then you probably won't be able to see the symbol when the light is off.  Either way you'll need to sand the Plexiglas prior to painting to ensure that it will stick.

Sand the Plexiglas on one side, make sure to do this very thoroughly, it will help to keep the paint from coming off. Doing this with a rotary tool or fine grit sandpaper will probably turn out better than trying to do it with the coarse grit paper that I used. Once thoroughly sanded, align and apply your stencil, this may take a couple tries to get it just where you want it but its worth taking the time. Just remember that if you put the stencil on wrong peel it off slowly and carefully to avoid ripping it or leaving pieces of the adhesive side behind.

Once that's finished, begin cutting the black parts out of the stencil with your X-acto knife, I used #11 blades for this. They work a little better for this fine detail work than some of the other blades I've used, and they are relatively inexpensive.

If your picture is pixelated (like mine) there should be rather distinct layers of shading around the black parts. If you start cutting on one level of the shading make sure you continue along the same line or your stencil will have uneven and unintentionally curvy lines. When painted, this will be unnoticeable from a distance but up close it will show a little bit. Once you have the stencil cut out, lift up the edge of each of the black parts with the tip of your x-acto knife and peel them out.

Now tape some masking to the other side of the Plexiglas. This can be as simple as a piece of paper but is necessary if you want to keep from getting paint on the other side of the glass. Start by painting the black paint on the stencil; after doing the first layer of paint hold it up to a light source. If you see little pinpricks of light poking through the paint do another layer and check it again. Any little holes will leak white paint through and your warning sign will have mini polka dots. After the black paint is thoroughly dry slowly remove the stencil. Next, paint the white over top of the black paint. This only needs a thin coat, thick enough to not leave any holes but thin enough so that light still easily passes through, this is most easily achieved with spray paint. Once dried it's time to move onto the next step.
so black on the front and white on the back?
I had a feeling someone was going to ask that so I'm going to feature your question.<br><br>I wanted a smooth glossy finish on the surface that the paint wouldn't scratch off of so I didn't paint on one side. After I finished painting the black paint I painted the white paint directly over top of it. So all of the paint is on the non-exposed side.
<p>cool &amp; I probably have the skill to make it! =D yay</p>
<p>I do not have a whole lot of time because I am just wrapping up a semester for my masters program. I would love to PURCHASE one of these from someone who has made one... I really want one with the &quot;don't drink the water&quot; warning sign on it. Can anyone help me with this??</p>
Tried this, but changed the color of the cube and used different materials for the warning sign. Came out awesome, though. I use them as candle holders and the flickering light adds a whole new element of creepy :)
Those look great! Glad to see pics from someone who tried it. I only made just the one but I'd love to make more of them. The next will hopefully be with opaque plexiglas and LED lights. However I still need to figure out how to disperse the light more evenly if I'm going to do that.
Ooh, idea. I could vacuum form the box, perhaps? Good job!
Thanks for the post, used it as a guide to make my own with some modifications. Used glass panes with printed computer paper in between on both sides of the sign and had my bulb wires come out from the bottom (I bought some adhesive 1&quot; furniture feet to give me clearance). Also tried out an ebony stain and a flat finish-- looks good, but for the time it took I could have spray painted myself four more boxes. Good instructible, cheap and easy project, and it was nice to show off at my colege LAN party ;)
i may make this soon, but with multiple signs, mostly the hazard (and cake :P ) signs for my lab. great job! :D
4lifenerdfighter, that means that the water in that test chamber is NOT safe to drink.
Not related to this but... What is the thing on the second row, to the left of the cake? Is it warning you about the radioactive drinking fountain? Anyone know?
Earlier you said this could be done on glass. Can an exacto knife cut through glass? idk, i might sound dumb now. lol<br><br>
No, the exacto knife will not cut through the glass, but that is not the objective. All the exacto knife needs to do is cut through the paper stencil. If you can avoid cutting into or scratching the surface you are going to paint that is better.
Awesome! P.S. Corsi, love the avatar image! =D
cool idea for a project! I like the fat that it lights up, have you considered replacing the wheel-switch with a pressure switch mounted behind the glass?<br><br>
I actually thought about doing that for a while but space in my case is rather limited so if I made the glass move it would have probably pushed against the bulb. <br><br>I probably could have wired it with LEDs but I was worried that by the time I diffused them to the point where their bright spots were no longer visible I wouldn't have enough light left to illuminate it.
Would lining the box with tin foil help with the distribution of light?
I was thinking the same thing but with aluminum tape.
Seems like it would be cool to make a second plexi-panel for the back and use the same process as the front to make a two-sided sign instead of just black. I suppose it depends where the sign will be. Attached edge-wise to a wall or in a window, or on some kind of swivel so you could choose which sign you waned displayed- or making one side or the top open-able so you could switch out plexi-panels would make it adjustable. You could slide in different panels for your mood, season or special occasion. <br>Great idea, thanks for the instructable!
Never thought of that. My original intentions were to make something that would hang on the wall, but it would be nice to have one that was interchangeable. Maybe I'll do that if I make another one.
I think lining it with LED lights would make it brighter. but thank you for posting this instructables up for us all to view.
I thought about that but it would probably have to be powered by a wall-wart and no one needs anymore of those. Also most LED's have weird light dispersion cones even when frosted that cause some unwanted bright spots.<br><br>You're welcome I had a lot of fun building it.
Cool! Good job! (I don't play Portal but I would like to make this and replace the image with a warning sign and hang it outside my door! :D<br> <br>
I'm going to build... ALL OF THEM!
Just as a suggestion, the light might be more evenly distributed if you wired up two of the bulbs and placed one off center to the left and the other upside down off center to the right. They could also be placed horizontally.<br><br>I'm not sure how bright those bulbs actually are in a box like that, but I'm sure you could add more paint to offset it being too bright.<br><br>Nice instructable! I think I'd like to make one over the summer.<br><br>Cheers.
Great! It was relatively easy to build, the whole thing went from concept to the completed project in about 3 days. Including time to let the paint dry, various mistakes, a trip to the hardware store, etc.
Fun idea for a project!<br />(A picture of the finished results would work better as the main image)
Thanks I wasn't sure which would be a bigger draw.

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