I’m trying to put together a control panel using 1/4" plexiglass. I have transferred a paper copy of my layout on to one side of the plexi and carefully copied it to the flip side with 1/8" width tape; I’m at the point I should apply a coat of black paint on the taped side but not sure what to spray. Do I use good old black primer or use a glossy black? With the present cost of plexiglass, I didn’t buy a spare piece on which to practise and don’t want to mess this up. Can one of you who has done this tell an old geezer what’s the next step? I have no idea what the underside of paint looks like. I’d like to stick with black as the background since I plan to indicate my 4 power sections in other colors. All good advice appreciated Roy
Well, having never made a control panel I can’t help much but,… The underside of paint looks just like the topside if that means anything to you. Tom
The other Tom above is right, although you didn’t mention whether you had done this as a reverse. Gloss or flat paint won’t matter as you’ll have the gloss of the plexiglass from the front side. The important things are the choice of paint, and cleaning the plexiglass before trying to paint it. There’s a release agent and possibly glue residue from the protective sheet that will give you problems trying to make the paint adhere to the surface. If you’re using colored chart tape, this may also cause a problem for this getting it to stick to the surface. Goo Gone is probably the best choice for cleaning prior to taping and painting. After cleaning, don’t touch the surface with your fingers as they’ll leave a residue of body oil and you’ll be right back where you started.
For paint type selection, you need a plastic compatible paint. Testors on the model side and Krylon (check the label, not all of their paints are plastic compatible) make paints that will adhere well after you clean the surface. As always
Plexi is very smooth and I don’t know if the paint will adhere to it without first sanding with 400 grit wet or dry used wet
Our machine shop throws away 20 pcs of that stuff a day. I use sizes ranging from .125 (1/4") to .187 (3/16’). Wish I would have seen this, I could have cut you some and mailed it out for free. You would have to pay shipping, but the glass is no charge. We just throw it away anyhow. Man it couldn’t cost that much to ship.
Mike
DuPont Krylon makes a special spray paint for plastics. It’s formulated to not attack the plastic and also to take a certain amount of expansion/contraction. My [2c]
What I did for my control panels was to use 2 thin pieces of plexi, and print the control panel on heavy paper on my color printer, and sandwich that in between the plastic. This way there is no contact with the actual diagram portion, so it will never wear out from people using the panels. There’s a few pictures on my web site under the old stuff sections.
–Randy
OK a little story here. I have found that Wal-Marts $.98 spray paint in all colors does NOT attack any of the plastics I have sprayed it on down through the years and that means years. I started using the stuff when it was $.59 so you do the math. I use cans of it and the flat black is primo.
Now about the NEW high priced “Formulated for plastic” paints out there. Do NOT even fall for that. It’s a marketing ploy I believe. My aged mother has some plastic lawn chairs she wanted repainted green so I got some 98 cent Wallyworld paint and proceeded to paint one for her showing her the drill as I went along. Voila, a new chair. Subsequently she later bought some Krylon “:Formulated for plastic” paint at about 6 bucks per can and painted the other 3, quite an expensive endeavor I though but hey… Anyway about 3 weeks back we were talking and she told me the paint she applied was not adhering worth salt. I KNOW this woman and can assure you she followed directions AND also did all the prep work I showed her how to do.
Bottom line, save money, use the 98 centers, and be happy… :)~
Rich
Always be careful to check on a scrap piece before using Goo Gone on plastic. I once bought a clear plastic measuring cup and tried using Goo Gone to lift the rest of the adhesive from the price sticker off of it. Net result? A smeared mess that also destroyed the markings on the measuring cup.
OMG… Goo gone is usually ananthema to plastic. The OLDEST and BEST way to remove price stickers is, and always has been, to hit the sticker with a blast of WD-40 and give her a minute to soak in. Off it slides AND a dab of WD on a paper towel finishes off residual adhesive like magic. Try it, you’ll like it. Another trick from “down through the years”.
Rich
A major problem with using WD-40 for cleanup before painting is that it leaves an oily residue, so you’re right back where you started with a possibly oily surface that paint won’t stick to. A slight etching of the surface before painting is a good thing.
“problem with using WD-40 for cleanup before painting”
I did not address using WD-40 to prep for painting or anything BUT your comment about adhesive labels my friend.
However IF you do want to paint after simply wipe with a cloth and rubbing alcohol. Voila.
BTW I used WD-37, 38, AND WD-39 in the research program during development. Formula #40 was finally considered to meet ALL design criteria and marketed. FYI the goal was to create a “Water Displacer” hence the letters WD.
Now in the future please keep what I say in context and good luck with those “labels”
Rich
Thanks folks for the needed info- I’m off to WalMart since my black primer seems to be the plastic eating type. I prepped the surface with 90% alcohol and will lightly sand it to give the spray paint some footing. Thanks again- you all are my primary source of good advice and I really appreciate your help. Roy
I tried to do a plexiglas control panel once. The plan was to create the artwork (track diagram and lettering) with a CAD program and print it out full size on my desk jet printer. Then stick the artwork to the back of the plexiglas, and drill holes to accept the toggle switches and indicator lamps. The artwork part worked, looked good and stuck well. The drill-the-holes part didn’t work. The drill kept cracking the plastic. I drilled and cracked two pieces before giving up on the plexiglass and going with a plainer panel made from masonite.
Since that time, I have heard that you need a special drill for plexiglass. Something about the rake of ordinary twist drills being too aggressive, causing the drill to dig in too deeply and too fast. You might ask a plexiglas shop what they use for drills.
As far as painting, surface prep is everything. Get it squeeky clean and don’t touch it barehanded. I’d wipe it down with something that will eat the left over stickum and any mold release agents. Say alcohol or GooGone or paint thinner. Then finish up with lots of hot soapy water, followed by a rinse in clean water.
Any spray paint will stick. I have never had trouble with any spray paint attacking plastic. Even the solvent based spray cans work fine. The solvent mostly evaporates before the paint even hits the surface, and what little is left evaporates before anything bad happens. As far as gloss goes, I don’t think it matters much, the look of the surface will be set by the glossy surfaces of the plexiglas, more that by the paint. Was it me, I’d think about using a dark gray rather than black. Say dark gray auto primer.
All you need to do to drill a hole in plexiglass is drill at a slow speed with light pressure.
Sheldon
To keep your own “comments in context” you need to follow the quotes. I was the one who recommended Goo Gone for cleaning plexiglass prior to taping and painting. After another posters recommendation to use WD-40 (and not followed by a recommendation to clean off the oily residue with anything) I pointed out the fact that it will leave an oily residue that will prevent the tape and paint from sticking. This whole thread is about making control panels from plexiglass.
I used Plexiglas many moons ago. I painted the back of my panels dark blue or dark green. Then I masked off the track schematic on the front and painted it gloss white. The result was a really neat looked 3D effect.
I had no problem getting regular Krylon to stick to the Plexiglas, with just a basic surface cleaning. I never had to roughen the Plexi before painting it.
Nick
I’ve made three panels using the computer printed paper between two plexiglas sheets. All turned out excellent. I taped the two sheets together around the edges with masking tape before starting, and used clamps to hold them to a flat surface. I used a nail to make a small indentation for the hole centers. I found using the smallest size drill at slow speed is good to start the holes. Then going up no more than two drill sizes at a time until the proper size for the hole is reached, created no cracking or splitting of the plexiglass. (My initial try was using almost the final hole size at the beginning, and it did ruin the plexiglas). My hole sizes were for LED holders or mini-switches, or screws at the corners for holding the two sheets of plexiglas together. I do have one hole which was larger than the drill bit shank size for a rotary switch, and it did split a little but doesn’t show beneath the switch. Getting into the 3/4" range or above requires great care!
Hal
My father and I did the same thing as Nick on my control panel, except we used Lexan. We painted the Lexan grey on the back side, then used blue and white pinstriping for my track schematic on the front side. The pinstriping was then sprayed with a sealer. This panel is still in use after 22 years.
Keith Baker