Photo Etching Tutorial Using Negative Photoresist

today I'm going to show you how to make your own photo etched metal parts at home there are many companies that you can pay to do this for you but why do that one for a fraction of the cost you can do it yourself professional edging houses use the same techniques that I'm going to show you here typically the size of metal ranges from a half a thousandth of an inch to thirty to thousands of an inch and sometimes going up to an eighth of an inch the thicker the material you use the less precise your final part will be in this demonstration I will be showing how to get your artwork ready making a stencil application of photoresist putting your design onto your resist developing the film the process of etching removing the remaining resist an environmental cleanup your artwork is the most important part of this process and so you will need to spend a lot of time on getting your artwork ready whether you draw it yourself and scan it into your computer or find your design online you'll need to do some additional work to make it usable once you get your design onto your computer you'll need to use a program like Microsoft Paint Photoshop or CorelDraw to clean up your edges this is a circuit board that I designed inward then did a print screen and copied into paint once zoomed into you can see all of the error correcting that needs to be done black needs to be black and white needs to be white there should be no gray when I use the Paint Bucket to change colors you can see what still needs to be changed when we put the design onto our metal we are going to use a negative image so I'm going to change black to white and white to black using red and green to help it should be noted here that paint has a maximum of 96 dots per inch if you are taking your work to an etching house they will ask for at least 600 dots per inch if you need that kind of resolution photo shop or CorelDraw is the way to go this is a panel I scanned the process is the same but obviously there's more work to do be aware that cleaning up the artwork is a very long procedure that can and most likely will take several hours to complete there are three ways I will describe on how to design yard work the first is if you want to make a single sided circuit board the second is if you to have holes completely through your metal the third is if you want raised or lowered areas of your metal and of course you can have combinations of the ladder to a single sided circuit board is a laminate board with a thin layer of copper only a single piece of artwork will be needed and printed only once the edges are determined by the laminate board and cannot be H through only the metal will be etched away a design that is fully h2 and is the same on both front and back will require one piece of artwork but will be printed twice the artwork will end up creating the outer and inner edges during the etching process if you want raised or lowered edges on your metal you will need to have two different pieces of artwork the top piece in this example shows where the outer edges are but also what will be partially at creating erased or lowered effect the back piece of art only gives a border if you do not have a border piece you may end up with two and more pieces when you've finished edging sometimes that's going to be okay but sometimes you might end up with more than you bargained for this is a combination of the last two options the artwork is designed to through holes as well as raised and lowered edges once you have your artwork done you'll need to print your design onto transparency film there are many kinds available through office supply stores or through ebay make sure the kind you buy is correct for your type of printer if you're going to etch a circuit board then you will only need one copy otherwise you will need to print out at least one copy of front and back maybe more look closely at your page you will probably notice some tiny areas that your printer missed if that's the case you're going to need to use a sharpie and fill in those tiny spots if you have a high quality printer that hasn't missed anything consider yourself lucky now you have your artwork and it's time to make a stencil out of it I use optics Plexiglas for my stencils there are many brands out there and not all are created equal your Plexiglas needs to allow ultraviolet light through it if the Plexiglas you buy has UV protection you will not be able to use it lexan is popular but it will not work here it does not allow UV light to pass through when we transfer the design onto the film it is done through UV light I will be showing other ways to put an image onto your meadow later but this method requires UV light if your design is for a circuit board all that's needed is the tape a copy of your design onto a slightly bigger piece of plexiglass with this design I'm going to want to etch through from both sides I've made a few copies of the design page and cut them in half with some tape I secure the first one down and go through the other design pages to find one that matches exactly with the first it's important to use the word exactly as being slightly off will change how the finished design looks dramatically tape the top page to the bottom page on the same side when they line up correctly cut two pieces of Plexiglas to the size and shape of your artwork place the artwork between both pieces of Plexiglas and secure with a few clamps using appliers in a butane torch I heat up a brad nail and push it all the way through both pieces of Plexiglas and the artwork trying not to wiggle the nails I go through a wiggle may create a distortion and distortions are bad for this piece I used five nails for this one I used ten and have them on both sides your stencil is now complete as long as you don't damage your stencil it will be good for years and many thousand copies of your design photosensitive film is also called photoresist the resist has three layers appeal sheet the resist and a cover sheet for some reason in the state's is ridiculously hard to find at reasonable prices that is why eBay is our best friend it is found mostly in China although some suppliers are in Sweden or Poland so it will take a few weeks to get from there to the states when you get it it will likely be wrapped in black plastic or something that will block light it also has a distinct chemical smell that reminds me of a Walgreens photo map from the 80s keep the resist in the black bagging out of any light until you plan to use it before we get into how to use it it is very important to see how the manufacturers intended it to be used while DuPont does not make their resist available for the common consumer their data sheets are readily available online this is negative working which means that the black part of your artwork will be etched away while apart that is clear whilst a surface preparation for your mild alkaline cleaner simply put Don takes Greece out of your way laminating temperatures exposure rates in terms of Stouffer's insa tivity guide we will be using trial and error but it's good to know about the skyed it gives you a visual guide to how much UV light your resist should be exposed to this scale is not accurate but it gives you the idea if you'd like a guide this is the place to get them the chemicals that are used for developing are listed na2co3 is sodium carbonate also known as washing soda or soda ash this is readily available in the States as soda ash in pool supply stores or super washing soda in Ace Hardware stores edging is compatible with most acid etch ins I will be showing a hydrogen peroxide and muriatic acid etching solution the stripping recommendations suggest sodium hydroxide or potassium hydroxide I will use a higher percentage of sodium carbonate I will also show the effects of stripping with sodium hydroxide on bras you will not likely get this information if you go through ebay but luckily there is little difference in technique between brands it should be noted that there are different types of photoresist material available and not all of them are created equal if you do a google search on the term photoresist you will very quickly run into Sam carving photoresist under different proprietary names sand carving is an etching technique that is used to put images into glass it uses sandblasting as the method of itching the glass the resist for Sam carving is similar to what we will be using in that it is sensitive to light but is not meant to be used for chemical photo etching please make sure you get the correct type of resist for your needs photoresist film is UV sensitive and has different reactions to different types of lighting instead of rambling on about different ways light reacts to the resist I'll show you this is fresh out of the package resist this is after being exposed to incandescent lights for six hours fluorescent lights for an hour and for three and a half hours blacklight for eight minutes direct sunlight for one minute for our purposes I will be using a ballasted backlight there are many different types but if it doesn't have a ballast it isn't going to work these are not black lights they are nothing more than colored incandescent lights I do not use CFL bulbs for any reason so I do not know how the resistor will react to it now that you have some understanding of lights and lighting it's time to figure out your exposure times and how to set up your exposure area your lamps should be eight to twelve inches away from your exposure area I use Baker portable work lights with the reflector removed I use two of them because of the length of my stencils you may only need one or may need more take a small piece of resist and put it in your stencil clamp it down put it under your exposure area and turn on the lights expose it for a minute turn off the light and see how well of a defined edge you have on your resist this is an eight minute exposure and it has clearly defined edges it's what I use for this brand of resist now onto the fun make sure you've cleaned your metal first we're going to apply the resist to the metal there are two ways I do this for the first one you're going to need there is this cut just bigger than the metal scotch tape water and spray bottle or bulb syringe scissors and something like a plastic spreader take a piece of scotch tape and put it on the edge on one corner take another piece and do the same thing on the opposite side of the same corner make sure they on tight and pull apart the clear plastic is trash apply water to the metal and to the resist side of the film put the resist side onto the metal and apply water to the cover sheet use your spreader and push the film onto the metal make sure there are no bubbles use a rag as needed to clean up excess water cut the excess resist from the edges and do the same thing to the other side the second method is not as easy and not as accurate but I'm going to show it in an attempt to be thorough remove the film and place the resist over your metal using your finger or something round push the resist onto your metal your finger may produce enough heat to start adhering the resist to the metal this can cause problems if bubbles form and you are unable to get them out as long as the resist doesn't adhere to the metal you may be able to readjust the film if for some reason the resist doesn't adhere properly you may need to go through a stripping process to remove the film and start over it's better to spend a few pennies on a different piece of film than ruining your metal next we use heat to adhere the resist to the metal there are two ways that I've used to make this happen the first use is a laminator this one has the top off but it's not necessary to do that I've had some pieces get stuck and I just find it easier to keep it off for when I need to pry out the next thing and clean it I'm going to use a piece of white paper on top and bottom to act as a carrier pouch you don't want to have the film directly touching the hot rollers the infrared thermometer shows the output temperature to be around 155 degrees Fahrenheit it's little hotter than it should be but it worked for this application the second technique uses a portable heater or even a hairdryer the metal is passed in front of the heater until it has reached optimal temperature once it has pressure is reapplied to the film to make sure it has properly adhered to the metal this is used if you don't have a laminator or if a piece of metal you plan to etch is larger than the laminator will allow once the metal has cooled down it is put carefully into the stencil and clamp down its exposed for the amount of time done in the testing phase for me it's eight minutes the lights are turned off and the pieces flipped over it is again exposed for eight minutes once again the lights are turned off the clamps are removed the stencil opened and the metal removed some data sheets require a 15 minute window between exposure and developing not all do but it doesn't hurt to wait the 15 minutes before exposure and developing keep the resist away from any light to prevent overexposure during that 15 minutes you can set up your developing tray you are going to use super washing soda and water at the ratio of 1 to 115 for every gram of soda you will use 115 grams of water 3 grams soda 2 345 grams of water make sure it's mixed well once you're ready to develop you're going to need to remove the cover sheet take a piece of tape and put it on one of the corner and peel back the cover sheet make sure you do it to both sides put your middle into the tray and rock the developer over your design for a minute or two then turn it over and do the same thing on the other side after 2 minutes on each side take your metal out and put it under a spray nozzle on your sink if you don't have a spray nozzle just put it under the faucet on high using cold water you will need to do this a couple of times to get the non exposed resist off your metal you will be able to feel when the resist is gone your metal will feel slimy when there is still resist on the metal you may need to use a soft sponge into the water to remove any unwanted resist when developing is done there will be a distinctive edge between the exposed resist and the metal the datasheet says to blow dry thoroughly hot air preferred keep in the dark place until you plan to etch you now have your image on your metal there is another way to get an image onto your metal it's called the toner transfer method this method also uses your artwork on transparency paper instead of using a resist film heat is used to transfer the image directly onto the metal and iron is turned on and heats the transparency film along with the metal until the image goes from the paper onto the metal this is useful in certain situations but not for detailed through-hole itching for the etching of our metal we're going to need a few things most important are rubber gloves and eye protection and a plastic container you will be working with us it and safety is most important because we're going to be working with acid you're also going to need a very well ventilated area do not use any metal measuring cups or tools during this process the only metal should be what you plan to etch the most well known itching solution is ferric chloride however it's far more expensive than the alternative I will be showing I will be etching with a two-to-one mixture of hydrogen peroxide and muriatic acid if you're going to be using three cups of edge and you'll use two cups of hydrogen peroxide and one cup of muriatic acid in a plastic container put your two parts hydrogen peroxide then your one part muriatic acid then with gloved hands place your metal to be etched for demonstration purposes I use the whole sheet normally you would trim off at around the edges or even cut this one sheet into three you can see holes developing in the metal then it coming apart unfortunately I decided to use a black container so you cannot see the effects of the etching on the solution the solution will turn from clear to deepening shades of green as the colour deepens the strength of the etchant dilutes this is the solution after the etching of these three were done after you've completed the etching thoroughly rinse off your metal in cold water do not dump out your edge in solution I'll get to that shortly to remove the remaining film from your metal you're going to mix your water and washing soda at the rate of one cup hot water to one spoonful of soda mix and when the crystals dissolve put in your metal unlike during etching or developing you will not agitate the solution just let it sit for a few minutes you'll see the film separate from the metal flip the metal and let it soak on the other side if there's a southern piece of film just let it soak do not scrub or try to remove it manually it can leave a stain on your metal while I do not recommend stripping with sodium hydroxide it does produce some interesting results that you might want to employ in your design the datasheet mentions stripping with sodium hydroxide at a 1 and a half to 3 percent ratio to water this used to be available as red devil lye now it can be found as Rudo my drain opener not all drain openers are equal and only Rudo is pure sodium hydroxide it can be found in the States through Ace Hardware when you mix it only use cold water this piece soaked in a 3% solution for one minute you can see the reaction this odium hydroxide has to the brass this is the difference between stripping with sodium hydroxide and washing soda your pieces are now done but you still have some work to do the stripper and etching solution both need to be properly disposed of the sodium carbonate and resist film solution should be filtered and the liquid can go down the drain to filter I put some paper towels over the sink brain and pour the solution out the resist film pieces can be thrown away the etching solution is a little more difficult to dispose of properly different states and countries will have different on how to properly dispose of this I recommend you contact your local hazardous waste disposal center every city has one tell them you've been itching with hydrogen peroxide and muriatic acid also tell them what type of metal you've been itching like brass or copper they will tell you what steps to take if for some reason they don't mention a few things I will mention them here first do not ever put a tight lid on used edging solution that involves muriatic acid and hydrogen peroxide a two-liter bottle with used edging solution and a tight cap will quickly become an acid rocket the solution gives off gas even after you take your metal out of the solution that gas will pop your two-liter bottle spraying acid everywhere while skidding across the ground the waste disposal people might tell you that you can neutralize the acid with baking soda if they tell you to do this there is a reaction that you need to know about when you put baking soda into your acient solution there is a violent reaction between the two make sure to do this in a well-ventilated area and in a container large enough to handle the reaction then dispose of as described by your local authorities that's it you're all done now go make something

Channel: TheDarkPopedotcom

Views: 145,513

Keywords: etch, hellraiser, brass, photoresist, photo, panel, resist, circuit, board, pcb, chemical, box, make

Id: UsmE1gLbHqI

Length: 18min 59sec (1139 seconds)

Published: Wed Feb 13 2013