Making Printed Circuits
Spike Tsasmali, Board Products Engineer
Lupine Systems

Yes you can make your own printed circuits! Making PC boards is fun, easy and can save you tons of money!

Many folks have said that making your own printed circuits cannot possibly be cost saving, but that is not true. Once you get the technique down pat you will find yourself drafting PC boards for all kinds of applications.

This webpage contains detailed directions on how to make PC boards yourself. It is an extensive, lengthy webpage which goes into the intricate details of every step necessary to produce a high quality PC board yourself. Read it carefully and be patient and you will produce PC boards which will rival the manufacturers and last just as long.

The methods described in this website are designed to accomodate the average user, and may contain techniques which are "manual" in nature. Although some of the processes can be shortened by using specialized equipment, this site is written for the average person who has access to simple and basic equipment. This site also incorporates techniques which save money, time and hassle. Once you become accustomed to how the processes work, you may wish to expand your equipment to include several specialized items which may save time in the future.

What Materials Will I Need?

The first thing you will need is a CAD software to draw, view and print out the PCB layout files. I HIGHLY recommend using Protel's EasyTrax, a FREE and very powerful PCB drafting software. EasyTrax was once Protel's premier software before the Windows revolution, and has since been abandoned to their Windows version called AutoTrax. What this means is that you can have professional software to do your PC board layouts for FREE! Protel has made EasyTrax a shareware program and is legal and licensed to use and freely distribute.

EasyTrax runs under MS-DOS 6.0 or better (a Macintosh version is coming soon!) or Windows 95/98 using an MS-DOS Prompt. PC requirements are 286 processor or better and mouse. You will also need either a laser printer or inkjet printer for printing layouts, and it is recommended that you use VGA monitor of 640x480 or better.

EasyTrax will run under an MS-DOS promt in Windows XP and higher but you may need some assistance. Send WOOFY for help!

I have also written a tutorial on how to download , install, setup and use EasyTrax. You can read this tutorial by clicking Here.

All of the PCB files on the Lupine Systems website are written in the EasyTrax format. Once downloaded you can use the EasyTrax software to view, print or modify the layouts.

Other Things You Will Need

Most of the materials you will need are commonly found items around the shop. Some of the materials are specialized items and must be purchased from PC board suppliers. Sources for all of the specialized items are given in the table below.

Item
Source
Scotch TapeOffice Depot
Acetate Transparency FilmOffice Depot 3M Part# PP2500
(2) Plastic Trays, 12"x8" 2" deepDollar Store
Fluorescent Table Lamp, 2 bulbK-Mart, Wal-Mart
(2) pieces of CLEAR window glass, 14"x10" smooth edgesHardware Store
Sharpie Marker (MUST be this brand)Office Depot SANFORD Series 37000
PC Board EtchantJameco 616438
Coated PC Board
      Single Sided BoardCircuit SpecialistsPart# GS-153
      Double Sided BoardCircuit SpecialistsPart# GD-153
PC Board DeveloperCircuit Specialists Part# POSDEV
1 Gallon Jug (plastic milk jug)
Drill Press
Sabre Saw or Band Saw
Belt Sander
PC Board Carbide Drill BitsEbay!
Rubber Gloves (optional, recommended)
Apron (optional, recommended)


Items needed to make PC boards

You will also need about 3 square feet to set up your PCB exposure site and a bathroom with toilet, sink and running hot water.

There are four major stages to making PC boards:

  • Artwork

  • Exposing and Developing the PC Board Etch Resist

  • Etching the Copper Clad

  • Machine Shop (Drilling, Notching, Cutting)

  • Getting Started

    Once you have obtained the above mentioned materials you are ready to begin!

    Step 1. Artwork

    First you must create PC board artwork. You can create this artwork by using the EasyTrax software as mentioned earlier, or you can draw your PC board by hand using pens and drafting tape on clear acetate film.

    If you are using EasyTrax, you will use the EasyPlot application to print out each layer of the layout on separate sheets of film. When printing out layouts, do NOT try to recycle film sheets! Although some layouts are tiny, ALWAYS use a fresh sheet for each layer.

    All of Lupine Systems layouts are in EasyTrax format, and are assembled in the following sequence:

  • Top Layer

  • 1 Mid Layer as the Legend Layer

  • Bottom Layer

  • Multi-Layer (this is where pads are located)

  • None of the Lupine Systems layouts use the 2 Mid Layer, 3 Mid Layer, 4 Mid Layer, Overlay Layer, Ground Plane, Power Plane or Board Layer. These layers can be turned OFF in software. See the Tutorial on how to download, install and use EasyTrax for more information.

    Single Sided Artwork

    From the EasyPlot screen, print out the Bottom Layer on a sheet of acetate film. Once printed, inspect the printout for flaws. When using a laser printer, the image may appear to be slightly foggy with thicker borders. This is OK as long as the foggy appearing interiors of the tracks are not fully transparent. If you feel that there is too much light making it through, you can touch up the artwork by using a Sharpie pen. Draw on the INK SIDE of the artwork until the trace is completely opaque.

    Remember that the BOTTOM LAYER is printed out as an x-ray view. It will appear to you as if you could see the traces through the PC board from the parts side.

    You may also wish to print out the 1 Mid Layer on a regular sheet of paper. The 1 Mid Layer has the component placement LEGEND which will help you assemble the final PCB.

    Once you have touched up your layout artwork, you are ready to proceed with Step 2.


    Single-sided artwork on acetate film

    Assembling Double-Sided PC Layouts

    Double-sided layouts require special attention. Several issues involving alignment require particular attention.

    First, from the EasyPlot screen, print out the TOP Layer and Bottom Layer on acetate sheets and the 1 Mid Layer on a regular sheet of paper. Inspect each acetate sheet for flaws and touch-up as necessary.

    Next, align the TOP LAYER to the BOTTOM LAYER by placing them on top of each other. At this time you are checking to make sure the printer has not created unwanted nonlinear errors between the two layouts. If you can align the pads on the Top Layer to the pads on the Bottom Layer, then you are OK. If they do not align, one of the two printouts has errors. It is difficult to eyeball this error so you will have to reprint both layers and try again. HINT: When loading your printer, do NOT put the acetate sheets in with the paper! Also, do not "jog" the paper stack, instead feed each acetate sheet by hand into your printer.

    Once you have a set of layouts that align, use a pair of scissors to trim off a 1" section of the TOP LAYER in an area of unused acetate. Then, re-align the two layouts, being sure the TOP layer is actually on the top! Once alignment is perfect, use Scotch tape to tape the two layers together. The trimmed area will expose a section of the Bottom Layer's acetate sheet. Apply the tape to this artificial interior edge. Do NOT attempt to tape the factory edges together! Only tape the ONE edge together along the cut edge of the TOP layer.


    Aligning and taping together double-sided artwork

    Step 2. Exposing and Developing the PC Board Etch Resist

    Once your artwork has been prepared it is time to expose the PC board. This process transfers the PC layout pattern from the artwork to the etch-resist emulsion coating the copper-clad PC board material. This is done by placing the artwork on top of a pre-sensitized PC board and exposing it to light.

    If this is your first time running a PC board, you will need to prepare a work space where you can expose the PC board. You will also need to prepare the developer solution and have it ready to use immediately after the board has been exposed.

    Prepare your workspace by clearing off a space on your workbench about a square yard. Plug in the fluorescent lamp and set it aside. Then prepare the two panes of glass by cleaning both sides of both sheets with Windex and paper towels. Try your best not to touch the interior area of the glass. Remember you are preparing to do a photographic process, so be sure your workspace and all its surfaces are dirt and dust free. When you are sure your workspace is clean, place ONE sheet of glass flat in the center of your workspace and place the other one on a clean surface elsewhere. You will be making a stack of glass, PC board and artwork later, so keep the second sheet of glass so it can be easily accessed.


    Workspace setup for exposing PC board

    Before exposing the PC board, you may wish to cut the PC board material to fit the layout. This will save you money, prevent waste and make the process much easier. Use the paper-printed 1 Mid Layer legend as a guide to mark the WHITE PEEL-AWAY backing of the PC board. Use a Sharpie marker to mark on the PC board. Do NOT mark on the non-copper side of the board! Use a sabre saw or band saw to cut the PC board material to size. Cut the board about 1/8" LARGER on each side than the layout. This will allow you to be more liberal with the alignment. After the board has been cut, use a knife to scrape the cut edges smooth. Be sure to remove any ridges or burrs left behind by the saw. Try not to peel any of the white backing paper from the PC board. After cutting, dust off the board thoroughly using compressed air or a paper towel. Do NOT wash the PC board material!

    After you have your workspace set up and your PC board cut to size, prepare the Developer solution. Use 4 packs of developer per gallon. Empty all 4 packs into a gallon jug at the same time, then fill the jug about 3/4 full with luke-warm water. Next, put the cap on the jug and vigorously agitate the solution for 3 minutes. Once agitated, top off the gallon with cold tap water. If kept in a dark cool place, the developer will stay good for up to 4 months.

    Using the Ever-Muse pre-sensitized PC board material is easy and nearly fool-proof. It is rare to have problems using this process.

    Single Sided Boards

    In subdued light, peel the white backing paper from the copper side of the PC board. This will expose the green light sensitive emulsion. Carefully and quickly inspect the surface of the emulsion for scratches (rare but sometimes manufacturing defects occur). Once inspected, place the PC board with emulsion side UP in the center of the piece of window glass laid flat on your work surface in the previous step. Next, place your artwork on top of the green emulsion. Be ABSOLUTELY SURE you have the artwork PROPERLY ALIGNED. Remember, the BOTTOM LAYER is X-RAY VIEW. You will have to turn the artwork UPSIDE DOWN before placing it on the PC board. Carefully align the artwork to the center of the PC board then slowly place the other piece of glass on top of the PC board/artwork stack. This will "sandwich" the artwork and PC board together and form a tight fit. Make sure the top piece of glass does not "rock" on the stack and that the top glass actually is holding the artwork tight against the PC board.

    Once you have the artwork and PC board sandwiched together, turn on the fluorescent lamp and place the lamp so the bulbs are about 4" above the center of the PC board. Expose the board for 10 minutes.


    PC board shown sandwiched between glass sheets


    Exposing PC board with fluorescent lamp

    Double-Sided Boards

    In subdued light, peel the white backing paper from both sides of the PC board. Carefully inspect both surfaces for scratches. Once inspected, carefully slide the PC board in-between the layers of the taped together artwork. Avoid touching the green emulsion on the PC board. Align one side of the artwork to the center of the PC board. Once aligned, place the artwork and PC board in the center of the piece of window glass laid flat on your work surface in the previous step. Then carefully place the other piece of glass on top of the artwork/PC board stack. Be sure that the top glass does not "rock" on the stack and that the top glass actually is holding the artwork tight against the PC board.


    Placing PC board in between artwork layers

    Once you have the artwork and PC board sandwiched together, turn on the fluorescent lamp and place the lamp so the bulbs are about 4" above the center of the PC board. Expose the board for 10 minutes. After 10 minutes, carefully FLIP the glass stack and expose the other side of the board for 10 minutes. BE ABSOLUTELY SURE the artwork/PC board stack does not shift inside the glass sandwich during the flip.

    Developing the PC Board

    Now that your board has been exposed, you may notice the pattern of the PC layout in the emulsion. This is because the fluorescent light has changed the molecular structure of the emulsion where the artwork film did not protect it from the light. Only the black areas of the artwork protected the emulsion, thus exposing the emulsion to light in the areas where you do NOT want copper traces.


    PC board after exposure

    Inspect one of the two plastic trays mentioned in the supplies list. Be sure the bottom surface is smooth and has no rough areas. Some cheap plastic trays are injection molded and have small rings which have sharp rough edges. These rough surfaces will actually scratch the emulsion off the PC board and will cause the etching process in the next step to damage the PC board traces. If your tray has rough edges or surfaces, use a knife blade or sand paper to smooth these edges and/or surfaces before using the tray. This issue is more critical on double-sided boards than for single sided, but it is a good idea to have smooth trays for both.

    Place the PC board in the tray. Then fill the tray with developer solution about 1" deep. SLOWLY agitate the solution. You may notice the PC pattern showing up quickly in a smoky haze. This is normal. If the pattern does not show up within 3 minutes, the developer solution is too cold or is too old. You may want to mix a new batch if your solution is more than 4 months old. Heat the solution in the microwave for 30 seconds if it is below 60 degrees. On double-sided boards, observe both sides as they develop. Use your fingers to flip the board from one side to the other (the developer is mostly harmless, being primarily a soda-ash material, but it does irritate small cuts on your fingers, so rubber gloves are recommended.). Develop the board until the smoky effect has stopped or you are sure all the unwanted emulsion has been removed (don't worry about stuff OUTSIDE the perimiter of the PC layout..things such as edges, etc which will be cut away later). It IS possible to overdevelop and ruin a board, so be careful not to leave the board in the developer too long. A properly developed board should appear as a sharp green pattern on a bright shiny copper background.


    Properly developed PC board

    As soon as the board develops, rinse it off under luke-warm water for at least 30 seconds. If you plan to take a break and finish the board later, now is a great time to pause for a while. But before you break, you may dry the board with a SOFT paper towel or allow it to air dry. The board is no longer light sensitive and can be exposed to any light for any amount of time. Dispose of the used developer solution in the commode and flush it down. Thoroughly rinse your tray so it will be clean for use the next time. Store the tray in a dust-free environment.

    Step 3. Etching the PC Board

    The next step is to etch the PC board in an etching solution. This process removes all of the unwanted copper from the board and leaves behind the circuit pattern.

    Pre-Etch Inspection

    Before etching, inspect the board for scratches in the artwork. Also pay close attention to weak spots created by overdeveloping. If there are any scratches or weak spots, you can touch them up with a Sharpie marker. Be sure you use a Sharpie brand marker because the ink contained in these markers is resistant to the etchant and will protect the circuit traces.


    Touching up scratches on the emulsion with Sharpie marker

    After you are certain there are no breaks in the traces, you are ready to etch.

    Etchants

    There are two types of etchants commonly used to etch PC boards. These etchants are Ferric Chloride and Ammonium Persulfate. Each of these etchants have their benefits and drawbacks.

    Ferric Chloride solution is a brownish-yellow thick liquid with somewhat oily properties. The benefits of using Ferric Chloride is cost. It is commonly sold at Radio Shack in 16 ounce bottles (Catalog number 276-1535a). Contrary to the label directions, this etchant is strong and can be diluted with water with good results. You can re-use the etchant several times but it is recommended to dispose of it after each use. The drawbacks of Ferric Chloride is that it is messy and emits chlorine gas during the etching process. Stains created by the etchant, although mostly harmless, are permanent. Use of rubber gloves and apron is highly recommended due to its stain properties. Also, Ferric Chloride works best when heated to very high temperatures, and at high temperatures the chlorine gas emission is increased so extreme ventilation is also recommended.


    Radio Shack Ferric Chloride Etchant

    Ammonium Persulfate comes as a white, crystalline powder which dissolves readily in water. Mixing the solution is easy and when mixed with water appears to be a water clear, colorless, odorless solution. During the etching process, the solution will turn a turquoise blue and precipitate a turquoise crystalline powder (especially at lower temperatures). This blue precipitate can solidify in the bottom of the etching tank or tray and can be extremely difficult to get rid of. The benefits of using Ammonium Persulfate is the transparency of the solution allows you to view the etching process more clearly than Ferric Chloride. Ammonium Persulfate also has a longer shelf life. It also does not readily emit dangerous gasses (although there is a light ammonia smell). The drawbacks are cost, being about twice as much as Ferric Chloride, it saturates faster, requires frequent reheating and one hidden horror -- if this water-clear solution gets on your clothing, it will appear to be just a "wet spot", but when you wash your clothes the area contaminated will literally dissolve, leaving huge holes. Use of gloves and apron are mandatory due to the damaging properties this etchant has to clothing.


    Ammonium Persulfate etchant powder

    Use of Ferric Chloride is recommended for beginners because of its ease of use, cost and good overall results.

    Etching the Board

    Place the PC board in a plastic tray. Do NOT use the same tray as you used earlier to develop the emulsion! Be sure to inspect the tray for rough surfaces because these surfaces may scratch the emulsion and expose wanted copper to the etchant. Remove all rough surfaces before you begin etching your board.

    Next, pour about 1/3 bottle of etchant into the tray and add about the same amount of HOT tap water. Agitate the tray back and forth and side to side vigorously for about 10-15 minutes until all unwanted copper has been etched away. On double sided boards, you may need to flip the board over to complete the other side. You will be able to tell what is going on by observing the copper as it dissolves away leaving behind bare fiber-epoxy PC board surfaces with distinct circuit traces. Etch the board for 1 minute AFTER all visible copper has been removed. This prevents micro traces from forming and insures all microscopic shorts are removed.


    Etching PC board in Ferric Chloride solution

    Once the etching process is complete, dump the used solution in the commode and flush twice. Rinse off the PC board and etching tray in running cold water for 1 minute to stop the process. Be sure to clean the etching tray thoroughly before putting it up.

    You may dry the board using a rag or paper towel. The PC board is now complete and ready for machining.


    Completed PC board

    Machine Shop -- Drilling and Cutting

    Drilling all of the holes is the most detailed process of making a PC board. You will need the proper tools to do a professional job. Use of a drill press is mandatory and carbide drills is HIGHLY recommended.


    PC Board Drill Setup

    For best results, try to use the smallest bit for the job. Different components use different hole sizes. Using a large bit can remove too much copper from the pad and make assembly difficult and reliability low.

    Here are some of the typical drill sizes used for common components:

    ComponentSize in mils (.001")
    Small Resistor32
    Large Resistor42
    Small Capacitor32
    Large Electrolytic38
    IC's Chips, Sockets30
    Small Transistors32
    1N4000 type Diodes40
    .100" Molex Connectors54
    .156 Molex Connectors68
    TIP-122 style Transistors38
    Via Holes (double sided boards)24
    Board Mounting Holes225

    Take your time drilling holes. Patience makes perfect during this process. Eye strain is also an issue so you may wish to use a pair of magnifying glasses. Good light is also a plus, so be sure you have plenty of light shining on your work.


    Drilling holes in PC board

    Use of carbide bits is highly recommended. This is because carbide bits do not bend when the tip of the bit touches the PC board surface. Small hobby bits found at model train shops will work, but they will twist at the tip. They also tend to dislodge the copper traces on the non-drill side of double sided boards. Carbide bits give a clean burrless hole which is precision in size. The drawback of using carbide bits is cost and delicacy. These bits will break very easily unless you spin them at high speed. They also are very expensive when purchased new (up to $8 each!). Dremel tool drill presses work the best, giving up to 22,000 RPM, but standard shop presses that can make 4400 RPM or better work fine. You can buy these bits by size or drill number at any good machine shop or on Ebay. Typically Ebay auctions are for assortments of sizes in used or new condition. Ebay auctions can be a gamble, but for the cost savings you just about can't go wrong.


    Carbide Drill Bits used on PC boards

    Cutting the Board

    Now that your board is etched and punched (drilled), you are ready to size the board to the exact size marked by the edge marks.

    You can use shears to do the job, or a band saw, but use of a belt sander is recommended. You can cut a board to precise size by sanding away the unwanted board material. Use a saw to trim as close as you can to the edge mark first, then sand the remaining board material away.


    Sanding PC board down to size

    After sizing the board, clean the remaining emulsion off the board with an Industrial Rush Brush or fine steel wool.


    Cleaning PC board with Rush Brush

    You are now ready to assemble your circuit!


    Completed PC board ready to add parts

    What to Do Next??

    There are several things you can do next. You can go straight to work assembling your PC board or you can:

  • Tin plate the board

  • Clear Coat the board

  • Add legend or solder mask

  • If you decide to tin plate the board, you can use a product called TIN-IT, available at Circuit Specialists. This process plates the copper board with a fine layer of tin and can protect the board from corrosion and make assembly easier. It also makes for a more professional looking board. TIN-IT works much like the developing or etching process. It is a mixture of two white powders mixed in water, heated and used to soak the PC board until it is plated.

    Clear coating covers the bare copper areas of the board with urethane finish. Again, this is a process which protects the bare copper from corrosion.

    Adding legend to your board is as easy as printing out the 1 Mid Layer on self-adhesive backed clear plastic film, then sticking it onto the top of your PC board. Just punch the parts leads through the plastic when mounting the components.

    Good Luck with your project! If you have any suggestions, please send E-mail to the Wolfman at Lupine Systems

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