PDF - Iron it On
Etch your own Circuit Board

This is easier to do than it reads!

Here is my experience:    (Read completely before beginning)

The RS Theremin PDF file will open in Adobe Acrobat looking crude, prints with crystal clarity with a reversed image.

In Adobe un-check the boxes, especially the "Fit to Page" box.

I prefer a single-sided copper on a fiberglass epoxy board from another store, not at Radio Shack.


Paper to Use:

Laser Toner type printers are available today for less than a $100, check with Fry's Electronics.

Use a Laser Printer like the HP-4. Print the PDF files onto a blank piece of 70#, 80# or 100# glossy paper like that used in magazines. Gloss computer photo printer paper can work but I prefer the 70#, it is thinner and more transparent after ironing. These HP-4 laser type printers use a big plastic container of black powdered toner.

or 

Others have recommended:

This paper at Staples - HP Soft Gloss Presentation Laser Paper as of 06/28/08   www.staples.com  $14.99 - 200 sheets  (If you use this let me know how it works for you)

Last resort if you don't have Laser Toner type Printer: (I have not tried this)
Print a good quality Ink Jet copy of the PDF, then use a Xerox Copy Machine to convert your Ink printout into your Toner iron on copy. You must put your special gloss paper into the copy machine paper tray. Print at least three sheets.

View another builders page on etching

View My Board Photo (before & after)


Start: (Once you have everything ready, ironing, etching and drilling takes about an hour)

If you use the Radio Shack two sided copper board when building the RS Theremin projects, the unused copper side must be completely etched away. (removed)  Cut your raw copper clad circuit board to the proper size. You could leave your board larger if you're unable to cut it.

Clean your raw pc board with something like Windex window cleaner and a kitchen scrub pad to remove any oxidation or grease films. Do a final cleaning with pure water, then dry without touching the copper surface with your fingers.

Cut apart the top and bottom board PDF images which were printed on the laser printer. Scissor trim each PDF image to have about 1/2" to 1" (1.3 cm) to (2.5 cm) overhang around the raw copper board size.

Position the PDF pattern against the copper on the raw board, the sheet should lay out flat with about a 1" (2.5cm) overhang.

Place a second piece of blank 8.5" x 11" paper over the PDF paper and tape down two corners of one side. This keeps the underneath PDF in place while ironing. I use my thick glass dinning room table with a lamp underneath for positioning.

Pre-heat your iron on the cotton setting or hotter (no steam, duh). Place the iron on the top blank paper, heat up everything for about 30 seconds. If your iron is too hot the toner/ink between the IC pads could melt together but not likely, to cold and the toner  transfer will not adhere properly. The paper must look a bit scorched from this iron pre-heat.

With firm rubbing pressure,  iron the pattern onto your copper board using the tip and edges of the iron. Do this all around the board, especially the board edges.  

You must use the edge of the iron and the tip for solid contact.

The toner/ink liquidizes onto the copper with solid adhesion if the board is clean!

Let the board cool down naturally, don't shock it in cold water which can make the paper more difficult to remove.

Now soak the board in a bowel of water or saturate it Windex with Ammonia (window cleaner) for about 5 minutes to release the paper. Peel back the excess paper, use gentle rubbing of your finger and your finger nail in between pads. The black toner/ink will stick tight to the properly cleaned copper.

In between the eight IC pads use a point to carefully scratch a line so you can visually see raw copper. This way proper etching will occur between the pads.

If you have one weak line or pad the best thing to do is protect the area with a BIC Wite-Out correction pen. As a last resort use a medium tip black ink zippy resist marker. 

Don't proceed with a board with a defective transfer of the black laser toner!

If you are not happy with your results, consider your first try practice and do the above again. I removed the black toner by heating up the board a bit, using a scrub pad, warm water and some elbow power. Using acetone is good, a little charcoal lighter or kerosene also helps.

*******

A light gray coating from the papers gloss glaze is left on top of the black toner. Leaving a little bit is better than rubbing off the toner transfer. It is this gloss glaze that allows the black printer toner to release from the paper fibers when soaked.

In between the IC pads use a needle or sharp point to scratch a line to be certain in between the pads etches  properly.

Now you need a rubber bowl.

If you use the Radio Shack two sided copper board make certain the opposite side copper is completely removed. Make certain the bottom of the board has room for the enchant to move freely. If you use a round bowl the sides of the bowl could hold the board away from the bottom. Pour enough etchant so the board is covered about 1/4" (6mm).

ferric chloride solution Radio Shack # 276-1499

Use a rubber bowl and gently rock it back and forth to manually agitate the solution while the etching occurs.

Etching in the ferric chloride solution takes about 20 - 30 minutes if warmed to above 75 degrees F, I set my solution in the sun while working. Cover the board about 1/4" (6mm) so you can observe the etching process easily. Carefully watch for the last area of copper as it begins to dissolve away, make certain in between the IC pads are etched properly, then your done.  

Now rinse your board thoroughly under tap water. 

The solution will stain so use caution in how you rinse!

Scrub off the protective black laser toner from the copper traces with a kitchen scrub pad. Acetone works good or charcoal lighter fluid which is a bit slower. Elbow grease is the key.

Drill using the smallest drill bit you can purchase so the part wire leads fit snuggly through the copper pad holes. A drill press and a ¹/₃₂ bit works great for most resistor and DIP holes. A #66 bit is even better.  A slightly larger bit for the output cables and pots is preferred.
.

Dremel Accessories a Lowe's Hardware have a drill combination 5 pack with one 1/32"  bit.

Drill Bit City has mail order #66 drill bits with a fatter shank for holding in the chuck. 5 bits $8.15 usd

Mom & Pop hardware stores usually carry good assortment of small drill bits.

If needed use a small center punch or nail to dimple the pad if etching did not make a mark. After drilling use a disposable shaving razor to clean the component side of the board of drilling bumps and debris.

After Drilling the holes and shaving align the top silkscreen on the board. My glass table and a light on the floor works great for this. 

Now iron on the component images in the correct direction.

After a natural cool down, once again soak the board in water or better yet use a Bath & Shower cleaner that removes calcium & soap build up (Shower Power). Soak for about 5 minutes to release the paper. Peel back the excess paper, use gentle rubbing of your finger or a "very soft" toothbrush to gently remove the gray paper glaze that adheres to the top of the black toner on the board.

Special Notes:

* Use a scrub pad to clean the copper traces of oxidation before assembling and soldering.

* I like to spray the top silkscreen component images with a light coating of lacquer spray paint to protect them from scuffing and enhance the contrast.

* When the board assembly is finished it is wise to cover any unused copper pads with a light coating of solder for any future connections. Then spray lacquer paint on the copper foil patterns to prevent the rapid oxidation of the copper that does occur. The pre-soldered pads will allow for new solder connections without paint removal. It is best to mount all the components, solder and spray lacquer paint all on the same day!