1. Setup

Protect surrounding area's from developer and etchant splashes. Plastic is ideal for this. Work under safe light conditions, a 40W yellow or red incandescent bulb works well. Do not work under fluorescent light.

2. Applying the Resist

Clean the board using fine steel wool or similar abrasive pad and rinse well with water. Dry the board quickly with a hair dryer to prevent corrosion.

Enter your safelight environment, and take the resist out of the package. Cut off a portion of resist large enough to cover both sides of your board, folded over one side, leaving 1 cm of excess resist on all sides except the side the resist is folded over. The easiest way to do this is to lay the resist flat, lay the board on it, and then cut around the board with a fabric cutter, flipping the board over one side while cutting to double the area. If you do not have a fabric cutter, sharp scissors or an exacto knife will work fine.

The resist has a protective coating on both sides, a soft coating on the side facing the inside of the roll and a harder coating on the outside. Remove the soft coating from the resist that has been cut for use (This can be tricky to do so be patient).

Next, apply the resist to the board. If it is a double sided board, fold the resist in half over one edge, sandwiching the board between the two sides so they come together forming a 1 cm strip of excess resist around the board, except for the side the resist is folded over. Ensure the resist is flush against the board and free of wrinkles (you may have to practice a few times to do it wrinkle-free). Also, ensure that the side with the protective coating removed is against the board.

If it is a double sided board, fold the resist in half over one edge, sandwiching the board between the two sides so they come together forming a 1 cm strip of excess resist around the board, except for the side the resist is folded over. Ensure the resist is flush against the board and free of wrinkles (you may have to practice a few times to do it wrinkle-free). Also, ensure that the side with the protective coating removed is against the board.

If it is a single sided board, the process is almost the same but the back side of the board does not need to be covered. Make sure, however, that there is at least 1” folded over one edge; this edge will be the first one through the laminator.

• Seal bar temperature: 50 – 80 °C (120 – 176 °F)
• Laminator roll temperature: 100 – 115 °C (212 – 239 °F)
• Speed m/min(ft/min): 2.0 +/- 1.0 (6.5 +/- 3.3)
• Pressure kg/cm2(psi): 2.5 +/- 1.5 (40 +/- 20)

Store finished board in a dark and dust free environment until ready for use.

See the full instruction for the Negative Dry Film Resist application

3. Exposing your board

For best results, use M.G. Chemicals Exposure Kit (Cat. No. 416-X), however, any inexpensive lamp fixture that will hold one or more 18" daylight fluorescent tubes is suitable.

Directions: Place laminated board, copper-side toward exposure source. Negative film artwork should be laid onto "presensitized" copper side of board and position as desired. Artwork should be placed printed side down to prevent light leakage through the side of the transparency, and should have been produced by a 600 dpi printer or better. A glass weight should then be used to cover artwork ensuring no light will pass under traces (Approx. 3mm glass thickness or greater works best). Use a 10 minute exposure time at a distance of 5 inches.

4. Developing your board

The development process removes any photoresist which was not exposed through the film positive to ultraviolet light.

Warning: Developer is corrosive. Wear rubber gloves & eye protection while using it. Avoid contact with eyes and skin.

Directions: Using rubber gloves and eye protection, dilute one part Negative Developer (Cat. No. 4170-500ML) with ten parts tepid water (weaker is better than stronger). Remove the outer protective coating of the resist. In a plastic tray. Immerse the board copper side up into the developer, and you will quickly see an image appear while lightly brushing the resist with a foam brush. This should be completed within one to two minutes. Immediately neutralize development action by rinsing the board with water. When you are done the developing stage, the only resist remaining will be covering what you want your circuit to be. The rest should be completely removed.

5. Etching your board

For best results, use the Professional Etching Process Kit (Cat. No. 416-E) or Economy Etching Kit (Cat. No.416-ES).

The most popular etchant is Ferric Chloride (Cat. No. 415), an aqueous solution which dissolves most metals. Use this solution undiluted, and be sure to completely cover your board.

Warning: This solution is normally heated up during use, generating unpleasant and caustic vapors, it is very important to have adequate ventilation. Use only glass or plastic containers. Keep out of reach of children. May cause burns or stain. Avoid contact with skin, eyes or clothing. Store in plastic container. Wear eye protection and rubber gloves.

Directions: If you use ferric chloride cold, it will take a long time to etch the board. To speed up etching, heat up the solution. A simple way of doing this is to immerse the ferric chloride bottle or jug into hot water, adding or changing the water to keep it heating. A thermostat controlled crock pot is also an effective way to heat ferric chloride as is thermostatically controlled submersible heaters - glass enclosed such as an aquarium heater. An ideal etching temperature is 50°C (120°F). Be careful not to overheat it. The absolute maximum working temperature is about 57°C or 135°F. The warmer your etch solution, the faster your boards will etch. Ferric chloride solution can be used over and over again, until it becomes saturated with copper. As the solution becomes more saturated, the etching time will increase. Agitation assists in removing unwanted copper faster. This can be accomplished by using air bubbles from two aquarium air wands with an aquarium air pump. Do not use aquarium "air stone". The etching process can be assisted by brushing the unwanted copper with a foam brush while the board is submerged in the ferric chloride. After the etching process is completed, wash thoroughly under running water. Do not remove the remaining resist protecting your circuit or image, it protects the copper from oxidation.

6. Stripping

After plating or etching is complete, remove the resist by submerging it in Resist Stripper (Cat. No. 4185-500ML).

Watch this process on video