Reptilian Copper Infused San Mai

Step 1: Sanding

Bring your Damascus to a 400 to 600 grit finish. If you’re using muriatic acid, you can bring the Damascus up to 1200 grit, or you can leave it at 400 grit. Either is effective however the color contrast is darker with Ferric Chloride For ferric acid, keep the grit between 400 and 600.

Do not buff before etching. Buffing closes the pores in the metal, which will keep the acid from absorbing, and you’ll end up with an uneven etch.

Step 2: Washing

To etch Damascus, it should be perfectly clean. Thoroughly wash your piece, we recommend washing with dish soap and sponge and then a final wipe down with pure alcohol.

Step 3: Dilution

If you’re using ferric acid, dilute it with Distilled water to a 10% Ferric, 90% Distilled water ratio.

Never use tap water, spring water, or filtered water – they will all cause problems with the etc. Be sure that your distilled water hasn’t been sitting for more than a year. Muriatic acid needs no dilution.

Step 4: Warming the Acid

For both muriatic acid and ferric chloride, the temperature should be between 70 and 100 degrees Fahrenheit, about room temperature. If you need to warm your acid for use, the best method is to place your container of acid into a large bowl of warm water. **Never put acid in the microwave**

Step 5: Submersion Etching

Hang your Damascus piece in the etchant so it is fully submerged and hangs freely without touching the sides or bottom of the container.

After 5 minutes, gently lift the piece out of the etchant and lower it back in a few times. This helps clear away material loosened by the acid.

Then leave the piece submerged for 10 more minutes.

Step 6: Neutralization

Remove your Damascus piece from the acid and submerge it into your baking soda bath for 5 minutes to neutralize the acid. (You can also spray piece with Windex to neutralize the acid) Pat dry. After neutralizing you can spray the damascus with WD-40 and hang for 3-5 hours which can darken the color contrast, this works better with carbon steels, stainless steels won't get much darker.

 ***You can repeat steps 5 for a deeper etch if you desire***

Coating: ATP-641, Turco, or similar high temperatureanti-scale/decarburization coatings can be used in replace of foil to reduce scale or surface decarburization.

Data is representative of controlled heat treating equipment (e.g. oven,salts, etc.) temperatures and industrial standard quenchant.

Suggested quench oil: Parks 50–expected as quenched hardness may be lower if a slower quench oil or non-industrial quench medium is used.

Austenizing: Austenizing temperature (1,450 to 1,480°F /801°C) Soak time varies 5 to 15 minutes based on heat treating equipment and cross section–soak times are reduced to minimum for people heat treating in a forge–forge heat treating without PID temperature control limits accurate means of maintaining temperature. If using calibrated, proper industrial equipment for heat treating, use the supplied extended soak times based on over all steel thickness.

**Do not put blades in oven when cold, insert at or just below austenizing temperature–temperature variances is for difference in stock thicknesses and a window of margin for error.

Tempering: Once blade is quenched and near ambient temperature, blades should be tempered accordingly, the times suggested are to ensure even, consistent temperature.Figures supplied are as representative of industrial standards.*If using a small toaster oven or household kitchen oven for tempering, using a blade holding rack made from kiln furniture, a roasting tray lined with fine sand, or similar large object will help retain thermal mass to reduce wide swinging temperatures as the device fluctuates trying to maintain temperature.

Note: Final hardness values vary based on initial as-quenched hardness and percentage of conversion to Martensite. Only reliable testing methods, e.g. calibrated Rockwell hardness tester, can provide actual hardness values–hardness calibrated files and chisels are relative testing methods and inaccurate for true hardness value reading.

Temper twice for 2hrs.

For knife damascus blades and similar parts made with annealed O-1 Damascus or San Mai with an O-1 core.

Use a temperature-controlled heat-treatment furnace for accurate, consistent heating.

Step 1: Apply an Anti-Scale Coating

Clean the material and apply ATP-641 or another suitable anti-scale coating according to the coating manufacturer’s instructions. Allow the coating to dry as directed before heating.

An appropriate coating helps reduce oxidation, scale, and surface decarburization during heat treatment.

Step 2: Prepare the Quench and Tempering Equipment

Prepare a suitable commercial quenching oil, such as Parks AAA. Bring the oil to the operating temperature recommended by its manufacturer, and use enough oil to fully submerge the piece and maintain effective cooling. Parks AAA is a suitable option for O-1.

Have the tempering oven ready at 400°F (204°C) before quenching so the first temper can begin promptly.

Step 3: Preheat the Material

Heat the material to 1250°F (677°C) and hold until it is evenly heated throughout.

Allow the steel itself to reach the preheat temperature before increasing to the hardening temperature.

Step 4: Austenitize — Heat and Soak

Increase the furnace temperature to 1475°F (802°C).

Once the entire piece has reached this temperature, hold for 30 minutes. Begin timing after the material has heated through; the time spent bringing it up to temperature is separate from the soak.

Step 5: Oil Quench

Immediately after the soak, transfer the piece into the prepared quench oil.

Keep it fully submerged and move it straight up and down to promote even cooling. Avoid sweeping a blade from side to side, which can contribute to warping.

When the steel reaches approximately 125–150°F (52–66°C), remove it from the oil, remove excess oil, and begin the first temper promptly. This temperature refers to the workpiece, not the oil-bath setting.

Step 6: First Temper

Temper at 400°F (204°C) for a minimum of 2 hours, beginning the hold once the piece has reached tempering temperature.

After the first temper, remove the piece and allow it to cool completely to room temperature.

Step 7: Second Temper

Repeat the temper at 400°F (204°C) for a minimum of 2 hours.

Afterward, remove the piece and allow it to air cool to room temperature. Complete both tempering cycles, with cooling between them. The 400°F setting falls within published O-1 tempering guidance, and two cycles with intermediate cooling follow Uddeholm’s O-1 procedure.

Final Hardness and Finishing

Confirm the final hardness using a suitable test area or representative sample. For San Mai, evaluate the O-1 core; a reading from the outer layers does not establish the core’s hardness.

The 400°F temper is a general starting setting. Select any adjustments according to the required hardness and verified results for the material. Published tempering curves provide guidance, while actual results depend on the material and heat-treatment conditions.

Once both tempering cycles are complete and the piece has cooled, proceed with final grinding, finishing, and etching.