E-Prep 221 — Stabilized Peroxide Bright Dip Process for Copper and Brass
It accelerates and stabilizes the brightening reaction, minimizes the breakdown of the peroxide and prevents retarnishing of brass and copper after brightening. E-Prep 221 does not contain Nitric or Chromic acids or chromates and is environmentally safe. It does not contain chelaters or complexers, simplifying waste treatment. E-Prep 221 is supplied as a liquid concentrate. E-Prep 222 is recommended for leaded brass.
Operation
Pre-Conditioning and scale removal
75% by volume in water
15% by volume concentrated Sulfuric Acid, 66° Be
10% by volume E-Prep 221
Temperature: 70°-80° F
Time: 1-2 minutes

Cold Water Rinse

Bright Dip
75% by volume water
10% by volume E-Prep 221
15% by volume Hydrogen Peroxide, 35% strength
Temperature: 110°-120° F for bright finish
Time: 1-2 minutes or longer for a bright finish depending upon the original surface.

E-Prep 222 — Stabilized Peroxide Bright Dip Process for Leaded Brass and Copper
It is a stabilized peroxide process which accelerates the brightening reaction, stops the breakdown of the peroxide and prevents retarnishing of the brass after brightening. E-Prep 222 does not contain Nitric or or Chromic acids or chromates and is environmentally safe. It does not contain chelaters or complexers, simplifying waste treatment. E-Prep 222 is supplied as a liquid concentrate.
E-Prep 222 is specifically designed to work on leaded brass and on tin/lead soldered areas where it offers a more uniform finish and minimized white powdery deposit of the insoluble lead onto the brass surface.
Operation
Preconditioning and scale removal
75% by volume in water
15% by volume concentrated Sulfuric Acid, 66° Be
10% by volume E-Prep 222
Temperature: 70°-80° F
Time: 1-2 minutes

Cold Water Rinse

Bright Dip
75% by volume water
10% by volume E-Prep 222
15% by volume Hydrogen Peroxide, 35% strength
Temperature: 110°-120° F
Time: 1-2 minutes

E-Prep 224 — An Additive for Stabilized Peroxide Bright Dips for Copper and Brass
A concentrated liquid accelerator, stabilizer and anti-tarnish that replenishes E-Prep 221 or can be used with sulfuric acid and hydrogen peroxide to customize your own bath.

E-Prep 224-LB — An Additive for Stabilized Peroxide Bright Dips for Leaded Brass and Copper
A concentrated liquid accelerator, stabilizer and anti-tarnish that replenishes E-Prep 222 or can be used with sulfuric acid and hydrogen peroxide to customize your own bath.

E-Prep 270 — Stainless Steel Chemical Brightening and Passivation
E-Prep 270M and E-Prep 270B are designed for the chemical brightening and passivation of 300 series stainless steel alloys and also other nickel bearing alloys, such as Inconel and Kovar. They produce a uniformly smooth finish with good specular reflectivity.
E-Prep 270M produces a matte finish, whereas E-Prep 270B is formulated to produce a relatively bright finish.
Unlike electropolishing, E-Prep 270M or E-Prep 270B chemical polishing eliminates the grain boundary attack and the danger of hydrogen embrittlement and stress corrosion. The products can find application in the aircraft, electronics and surgical implants industry.
Both E-Prep 270M and E-Prep 270B assure minimum metal loss during the brightening process and offer definite advantages over the Nitric/Hydrofluoric Acid based formulations which produce a rough finish. A metal removal rate of about 0.05 mil/min/side is achieved when brightening 300 series stainless steel with 2B finish.
E-Prep 270M and E-Prep 270B can remove heat treatment and welding scale. They are safe on silver and brass solder, but should not be used with tin or lead soldered stainless steel work.

Operating Parameters