Birchwood Technologies Presto Black® Gel

Article number: 745002
Availability: In stock (4)

PRESTO BLACK GEL Blackening Gel for Iron and Steel

Operating Instructions


PRESTO BLACK GEL is a Room Temperature brush-on blackening agent for all iron and non- stainless steel surfaces. This new blackening gel makes it easy to achieve uniform, tightly adherent black finishes on surfaces of any size and shape and offers the user an extra measure of control over the finishing of the work piece. The unique gel consistency makes it possible to overcome many common application challenges, such as controlling runs & drips, minimizing solution loss due to runoff and inhibiting flash rusting of the surface. The gel stays put, even on vertical surfaces, with no loss of product due to runoff. Blackens more slowly than a liquid blackener, simplifies the blackening operation and improves the uniformity of the final finish.


In short, the surface must first be thoroughly cleaned of all oil and oxide. The black finish is then applied, rinsed, dried and sealed with a topcoat appropriate to the end use of the article:


  1. CLEAN the surface, using a solvent that does not leave a residue. Use alcohol, acetone, lacquer thinner or equivalent (Do not use mineral spirits or kerosene). Repeat as
  2. REMOVE OXIDES, if necessary, by bead blasting, or use other abrasive cleaning methods, such as buffing with Scotchbrite abrasive pads or flap wheels.
  3. APPLY THE PRESTO BLACK GEL liberally with a synthetic brush. Allow the GEL to react while lightly brushing the surface with the applicator until a uniform gray/black finish is achieved – usually about 5-10 DO NOT LET THE GEL DRY ON THE SURFACE, or flash rusting can occur.
  4. STOP the REACTION by sponging the surface with warm water to remove the GEL residues. Flat surfaces can be squeegeed off, and then sponged with warm water. To inhibit flash rusting during drying, neutralize acid residues in the recessed areas, using baking soda solution (mix 3 tablespoons per gallon of water).
  5. RINSE thoroughly with clean water after
  6. FORCE DRY the surface with warm air, compressed air, etc. The dried surface may be highlighted with a mild abrasive pad, if desired, to produce an antique pewter finish or a distressed finish. Or, the surface can be left as a solid black.
  7. SEAL the surface with a topcoat appropriate to the use of the article: Tooling/machine parts can be sealed with a water-displacer, such as DRI TOUCH AMBER IRP2. Decorative surfaces can be highlighted, if desired, with Scotchbrite pads, to produce a distressed or antique Then seal with a clear, satin lacquer or for light-duty, indoor pieces, use paste wax.


Some practice on scrap material is usually advisable in order to optimize application techniques.

Before Using This Product – Please Read, Understand and Follow all the Precautions shown on the Product Label and on the Safety Data Sheet.


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