This is a continuation of another Instructable, Archaeology: Repairing and Modifying a Trowel

I started writing this as a second part to the step-by-step above, but it quickly seemed like this was two separate projects. This will guide you through a basic application of Traditional Black Magic Patina as well as staining and sealing the handle. The result gives the tool a sort of antiqued look, by oxidizing and staining the metal as well as giving the wood handle a darker hue. Whether you are digging an archaeological site or doing some weekend garden work, you will be awesome! That being said, this Instructable has very little to do with Archaeology itself, this is purely cosmetic.

As usual, this was all done at TechShop San Jose! The Sandblaster as well as the other facilities make this project much easier to accomplish. However, if you aren't near a location refinishing like this can easily be done at home (it just takes a bit more elbow grease to prepare the metal for the patina).

To use the Sandblaster, a Safety and Basic Use (SBU) course is needed.
Other Tools or Materials Needed:
  • Black Magic Patina
  • Wood Stain of your choice (I used Cabernet and Dark Walnut)
  • High Grit Sand Paper (low number <100)
  • Low Grit Sand Paper (high number >300)
  • Masking Tape
  • Scotch-brite pad (for scraping off too much patina or to clean surface without sandblaster)
  • Sponge or Paper Towel (To apply Stain)
  • Gloves

Step 1: Preparing the Metal

The easiest way to clean the metal surface before finishing it is taking the trowel to the sandblasting cabinet. The way I like to think about it, is that it is a pressurized rapid sanding tool. Using compressed air and aggregate material to blast of the top surface of metal or whatever object you are sanding. Highly efficient at removing rust or grime, this tool is crucial for convenient finishing such as a patina. powder coating or painting.

Since the trowel is so small. it does not take very long to clean off the entire surface. Be sure to be careful of blasting the wooden handle! While there is a later step to sand off the original finish, the sandblaster will remove a bit too much material from the tool. At TechShop, it is standard procedure to wear some sort of gloves (I just used nitrile myself) when using the sandblaster. Since it is one of the tools in the shop that get used often, the dirt and grime from projects builds up in the cabinet's gloves which is unsanitary. The tool is pedal operated and it's basic use is covered in the SBU mentioned earlier.

Once the sandblasting is done, the metal will be cleaned off and will be a dull grey color, as opposed to the shiny quality it has after grinding. Keep in mind, if you are intending on putting an edge on the trowel as mentioned in the last instructable, be sure to sandblast first or be prepared to put another edge on it. (I learned this the hard way).

You are now ready to apply the patina!
Great!..I wrap wooden handles in old bicycle inner tube for protection from being blasted..
<p>darn! I never thought of that...cool idea Sir! : ) TY for sharing. </p>
<p>Very interesting. I like it....ALOT! : ) Very educational, great &quot;ible&quot;...I think you explained everything well, &amp; according to the pics, it turned out great!</p><p>TY For sharing Sir. : )</p><p>I just would like to add that as you said, wait at least 30 - 60 minutes between coats of the clear coat...and after the last coat is applied, waiting 12 - 24 hours before using for the first time, would not be a bad idea either. </p><p>Seldom does it take more than 24 hours for a finish to cure &amp; completely set.</p>

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