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spotting compound for use on granite

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  • spotting compound for use on granite

    I recently acquired a 18X24 Starrett Pink Grade A Inspection Plate and would like to use it as a reference for scraping. What should I use as a spotting compound that won’t stain or damage the surface of the granite?

    Richard Chase

  • #2
    I've used Dykem Hi-Spot Blue. It washes off with denatured alcohol. It may darken the surface slightly over time, but it won't cause any damage.

    Don't worry (too much) about keeping the surface plate absolutely pristine in appearance. It's a tool like any other tool -- meant to be used.
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    • #3
      I'm curious, did you buy it new or used?

      Pursue Excellence and the rest will follow.
      Pursue Excellence and the rest will follow.


      • #4
        Yep, diffinitly Hi-spot. All of the other types I've ever tried didn't work worth a darn. The Permetex Prussian Blue is too oily or greasy. And the water based blueing meant for spotting dies is too thick. Another option is carbon or lamp black. But it is even messier than the Hi-Spot. Almost if not more important is the base coat that you are using to dull the surface. In the past we used white lead but I don't know if it is sold anymore do to enviormental concerns. Now we either use what is called "gear compound" or what I perfer to use isopropyl or denatured mythal alcholol. Wetting the surface to be scrapped with the Alcholol on a rag and letting it dry will leave a slight haxe that really makes the blueing stand out. Just another trick from Reconditioning Machine Tools

        PS. Some times the cooling effcts of the alcholol can cause problems with temperature differences if applied too liberally
        Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.


        • #5
          <font face="Verdana, Arial" size="2">Originally posted by Excitable Boy:
          I'm curious, did you buy it new or used?

          I got it used, locally from a friend whom recently laid-off his machinists and is now running the shop buy himself part time. He has a couple of turret lathes he wants to sell off, if anyone is interested contact me of list and I'll get the info.


          [This message has been edited by Alaric (edited 06-01-2004).]


          • #6
            The Canode compound that Dapra sells works pretty well and it is water soluable.