From: "Russell Jocoy" 
To: k_patel{at}vsnl.com, atm{at}shore.net
Reply-To: "Russell Jocoy" 






>From: Kartik Patel 
>Reply-To: Kartik Patel 
>To: atm{at}shore.net
>Subject: ATM Monsters in Wax filled channels
>Date: Thu, 20 Mar 2003 11:19:36 +0530
>
>
>Hello, all,
>
>A cement tool onto which glass tiles have been epoxied is presently being
>used to grind a 10" mirror blank for my latest project. The gaps between
>the tiles which have been filled with candle wax.
>After completing the hogging stage and bringing the tool and mirror into
>full contact, it was noticed that the wax, initially greyish-white, was now
>dark grey to black in many places. Closer inspection revealed that there
>were grit particles embedded in the channels. Not a problem, I thought, and
>ran the tip of a soldering rod over the channels to melt the wax. This it
>did and, as expected, the grit particles promptly sank to the bottom. The
>excess wax scraped off, fresh wax deposited where required, and I moved on
>to grinding with 120 mesh SiC.
>It seems logical that that this procedure would have immobilized the larger
>grit from the hogging stage. However, the smaller particles of 120 grit
>also have a tendency to get embedded in the wax. After every few wets,
>there is a layer of sludge in the channels which closes the air gap between
>the tool and the blank, thus making them stick.
>This layer is stubborn, and does not go away easily on brushing. I have had
>to melt the wax channels again to clear the grit, and while it is not a
>problem, I anticipate that this will have to be done often as the grit
>reduces in size.
>During the process of melting, the heat form the soldering rod creates
>turbulence in the narrow channel. This churns the grit, and as it
>solidifies again the particles are trapped at different depths, depending
>on their sizes.
>During grinding, the wax surface is also removed, and if a particle is near
>to the surface it may get exposed. At some stage I fear that a large
>particle may dissapparate like a monster from out of the deep and create
>havoc.
>Prudence dictates that the wax should be completely removed and replaced,
>to prevent this from happening. Sooner, rather than later. The problem is
>to decide when.
>What experience have users had with this kind of situation? Advice,
>comments and user experience would be highly appreciated.
>
>Sincerely,
>Kartik Patel,
>Mumbai, India
>http://www.geocities.com/letapk
>
>
>
>
("atm{at}shore.net")

    I would get rid of the wax altogether, scrub out the channels with
solvent to remove all the wax.
Then scrub the whole surface of the tool with detergent. Let it dry real
good and fill the channels
half way with epoxy. Round out any sharp edges on the glass tiles with a
wetstone. Your problems
are solved. Remember to use a toothbrush to scrub the tool between grits.
(a new toothbrush for
each grit)                                                    Russ Jocoy
("atm{at}shore.net")

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