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Re: Metal Tools

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Posted by Walt Hamler/">Walt Hamler on February 25, 2000 17:47:32 UTC

: Depends upon the size of your mirror. Your plumbing supply doesn't have the caps to block off a pipe end? My Home Depot has them from the 1/2" to 2" pipe size in black iron and galvanized. Either works well. Get one that's about 1/3 the size of the mirror for better results. One guy used a 1/2" flange (about 4" in diameter) on a 12" mirror and it also worked well. Your not even stuck with iron but I've heard of aluminum being also used for the intitial grinding and somebody is selling preground tools (full size) for the grinding. The effort here is to do the coarse grinding with something that's not going to wear out fast but does form the spherical surface needed for the mirror. After the initial curved surface is developed, you can then cast a tool with embedded tiles in it and finish the curve to the required shape. : I might note that the pros use large diameter iron tools that are turned to the required radius of curvature and the glass is precurved with diamond grinders. The iron tools are used through all of the steps in grinding as the mirror is a bit smaller than the tools and it keeps it's shape well as the grinding progresses.

Robert, I got the kit from WB yesterday afternoon! Started grinding with the 4" closet flange a couple hours later. I've gone through 15 or 20 wets, maybe 25, and have it down to .060", heading for .091 for an f/6.8. About where should I stop before making the dental stone /tile tool? I already have the hex tiles layed out and beveled, so that won't take long to do. Should I continue with the #60, or go on to the #80 with the new tool? Thanks!! Walt

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