Attendees: JerryW, EdK, TomT, TimC, TomW, ChrisU, DmitriiZ
TomW- melting and pouring pitch for 9” tool to be used on EdK’s 12.5” mirror. The pitch was poured into a release (isopropyl/detergent solution) coated silicone waffle pitch lap pad with 1/8” divisions between the .75” squares of pitch 1/4" deep (LM-4 "Perfect Pitch" Lap Mold
https://home.comcast.net/~kevin.mccarthy137/Pitchlaps/index.html#top $56 shipped ). Two 3/4” plywood disks provided by EdK, which TomW glued together and sealed to waterproof, the now 1.5” thick disk, with Dap clear varnish (water based, that dries in about 10 minutes between coats, 6 coats used). The disk was placed on the pitch while it was still hot & soft with a gallon of water placed on top for forming weight. Thirty minutes of cooling time is then needed. The waffle pitch lap mold was pulled off the pitch very gently and it released perfectly. TomW then chipped off the pitch pieces that extended over the edge of the disk. As a test, Tom placed the pitched disk directly onto the mirror and the fit was great. A little polishing with the Cerium Oxide solution was done, and after washing it off, a few squares of the pitch was beginning to show the polishing compound, white, loading into them.
TomW’s Pitch is basically beeswax and pine sap purchased from Willmann-Bell that TomW has had stored for about 10 years. TomW broke off some of this “new” batch to add to the pitch left in the pan. JoeD gave electric heating pad and pitch pan to TomW some time ago. Five pounds of pitch is about $60 from http://www.willbell.com/ATMSupplies/ATM_Supplies.htm
TimC-continued his work on donated 8” mirror grinding to f/5, now today with 220 grit. TimC used the 8x loupe to check the surface at the end.
DmitriiZ- continuing polishing his 12.5" mirror to improve characteristics (after forming his pitch to the mirror).
ChrisU- talking telescope supplies with JerryW and TomW. TomW recommended TMB, Tom Back, eyepieces, maybe an 8mm for ChrisU. TimC has one he can test. Chris will take photos of his setup so far that he is making, and next week maybe bring in for discussion. http://www.tmboptical.com/
TomW will be teaching an optics class at Westmont and he discussed the textbooks available with Jerry (JW mentioned Kline, Rossi) http://scienceworld.wolfram.com/physics/Optics.html
See more photos / videos here: http://www.flickr.com/photos/27241501@N03/sets/72157635885172366/
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