Mirror Making-Material
From Stathis Kafalis
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| Material order I keep borosilicate blanks in the usual sizes on stock and can get sizes that I currently not have in approx. 4-7 weeks delivery time. If you are interested, please contact me at the above e-mail address or call at +49 / 89 / 62 42 01 71. The blanks are from Schott borosilicate glass, which has the same thermal and mechanical properties like Pyrex or Duran. The material is homogeneous, free of visible bubbles and free of internal stress or stain (as seen in the polarizer test). The blanks are cut from large sheets, they are considerably flat on both sides and come with a ground edge. Very many fine mirrors have been made with them already. See examples in our mirror making workshop in Munich or in the Astrotreff Forum. |
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Prices including 19% VAT are as follows:
Borosilicate Glass Blanks:
| Diameter | Thickness | Weight | Price Euro | Delivery Status: 17.May.2013 |
| 4,5" = 115 mm | 15 mm | 0,35 kg | 18,- € | Stock |
| 5" = 130 mm | 15 mm | 0,44 kg | 21,- € | Stock |
| 6" = 155 mm | 21 mm | 0,89 kg | 38,- € | Stock |
| 8" = 205 mm | 21 mm | 1,56 kg | 59,- € | Stock |
| 8" = 205 mm | 25 mm | 1,86 kg | 63,- € | Stock |
| 10" = 255 mm | 25 mm | 2,87 kg | 94,- € | on request |
| 10,6" = 270 mm | 25 mm | 3,22 kg | 103,- € | on request |
| ~12" = 300 mm | 25 mm | 4,11 kg | 132,- € | on request |
| 13" = 330 mm | 25 mm | 4,81 kg | 153,- € | on request |
| 351,5 mm (*) | 25 mm | 5,46 kg | 155,- € | Stock |
| 14" = 355 mm | 25 mm | 5,77 kg | 175,- € | on request |
| 396 mm (*) | 25 mm | 6,93 kg | 200,- € | Stock |
| ~16" = 400 mm | 25 mm | 7,08 kg | 225,- € | Stock |
| 16" = 405 mm | 25 mm | 7,27 kg | 225,- € | Stock |
| 425,5 mm (*) | 25 mm | 8,00 kg | 230,- € | Stock |
| 18" = 460 mm | 25 mm | 9,35 kg | 285,- € | Stock |
| Bigger or other sizes: | on request | |||
On request I can grind the backside flat up to grit 320 for 10,- to 30,- Euro, according to effort (recomended for 10" and larger)
The big ones make sense for experienced glass pushers only.
New: Thicker Borosilicate Glass Blanks:
Available in the thicknesses 31,5 / 34,5 / 41,3 / 47,6... (up to 66,5 mm). Ideally suited for larger diameter mirrors. Same thermal and mechanical properties like the thinner material. Please ask for a quote and delivery time.
Grinding and polishing Material:
Grinding and polishing compounds I have nearly always in stock. A complete material set includes silicon carbide grit #80, #180, #320, Aluminum oxyde with specific flat gritshape and tight size distribution Microgrit WCA 25my, 15my, 9my, 5 my, 3 my, polishing powder CER-SKX (a very fine and pure cerium oxide) and optical pitch of 28° hardness. The grit K80 for rough grinding is in any case sufficient for f/5 or slower, the amounts on the finer grits, pitch and ceroxid are very generous, to handle even several setbacks. Everything is packed in double plastic bags to prevent cross contamination. Prices including VAT:
| Material-Set | Weight | Price Euro |
| 4,5+5" | 0,75 kg (contains 0,25 kg K80) | 21,- € |
| 6" | 1,2 kg (contains 0,35 kg K80) | 26,- € |
| 8" | 1,9 kg (contains 0,7 kg K80) | 34,- € |
| 10" | 3,2 kg (contains 1,4 kg K80) | 47,-€ |
| 12-14" | 4,1 kg (contains 1,8 kg K80) | 60,-€ |
Shipping cost see here and add 19% VAT or here or just ask me
The grinding and polishing tool is not included in the set. You will need to make this yourself or just order 2 blanks (which is still affordable at least for the smaller sizes). Tips on how to make your own tool see at tips and tricks (German text).
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