· Get a Cloudy Nights T-Shirt · Submit a Review / Article    Click here if you are having trouble logging into the forums Cloudy Nights - Official Forums of the 2009 International Year of Astronomy Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User   You are not logged in. [Login] Forum Archives · Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar Equipment Discussions >> ATM, Optics and DIY Forum Previous   Index   Next   Flat   Steven Aggas sage Reged: 04/15/08 Posts: 463 Loc: Arizona Re: RTV, Glass, and Holder Material       07/06/09 03:18 PM Edit   Reply   Quote   Quick Reply:   Ok, for those holders which use a piece of tube cut off to 45 degrees, is there a gap between the holder and glass in which the glob of RTV resides (holder not in direct contact)? Given what read above the answer is 'yes' and the thinner the better given the sag of the suspended glass and its effect on the non-rigid RTV, but, thin must only be used on objects that don't expand and contract large amounts. Is this because the RTV will lose adhesion from the repeated expansion/contraction of very dissimilar materials, less so with Carbon Fiber and Glass v. Aluminum and Glass? So, if a 5" diameter Carbon Fiber tube were used (0.156" wall thickness) and cut to 45 degrees, and, a CF plate (0.100" thickness) adhered to the cut-off, then would many globs, uniformly spaced, on the plate give little to no deformation of the wavefront, relative to an aluminum plate, or what would the dot formation look like on the 5"ma plate to hold a 6"ma, 1.5" thick elliptical mirror? Or would the 5"me plate not be needed and RTV applied only on the 0.1" wall thickness of the 5" ma cut-off tube be enough? Thanks, Steven -------------------- Mr. Wizard Walking on a Dob: http://darkskyobserving.com/MtGraham.html Elements in Harmony I, an 8"f6 German Equatorial - Stellafane Winner, II a 20"f4.2 Newt-Dob - Astrofest Winner, III a 6"f3.5 Finder/Newt-Dob, and IV a 36"f4.5 Newt-Dob - "If it's up there, it's in here." Apache-Sitgreaves Center for Astrophysics www.DarkSkyObserving.com Post Extras       Entire thread Subject Posted by Posted on RTV, Glass, and Holder Material Steven Aggas 07/02/09 04:20 PM Re: RTV, Glass, and Holder Material mark cowan   07/02/09 08:33 PM Re: RTV, Glass, and Holder Material Biff   07/09/09 03:03 PM Re: RTV, Glass, and Holder Material Mark Harry   07/03/09 07:18 AM Re: RTV, Glass, and Holder Material PrestonE   07/03/09 03:36 PM Re: RTV, Glass, and Holder Material mark cowan   07/04/09 02:42 AM Re: RTV, Glass, and Holder Material PrestonE   07/04/09 04:12 PM Re: RTV, Glass, and Holder Material Steven Aggas   07/06/09 03:18 PM Re: RTV, Glass, and Holder Material PrestonE   07/06/09 08:55 PM Re: RTV, Glass, and Holder Material Steven Aggas   07/07/09 12:25 PM Re: RTV, Glass, and Holder Material PrestonE   07/07/09 04:11 PM Re: RTV, Glass, and Holder Material Steven Aggas   07/07/09 05:34 PM Re: RTV, Glass, and Holder Material mark cowan   07/07/09 09:10 PM Re: RTV, Glass, and Holder Material Steven Aggas   07/08/09 12:39 PM Re: RTV, Glass, and Holder Material PrestonE   07/10/09 02:43 PM Re: RTV, Glass, and Holder Material Steven Aggas   07/10/09 03:33 PM Re: RTV, Glass, and Holder Material PrestonE   07/11/09 11:12 PM Re: RTV, Glass, and Holder Material Steven Aggas   07/13/09 12:14 PM Re: RTV, Glass, and Holder Material PrestonE   07/15/09 05:50 PM Re: RTV, Glass, and Holder Material Steven Aggas   07/16/09 11:28 AM Re: RTV, Glass, and Holder Material PrestonE   07/17/09 10:37 AM Re: RTV, Glass, and Holder Material Steven Aggas   07/13/09 12:16 PM Re: RTV, Glass, and Holder Material Steven Aggas   07/13/09 05:06 PM Re: RTV, Glass, and Holder Material mark cowan   07/08/09 03:42 PM Re: RTV, Glass, and Holder Material Steven Aggas   07/09/09 12:28 PM Re: RTV, Glass, and Holder Material Charl   07/06/09 06:43 PM Re: RTV, Glass, and Holder Material PrestonE   07/02/09 06:13 PM Extra information 6 registered and 6 anonymous users are browsing this forum. 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