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Re: Re[2]: [ATM] RE: Silicone Failure
I am a formally trained machinist and I know what you are talking about.
More complex than a simple, manually operated lathe; takes more man hours to
build, too.
It takes a lot more man hours to build a Boeing 777 then a Wright Flyer. I
am saying that technological advances tend to be more complex, not simpler-
and they invariably require MORE man-hours to build. PUT MORE MAN-HOURS IN
YOUR SCOPE; YOU WILL LIKE IT BETTER AND IT WILL TURN OUT BETTER.
Your other point is quite well taken, Martin. I have a little more time than
most, being disabled (though caring for my terminally ill wife is getting
more and more time consuming).
A Hindle type 18 point suspension floatation system for a big mirror has to
be a better proposition than the grey stuff- and it takes longer to
fabricate.
Dave
P.S.- The space shuttle is already as simple as it can be. Martin Lockheed's
new version of the STS will require a lot more man hours to build; will be
much more complex. There is a minimum level of complexity to anything.
Silicone is not complex enough for Dave Harbour. "Different strokes for
different folks"
----- Original Message -----
From: "Martin Lyons" <mlyons@iafrica.com>
To: "'David Harbour'" <scarab2@cox.net>; "'ATM List'" <atm@atmlist.net>;
"'Jerry Reddell'" <jerry.p.reddell63@sbcglobal.net>
Sent: Friday, May 27, 2005 2:25 PM
Subject: RE: Re[2]: [ATM] RE: Silicone Failure
> Yeah, and the space shuttle would still be made of spruce and canvas.
> Imagine how the dope would burn on re entry.
>
> I agree about taking the right amount of TIME to do something properly,
but
> seriously, technological advances can be utilized for various improvements
> and time saving convenience.
>
> David, do you mean to tell me that using a CNC lathe or mill is wrong
> because it does things quicker?
>
> In years gone by, people had more time available to kill.
> Today, finding time to do all the things one has to do just to survive
> (never mind a hobby) causes enough stress to kill.
>
> I suppose it's a sign of the times.
> In the past, you found a hobby to kill time, nowadays, finding time to do
a
> hobby kills.
>
> And they call it progress?
>
> Martin
>
>
>
> -----Original Message-----
> From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf
Of
> David Harbour
> Sent: 27 May 2005 19:28
> To: ATM List; Jerry Reddell
> Subject: Re: Re[2]: [ATM] RE: Silicone Failure
>
> Jerry,
>
>
> "Thou shalt not look for shortcuts in making a telescope"
>
> Seriously, friends, I read some sage advice somewhere, and have had it
> validated in everything I have accomplished: seek the longest way to build
> something, write something, mount something. There is an unspoken rule in
> craftsmanship: the longer you take to craft something, the finer the
results
> will be. I have had this validated over and over again in my life; I have
> built quite a few things- mostly telescopes. The fact that people are
having
> trouble with silicone is prima facia evidence that they should be seeking
> less risky solutions (more TIME CONSUMING) solutions. In my pursuit of
> perfection, I actually looked for ways to make the project last longer.
One
> of the contributors to the Albert Ingalls/Scientific American 3 volume atm
> books said: "the purpose of a hobby is to kill time".
>
> The whole concept of the Dobsonian, for instance, is one Kolossal
shortcut.
> The largest mounting I ever built required 3,500 hours, 3.5 years to
build.
> It was very fine; no field rotation, one person transportable. No silicone
> in it, never would have been. The mirror cell platform was designed to be
a
> platform for a variety of experimental rockers on axles, or astatic
> levering, for mirrors between 12" and 18". The thought of that grey stuff,
> with its propensities to flex, and sometimes lose its grip, would never
have
> been an option in my mind. My mirror cell platforms are designed to be
well
> ventilated (cutouts, like in aviation design) but strong, with radial
struts
> to locate rockers and their bearings. My old 12.5" would routinely carry
> 1,000X with no visible distortions. No fans, no silicone. See it here: I
> used to have it in kit form; it was easy and cheap to build, and it was
just
> as one person transportable as any Dobbie. Took longer to build, that's
all.
> NO FIELD ROTATION:
>
> http://www.atmsite.org/contrib/Harbour/StoppingDown.html
>
>
> "Nothing tests truth like time"
>
> On the other hand, "Different strokes for different folks". Good luck to
all
> of you silicone fans. The grey stuff does make the neatest lap molds you
> ever saw: draw a picture of your lap, squeeze a bead of this stuff all
over
> it the pencil lines, (pick your own custom designed facets), wait till it
> cures, soak the paper off, make your polishing tool with it- IT WILL NOT
> STICK TO PITCH- and press, and polish away. So it does have an ideal use
in
> atm-ing.
>
> David
>
> P.S.- Do not use the kind that has acrylic pigment in it; it will stick to
> pitch, and you will grind your teeth or break things, depending on what
kind
> of personality you have, when trying to separate the mold from lap. Grey
RTV
> only. "The grey stuff".
>
>
> ----- Original Message -----
> From: "Jerry Reddell" <jerry.p.reddell63@sbcglobal.net>
> To: "ATM" <atm@atmlist.net>
> Sent: Friday, May 27, 2005 11:35 AM
> Subject: RE: Re[2]: [ATM] RE: Silicone Failure
>
>
> > Silicone mounting of mirrors has been highly successful by a number of
> > people. I personally believe all the "bad press" is that some people
have
> > made improper assumptions about its properties, applications, and use in
> > analyses. Those assumptions include things like considering it a rigid,
> > none flexible material (as if it 'welds' the mirror to its cell attach
> > point) which cause mirror distortions.
> >
> > Jerry Reddell
> >
> > -----Original Message-----
> > From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net]On Behalf
> > Of Richard
> >
> > Subject: Re[2]: [ATM] RE: Silicone Failure
> >
> >
> > Hi David,
> >
> > Friday, May 27, 2005, 1:01:22 AM, you wrote:
> >
> > DH> Don't mount mirrors with it
> >
> > Why not?
> >
> > --
> >
> > Best regards,
> > Richard
> >
> >
> >
> > _______________________________________________
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> >
> >
> > _______________________________________________
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> >
>
>
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