Making your own mirror?

[Glasspusher]

I would be more than interested to know how many folk are in the process of grinding their own mirrors, or maybe seriously thinking about it.  There are more resources out there than ever and new methods and techniques make it a lot easier to make a mirror than used to be the case. I will admit that it is not always easy to find materials, but with enough determination they can be found. In my experience mirror makers tend to be a little shy and seem to work in relative isolation. What is the true state of mirror making today? Come on it's time to speak up, let's hear about what you are doing!     Please!

John

[Ericgraham]

I made 4 mirrors around 50 years ago, and finally have the time to get back to it. Yes, things have changed a lot since then, especially in the area of testing and new designs. Cheap imports have reduced the incentive to make your own mirrors. But if you want a large mirror or a premium quality one, then making your own still makes sense- at least for me. Nothing compares to the satisfaction that comes with observing with optics that you have made for yourself!

Eric

[starman345]

Hi John, I'm grinding my first mirror, a 10" pyrex mirror, it's about 1.6" thick and I'm going for an f6.5..or so. From what I'm reading it should be simpler to do than a faster mirror. Its a great challenge and I'm having a lot of fun. 

[JamesF]

I'd love to start making some of my own mirrors.  I'm particularly interested in the "mirror-o-matic" designs for grinding.  What I seem to be sadly short of is time

James

[Glasspusher]

Thanks for the responses guys, what is coming across is that mirror making is an enjoyable pursuit, I will certainly agree with that. Like anything worth doing there are times when the going gets stuff. Eric, I could not agree more with your comments. Brian, good luck with the 10 inch, why not keep us up-to-date with your progress? James, I like working with machines, by far the best starting point is with a fixed post machine. Have a look at Gordon Waite's machine on YouTube, it is simple and very effective. 

John

[crashtestdummy]

It is a massive shame that more people aren't doing it.can't wait for mine to be finished

[Astrobits]

I've got plans for the bits of glass that I have unused at the moment. Firstly a portable 8" or 10", then a highly portable larger one and thirdly a big one (18") of interesting design as a prototype for a 24/25/26" job.

Unfortunately there are other things higher on my to do list so I don't expect to be grinding very soon.

Nigel

[Rustysplit]

As you know, I did my first mirror last year, a 14" f5. One of the most enjoyable and satisfying things I have done. I would really like to start a larger grind this year, but spare dosh is at a premium right now. The bug has well and truly bitten though, so it is only a matter of time....

[Rustysplit]

John, I had seen Gordon Waites videos of his single post machines, they look very appealing for larger mirrors.

[Astralstroll]

If my telescope build ever comes to completion, I might have to think of the next obvious step and delving into the mirror grinding game. I've found the scope build enjoyable and frustrating, thankfully not in equal measure.

Dave.

[crashtestdummy]

I found the most frustrating part so far is finding someone to get a mirror blank from!!

[Glasspusher]

Alan, Gordon Waite has made a great contribution with his fixed post videos, I can testify that the concept is good and my own fixed post machine works a treat.

Rich, I know the problems that you had getting a mirror blank.....but then not everybody starts with a 22 inch!!

If any body is reading this thread who has fixed ideas about why they will not to try mirror making perhaps you would like to share your reasons.

John

[Ptarmigan]

perhaps you would like to share your reasons.

Hi John, very thought provoking !

No fixed idea of why I wont, I may one day !

So I'm not sure if this what you want, but for what it is worth (off top of my head whilst I wait to see what todays bargains will be in another place ) :-

Firstly a brief bit of intro :

50+ years ago I devoured ATMs1, 2 & 3 ***, read Dall, JBAS, SAmerican, et.al., and made plans,

after being an impoverished student (with no fixed abode in which to grind)

then got my first big paycheque, all of £30/month, being impatient I bought (could just about afford) a David Hind 6" mirror and diagonal. ( I think it took a bit over 2 months wages ! )

Cars, girls, etc

Never did get round to a grind !

To the point :-

For and against :-

A) 'big' telescopes are now available at an affordable price

A) _quality_ (and even bigger) mirrors are available/affordable.

Made by people who know what they are doing,

(hint ! and a touch of creep there ! )

A) given the two previous (A)s I have not the confidence (foolhardyness? LOL !) of CTD et.al. (sorry CTD !) to jump straight in at something _even_bigger_. (where would I get a 28"+ blank, manicLOLs )

A) a life-time of diy, from amateur radio gear to homebrew(beer) via all manner of ports, leads to the final (A) :-

A) time waits for no man,,, and I ought to put an order in the post !

F) an experience

F) knowledge/curiosity.

am trying and failing to think up another (F) !

Not sure if this is an (A) but a few years ago I got the 'urge' again and went to the library (Bristol) to get the ATMs,

not on the shelves,

had to go to the 'stacks',

only ATM1 was there, 2 & 3 gone AWOL

Who/where is this Gordon Waite video ? link?? , , , >> off for a google >>>

[Ptarmigan]

Hmmm, looks like I cant sign out then back in to edit my post ,,,

Who/where is this Gordon Waite video ? link?? , , , >> off for a google >>>

OK found him !

Drools over > Renegades >>

[crashtestdummy]

You tell me where you can get a 22" mirror for anywhere near the price you can diy one!!!! Same with a big scope.cheapest 22" I've seen is £5850 and that's with a standard crayford and finderscope.I'm estimating mine to cost around £3000 with a feathertouch,paracorr and an 80mm finderscope.

With smaller builds I agree that there's not much savings to be made but grinding your own mirror is about more than savings,it's about the sense of achievement looking through your own optics.

I agree with the potential foolhardiness of jumping into a 22" mirror but tbh If I mess it up I will pay to have it out right and try again another time

[Ptarmigan]

foolhardiness

I did the 'foolhardiness' word totally and entirely in jest (I hope you appreciate ? ! ) I did go back later to add 'bravery' but found I could not edit

Yes, I agree with all you say,

but in my defense : John was asking for a personal view of why _I_ might not grind

and perhaps I was not clear about affordability of scopes and mirrors,

I tried to distinguish between big scopes (complete)

and _even_bigger_mirrors in the ( edit, my ) affordability stakes.

To be clearer, I was thinking of complete scopes up to somewhere 'twixt, say 14" to maybe 18"

then diy jobbies with   (edited, bought mirrors)  mirrors beyond that.

Does that make sense or just muddy things more ?

[JamesF]

Didn't someone buy a kiln some time back with a view to making their own blanks by melting thinner pieces of glass together?  I wonder what happened to that...

James

[crashtestdummy]

No harm no foul John himself warned me that taking on a 22" as a first time grind was a tall order.nah everyone is wholely entitled to their opinion on this forum and we encourage it

JamesF John will be along in time to tell you about his slumped blanks.infact I've planned my next build as a slumped 26"

[Glasspusher]

Ptarmigan, thanks for the input I find your comments interesting. Might I make a couple of points? I don't think that making a telescope (mirror) should be undertaken with economics in mind. In the old days (before cheap Asian imports) if you wanted an astronomical telescope making one yourself was a way of  saving money. Things are different today, the market place is awash with cheap telescopes from the far east and the quality is acceptable. Making a telescope (mirror) is an intellectually challenging experience, not unlike amateur astronomy.  It is a rewarding and absorbing pastime, something worth doing in it's own right. It does not have to be a means to an end. It is the best possible way to learn how a telescope works and how to get the most out of it.

Since the days of ATM book 1 things have changed, the old methods of working have been challenged and in some cases have been replaced. Computers now play a major roll in telescope (mirror) design and  testing, as a result there are now user friendly test methods. It is possible to make a high quality mirror without using the Foucault knife edge test,  a notion that would have been scoffed at not so long ago. Having said that, any one making and testing a mirror would soon wish to investigate the power of the knife edge test. The problem is that these new ideas have not been collected together in one place other that the internet and are not always easy to find. I don't expect amateur mirror making to ever return to the levels of popularity seen in the past, but I do think if more potential mirror makers were aware of what can be done and how they might have a go.

If you want to find out about what telescope (mirror) makers are doing today you could do worse than have a look here......

http://stellafane.org/misc/links.html

John

[Ptarmigan]

Might I make a couple of points?

I don't think that making a telescope (mirror) should be undertaken with economics in mind.

Yes please the more points the better, especially as it helps me realise how badly I express myself !

Because CTD picked up on the very same economics point as well :)

Must'av been because I started by describing my impoverished student past etc  !

Ie. in precis: in the past it would have been an economy thing with me, but now it is a time delimited and availability thing as well as, hang on I am overtaking myself ! :--

I _now_ see_ all these _affordable_ scopes and mirrors and they can save me time, which I dont have a lot more of to come, you see,

and they can be made for me to a very high standard, which skill I may not have the time left unto me.

BUT ____ >>>  I did go on !! to give the (F)s    experience knowledge curiosity. ______

your point of "intellectually challenging experience",  exactly so

That would be my prime reason for doing it if I now did it, iyswim !

Then once having learned the drill I would be able to go on to make specialist optics that are not available either from Asia or here. Lens making rather than mirror making for example could well grab me. (but that was not what you were asking !)

So I was trying to give both sides from my, ummm, little point in time/space,  you had asked for comments on why someone _would _not _do mirror making, whereas I am uncertain if I will or wont ! So I tried to give you my both sides, heheeee,

As I was reading thro' your interesting post and about the ATMs

 I was thinking "Yes, but it is a nightmare finding it all now "

and you came to that very point ! :)

Yes, thanks, I have seen the Stellafane site ( ahhh Porter, may he rest in peace ) and some years ago the Mel Bartels stuff

btw, I have been given, a few months ago, a set (a complete?set not sure yet) of "Telescope Making" Berry etc et.al.

facinating stuff but not exactly a condensed how to

I knew of it when it was first published but did not then subscribe (girls and things maybe !)

Hmmm, there you go John, your new calling, in life,

"The New ATM Guide" subtitled "a guide for prevaricating grinders" :)

Does that help in any way in your quest for why people may not 'do it' ?

Gosh, late at night, I'll edit this for speeling and logic tomorrow  ,,,,

[Ptarmigan]

Some edits to be going on with :

in the past it would have been an economy [EDIT: and necessary ] thing

all these _affordable_ [EDIT and attainable/acquirable/possible] scopes and

I suppose, in essence,

"I can now easily acquire a scope of (almost) my dreams with little further effort"

maybe

howzat

but further effort may be undertaken if I feel an intellectual urge

I think I'm done now ? lol

[Astrobits]

I don't think that it is for us to persuade you to get stuck in to making a mirror unless you are really keen to do it. There must be an awful lot of half-made mirrors lying in cupboards in the country where the initial enthusiasm has waned.

I am not too far from you ( Highbridge/ Burnham-on-sea ) so you could PM me and we can meet sometime. I am planning to make a mirror or two, maybe later this year. You would be welcome to visit when I get going.

Nigel

[crashtestdummy]

as above-if you have to convince yourself that making one is the best option then you wont enjoy it.

[Ptarmigan]

Thanks Nigel

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Woa! Hang on fellas, go easy !
John asked a question
"If any body is reading this thread who has fixed ideas about why they will not to try mirror making perhaps you would like to share your reasons."

I thought I would offer some thoughts  both (F)or and (A)gainst

It wasnt meant to be a manifesto (on an enjoyable route to nirvana or anywhere else! )

Wish I hadnt bothered, I'll crawl back under my stone now.

[crashtestdummy]

No fella,I'm happy for open debate.keep it coming