I got my 10" stuck to my pitch lap.. Seriously, with pictures..

[denbot]

I'm doing the finishing polish on a 10 inch telescope mirror. Today I re-poured my pitch-lap (a polishing tool) and while warm pressing it the freaking mirror they locked together.. While viewing the pictures give a rough estimate of how many double entendres you've made out of this post so far..

My big ten incher, mirror blank that is..



My ten inch tool taped off so it will hold the hot pitch pour..



Hot pitch cooling to right consistency before pouring..



The pour..



In order for the pitch lap to properly polish the mirror it has to be pressed together so the fit is exact.
There is always a chance that they stick together but usually they can be muscled apart.. I can't for the life of me
get them apart. Tomorrow I will head over to a telescope making lap and ask the old hands what to do.

PS.. Shame on you.

[CaliforniaPeggy]

1. My dear denbot!

I like your pics! But I'm too tired from my open mic reading to count how many double entendres I've read!

Maybe I'm missing something, but it seems you made an error?

:shrug:

:hi:

[denbot]

2. Yea, I let them stick together..

I did not re-coat the mirror with a little dish soap to keep the pitch lap in mirror from sticking together.
These pyrex mirror blanks are VERY expensive for a piece of glass, so I don't want to whale on it to get it off, and I don't have the muscle to slide it off, so right now I'm stumped.

[CaliforniaPeggy]

4. Yikes...

I wish I could help...

:hug:

[Tom Kitten]

3. In the old days, people would be spot on with helpful hints...

At least they still have telescope making labs here!

[Fire Walk With Me]

5. That's going to provide you with one heck of a view!

Especially in the desert where you folks appear to be fond of taking vacations!

Sweet. Thanks for sharing that, and I appreciate your continuing exploration of things made by hand. (A glassblower's shop in San Diego had a woodcut sign outside the entrance stating that "Technology does not teach reverence".)

[bluesbassman]

6. Very cool.

I got to help polish a mirror like that when I was a kid. That's a lot of work, but man the end result is so worth it. Can't wait to see your 'scope when it's done!

[denbot]

9. The way things are working out, you will have a wait.

Do you still stargaze?

[lob1]

7. K-Y Jelly? Slickery, slippy-slidey.

[denbot]

8. I imagine that would work very well.

But in order to get the lube between the mirror and tool, I would first have to separate them.. And Therein lays the rub.

[lob1]

10. Sorry, I was being a bit of a wise-ass.

But I hope you get them separated. You should get a magnificent view.

[seemunkee]

11. Impressive project

I love seeing peoples DIY projects. Show us the finished scope when you get it all together.

[Deep13]

12. More patience than I have.

The telescope I built has a commercial mirror from Discovery. It's a 6" f/5 truss-tube for airline travel.

[denbot]

13. Send me pictures and scope vibes..

Really, I'd like to see pictures, and if you have the plans, those too!

[Deep13]

14. I'll try to find some pics and scan them.

There are no plans. It's made mostly of 1/2" plywood. The mirror box fits inside the rocker box which fits inside a larger carry box that also functions as the ground board. The secondary cage is an octogon of 1/4" Baltic plywood and that fits inside the mirror box. Four aluminum poles make the trusses. It has a 1.25" cheapo rotating focuser and a unit power finder. I have it balanced for a 22mm Panoptic. The poles, altitude bearings, legs and assembly hardwear get checked in. The mirrors and nested boxes conform to airline regulations.

[denbot]

16. Sweet..

I want to be able to pack mine final finished scope with the rest of my camping gear. The first iteration will be a more classic Dobsonian (met him 3 weeks ago at the Griffith Park Observatory star party) design, for simplicity and to actually have a working scope before I get all fancified.

[kentauros]

15. I respect anyone that can grind their own

mirror ;)

I built a 10" way back in 1980, but I didn't have the confidence (nor the tools and patience) to grind the mirror myself. No clock drive, so you have to move the telescope periodically, depending on how far off you're viewing. My father keeps it at their place out in Dripping Springs/The Texas Hill Country. I'll have to look it over next time I go and see if the mirror needs cleaning. Any advice on how to do that without ruining the surface?

Are you grinding the secondary, too? :)

[Deep13]

17. Cleaning instructions.

If possible, do not clean the mirror. Specs of dust are actually pretty insignificant.

Remove mirror and soak in a luke warm solution of distilled or filtered water and either plain Ivory liquid or plain, no-scent Dawn.

Starting in the center, push a sterile cotton ball to the edge using only the weight of the cotton as pressure. Discard cotton and use a new piece for each swipe.

Rinse with distilled water, isopryl alcohol and a drop of detergent to break the surface tension.

Stand on edge in a dust free place to dry.

CAREFULLY blow any stubborn droplets off with canned air. Be careful not to spray any propellant onto the mirror.

Reinstall.

Even the most careful cleaning leaves microscopic scratches that degrade contrast if they accumulate.

Secondaries are optical flats and are not ground. There really is no way for an amateur to make them.

[kentauros]

18. Okay, thanks!

I'll have to bookmark this one :)

[scubadude]

22. There's a better way to clean mirrors,

but here's the rub. You have to get this stuff called colodion. It is a colloidal substance dissolved in ether and or alcohol.

You paint the collodion onto the mirror, allow it to dry, then peel it off. This method literally removes dirt to the microscopic level.

Collodion used to be readily available at drug stores, but because of it's flammability is hard to find now.

Go here for all your telescope making questions.

http://www.astronomyforum.net/atm-diy-telescope-making-forum/

Best,
Scuba

[Deep13]

23. Cool! nt

[denbot]

19. By the way things are going I will likely buy my secondary mirror

My club does have a vacuum chamber so we can reflective coat our optics, but I think I'll be happy with figuring my primary, and building my secondary spider.

Here's a link on cleaning mirrors.

http://www.iceinspace.com.au/index.php?id=63,345,0,0,1,0

[pokerfan]

20. I have a ten inch

but I didn't grind it myself.

This guy in our local club got a little carried away with aperture fever:

http://www.runway.net/pilots/dan/fortyone-page1.html

[denbot]

21. I've drooled over his site before.

Man this would be a cool guy to know.
Here is a link to my club's dark sky site.

http://www.laas.org/Resources.htm

We are also building another scope using a literally perfect 32" mirror. Our project mirror is the twin to the mirror that went up on the old sky lab. and is accurate to something like one tenth of one millionth of a wave length. Can't wait to get a look through that puppy!

[Brewman_Jax]

24. I have a 12"

vinyl single of "Rapper's Delight"!

What were you thinking? :P


That is an impressive mirror project. :thumbsup:

[struggle4progress]

25. Pyrex blank? If you have no other ideas, maybe repeated application of

boiling water

Can you safely boil the whole thing?

[denbot]

27. I ended up bathing it in very hot tap water.

I placed a 2x4 across my bathroom door way. With the tool side down the mirror cleared the board by a half inch. I would bathe the stuck pieces in very hot water the brace the tool against the board and using the other side of the hallway as a braceing point push my glass mirror as far as the cooling/hardening pitch would allow me. It took 4 very hot baths, and every thing I had and still I had to ask my stepson to finish the last couple of inches. I will no longer refer to him as a kid or child. I told him now he is a Man Cub

[struggle4progress]

28. He's good for something after all!

:D

[Orsino]

26. Save me a slice.

It looks delicious.

[Strong Atheist]

29. Keep this up and I will have to take you off of

"Quiet Types"... :rofl: