Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> ATM, Optics and DIY Forum

Pages: 1 | 2 | 3 | 4 | 5 | (show all)
mark cowan
Vendor (Veritas Optics)
*****

Reged: 06/03/05

Loc: salem, OR
Re: melting pyrex for blanks new [Re: Mark Harry]
      #5599024 - 01/01/13 01:20 AM

Quote:

Instead of doing a displacement of volume, just calculate volume instead. I used this to identify a pyrex blank that was moulded in a KzFS4 mould with those initials on the glass. I came out to within 3 places of the decimal point of pyrex value---close enough.
M.




Yup. I did this to ID a suspected Zerodur blank (oh, like the color isn't a giveaway - - but they've come in all shades). Measurement and an accurate scale gets to digits.

Best,
Mark


Post Extras: Print Post   Remind Me!   Notify Moderator  
FlorinAndrei
scholastic sledgehammer


Reged: 09/28/10

Loc: California
Re: melting pyrex for blanks new [Re: danjones]
      #5600135 - 01/01/13 06:49 PM

Dan, how many watts (or amps) are required by the 17" kiln at peak temperature?

Post Extras: Print Post   Remind Me!   Notify Moderator  
John Carruthers
Skiprat
*****

Reged: 02/02/07

Loc: Kent, UK
Re: melting pyrex for blanks [Re: mark cowan]
      #5602328 - 01/03/13 03:40 AM

or immerse the suspected Pyrex in vegetable oil, if it 'disappears' it's pyrex (or something with a similar RI).

Post Extras: Print Post   Remind Me!   Notify Moderator  
danjones
super member


Reged: 09/26/12

Re: melting pyrex for blanks new [Re: FlorinAndrei]
      #5607519 - 01/05/13 11:24 PM

hi florin. thanks for the interest. i'd have to go out and look at the label of the kiln, but i'm sure it's requires 30 amps for peak temp topping out at near 2300 degrees. for melting plate glass, it can be just melted enough at 1700-1725 or so. melting broken chunks or strategically cut chunks in a stack, needs more 1800. other substrates like pyrex and others need more, but well within my kiln's max. it needs 230v to operate fully, but requires more technology than the onboard temp control. glass is finicky, and the temp needs to be controlled precisely. i'm working on a ramp/soak controller to exactly control the kiln's temp operation. the ramp up heat and soak times need to be controlled, especially to well anneal the glass and take out any strain, even in the thickest of blanks.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Babaloo
newbie


Reged: 10/28/13

Re: melting pyrex for blanks new [Re: danjones]
      #6225748 - 11/30/13 07:18 PM

Boy, you can tell a lot of you guys haven't been doing much of the cooking! The new 'Pyrex' has a greenish tinge to the cookware edges, extremely noticeable. And it is just tempered glass. The real Pyrex cookware (which may be different from the Pyrex used in labware) has no tinge (termed colorless). I think one would be safe in scrounging up a lot of old colorless Pyrex cookware from garage sales and melting it all together (better yet, some old labware.) It would also be advisable to cast/slump a test piece from the molten batch, anneal it, and run it through some heat shock tests to make sure. But if the melt can be mixed thoroughly (stirred?), that might very well negate any slight differences in C.O.E.s of the constituents, if different.

Post Extras: Print Post   Remind Me!   Notify Moderator  
ccaissie
professor emeritus


Reged: 09/13/10

Loc: Whitefield, Maine
Re: melting pyrex for blanks new [Re: Pinbout]
      #6226467 - 12/01/13 07:02 AM

Quote:

A 16 x 3.25 would make a 24 x 1.5?




Interesting. I've got a few of the old yellow monsters.


Post Extras: Print Post   Remind Me!   Notify Moderator  
ccaissie
professor emeritus


Reged: 09/13/10

Loc: Whitefield, Maine
Re: melting pyrex for blanks new [Re: TxStars]
      #6226470 - 12/01/13 07:07 AM

Quote:

Isn't the old way of mixing glass to cast/break/re-cast several times?




I think they melt a raw batch, shatter it, select for homogeneity and correct dispersion, then remelt for greater quality as needed. I've got a 10" piece of BK7 that is "A/PK" and that must've been gone through several times to reach such quality.


Post Extras: Print Post   Remind Me!   Notify Moderator  
steveastrouk
super member


Reged: 08/01/13

Loc: Rochdale, UK
Re: melting pyrex for blanks new [Re: ccaissie]
      #6226594 - 12/01/13 09:42 AM

European 'PYREX' IS 100% borosilicate, I used to supply equipment to the UK factory, before it moved to France. I did negotiate a deal to buy broken returns, in ton lots, for around $2000, but when I punted the idea in forums like this, the silence was deafening. I have the actual glass formulation used written somewhere.

LCD monitors have boro glass faces too.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Napersky
Carpal Tunnel
*****

Reged: 01/27/10

Loc: Chicagoland
Re: melting pyrex for blanks new [Re: steveastrouk]
      #6228643 - 12/02/13 09:27 AM

Awesome I hope making optical glass is the next trend for ATMs. The major glass companies have been gouging the community to the max!

Post Extras: Print Post   Remind Me!   Notify Moderator  
JohnH
Carpal Tunnel
****

Reged: 10/04/05

Loc: Squamish BC Moved!!!!!
Re: melting pyrex for blanks new [Re: Napersky]
      #6228738 - 12/02/13 10:19 AM

I have a pair of these huge 16" X 3 /14" blanks and a better use of them would be to cut them into 2 1 1/2" blanks.

I found the cost of around $150 to cut without any other work (lapping or diamond generation) quite reasonable


Post Extras: Print Post   Remind Me!   Notify Moderator  
Napersky
Carpal Tunnel
*****

Reged: 01/27/10

Loc: Chicagoland
Re: melting pyrex for blanks new [Re: careysub]
      #6228755 - 12/02/13 10:25 AM

Quote:

You can buy authentic Corning Pyrex 1" rod for $8 a pound (a 4 foot 1" rod weighs 3 lb) from glass blowing supply places:

http://www.waleapparatus.com/catalog.asp?prodid=547940&showprevnext=1

It appears the Pyrex brand name was sold to World Kitchen just for the cookware product line.

http://www.corning.com/lifesciences/us_canada/en/technical_resources/product_...





I would guess that there is quite a difference between optical Pyrex and Kitchen glass which is still manufactured. Only the former was discontinued.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Napersky
Carpal Tunnel
*****

Reged: 01/27/10

Loc: Chicagoland
Re: melting pyrex for blanks new [Re: Napersky]
      #6228778 - 12/02/13 10:34 AM

http://www.newportglass.com/pyrexmkt.htm

"From a distributor and a fabricator perspective, both Newport Glass Works, Ltd. and Newport Industrial Glass, Inc., will continue to offer “Pyrex” parts and sheets from equivalent replacement material. Newport will be stocking and distributing Schott’s Supremax 33 and Borofloat in lieu of “Pyrex”. They will also offer “Pyrex” replacement material in strip form made by other manufacturers."

http://www.matweb.com/search/datasheettext.aspx?matguid=5bb651ca58524e79a5030...


Post Extras: Print Post   Remind Me!   Notify Moderator  
Napersky
Carpal Tunnel
*****

Reged: 01/27/10

Loc: Chicagoland
Re: melting pyrex for blanks new [Re: Napersky]
      #6228790 - 12/02/13 10:41 AM

Apparently Corning sells a ULE that's better than Pyrex and in bulk.

http://www.pgo-online.com/intl/katalog/ule.html


Post Extras: Print Post   Remind Me!   Notify Moderator  
careysub
Carpal Tunnel
*****

Reged: 02/18/11

Loc: Rancho Cucamonga, CA
Re: melting pyrex for blanks new [Re: Napersky]
      #6228808 - 12/02/13 10:49 AM

Quote:

Quote:

You can buy authentic Corning Pyrex 1" rod for $8 a pound (a 4 foot 1" rod weighs 3 lb) from glass blowing supply places:

http://www.waleapparatus.com/catalog.asp?prodid=547940&showprevnext=1

It appears the Pyrex brand name was sold to World Kitchen just for the cookware product line.

http://www.corning.com/lifesciences/us_canada/en/technical_resources/product_...





I would guess that there is quite a difference between optical Pyrex and Kitchen glass which is still manufactured. Only the former was discontinued.




Laboratory Pyrex is still manufactured, and actual Corning Pyrex rod would be this same material.

This is exactly the material wanted for mirror manufacture since it has the very low thermal expansion property (one does not want a beaker of acid shattering from thermal stress).

The discontinuation of the production of Pyrex mirror blanks would be a separate issue.

The original kitchenware borosilicate Pyrex with the same low thermal expansion was discontinued when the tradename for that product line was sold to World Kitchen in the late 1990s. World Kitchen sells cheap soda lime glass that has been tempered through a heat heating process under the name "Pyrex" (essentially the same as that produced by Anchor Hocking).

http://www.consumerreports.org/cro/magazine-archive/2011/january/home-garden/...

World Kitchen makes a business out of buying famous high quality kitchen brands, then selling cheap knock-offs under that old famous name.

They did this with Magnalite cookware also, replacing the original magnesium with cast aluminum; and with Revere Ware, replacing the clad copper disk which provided excellent heat distribution with thin copper plating which quickly comes off in a most unsightly manner.


Post Extras: Print Post   Remind Me!   Notify Moderator  
TxStars
Pooh-Bah
*****

Reged: 10/01/05

Loc: Lost In Space
Re: melting pyrex for blanks new [Re: Napersky]
      #6228926 - 12/02/13 11:37 AM

One could also remelt Zerodur sheets.
http://www.capovani.com/iinfo.cfm?itemno=105019


Post Extras: Print Post   Remind Me!   Notify Moderator  
kfrederick
Carpal Tunnel


Reged: 02/01/08

Re: melting pyrex for blanks new [Re: TxStars]
      #6228931 - 12/02/13 11:40 AM

http://www.pottersweb.net/index.php?ad&cat=kilns

Post Extras: Print Post   Remind Me!   Notify Moderator  
Napersky
Carpal Tunnel
*****

Reged: 01/27/10

Loc: Chicagoland
Re: melting pyrex for blanks new [Re: careysub]
      #6229231 - 12/02/13 02:06 PM

Quote:

Quote:

... There's something about Pyrex that I don't quite understand: how could a product with such usefulness and value just be pulled out of production?




You never saw a product with an established brand-name be replaced with a cheaper substitute trading on the original's reputation?

This is extremely common, I would say the rule rather than the exception, when a brand-name is sold to another company that did not build up the brand's rep. This is what happened here when Corning sold off its consumer product line to World Kitchen.

Quote:

I think that the answer is more complicated than just business buying and selling, and may involve the EPA and other agencies.




Why would you think this?

Maximizing profit is more than sufficient explanation.

NB: Just within the realm of cookware I can cite several examples of former prestigious brands being debased with cheaper knock-offs.

World Kitchen not only did this (apparently) with Pyrex cookware, they also did it with Magnalite - a premium brand of cast magnesium cookware (hence its name) dating from 1934 now consisting only of cheaper and heavier cast aluminum.

Revere Ware once consisted of premium stainless steel pots clad to a disk of copper for rapid heat distribution. The pots today have the same appearance, but the "copper bottom" is now thin plating for show, which quickly wears off in an unsightly manner.

West Bend was once a brand of cookware that produced a very popular and nifty electric wok (famous for its red enamel exterior) with a thermostatic control. I used mine for decades until it finally wore out, and bought a new "West Bend" wok, to find that the "control" was now just a potentiometer and the "temperature" scale on it meant nothing. After burning the first dinner I tried to cook in it, and then have it shed screws and nuts into my garbage disposal, destroying it, I threw the worthless thing out.

Regal has been cheapening its own classic line of cast aluminum cookware, with ever thinner and more poorly cast products.

This is a very, very common practice. U.S. made real premium cookware is mostly a thing of the past it seems.





Corporate America seems today to be run by Frauds and Crooks. Executives without conscience who deceive the consumer.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Napersky
Carpal Tunnel
*****

Reged: 01/27/10

Loc: Chicagoland
Re: melting pyrex for blanks new [Re: Napersky]
      #6229266 - 12/02/13 02:23 PM

World Kitchen, I've seen their junk, I believe their cutlery is made in China. It doesn't surprise me they would lie and say Corning swapped kitchen borosilicate Pyrex for *BLEEP* soda glass!

Post Extras: Print Post   Remind Me!   Notify Moderator  
careysub
Carpal Tunnel
*****

Reged: 02/18/11

Loc: Rancho Cucamonga, CA
Re: melting pyrex for blanks new [Re: TxStars]
      #6229406 - 12/02/13 03:14 PM

Quote:

One could also remelt Zerodur sheets.
http://www.capovani.com/iinfo.cfm?itemno=105019




Are you sure that you can?

I'm not saying you can't, but Zerodur is a two-phase glass-ceramic composite and I have always supposed that special temperature cycles were necessary for production to produce the desired properties.


Post Extras: Print Post   Remind Me!   Notify Moderator  
kfrederick
Carpal Tunnel


Reged: 02/01/08

Re: melting pyrex for blanks new [Re: careysub]
      #6229839 - 12/02/13 06:07 PM

Those would make nice 10 inch blanks Get them water jet cut . And generated .

Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | 5 | (show all)


Extra information
3 registered and 16 anonymous users are browsing this forum.

Moderator:  ausastronomer, richard7, Starman81 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 5958

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics