Where to buy lens blanks

[dark star]

I would like to have a go at making a refractor. Or possibly a Schupman telescope. For this I would need some lens blanks, probably for a first attempt 4 inch blanks. For the Schupman I would need 2 BK7 blanks or other similar glass. For the refractor one Crown BK7 glass blank and one flint glass blank.. I have a book about making a refractor and another one about making a Schupman telescope. I have a couple of optical flats that would help with testing.

In the longer tem I would also like to try making an 8 inch Houghton telescope.  For this I would need 2 eight inch BK7 blanks. On the Cloudy Nights website I have read that BK7 is the most common form of optical glass. However, I have not been able to find anywhere to buy lens blanks in the UK, by looking on the Internet.

You can buy glass blanks from China on Ebay and to other sites, but not much information is given about the type of glass or how good it is. You can also buy from Ebay, from a place called Silo Surplus in America. Again, there is often little or no inofmation about the quality of the glass blanks. Also, for all these blanks from China and America I would have to pay import taxes.

Does anyone know where I can buy BK7 blanks in the UK? Or possibly from the E.U. if I could be sure of the quality of the blanks.

I already have a 9 inch blank for making a Maksutov corrector. However, the tolerances for this are very tight,  so I would prefer to have a go at making some lenses to get experience before attempting to make Maksutov.

I have made one 14 inch mirror for a Dobsonian and am making a larger mirror for a bigger Dobsonian at the moment. But I would also like to have a go at making something different.

David

[fozzybear]

16 minutes ago, dark star said:

I would like to have a go at making a refractor. Or possibly a Schupman telescope. For this I would need some lens blanks, probably for a first attempt 4 inch blanks. For the Schupman I would need 2 BK7 blanks or other similar glass. For the refractor one Crown BK7 glass blank and one flint glass blank.. I have a book about making a refractor and another one about making a Schupman telescope. I have a couple of optical flats that would help with testing.

In the longer tem I would also like to try making an 8 inch Houghton telescope.  For this I would need 2 eight inch BK7 blanks. On the Cloudy Nights website I have read that BK7 is the most common form of optical glass. However, I have not been able to find anywhere to buy lens blanks in the UK, by looking on the Internet.

You can buy glass blanks from China on Ebay and to other sites, but not much information is given about the type of glass or how good it is. You can also buy from Ebay, from a place called Silo Surplus in America. Again, there is often little or no inofmation about the quality of the glass blanks. Also, for all these blanks from China and America I would have to pay import taxes.

Does anyone know where I can buy BK7 blanks in the UK? Or possibly from the E.U. if I could be sure of the quality of the blanks.

I already have a 9 inch blank for making a Maksutov corrector. However, the tolerances for this are very tight,  so I would prefer to have a go at making some lenses to get experience before attempting to make Maksutov.

I have made one 14 inch mirror for a Dobsonian and am making a larger mirror for a bigger Dobsonian at the moment. But I would also like to have a go at making something different.

David

David,

Have you tried Galvoptics in the UK?

Edited May 1 by fozzybear
spelling

[dark star]

I have completed an enquiry form to Galvoptics asking about BK7 blanks. I should have thought of this myself, as I have bought pitch from them a few times.

I will post again when I receive a reply.

[mikeDnight]

Pilkington Glass used to produce optical crown and flint and would cut it into disks of any specified size. They also made ED glass, but I haven't heard from them for over 20 years, so maybe they are nolonger in business.

[fozzybear]

Back in my IT days in the UK and sub contractor to Pilkingtons  in St Helens they only did float glass now rolled glass but yes still going. But not available options to us in the astro form... bummer

[Astrobits]

Schott glass in wolverhampton would be my first choice.

Nigel

[dark star]

I looked at the Schott UK website. It appears that in order to see the prices, for example for BK7, you have to register. It is not possible to register unless you are a company as there is a mandatory field asking for a tax number. Do they sell small quantities of glass to individuals?

On the form to contact them it asks for a company name and email address?

[Astrobits]

It is possible that they have changed their procedures since I purchased stuff from them ( quite a few years ago ). You could always try phoning them to discuss your requirements.

Nigel