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Frequently Asked Questions

What is a glass master?

A glass master, also referred to as a ‘stamper’ is used to punch all of the data pits into a CD or DVD during the process of replication.

The reason why it is called a glass master is because the information is copied onto a special chemical coating on a circular block of glass. The block of glass is actually much larger than a CD (they are typically 240mm in diameter and 6mm deep) to facilitate handling and to avoid the sensitive data area from being touched or damaged.

The glass master is polished until it is ultra smooth as even microscopic scratches can affect the quality of the CDs being produced.

Glass mastering is performed in a Class 100 clean room (10 times cleaner than an operating theatre). A Class 100 cleanroom is designed to never allow more than 100 particles (0.5 microns or larger) per cubic foot of air (typical office building air contains from 500,000 to 1,000,000 particles per cubic foot of air). This is because dust, pollen and smoke particles can all affect the quality of a CD glass master whilst it is being prepared, so the mastering facilities are kept as clean as possible.

There are three principle steps involved in creating a glass master:

Step 1 – Photoresist mastering and Laser Beam Recording (LBR)

The first step in producing the glass master is to clean the glass plate with detergents and to then apply a photoresistive light-sensitive material of about 140 to 150 microns that is then burnt using a Laser Beam Recorder (LBR) which is a deep blue or ultraviolet laser. When exposed to the laser light, the photoresist undergoes a chemical reaction which hardens it.

After mastering, the glass master is baked at about 80°C for 30 minutes to harden the developed surface material and prepare it for metalisation. Metalisation is a critical step prior to electroplating with nickel.

Step 2 – Metalisation of the glass master

After the photoresist mastering, the developed glass master is placed in a vapour deposition metaliser which lowers the pressure inside a chamber to an extreme vacuum. A piece of nickel wire is then heated to white hot temperature and the nickel vapour is deposited onto the rotating glass master. The glass master is coated with the nickel vapour up to a typical thickness of around 400nm before being removed.

Step 3 – Electroforming

glass masterThe information contained on the metalised glass master is extremely fragile and it must be transferred to a more resilient form for use in the injection moulding equipment.

The metalised master is therefore rotated in a plating tank containing a nickel salt solution (Nickel Sulfamate). The electroforming process takes approximately 1 hour to create a 0.3mm thick uniform nickel layer.

This master is then called the ‘father’ and a negative of the father, the ‘mother’ needs to be created to be able to punch the pits and grooves into the membranes on the final CDs or DVDs that the customer will receive.

The mother glass master is created from the father using electroforming and the mothers are then used to punch holes in the membrane layer on replicated CDs or DVDs that will then allow light through to reflect off the silver aluminium layer above the membrane layer in the centre of a CD or DVD.

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What our customers say

4.8/5.0 on Facebook

Great service - quick to respond and were very informative about my technical questions at the start. Products look fantastic and care is taken to deliver great products. If any issues arise (as can sometimes happen with old mediums like cassettes!) they are fixed very quickly, and professionally. I had used other very slightly cheaper companies for tapes and received awful products in the past, wouldn't go anywhere else now. Thanks to Paul for his help and support with each release.read more
Chris Le Monde
Chris Le Monde
2019-01-24T16:24:09+0000
On behalf of The Lack of Commitments we'd really like to thank Charlotte and the team for producing our live double album CD. We went for the vinyl CD look for our double album with a four page booklet. The quality, print and help was great. Thank you.read more
Dave Patrick
Dave Patrick
2018-12-03T20:03:31+0000
We absolutely LOVE Band CDs in our house. The service was quick, almost instant, friendly, and everything happened as it should. I would deffo recommend them. Just one teensy little thing...please get some mastering software that allows you to join tracks together. xread more
Stephen Butler
Stephen Butler
2018-11-23T16:11:49+0000
Excellent experience using these guys. I’m in a band called, Pulverise and we used Band CDs to print digi-packs of our debut album - Chaos Games. It’s the first time we’ve ever done anything like this and they supported us from the first contact to completion and delivered a beautiful product that we’re all proud of. Tom G is a legend! Thank you!read more
Vicky Reader
Vicky Reader
2018-10-03T14:57:15+0000
We printed our first release (Nordkväde) on tape here, the maltese cross folding cover looks amazing and we are really impressed by the all over print of the cassette. Most importantly the sound quality is great! We couldn't be happier with the result and great support they gave us when printing this product. Highly recommended!read more
Olle Olsson
Olle Olsson
2018-10-01T10:28:30+0000
Can't thank Charlotte and BandCDs for their help in turning my order for LIINES around so quickly and producing quality CDs. They answered my (many) questions by phone and email and nothing was too much bother. Can't wait to get these out to people who have ordered and to sell them at gigs. Thanks again.read more
Leila O'Sullivan
Leila O'Sullivan
2018-07-20T09:44:48+0000
Brilliant service and product . Couldn’t fault Charlotte who looked after our order, great advice and support with regards design etc . Would recommend any indie bands out there to use this company , you won’t be disappointed .read more
Kenny Martin
Kenny Martin
2018-06-12T11:50:32+0000
Band CDs has provided Brilleaux (New Zealand) with UK based CD production for all their tours of UK and Europe since 2013.Great service, innovative and impactful products, fast delivery and keen pricing make them our go-to partner for this part of our Merchandising strategy.Paul's customer-facing approach is like a breath of fresh-air - It's an *absolute pleasure* to do business with these guys!Highly recommended :-)read more
Rob Vernon
Rob Vernon
2018-04-15T11:27:23+0000
Thank you so much Band CDs team (Charlotte was the person who took care about my release😉) The artist KEYVANOTH and I are very pleased of the result and I deeply support Band CDs and will renew as soon as I can afford😊 thank you for your very nice photo and I'm pleased to have added some other one about this great product (the vinyl style CD with microgroove relief and deepl black reverse is awesome !) The CDs were safely delivered this afternoon. Many thanks.phoenixread more
Emmanuel Duchez
Emmanuel Duchez
2018-01-31T21:44:31+0000
I've had a 50 CD order for a classical music project. The audio quality was very high, and I loved the black vinyl CDs. The digipak printing was perfect, the staff was friendly and helpful, and overall it was a lovely experience. As a minor issue, I personally find the booklet pocket needlessly large, but that is a matter of taste. I would definitely recommend them. Many thanks for the professional services!read more
Maria Suciu
Maria Suciu
2017-09-27T14:17:18+0000
I've now had 4 different CDs produced by the Wizbit/BandCD team and can thoroughly recommend them for attention to detail, courteous and careful correspondence, good design advice, speedy service and high quality production. Absolutely no complaints!!read more
Andy Beaumont
Andy Beaumont
2017-09-13T20:44:41+0000
Can't rate BandCDs highly enough, 5 stars doesn't even come close, from day 1 they help me with every issue I had with my CDs right through to the final product, the range of products is also mind blowing , from normal everyday CDs to mini vinyl CDs which is what I opted for for my own release, there is something for everyone here, can I personally thank everyone at BandCDs for their excellent service and friendly approach, The Plastic Fantastic Ep was The Skalps first release and we will 100% return to BandCDs for future releases. Thank you from all at Skalps Hq.read more
Tommy Byrne
Tommy Byrne
2017-09-12T22:40:33+0000
Band CDs did a run of cassettes for me in August and they are beautiful. The full on-body printing is a great option and the quality of the J-cards is excellent. Delivery was very fast and the price quoted was extremely competitive. I have since ordered from them again.read more
James Griffin
James Griffin
2017-09-09T17:11:13+0000
Band CDs are doing an awesome work with tape manufacturing, their professionalism and efficiency is amazing and the tapes I received are high quality products and they know how to handle problems such as delivery issues. I ordered a batch of 50 tapes for my label, which was lost by the delivery service and after a few months of being in contact with the delivery service trying to locate the parcel, they sent me another batch of 50 tapes that they re-produced. Couldn't recommend Band CDs enough.read more
Maël Gilabert
Maël Gilabert
2017-03-13T20:44:07+0000
Excellent product, great customer service and did exactly what was asked for!! Thanks Charlotte for a great product and super duper service! Would highly recommend - Ian (Gone Savage) Check it out on our bandpage - facebook com gonesavageukread more
Ian Salpekar
Ian Salpekar
2016-10-27T13:00:28+0000
Can't recommend these guys enough. I worked closely with a chap called Michael at BandCDs on a small batch of cassette tapes. He was an absolute legend! His meticulous attention to detail was unlike anything else I've experienced from any of the printers/manufacturers I've dealt with in the past at other companies. He ensured that certain elements of the design lined up and also bent over backwards to make sure the colour of the printed J Cards matched nicely with the colour of the plastic cassette. Top this off with an extremely quick turnaround, high quality products, great sounding audio and all at the lowest price I could find anywhere online and you can see why it's smiles all round in my house! Great job, thanks again all! :)read more
Alex Foster
Alex Foster
2016-08-02T09:36:59+0000
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Bands & Artists we've worked with

We've manufactured products for some of the biggest bands and artists in the world...