In Australia HF based products for glass etching have been banned since 2003 because of (damn) graffiti taggers using them to deface shop windows. So glass etching products are no longer available to the retail market. After some disatisfaction with the quality of the ground glass I was making via the valve grinding paste method I decided to do some investigation into other sources of HF products. Some Googling revealed that HF is primarily used in the metal fabrication industry for removing oxides on aluminium and stainless steel. These 'pickling pastes' are readily available at welding supply stores however not in small quantities and not cheaply (4L for AUD$65). Further Googling revealed a less expensive and easily available product which contains 9.8g/L HF and 38g/L H2SO4, making it ideal for glass etching. SEPTONE (www.septone.com.au) 'Ali-Brite Aluminium Cleaner' is available in a 1L bottle for AUD$11.99 at Super Cheap Auto stores. Apparently it is also widely stocked at boating and marine retailers. I am sure there would be a similar product available to overseas buyers - check your local marine or auto shops for aluminium cleaners (or aluminum for those unfortunates who cannot afford to waste an extra 'i'). Before you rush out to buy some please read the MSDS (http://www.septone.com.au/msds/ATA1.htm) as this is one of the most toxic, corrosive and plainly dangerous chemicals that you could have at your house. Make sure you use all the personal protective equipment (PPE) specified and that you are suitably qualified or confident to handle toxic and corrosive chemicals. Last night I cracked a bottle open (wearing appropriate PPE) and sat some 3mm glass in undiluted Ali-Brite for an hour. The glass had been etched to about 2mm where it was submerged. This product is very effective at etching glass and from now on I will use it to make ground glass for my cameras. To pattern the glass I am considering using plain candle wax as a mask, from memory this is resistant to hydrofluoric and sulphuric acids. (Please let me know if this is not true or if there are better materials). Notes: 1. I have no affiliation with any of the companies mentioned, I am merely passing the information on for others wanting to chemically etch glass. 2. Do not even think about using this stuff if you are not willing to take adequate precautions, I don't want to read about your death or amputation of your limbs due to HF accidents.