Carborundum is very hard and used for grinding tough stuff. You can
buy a carborundum block to aid in the
sharpening of knives and it comes in various grits.
A quality sandpaper of fine (600 or slightly less) grit like that in a
wet-or-dry type can give a slight texture
to glass. I use a grittier version to sand the edges of glass cut for
framing photographs.
Also, you can purchase hydrofluoric acid (of course wear gloves and
eye protection as well as a high quality
mask if you work indoors) to etch glass.
Jack F
On May 18, 2009, at 8:30 PM, Jacek Gonsalves wrote:
> Hi Tom,
>
> Thanks for the information. Can you elaborate more on carborundum?
> Is there a specific product I can get? Is it this by any chance?
> http://www.hoskindiamond.com.au/prod2016.htm
>
> Ammonium to clean glass, will try some Windex, that i'm sure has
> ammonia in it ! :)
> Ta
> Jacek
>
> Quoting Tom Sobota <tom@sobota.net>:
>
>> Jacek,
>>
>> Printing on glass is not very difficult but the exact procedure
>> depends
>> on the process.
>> I have made three-color gums on glass, but gum doesn't stick very
>> well
>> on plain glass, so I first 'frosted' the glass surface with
>> carborundum. Well, actually a valve-polishing compound that has
>> carborundum.
>>
>> I use carborundum because just 'sanding' the glass is, in my
>> experience, very slow.
>>
>> On the other hand, gelatin sticks to clean plain glass very well, so
>> any gelatin based process such as carbon works very well without the
>> need of any additional substrate. But the glass has to be VERY clean,
>> and that means at least some ammonia-based detergent. You could also
>> consult instructions for preparing glass for collodion. Glass is
>> notoriously difficult to clean well :-)
>>
>> For maximum adherence of gelatin you could use some sodium silicate
>> substrate as used for collotype. However, for a quick test a
>> reasonably
>> clean glass will do.
>>
>> You don't need to brush the gelatin on the glass. Just flow it from a
>> flask, and help to spread it with a finger (or a glass rod). The
>> gelatin will dry to a nice transparent thin coat. Keep the glass warm
>> while spreading, and then cool it on a very level surface.
>>
>> cheers
>> Tom Sobota
>> Madrid, Spain
>>
>>
>