I have gotten a lot of questions about what is the best 104 COE black glass to use, so I decided to address this recurring question with this blog posting.
When I started lampworking 23 years ago, I knew of only one glass factory that made 104 COE glass and that was Effetre (when it was still owned by and called Moretti). Now there are many more factories making 104 COE glasses which gives the lampworking community many more options to choose from.
It has come to my attention that the color base of the black glass produced by different factories is different. Effetre Black #591064 is a very dark, dark transparent purple and I found it problematic to use in fine stringer work because it would turn out looking kind of purple.
Frantz Art Glass got Effetre to make a new super dense black called Intense Black #591066 a number of years ago and this color became very popular with the lampworking community. I was hoping when we had Intense Black made, that it would be a great detail black for fine lines and such, but this color has a tendency to bleed a lot. Much to my surprise, Intense Black became popular with beadmakers who like to make organic bead designs and they loved the bleeding.
The black from Vetrofond has a dark blue base color and Messy Color/CiM Tuxedo (black) – #511872 has a dark gray base. I use to be a devoted Vetrofond Black user, but when I started using Tuxedo on a regular basis, I switched to Tuxedo because it is a great all purpose black. I currently use Tuxedo as the base for most of my dichroic beads because black is a great reflective base to use for getting the best out of the dichroic colors.
CiM/Messy Color also made a very dense black that they call Hades #511820, for when lampworkers need a really dense black. Hades bleeds a little bit like Intense Black does, but I think it has become as popular for its reduction properties as it has for its denseness.
When any lampworker calls or writes me about which black is the best to use, I have to say that I think Messy Color’s “Tuxedo” is the one. I have very good results using Tuxedo and I find the Tuxedo rods to be less shocky than any of the other blacks available on the market. I have also found that I can pull a Tuxedo stringer really thin and it stays a very dense black because of its dark gray base. I haven’t had any problems with a pitted surface when I work with Tuxedo either.
If you want to find out what the base color of a very dense glass is, blow it out in a very thin bubble and take it out in the sun.