Double Helix OP.6
I picked this rod up first to test because it is dark purple, which is one of my favourite colours. It looked like it had stars all the way through it, which is pretty cool. Ossa rods have some sort of silver inclusion within the rod. This means that when you use OP.6, the inclusions seems to shift colour from silvery white to reflective purple or blue depending on the base colour underneath. I didn’t have any expectations from this rod and I wasn’t sure if it was reducing or striking. After a quick google search I realised it was a variant of Ossa and a reduction glass. Now, I’ll be pretty honest here, whilst the idea of a silver glass with somewhat reflective inclusions is a cool idea. The little spots really didn’t do much for me at first as I couldn’t shake the impression that it looked like a whole bunch of bead release was stuck in my bead.
This particular rod liked to randomly break in sections. It does shock a lot, so make sure you preheat it. As I was working in the flame, chunks of Op.6 would break off the main length of rod. It was really frustrating because it meant I had to stop, spot heat and remove the chunk and my rod kept getting shorter and shorter. So what did I discover from that? The parts where the rod broke and left a thick blob, which then had to be spot heated to remove some glass created different reactions to the beads that weren’t spot heated. Spot heating is bad (in my opinion), unless you want lighter green blotches in your design, I’d avoid spot heating.
A thick layer of Op.6 looks better when not encased. When gently reduced and not encased Op.6 develops a dark shifting purple, blue-green oil slick appearance and some of the white speckling disappears. The more reduction, the darker and more metallic the appearance.
A thin layer encased and heavily reduced will give a strange blue shifting to green and yellow opaque look to the beads, I think of Magellanic Clouds, and I started to like this glass and Ossa in general a little more because of the starry night sky effect. I personally like the reaction I got when this colour was applied thinly and very gently reduced before encasing.
I really liked Op.6 encased over CiM Simply Berry, the white speckles in the glass reflect the purple plum colour which is a nice contrast to the blue green iridescence. A thick layer encased (and reduced for more than 30 seconds) means you will lose the iridescent look and the blue green blend will be more opaque.
Significant points to note, Op.6 needs a reduction flame (and a very gentle wafting in and out) to get it to go metallic. When encasing after reduction, don’t overheat (go slowly, super hot encasing strikes Op.6 too quickly to green or worse, yellow). I had no trouble encasing with either Effetre or Lauscha clear, they didn’t seem to effect any significant changes. You can’t “over reduce” Op.6, it will just go a darker metallic colour, but you can push the reaction along too far if you encase too hot. You will end up with wishy washy green and no opalescent iridescence if you over heat after encasement.
To keep the iridescence when encased, cool encase, do not get that bead overheated, I found it really hard to do on a bigger bead (small beads are easy) and you will need a lot of patience. It will be slow going to encase Op.6 and keep the iridescence, you will have to be very patient in smoothing your encasing out slowly. So if you want an oil slick look, its easier not to encase. Op.6 responds to cool marvering to slow down the reaction if you have accidentally over heated. Encased Op.6 beads should not be left garaging in your kiln at a hot temperature as they strike to yellow or pale green. Edit: December 2016 I tested out big beads using various Ossa variants this year by leaving them garaging for four hours and they were fine, but my garage temperature was on the cool side.
Op.6 looks really good for night sky effects and the white speckles reflect the tone of the base bead, but if you want that look, keep it applied thinly. The thicker the application the more white “speckles” and the speckles won’t do that cool colour shifting thing. Op.6 looks better (in my opinion) with a darker base colour to capture that iris blue green iridescent look. Edit: December 2016 I’ve since discovered that Op.6 gives you more of a purple to green oil slick iridescent look than any other type or variant of Ossa I’ve tried when used over darker base colours. I personally prefer Op.6 over CiM Simply Berry because the darker transparent gave more of a colour range (hints of purple and deep blue) than the lighter transparent (more overall green and blue tonality). Whilst I have a lot of Ossa, I don’t have any more Op.6 and I wish I had another rod to make a few more beads as I think the colour you can get from Op.6 is superior to Ossa.
Update: December 2016
OP.6 is my favourite version of Ossa after experimenting throughout 2016 with different test batches of Ossa. Regular Ossa is lighter purple in the rod and tends to the blue – green spectrum of the colour reactions. It is easy to encase and maintain the opalescence. The darker the rod the more purple – blue the reactions are, which is what I prefer, this is Op.6 and is harder to get an opalescent look encased. The royal blue rods of Ossa that are in the 2016 garage box will not give you any oil slick appearance at all and tend to the sea green – pale green range, however, they will give you a really beautiful opalescent sheen when encased and will do so very easily.