Before telling you about my test results and giving you my opinions, I should share that I didn't clean any of this glass with any real rigour. I wiped it vigorously with the hem of my shirt and then ripped the tip off the rod in the flame and got to work making the beads. I did it this way because it's how I generally approach the glass, and can concede that there might be more effective ways to get good results with clear :)
These are the four clears I had on hand when I decided I wanted to compare Clears. Effetre Super Clear, Reichenbach 104 Crystal, CiM Experimental, and Double Helix Zephyr. I kind of wish that I'd had some Lauscha Clear and some Uroboros 104 CoE Clear to test as well, but I didn't and I am on a buying break, so we will settle for these four.
Pretty much every batch of Super Clear I've ever had has been yucky, prone to scumming, and with long scratches down the sides of the rods that contribute to bubbles. I have heard through the years that cleaning Super Clear by pickling it can really improve its quality, but I haven't tried that myself because of all the clear you can buy that isn't so high maintenance. My favourite use for Super Clear is to core the inside of beads when I'm using expensive colours on the surface, but it can also be a nice encasing glass when the encasement layer won't be very deep. Super Clear is only $9.80/LB today at Frantz Art Glass, making it a very affordable clear. Maybe it's worth the effort to pickle it :)
Crystal is lovely and can be very clean and clear, but it has some unique challenges. First, it's much stiffer than other clears, making it a bit more challenging to encase with. Second, it will boil if you hold it in one place too long in the flame and it gets too hot. Those bubbles can be a real buzzkill when you're adding a final layer of clear dots to a complex bead, so you have to be really careful to work it cool and/or to keep it moving in the flame. Crystal rod diameter is not very consistent, so it's really nice to be able to go somewhere and handpick the rod diameter that pleases you most. I prefer the thin 4mm-ish rods of Crystal because I find them easier to encase with. Crystal is $28.74/LB at right now at Olympic Color Rods.
The new CiM Experimental clear is much nicer than I remember CiM's regular clear being. It doesn't boil or scum very easily, and is similar in consistency to Super Clear, somewhere between the soupiness of Zephyr and the stiffness of Crystal. My only issue with Experimental has been that while it does not scum up easily or in every single bead, I have had some scumming issues with it. I used it to encase a round bead and ended up with a snail trail of scum all around the world. Kandice Seeber told me that the scum that comes up on Experimental in this way can be eliminated by heating it up. So, with that solution in place, Experimental's only real problem goes away. You can see in the bead above that apart from the bubble scum that I did not heat up to eliminate, the clarity is very nice. Frantz has Experimental now for $14.70/LB which is half the price of either Crystal or Zephyr.
Note: Editing to add that as of Nov 24, 2016 I am only having intermittent luck burning off the devit/scumming that appears sometimes on Experimental. I'm finding that the times when I do get the scumming, it appears on the tip of the rod as I am applying the clear, and is sometimes easy to remove with additional heating and sometimes not. I rather like Experimental apart from this irritating problem, but this is a thing that I can't really get past.
Hands down, the least fussy clear in this grouping is Zephyr. Zephyr is also the softest clear and the easiest to encase with. It's so very soft that it glides right onto a surface and it's easy to get a thin layer and to minimize the 'join lines' between each wrap. In the picture above, you can see that Zephyr is almost perfectly clear, with only the teeny tiniest of little imperfections. My Zephyr is second quality, as I'm too cheap to pay the first quality price when the seconds are so wonderful. At the time of writing this, Zephyr seconds are $30/lb on Double Helix's website.
There are some interesting differences in the way that silver behaves on top of these clears. These beads have all been treated with a thick layer of silver leaf, which was then burnished on and melted in.
The first characteristic, which I'll call 'silver dispersal', is how the silver spreads itself over the glass' surface when it's melted in. Zephyr has the finest and most even silver dispersal, with the silver bits all being melted away and forming a fine cloudiness on the surface. Reichenbach Crystal has the lumpiest and most uneven dispersal. I wonder if this has something to do with viscosity?
The second characteristic in these beads worth mentioning is discolouration. Crystal has fumed a much deeper, browner colour than its friends in this picture.
In these beads, I took a core of the relevant clear, covered it in a thickish layer of silver foil, and then encased that with more of the clear.
You can see from this picture that Zephyr and Super Clear were both much less reactive with the silver than Crystal and Experimental, discolouring less.
The silver turned gold in the Crystal and Experimental beads, although the gold is a different colour in each. With Crystal, the colour is more like 10K gold, and with Experimental, more like 24K.
In this final picture, you see all four clears used to encase a small, reduced core of Double Helix Arke. I would have to do more testing to see how repeatable these results were, but it seems like less of the Arke's colour is lost when it is encased with Zephyr. In the beads that I made with Super Clear and Crystal, the Arke is more of a pale blue, and Experimental's bead is somewhere in between.
However, while I tried very hard to be consistent, this colour variation could also be because of differences in how I reduced the colour, how much I reduced the colour, how warm the bead was when I encased the colour or any other number of variables. If I had more time to spend on this clear project, I'd explore that further and maybe since I don't, one of you will give it a shot :)
Which clear should you choose? I wouldn't presume to tell you, but hopefully I've given you some information that will help you make the right decision for the work that you do.
