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Josh Bernbaum 07-11-2020 11:14 AM

Neodymium ruby?
I'd like to do another neodymium phosphate try, did one last fall with 4% neo that I liked. But thought I'd see if I can get a slightly different look after reading a page from Volf's (Chemical Approach) in which he said something about a glass with 2-2.5% neo and 0.1% selenium can make a "fine neodymium ruby" shade. Any experience out there with this? I know a higher potash glass is necessary for selenium pink, and most of my alkali is sodium, but I do have about 1/4 of my alkali potassium. Is this worth a try, or is that little bit of Se just going to volatize on me?

Pete VanderLaan 07-11-2020 11:45 AM

I think Se strikes best if the potassium content is at lease 2% Josh. I certainly got nice peachy strikes in my old clear which I recall had about 16 lbs of sodium based stuff compared to about 6 lbs of potassium based stuff. I dn't tend to think the Se really volatilizes as much as many people think, it's just that it can be in five states of valence and only one shows color.

You could consider using zinc selenate as a source on the Se. Se, loves zinc. I have about 20 lbs of it if you want to try .Perhaps John C will kick in.

It seems to me that the downside there is these aren't casing glasses we're talking about so the product is pricey not cased in clear.

Josh Bernbaum 07-11-2020 12:17 PM

Thanks Pete, I do have at least some zinc oxide in this mix, maybe or maybe not enough to aid in coloration of the Se like you indicate. I thought the Se was volatilizing since you can smell it, but maybe that's just an odor and not the elemental selenium coming off the melt. If Volf is correct in those percentages, I'm not so worried about price of 0.1% Se, but the neo is a real killer of an expense for sure..

I'm inclined to try adding some to this next neo melt but I guess I'm just hoping it doesn't go 'brownish' with the addition of Se to a sodium-heavy mix, but it's not that much Se so maybe if it doesn't work it'll at least just look like regular neo coloration?

Pete VanderLaan 07-11-2020 01:21 PM

what is the neo price per lb at this point. Eveline sent me selenium and I've had a fair amount of the Nd for some time.

Josh Bernbaum 07-11-2020 06:26 PM

$60/Lb. at US Pigment, just looked. I can't remember what price Dudley gave me, but I bought the 5 lbs. or so he had last fall. So is it any concern that only 0.1% selenium might discolor or brown up a soda-heavy phosphate glass? I'm hoping that if not then there's nothing to lose giving it a try at the ratio Volf suggests. I could do a small test melt if necessary but then it's just another day and more propane.

Pete VanderLaan 07-11-2020 08:03 PM

Se pushes peach in a potassium rich environment.

$60? Ouch! I should just sell my supply shed. I have no idea where Se is.

Eveline never bills me. I don't know how she is. She was stuck in Hong Kong and unable to return to Shanghai without quarantine. Since she has condos in both cities and her mom is in Hong Kong she has stay there. The world is a real mess. I don't know if I'll ever see her again.

Josh Bernbaum 07-19-2020 12:30 PM

So I did get some noticeable pink tones from this "neo ruby" I tried earlier this week. It was, by weight, a 3% neo and 0.12% selenium.
Definitely a little bit pinker than my previous try last year at a neo-only phosphate. Very nice color. However, this was the first melt out of my last 5 phosphates that had more small white stones than usual (1-2 in almost every gather). Fit was off too for the first time in these last 5 melts, which have been all the same base. I could saw a ring but a couple small cracks did run while sawing but I did get a decent ring, and there was a noticeable gap in the score. I'm guessing it was about 2 points lower than my SP clear? I'm really pretty meticulous with triple-checking my weighing amounts, and melt times, temps, and charge weights and intervals were otherwise the same for this melt vs. the previous four. Same bags of raw materials too. Fairly new pot, only these 5 melt cycles so far. The 3% neo was less than a 4% I did last year which seemed to fit, and I've read that the Lanthanides (sp?) don't effect expansion much. I can't help but think the only difference here is the 25 grams of selenium I put in..? Can Se have effects on preventing other batch constituents from going into solution? Only thing I've read about the melting of Se is that it can go to the bottom before going into solution, but I did seem to have noticeable, albeit subtle, coloration effects from the Se.

Pete VanderLaan 07-19-2020 04:49 PM

well, what you don't say is whether this is being cased in something else or not.
3% of anything is lots, not so much because of it but because of the necessary changes in percentages that occur in the other additives just based on the simple math.

If both the interior and exterior glasses are in the same base, a simple pull test should show you the difference and if your additive stuff is lower expansion, then add some flux.

The stones are a different matter, but it's not the selenium making the stones. I suspect calcium in the Sp87 would make them though. I just don't know whether SP87 figures into this.

Josh Bernbaum 07-19-2020 08:09 PM

No clear involved with the stones, just seeing them in this color mix.
Saw very little to no stones in the previous mixes which were all of the same base.

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