CraftWEB Hot Glass Talk

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-   Color work from rods and batch glasses (http://talk.craftweb.com/forumdisplay.php?f=31)
-   -   Calcedony Prep (http://talk.craftweb.com/showthread.php?t=11636)

Pete VanderLaan 08-07-2017 04:56 PM

well done!

Dan Vanantwerp 08-07-2017 05:30 PM

Awesome color spectrum Scott. The clear to opalized transition is a bit like magic. Would be great for live demos. I had a show this weekend and all the customers were drawn to these pieces. Inside of a conch shell will be a great application.

A bunch of boro artists came by and suggested that it looked just like "amber purple" in the COE 33 world.

The matte finish suggested by Sky on my other thread was pretty damn amazing. I didn't think it could look better but I have to admit that I like it even better.

Please post pics! I'll upload an image of the matte finish later.

Pete VanderLaan 08-07-2017 07:13 PM

matt, blasted in contrast is remarkable/ oil it.

Jordan Kube 08-07-2017 07:50 PM

That's the stuff

Mitcheal Veenstra 08-14-2017 01:43 PM

that's really nice

Greg Vriethoff 09-16-2017 10:38 PM

I'm nowhere near being able to play around with any of this stuff right now, but it gets me really excited to see what people are doing. I can't wait to get things up and running around here.

Thank you to everyone for sharing here.

Pete VanderLaan 09-17-2017 04:37 PM

Actually, this not a hard glass. It does depend on the basic clear formulation. It would probably be equally relevant if I had a class on clear bases for colors but it is not sexy. In all my correspondence with John we talk base glasses more than anything. I don;t think anyone pays a whit of attention to those basics. I think I have five bases and John, last time I checked, has nine.


Once through the base, then apply the rules for expansion and viscosity. Make it fit.

Dan Vanantwerp 12-21-2017 03:04 PM

Been working with the cullet formula for a while now. I'm trying to achieve more of the blue, lavender, red colors and less yellow-brown. I've recently tried 5g cinnabar in an 8lb mix of the normal chalcedony formula (no cobalt or copper) from Pete with no obvious benefits. I realize cullet could be my limiting factor and that whatever reduction state is needed for the "lovely" colors may be limited in an oxidized base glass. My ventures into batch are awaiting the availability of the commercial batch guys.

I did run across an interesting excerpt from Charles Bray in his "Dictionary of Glass" while looking up the possible effects of mercury in glass. I don't have the book (yet)....this came up in the eBook preview from Google.

from page 102...Into this was added a mixture of zaffre (a type of cobalt silica), iron oxide, copper oxide and mercury sulphide dissolved in nitric acid. The resulting glass was worked at the furnace in the normal way, but in common with some coloured glasses such as copper, gold and selenium rubies, it was necessary to get the colour to strike. When ware for such glasses are made the metallic crystals formed during the initial cooling are very small but reheating at the glory hole can be...

I can't wait to get the book and read the context and conclusion of this paragraph. Based on this, perhaps the cinnabar requires pretreatment with nitric acid...pretty nasty. The info I have read suggests this requires boiling temps on top of the already dangerous chemicals involved. OR...they are just dissolving everything in acid and the only benefit is to create silver nitrate. Any thoughts?

Pete VanderLaan 12-23-2017 12:11 PM

I never found Bray to be really informative at all. I do have the mercury sulfide and have yet to try it. I do use copper in it as well as occasional cobalt salts.

The effects Dino Rosin has gotten are by far the most remarkable I've seen. I did the work for Simpson's Corona stuff.

Dan Vanantwerp 12-28-2017 12:55 PM

I'll have to give the cobalt salts a try...only ever used oxide form. I'd like to maximize the amount of black tin for use in cullet. Also, in looking back at the original recipe you mentioned using window glass with a relatively high iron content. I'm going to try and find the optimal iron content for cristalica. It has seemed to help to bump up both the black tin and red iron in my preliminary deviations from the original. Some have mentioned sugar as an alternative reducing agent. Lots to try...just wish I had a couple more color pots.

Pete VanderLaan 12-28-2017 01:50 PM

If you push the iron too hard, it won't opalize. Sugar doesn't really work unless it's very short term with gas. Black tin is really the reducing agent of choice. The Mercury really is an unknown for me.

Dan Vanantwerp 12-28-2017 02:53 PM

2 Attachment(s)
I've eliminated the zinc with no change. I was trying to remove some of the off-white, yellow to beige opals but they still develop. The tin seems to push toward the purples, greens and blues. Wish it wasn't so pricey. I'll also try less silver. The reds in these photo are what I'd like to achieve. I sure didn't see anything start to pop out with mercury, but I'm far from exhausting the possibilities with it.

Pete VanderLaan 12-28-2017 03:54 PM

you have nothing to complain about.

Dan Vanantwerp 12-28-2017 05:10 PM

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Sorry...the pics are not my work. That's Dino.

Here is a platter from Josh Simpson with the red color spectrum highlighted...this is the color I've yet to see in my own work.

No complaining here...I'm very happy with my results. Just curious about the red not coming through...yet :)

Pete VanderLaan 12-29-2017 07:05 AM

It comes from red copper. Run your annealer hot. It will strike there. We periodically threw small wax balls onto the pot surface before the slap gather, sometimes we used an oxy acety;ene torch briefly on the surface. Don't gather, slap.

Dan Vanantwerp 12-29-2017 12:05 PM

Thanks Pete. I'll give it a shot. My color pots gather vertically which works nicely for the colloid formation. The hotter anneal is going to be interesting...I recall Jordan Kube also saying the red copper strikes in the annealer. I'll bump it up 50 degrees or so.

Pete VanderLaan 12-29-2017 01:14 PM

do keep in mind with Dino's, he's using more than one pot of glass. As to Josh's, that's not really a very good example. we did a lot better than that.

Jordan Kube 12-29-2017 03:19 PM

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Don't forget, process plays an important role in color formation. When I slap a large gather of chalcedony on the marver and pick it up on the side of a solid piece of clear to sculpt, it's nothing like blowing. I would go so far as to say it's an apples to oranges comparison. They've found that color formation in these types of silver glasses depends not only on the size of particle but also the shape. Good luck getting a handle on that! I'd love the hear about your good results though. I'm on the same path right now but with nothing significant to report.

I've found I can get Dino like results with the process I described. Doesn't look exactly like his but I've never been able to touch these colors blowing. I would stay away from mercury. There's a reason nobody uses it.

Pete VanderLaan 12-29-2017 03:46 PM

seriously, mercury is no worse than lead or Cadmium. Gloves and ventilation, wash rinse repeat...

Hard to get though

Dan Vanantwerp 12-30-2017 02:28 PM

I've ordered some more of it on ebay. It's the only place I've found...straight from Hong Kong. Reasonably priced.

The results from Josh Simpson and Pete are mostly blown. Dino does some bowls also with nice color results. That pink-lavender-red transition is my goal, currently. I start my day with a little solid work just to see the look of the glass. I agree that it likes to be thick. However, I did make some ornaments for co-workers and they looked pretty nice aside from the tiny pin needles which only I seemed to notice.

I'll keep plugging along with it and will be happy to share results.

Pete VanderLaan 12-30-2017 05:19 PM

saying "it likes to be thick is another way of saying, "It likes to be cooled slowly". Think on that.
Then Think on the notion that I don't think anyone's holding out on you. They;re saying there's a lot of stuff that hasn't been done. Some will be crap, some may not be.

This has been going on for four thousand years. Think on that. You have giants around you. You need to add to the knowledge.

Dave Bross 12-31-2017 04:22 PM

My understanding of Mercury is that it is WAY more toxic than most things, particularly vaporized.

Be damn sure your ventilation is up to it if you choose to use it.

Years ago people were experimenting with Mercury as a weight shifting mechanism in stock car racing. It was banned on the premise that if a few drops of Mercury found their way onto the hot manifold in a wreck the vapor could be fatal to anyone nearby.

Here's more on the subject:

https://web.stanford.edu/~bcalhoun/AStock.htm

Google has more.

Rich Samuel 12-31-2017 04:52 PM

Quote:

Originally Posted by Dave Bross (Post 137899)
Years ago people were experimenting with Mercury as a weight shifting mechanism in stock car racing.

Better to stick with moonshine.

Of course, when I'm looking for safety advice stock car racers are the first people I consult. :D

Brian Graham 01-01-2018 08:13 PM

The copper ruby matrix....copper, iron, black tin, and silver nitrate in cullet.

http://www.briangrahamglass.com/img/silver-glass2.jpg

Pete VanderLaan 01-02-2018 05:58 AM

seedy though....


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