Thursday, August 23, 2018

Research tips and tricks for SCAdians!

[Moving this here, since Facebook keeps deleting this post. I'm telling people how to find the information without stealing, and they claim I'm telling people how to violate Intellectual Property!]
--- Google "Dorks", advanced operators for Google searches and many other engines. You probably know making something "a quote" tells Google to return that exact phrase. You can also control results by the website, or phrase in the address, filetype, and more. For example, I'm very tired this morning of seeing pinterest:
"search term" -inurl:pinterest
This will return results with "search term" where the address does NOT include 'pinterest'. This is handy for removing ALL of the domains (.com, .ca, .co..uk, etc)
You can also search a specific site with "site:" or exclude it with "-site:"
Only want a specific filetype? Use it's common Windows extension, such as "filetype:pdf" to only return results within PDF files.
Others:
Related:domain.com (for finding websites 'related' to another)
cache: (for finding Google's last copy of it, see also Wayback Machine below)
--- Google Reverse Image Search, at https://images.google.com/, lets you search by uploading an image. Trying to find the source of a picture for attribution or to get permissions? Try and upload it here. If you use Google Chrome as your browser, you can also right click the image and just hit 'S' and this is done automatically.
--- Wayback Machine, provided by Archive.org, allows you to enter a website and see old cached copies of sites which may have been offline for years. A precious bookmark or unique site go down? Try this! The website also hosts a large amount of public domain content like books. I use it several times a week.
--- Academic Publishers pretty much look like a scam to me. I was trying to track down an article and one major publishers site would sell a copy to me for $25, another for $10. The website for the actual journal it was published in offered it as a free download without even a login. If you are not blessed to have well-connected academic or librarian friends (I won't name you for your sakes, but you three know who you are and I love you), many times you can get free access to massive academic databases by using the computer at a library or college campus. It may even work just using the wifi anywhere on site. If you are near an academic hospital, it may even work there, too.
One local academic library has great access, but no ability to save/email documents. I asked the Librarian if I could print the most important two and she said "no one prints here anymore, use all the paper you want".
On that note, many libraries which may seem closed are not if you ask nicely. Libraries associated with colleges and museums may easily give you access upon request. The academic library I just mentioned is in a museum, but an e-mailed request gets you a free pass to go ONLY to the library inside.
Your Public library may also provide patrons with database access (Ebsco, Jstor, etc). Check the website or consult your local reference librarian-- you might not even have to be at the library! Academia.com is also a good source for papers.
As a last resort, I have had great success just e-mailing the author. They are almost always allowed to give you a copy, even if it's only otherwise available through a paid publisher. I spent weeks trying to get a copy of a doctoral dissertation, including offering to pay fellow SCAdians to physically go to the university and scan their archive copy. The author kindly e-mailed me his second-to-last draft, the only copy he had on hand.
--- Speaking of Libraries, I've also had repeated good results e-mailing a Library and saying "You have this rare book and I would really like these 4 pages from it, is there anyway I can request photocopies? I'll gladly pay your xerox fees, postage, etc." has always gotten a reply with a PDF attached.
--- The term "Independent Researcher" carries a lot more power than "obsessive nerd with a burning passion for this subject" trust me on this. Seriously, though, many academic websites recognize "Independent Researcher" as a status/position, It's what you are, it's dignified, use it!
--- Storing your documents online is very handy. Someone (Jen? Dena?) pointed me toward Mendeley, an online 'citation manager'. Except it also lets you store and organize the entire documents too. I currently have 500 research papers and ebooks organized and searchable, and available anywhere with internet access, for free.
--- Did you know Interlibrary Loan (ILL) can be arranged even out of state? I didn't until recently. It all depends on your library, but you may just have to pay postage for the privilege.
--- Google Scholar: You can filter by content types, subscribe to alerts when something new matches your favorite search, and tons more! (my most-hit search involves a particular set of includes and excludes for digital preservation, for example.) http://scholar.google.com (From Dena)
This is not an exact match for all-museum searches, but you can do CC0 image searches here: https://search.creativecommons.org/ - Europeana is a huge collection of digital images that are largely European museum affiliated? (From Aurora)

Tuesday, August 7, 2018

A Glass Chemistry Primer

[Work in Progress! Likely revised often in the next week. My tables were broken when published, I will revise them shortly - Brynn 8/7/18]

Components of Glass
Formers - The material that makes up the bulk of the actual glass. Most commonly this is Silica Dioxide (SiO2), as in soda-lime glass. Aluminum fluoride and zirconium fluoride are also options.

Fluxes - As in other trades and crafts, fluxes lower the melting point of the former(s) involved. Feldspar, soda, natron, and potash are all fluxes.

Stabilizers - These materials impact a variety of attributes of the glass, like ability to withstand weathering. Limestone (calcium carbonate) is a stabilizer. Sodium and Magnesium are water-soluble and can leach out in water without stabilizers.

Colorants - Optional components to add (or remove) color and opacity to the glass. Mostly metal oxides. Gold, silver, copper, nickel, cobalt, iron, and many others act as colorants. Lead acts as a decolorant. Tin and antimony are opacifiers.

Fining Agents - Optional compounds to remove bubbles, e.g. arsenic trioxide.


Types of Glass
Soda-Lime - The type we encounter every day, roughly 90% of all glass produced. Silica’s very high melting point is lowered by the presence of soda (Sodium carbonate). Different formulations are used for flat (or float) glass vs other containers.
Potash-Lime/Forest glass - Potassium Carbonate (potash) is used instead of sodium cabonate (soda). The potash comes from burning inland plants, hence the term Forest glass. The ashes are soaked in water (leached) to extract the needed substances.
Borosilicate - Glass with a very low Coefficient of Expansion (around 33), which is very resistant to thermal shock. This makes it useful for cooking ware, scientific glass equipment, and artisan smoking vessels.
Fluoride glasses - Glasses which do not use silica as the predominant ingredient. Aluminum fluoride and zirconium fluoride are both options. This glass is usually used for advanced engineering and scientific applications, such as fiber optic cables.
Lead glass (Lead “crystal”) - Originally glass with a very high lead content (potentially over 50%, higher than the ~30-40% silica content). This glass has a brilliant reflective quality and is very clear, making it the best choice for cut ‘crystal’ glassware. Due to concerns over the lead content, modernly barium, zinc, and potassium oxides may be used instead of lead.
Flint glass - An early form of lead crystal. 4-60% lead, flint was used as the source of silica originally, giving it the name.
Fused quartz/fused silica - Silica fused into glass without fluxes. This requires extremely high temperatures, which were not attainable until modern technology (1650°C/3000°F). This is often used for engineering/scientific needs, though rods are also used by lampworkers.
Milk Glass, Vaseline Glass, Carnival Glass - Mostly names based off specific colors, rather than actual differences in the glass.
Porcelain, thermoplastics, glass-ceramics, etc. - There are many other things which, in strict technical terms, are glasses. They are not what any of us laypeople think of as “glass” however and are ignored for our purposes.

Specific Glass Chemistry Concepts
Striking Colors - Colorants are added to the batch of raw glass, and at the high temperatures involved they disperse well throughout the material. The colorants are able to bond with other elements in the batch and, when quickly cooled, stay in those compounds. The glass is often clear when leaving the factory.

Once the color is introduced to a torch or furnace, the temperature is hot enough to cause the colorants to break free from the compounds and form oxides or colloidal particles. Colloidal particles mean the colorant is dispersed throughout the glass without actually bonding with/truly becoming part of the glass (clouds, mayo, milk, and many other things are colloids too). This temperature is also cool enough to prevent the colorant from forming the original bonds at the factory (and/or is cooled more slowly).

Silver glass is a specific form of striking color. Particles of silver are colloidal particles in the glass. At the working temperature, larger chunks form and cause the glass to get beautiful metallic sheens.

Coefficient of Expansion (CoE) - The CoE of a glass is something that often scares people. It is a value indicating how much the glass expands when heated, and generally speaking all glass artists need to know is that you can’t join two glasses which have more than a 1-point difference in CoE. Glaskolben (a glass bulb-and-tube used to make ornaments, which borosilicate lampworkers may also call a ‘point’) that are commercially available have a CoE of 89, but are still compatible with CoE 90 glasses which are commonly available at art glass suppliers.

This value is actually an average! The CoE is tested at a number of temperatures, generating a curve. The number glass artists (and glass scientists) usually refer to is the average, roughly. While we usually refer to it by a number, in scientific terms this number is expressed in scientific notation, 10-7 per degree (in Kelvin). It’s further muddled by the fact that the change is expressed as a fraction of the length, rather than a typical unit like millimeters.

CoE 90 = 90 x 10-7 K-1 = 0.000009 change per degree Kelvin
(The space between 100 degrees Fahrenheit is roughly 55 degrees Kelvin, for comparison)

Trivia: Ceramic artists and scientists use the same values, usually expressed in terms of 10-6 x K-1, so CoE 90 in “glass” would be CoE 9.0 in “ceramic” shorthand.

But HOW is it measured? - With a “push rod dilatometer”. A sample of a material is fixed in place, a rod with a known CoE is placed against it, and a VERRRRY sensitive device is on the other end of the rod. The sensor has to be able to detect very tiny changes. As the sample is heated it will push on the rod and thus the sensor. Then “math happens” to correct for the reference material’s CoE. Fused silica/quartz rods are often the reference.

Example Coefficients of Expansion:



Satake Glass
(Used in Japanese lampworking)
CoE 120
Effetre, CiM, Vetrofond, etc
(Common in western lampworking)
CoE 104
Spectrum & Wissmach fusible glass
CoE 96
Bullseye & Uroborus fusible glass
CoE 90
Typical window/float glass
CoE 82-87
Borosilicate glass
(e.g. Pyrex pans)
CoE 30-33

List of Colorants - Below is a list of common colorants, and the basic color(s) they give to glass. I’m using the default “Crayola 12” colors rather than trying to describe the different shades, such as the green from Iron verses that from Chromium. Most of these only need to be added in tiny amounts to color glass. .001% Copper Oxide can impart an emerald green, 2% Cerium Oxide gives a light yellow.

Some of the decolorants below are also colorants. This works because the resulting colors balance/cancel each other out (e.g. Manganese brings in purple which ‘fills out’ the green from iron impurities). Sunlight could change Manganese over time, turning clear glass into purple!


Red
Copper-Tin, Cadmium-Selenium
Amber/Brown
Copper, Nickel, Sulfur
Yellow
Uranium*, Cadmium, Sulfur
Green
Iron, Chromium, Uranium*
Blue
Copper, Cobalt
Purple
Manganese, Neodymium
Black
Iron, Manganese, Cobalt, Lead
White
(Opacifiers really)
Tin, Antimony, Arsenic, Bones**
Pink
Gold, Erbium
Decolorant
Lead, Manganese, Cerium, Sodium Nitrate








* - Yes, Uranium as a colorant is as bad an idea as you think it is! Mostly discontinued
** - Bone ash, specifically. Yep, skeleton bones!


Sources:
https://www.cmog.org/article/chemistry-glass
https://en.wikipedia.org/wiki/Fluoride_glass
http://www.compoundchem.com/wp-content/uploads/2015/03/The-Chemistry-of-Coloured-Glass.pdf
https://en.wikipedia.org/wiki/Forest_glass
Introduction to Glass Science and Technology, 2nd Ed. Shelby, J.E.
http://www.tainstruments.com/wp-content/uploads/BROCH-DIL.pdf
https://www.ima-na.org/page/what_is_feldspar
http://www.chemistryexplained.com/Ge-Hy/Glass.html
http://www.compoundchem.com/2015/03/03/coloured-glass/
https://www.lehigh.edu/imi/teched/GlassProcess/Lectures/Lecture04_Shelby_ColoredGlass.pdf
https://www.mountainglass.com/tips-and-tricks
https://sha.org/bottle/pdffiles/TheColorPurpleLockhart2006.pdf
http://www.bullseyeglass.com/what-are-striking-glass-colors.html


Tuesday, May 16, 2017

Vitreous Paint Experiments (Malachite)

I bought a small bag of malachite chips to grind into pigment, to go into the William/Isolde scribal gift box. As I was having fun smashing it, it occurred to me that we do have greenish pigments, and I wondered if malachite might not compose one.

So, I smashed it and smashed it until I got cramping fingers and crossed eyes (Actually, not that long or difficult). I got out my handy 325 mesh sifter, as in theory that's the level Reusche grinds to, and sifted the malachite until I had a handy stash in an old spice bottle.


Because I am for scientific experimentation, I wanted to control everything except one variable. I used some Reusche clear glaze base so I could see what the malachite would do on it's own. I realize, I don't know the ratio of glass (or glass components) to oxides in pigments; One period text would say 2 parts glass to one part copper. I made four test chips to compare different ratios, 1:1 through 1:4.


I mixed them on an ad hoc glass palette with a muller. The muller, being glass, seemed the easiest to clean. I noticed how easily the pigment mixed, much like working with commercial (Reusche, Fusemaster, etc) paints and stains. The very fine mesh size seems to promote fluidity. I used a bit more water than I would for "real" but with this small quantity of paint it was rather difficult to get the right water content (I guess I could have tried to drip it off an eyelash or a cat's whisker, but neither myself nor Zod were willing to cooperate with that). The water won't change the performance of the paint, only how it handles on the brush, so having too much water shouldn't impact the results.


I weighed them on my mini digital scale to get the ratios. Although it does .1g increments, the floor seems to be .2 grams. That was what I used as a "unit", so the 1:1 chip is .2 grams of malachite to .2 grams of clear base. The 1:4 is .2 grams of clear base, and .8 grams of malachite. I wrote my name on the chips, for some reason the first thing that entered my head, to test the line work. I then smeared paint on the bottom block of each chip to show various values. I also marked the ratio at the top.

I then fired the chips on my standard vitreous paint schedule, which matches the range for the clear glaze base. The next morning I was fascinated to see significant change in pigment. What I was aiming for was something akin to "Grey green" pigment, a modern sample of which is here placed next to the chips:


The malachite DEFINITELY darkened. To my eye, it also seems more faintly blue than green. Azurite, a deep blue twin of malachite (both are copper (II) carbonate rocks) will turn into malachite when weathered, but nothing in my research shows the reverse. I did find that azurite when heated turns into copper (II) oxide, a black powder. That oxide is then used as a ceramic pigment, making blue as well as green, black, pink, red, and gray colors. I suspect that's what has come into play here, the malachite likely also forms the oxide which would account for the blueish hint and the darker color. I am not a chemist, however, and I couldn't easily find a reference to what happens when you heat malachite. [Edit: A friend reposted my link to get the attention of some chemistry-buff friends, and one Liz pointed me at this link. Malachite does turn into copper (II) oxide.]


I first picked up the 1:4 chip, and immediately noticed the paint flaking off onto my fingers. My fingertips were tinged grey/black/blue. I found, using a wooden skewer, that the 1:3 chip was also very easy to scratch paint from. The 1:2 I could leave some trace, but not much. The 1:1 completely resisted the stick like Reusche paints would. Looking at the reflected light, the 1:1 chip also looked much like a dozen other test chips I've made; the paint is completely glassy and adhered to the test chip. I fire my vitreous paints to the high end for that effect, so this is expected. The other three showed a rough, grainy texture I associate with previous experiments that had too rough an oxide.



             


                                                         


Lessons Learned:

  • Yes, a randomly selected mineral MIGHT make a usable vitreous paint!
  • Something near a 1:1 ratio is probably idea to bind the pigment to the glass, though 1:2 was also serviceable. My tests of the period formulas are 1:2, and were very similar.
  • It would be wonderful to find out what actually goes into Clear Glaze. My normal secret trick is to check the EU vendors, who seem to list MSDS's that US vendors do not. Unfortunately Peli doesn't include one for Clear Glaze. Reusche gives them out if you make a special request in writing, whereas Peli just has them on their website. I rather suspect this is because the MSDS sheets rather give away the secrets. 



Monday, March 27, 2017

Two Mistakes: Hamsa

I had the idea to make a Hamsa. The idea persisted, and turned into a large flop. So, I remade it. Which turned into a second flop.

Enamels are difficult.

I ended up making nearly the same design, but pieced. I was mad and determined, at that point.  I started with a design I found online; I found it on several websites, in several ways and places. I couldn't determine an original creator, etc and chalked it up to a generic cultural motif. Having learned much from Estelle's scroll, I thought I planned it well. I used the more stable blue, and skipped the idea of using silver stain.

Attempt 1, I painted on the black line work, then added a mat of blue enamel. In the past, again for one of Estelle's badges, I got a phenomenal sapphire blue right off the bat. That gave me incorrect assumptions about how easy it can be to use!

This happened over a year ago, and Facebook isn't helping me work out the order. I know at one point I discovered I had two different blues on hand, with no recollection of the opaque one. So much so that I went back and found the order and made sure I had consciously ordered it (which I had).

The next piece, I kept adding blue trying to get the Sapphire hue I wanted. After a few coats the enamel turned opaque and off-color, a grayish tone to it. I still don't know why, but I decided I needed to get it right from the start.

The next attempt, after doing the line work and the enamel I decided I wanted to shade the background and went back, to add more black mat. That tanked the whole piece as well, as shown below.




Ugly and wrong color, above!




 My "mistake" in going back to vitreous paint. Guess blue enamel isn't as stable as I thought.


A closeup of the weirdness that ensued. I suppose too many layers of enamel flattened out and blurred the black lines beneath, like layers of glass can displace one another when fusing.

The final piece I successfully made and framed, to get a Hamsa out of my mind. I've not included a picture of the pattern to retain my blog's G-rating, as each piece was named with a different profanity, instead of the customary numbers or symbols.

The bottom right corner was 'bullsh*t' if I recall. It was easy to cut, that was just it's nickname.

Lessons Learned:


  • Be sure you are using the glass paint you think you are using!
  • Blue enamels are also touchy. All enamels are semi-evil.
  • Weird things can happen if you apply them too thickly (?) or fire them too many times
  • It looks like many layers can displace one another between firings.


Glass and Gold and Gilding

I've signed up for a couple of mosaic classes in April and May. It reminded me I wanted to try my hand at making Byzantine-style tesserae, and then a friend's Facebook post kicked me into high gear. She had much better success than I did and shared some of her wisdom. My test piece:

Two pieces of clear fusible (Bullseye CoE 90 Tekta clear) with one layer of gold foil sandwiched

Rhode Kephalaina let me know in her sample chips, marked 1 and 2, thats the sheets of foil. So, chip '1' has four layers approximately, and '2' with 8. My samples above are 4" square, not 1", and had one layer. It's not exactly ugly! It's just not the beautiful gold glass expected. The nicer parts of mine are where the foil doubled on itself (see Lessons learned, below...) I know now to fix it, though, thanks to a conversation with Rhode.

Ive also fallen for verre églomisé. Predating Rome, pretty much, this art (gilding glass and painting the back black) was practiced through the Roman period into modernity. It gets its name from an art collector 200 years named Glomy. It turns out it's not super difficult!


Sorry it's sideways. I can't quite remember how the technique entered my awareness, either through researching mosaics or mirroring. A little gelatin, some gold leaf, and some glass. A fine needle to scratch it up, and black paint. I'm going to teach a class on it at Pennsic this summer, which is exciting to me. I've tried a few types of leaf, a few tools to transfer it to the size, and will be picking up a second (larger) gilder's tip this week. It's beautiful to look at and I'm excited to see how I can integrate it into stained glass and mosaic work.

Probably To Be Continued...

Lessons Learned:

  • Transfer foil is a lot better to work with for verre églomisé.
  • Tiny creases are almost unavoidable with loose leaf, but the gelatin size flattens them out as it dries. The end result isn't perfect but it is much better than what you start with.
  • TURN OFF YOUR CEILING FAN. Many people remark that gilding can be done at your kitchen table, and they are quite right. But when you bought a book of loose gold leaf and have the fan on medium, you are going to make a kaleidoscope of tears and gold for a moment. 
  • Making Roman Gold, as Rhode is trying, or Byzantine Tesserae as I am, costs a bit! The leaf is not terribly cheap, though you can find it reasonably. She speculates gold foil, not leaf, would work better but it runs $75/5 sheets. 
  • Don't use imitation gold. I did this before a year or two ago, without entirely realizing. It was an aluminum-based product, I believe. It turned horrible colors and crinkled up under the glass. 
  • I wondered at using silver to do this. I'm told it can work, but my experience with silver stain says it certainly cannot. Ken Leap's book shows an example of firing a piece of solid leaf, and it made a dark amber stain at just slightly higher temperatures than I use to fuse. Further, I've used ground silver leaf in a period formula at much lower temperatures, and it made a light lemon yellow. I'd think 'silver' would necessarily be platinum leaf, which I have not priced or looked at.


Friday, February 3, 2017

Silver Stain Experiments Part 2

[Edit: No idea what this is still a draft. Publishing now, three years later!]

Phase 2 has actually turned up some successful blends!

Detailed below are tests I ran with pure silver, silver nitrate, copper sulfate, and silver sulfate as the active compounds. Binders included a new, "brand name" red ochre, yellow ochre, gum arabic, and brick dust. After doing a round of tests I came up with several new ideas, particularly where pure silver and copper sulfate are used, and had to do another set.

Some notes on the binders themselves:

Silver dust and gum arabic - Almost indistinguishable from pure silver dust. Film formed, gum arabic undoubtedly. Weird to see it plainly, but interesting to get a clear visual of the effects of gum arabic. I've noticed recently, when I added too much water to some matting paint, how there is a "thickness" to the water, as you stir the paint you can see some of the unmixed water jiggle and repel the paint until you force it to mix. I've not tried mixing paint with no gum arabic but I think I'll try it to confirm my thought that that is also the GA (rather than the paint). That may be what they refer to as "body" when talking about other binders mixed with water.

Brick dust - Probably needs to be even finer. Works well. I ground pot shards with a pestle and mortar, but I think I need to get it even finer. I'd love to get my hands on a ball mill to do this, but it's not in any shape period.

And a correction from "Part 1" in that I realized I'm slightly blind. As I began to tag and catalog my samples, I almost threw out a few pieces that didn't take. As I was getting ready to toss them I realized that the copper sulfate chip DID stain:

On two slides it's almost imperceptible (this picture above is not a very good example, but it shows up at least) but it was actually there. Because of this realization I tried a stronger mix of copper sulfate for this round. As detailed below in Sample 6 it didn't work out, but I have a good idea why not (temperature).


The stain samples prepared and drying:


A closer shot of the samples:


Silver nitrate and gum arabic made an incredibly pretty, deep orange color while drying. This continued to intensify as it dried, becoming a dark red


The samples after firing:

Sample 1 - Pure silver dust and gum arabic (1:6). Oddly enough, this did nothing. I suspect it takes a higher temperature to work. I know from Leap's book that pure silver leaf will leave a dark amber stain on glass, I can't imagine the powder not having the same effect. Later review of Leap's book indicated he fired his pure-silver tests at 1500°, a full 500° hotter than I did. I know what to try next, and may throw some more of sample 6 in with it.

Sample 2 - Silver nitrate and red ochre (this time from Vallejo pigments). Clear proof that there was an issue with the red ochre I bought before, this name brand sample didn't have the same hazy effect that the first sample left behind, ruining what results there might have been. Part of the sample is a little darker, but I suspect that may be related to how I used it (no blending, possibly imperfectly even surface allowing oxygen to get in, etc) rather than the mix. I consider this one a success!

Sample 3 - Silver nitrate and terracotta dust. A bit of research indicated most of the bricks before the 14th century would have been very similar to what we call terracotta. I bought a small planting pot, smashed it, and started grinding it into a powder. It seems to work quite well, actually. The one downside was that it must be ground very finely. Small "pinholes" are visible in the sample (close-up later in the post). This was caused by less well ground (larger) bits of the terracotta that inhibited the even spread of the silver nitrate. This also left behind a bit of hazing on the edge, but I again suspect it has to do with handling rather than the compound. I also consider this one a success.

Sample 4 - Silver nitrate and gum arabic. Oddly, this didn't work at all. No effect was left behind. Isenberg's book has a chapter on painting and a page on silver stain. It mentions that the "Reddish material" has minerals which pull the sodium out of the glass and allow the silver in. I find it hard to believe, but at the moment have no other explanation for this chip's complete lack of stain. The silver sulfate and copper sulfate chips, both mixed with gum arabic, had visible staining. Silver nitrate did not. The same book also states that "other silver salts" (presumably silver sulfate) are added to stain powders because nitrate is unpredictable and melts unevenly. I haven't seen that to be the case, yet, either.

Sample 5 - Silver nitrate and yellow ochre (vallejo). This mixture was twice as strong as the same combination I tested in "phase 1" and likewise is a much stronger color. This is 1 part silver nitrate to 3 parts ochre.

Sample 6 - Copper sulfate and gum arabic - This is a 1:6 strength mixture, better than what I had previously made. I discovered, just before pitching the last test chip, that copper sulfate actually had stained the glass. The compound was in such a small quantity that it was in the form of tiny specks. I mixed this more strongly and used more of it to try and get a more visible effect. I didn't get it, though again I got visible effects. I think this merits a higher temperature or longer soaking period.

Sample 7 - Silver dust and gum arabic, 1500°
Sample 8 - Silver foil pure, 1500°
Sample 9 - Copper sulfate and gum arabic, 1500°



 
A close-up of sample 5


 A close-up of sample 3


All 13 test chips I've fired so far

Lesson's Learned

Future Plans ("Phase 3")

Sunday, April 24, 2016

Four Rivenstar Badges

A bit of a secret project! Malie bean MhicAoidh commissioned four suncatchers of the Rivenstar badge. Two for Moonwulf and Takaya, retiring as Baron and Baroness Rivenstar after 40 years (!!) of service, and two for their successors, then-unnamed.


Irony being what it is, Malie and Adhamh were selected. They still wanted their two, however!

The first two were made out of a dark cobalt blue glass. Very pretty. Unfortunately I didn't have enough for all four from that glass, and realized it after the first was done. I checked with Malie and she was ok with them being in sets of two. The other set (pictured above, being held by her then-almost Excellency) are made from Spectrum Dark Blue cathedral. The clear on all four is a seedy Kokomo. I have a thing for seedy glass! All four are wrapped with 1/8" zinc u-channel came and have ~1' chains.


They seemed pleased with the suncatchers, and I'm quite glad for it.

Lessons Learned:

Black Patina for Zinc does actually work... As in the past, I was getting fairly irritating results, weak and blotchy. I read the directions (...) and realized it implies you should apply it fairly heavily. It also says to leave it at least 15 seconds. Being patient with it, the patina does eventually work fairly well.

The two diagonal points, 8 and 11 in the picture above, are tricky because of the flanged base I put on them. Initially I tried cutting them out as "S-curves" and at that tiny size, It worked much better to do it as two C-curves.

Man, Zinc... there's gotta be a better way. The problem is the initial soldering to join the ends. The best solution I could find was to squeeze the ends tight from a few inches to the side, and press the piece against the wood edge of my soldering board, freeing one hand to pick up my soldering iron, grab a daub of solder, and seal it. Then I held it until the solder was colder than a Pennsic shower to be sure it wouldn't spring apart on me. That happened...

And cutting it! I usually use my lead dykes on it, but it deforms the end terribly. Makes it hard to get a clean joint on the other end of the circle. This time I cut the "leaves" individually, and then flexed it to snap the heart via metal fatigue. That gave me a much cleaner end to work with.

Chain. Always buy more than you think you'll need. And mounting them on a 180-degree arc (straight horizontal line) was not a fantastic idea, as the suncatcher wants to tip a bit.