Want to learn more about Amonium Bifluoride or Vari Etch.
I use BE glass with some URO 90 thown in.
How do you use it? What kind of setup do I need for safe use? What kinds of finishes can you accomplish with it? Could you use it to etch a surface to prepare to refire like you would a sandblasted surface... Like, if I have devit, or overglaze that didn't mature properly, grind marks or any flawed surface...could I chemically etch then refire to polish, or to get a matte to satin finish? Can I accomplish even, seamless matte and satin finishes with the Vari etch with BE glass? How do you neutralize it, then dispose of it? Is it as scary as Hydrofluoric Acid? Can I carve (grind) and chemically etch to soften the grind marks. I love bas relief, but want more variety of depth and texture beyond just kiln carving techniques....
Would like to persue other means of etching the glass for different finishes and remedies for problem surfaces other than a blasting system.
All(?) of the easily available glass etchants are bi-flourides, frequently in water, although weak acids may be added. In general, you can only do "white" surface etching with them.
These may be found locally at a craft store such as Michaels.
To deep etch, hydroflouric acid in combination with nitric or sulfuric acid is required. Unless you are a chemist, you will not find this stuff readily available, and is has become rare in industrial use due to the dangers involved.
http://www.hisglassworks.com/pages/varietch.html
i bought it from HIS
spec sheets come with it
some BE colors it will frost, others it dissolves but doesnt frost, so it's necessary to sandblast in advance for those.
i'm just at the beginning of using it, doing some tests before using it on plates. probably going to do the sandblasting first, although i had hoped that wouldnt be necessary. it appears that the blast beforehand will produce good result. somebody else from the board told me it frosts float very nicely without blasting.
Kitty wrote:http://www.hisglassworks.com/pages/varietch.html
i bought it from HIS
spec sheets come with it
some BE colors it will frost, others it dissolves but doesnt frost, so it's necessary to sandblast in advance for those.
i'm just at the beginning of using it, doing some tests before using it on plates. probably going to do the sandblasting first, although i had hoped that wouldnt be necessary. it appears that the blast beforehand will produce good result. somebody else from the board told me it frosts float very nicely without blasting.
Here is some more info on it
The link is there on the page Kitty gave but took me a while 2 find it
There's also some spray on and bake products on the market that will give a satin surface to glass.
I just had a visit from the Ferro Co. rep in my area and he'll be back to bring samples of this product for me to try -- Organic Bottle Coating. The visuals in the company literature are interesting. They achieve some very nice matte finishes on the glass. This coating is available in clear and various colors.
The product is water-borne and is sprayed on (you can brush it on but this will most likely leave brush marks in the finished coating), then cured at a 400 degree temp.
My big question regards it's durability - seems anything heat cured at this low temp won't hold up to scratching. Although my thought is to sand-blast the surface first and then apply & cure the coating. Maybe this will help it's durability.
Gale aka artistefem wrote:There's also some spray on and bake products on the market that will give a satin surface to glass.
I just had a visit from the Ferro Co. rep in my area and he'll be back to bring samples of this product for me to try -- Organic Bottle Coating. The visuals in the company literature are interesting. They achieve some very nice matte finishes on the glass. This coating is available in clear and various colors.
The product is water-borne and is sprayed on (you can brush it on but this will most likely leave brush marks in the finished coating), then cured at a 400 degree temp.
My big question regards it's durability - seems anything heat cured at this low temp won't hold up to scratching. Although my thought is to sand-blast the surface first and then apply & cure the coating. Maybe this will help it's durability.
I'll run some tests and post my results.
isn't this what they use for coloring a lot of booze bottles now?
Yes Charlie...........Ferro has pix of Absolut Vodka bottles in their literature. I slumped a couple of these bottles in matching colors for customers' kitchen decor. Tangerine and lemon, respectively were the drinks of choice for these ladies. The Absolut bottles have screen printed higher fire enamel colors.
I haven't seen booze bottles with these low fire Organic Coatings, but then I don't get out much - LOL! I'm too busy playing with glass & fire............
I think any chemist could verify that bicarbonate of soda will neutralize most acids. I wouldn't want to inhale the vapors, tho. Yes, I found hydrofluoric acid to be very scary, too.
I thought that my cream acid etching compound (like that used for screen etching) was hydrofluoric acid, not that other stuff. I am pretty careful with it (respirator, gloves, etc) but I didn't think it was all that dangerous. It seems to be pretty dilute and of course doesn't splash around because it's in a cream base. I have ended up with it on my skin for short periods without any burns.
However, I recently tried to etch a fused Bullseye plate with it. It didn't seem to touch it. I mean, not blotchy or uneven, still glossy! No sign that acid had been applied to it. I'm usually using in on float and it creates a frost in minutes. Weird.
Lynne, i learned something interesting about Vari Etch recently, something i never would have guessed on my own. i was given the following info from someone at HIS:
Vari Etch (and this is also true of cream etching stuff) can frost glass, or it can dissolve it. interestingly, it can dissolve it without frosting it. it eats away at it, but leaves the finish smooth. some colors of BE will frost with these etching compounds, and others will only dissolve.
when i was told this in an email last week from HIS, i was amazed, but after a little thought, i remembered trying the cream stuff on some BE a few years ago, and it did indeed frost some colors and not others. now i understand what's going on (or not going on, as the case may be). this possibility of dissolution without frosting is the reason why the sandblasting is needed for those colors that won't frost.
Kitty wrote:... some colors of BE will frost with these etching compounds, and others will only dissolve.
...when i was told this in an email last week from HIS, i was amazed, but after a little thought, i remembered trying the cream stuff on some BE a few years ago, and it did indeed frost some colors and not others.. .
Hi Kitty, we picked up some Vari-Etch at the GAS conference and will run some tests with our glass (once the hysteria of BECon has passed!).
Meanwhile, can you remember & relate what colors - or types of colors/glasses - in the BE line etched and which dissolved?
Biflourides in water dis-associate to form VERY weak hydroflouric acid (HF). Varietch, Etch-All, and the other craft preparations are "completely safe" (only) because there is so little HF involved.
HF attacks and disolves silicates SiO and lead oxide PbO in glass, but any calcium or sodium floride created by the HF does not disolve the HF-H2O solution.
In some etching processes, sulphuric or nitric acid is added to HF (in varying strengths) to disolve CaO, NaO and/or the other oxides.
"Classic" etching involves primatily white (clear) glasses, although acid etching was used in much cameo work between 1980 and 1920.
Obviously(to me) colored glasses containing other metalic oxides may respond differently. This could explaing differences between various Bullseye glasses.
I'm not a chemist, but my father was, and I took 12 hours of college-chemistry-for-chem-majors as part of a BA in physics. I knoe enough to appreciate that glass etching chemistry has a variety of complexities involving both acids and glasses.
Lani, i will do a little testing here and report on my findings. i can't remember anymore which colors did/didn't frost with the cream (Etch All, i believe). will also report on the Vari Etch results (without sandblasting). probably mess around with it over this weekend. a hui hou, kitty.
Interesting bit on the chemistry, but if you add even a drop of tap water to the cream etch, it won't etch anything.
And I don't know about the not burning bit. I'm pretty sure it will burn very deep if you had strong enough acid, or left it on long enough. It just doesn't hurt right away. I'm told that with the weak acids, it is probably the fumes that are the worst hazard.
Could the Bullseye be a bit acid resistant because of the borax fluxes? or maybe it's just the colors. My plate that wouldn't etch had large areas of transparent steel blue and teal green that stayed shiny. Some of the other colors are hard to tell how much etched, as the reason I was etching it was that some of them had devitrified (you don't want to know why). I really wanted the matte finish that acid gives, but I will probably resort to the sandblaster if I ever try again to recover the goof-up. Right now it's sitting on the reject shelf.
According to discussions on the Craftweb blowing forum, some opal glasses tear up furnaces because they contain flourine/flourides in their chemistry. If some Bullseye opals are flourine based, their reaction to etching materials may be very different than those opals which are not, and also much different from cathedrals.
It will be interesting to read a report on Bullseye's tests. I'd expect that the answer will be "make a test of your specific combinations before commiting to a final design."
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