Posted by Larry White on April 17, 2003
Lee LittlewoodI created a sample of acid embossing today for my next glass piece. (Wanted to make sure I knew what I was doing.)So at the same time, I threw in a few other ideas to see how they would come out and one came out quite spectacular. I prepped the glass in the usual way of cutting the vinyl mask and leaving the area that I wanted to etch on the glass then asphaltumed the whole thing (I prefer to use a japan brush over a roller). After the ashphaltum was dry, and the vinyl was weeded to expose the areas to etch, I painted a cross hatch grid of 1/16" lines at 1/4" apart with tempera color (per Rick Glawson). Per Rick, the acid will start eating at the clear glass and slowly fatigue the tempera color, it will fall away and the area under the color will also get etched. The clear area gets a head start. This etching was done with the "face down" method in a vat of acid (no mica). Well the very interesting and cool thing that occurred was that it seemed that the acid ate away more of the glass toward the center of the clear squares and less along the tempera color line, This gave each little square of the grid an almost pointed appearance as if there was a line created by the acid that went from corner to corner of each square. It made the grid appear as a series of prismatic diamonds. It looks really cool! I hope you can picture all that. E-mail me if you have questions or post a follow-up.
I also tried a few other techniques for applying the tempera; spattering, spounging, and feathering. These techniques didn't work as well. I'm gonna silver it tomorrow.
...carry on.... -LW
Robert BeverlyWe did some messing around with tempera and hydroflouric at Brad Johnson's in Corvallis and didn't get much consistency. Thinned down latex paint did better. One thing that gave a cool effect was painting latex over the glass and "twisting" it off with a rolled up piece of newspaper, making a series of swirls which were eaten away somewhat irregularly. I think we tried putting the paint on with a paper roll but it got soggy and mechanical too soon.
E C Matthews mentions something like this for matte gold backgrounds - put in varnish, twist away with newspaper roll, let dry and watergild. He called it a "Damascene effect."
The other one I'd like to see is from an old book (Ashmun Kelley I think) where he floats asphaltum on top of a pan of water, marbles a pattern with combs or sticks, and lays the glass over the asphaltum. Then acid etches to get a (?) lightly marbled background or letter. No picture in the book. If it worked, it might gild up like a champion.
Larry White - Acid Etching OverviewLarry
I have never acid etched and would really appreciate a breakdown on your process...and where to get materials...as well as your silvering and supplier thereof!
sounds very cool!
Robert
Darryl GomesAcid Etching overview-
There are 3 types of acid etching that I'm aware of. 1) White Etch-This uses hydroflouric acid to frost glass. To my knowledge, when executed on ground glass, each acid bath makes the glass go clearer. Details are added with aspaltum between each acid application. The steps of adding detail, then etching repeatedly, is how designs or pictorials are created. The finished glass is left "raw", the designs or images are frosted to different clarities (degrees of frost) in the glass. I have not done this technique. There are posts on this BB for more info.
2) Acid Etching-This incorporates combining the acid mixture with mica flakes. The mica flakes interupt the acid from etching the glass in small minute areas. The glass remains clear, but the mica puts a fine texture to the etched areas. A mirror finish gild can be done over the etched ares.
3) Acid Embossing- This is applying the liquid acid mixture straight, without using mica. The acid etches straight into the glass. It does leave a slight pattern due to the nature of the acid.
Technique Overview-
First, create exposed glass "windows" where the glass is to be etched. This is done by applying a vinyl mask to the glass, cutting out the areas to etch and leaving them on the glass while weeding out the background. The glass is then painted with asphaltum varnish. Typically it is painted on all sides and edges. (The fumes can fog the exposed areas of the glass.) After the asphaltum is dry, weed the vinyl out exposing the areas in which the acid will attack the glass. This prep is true for both acid etching and acid embossing. To etch, dilute 48-52% hydroflouric acid at a ratio of 2 parts acid to 3 parts distilled water. (Add some red food coloring so you know where the stuff is.) Wear protective gloves etc. Mix the acid mixture into the mica flakes so they are wet but not runny. (Kinda like the consistancy of oatmeal.) Apply mixture over the open "windows of the glass. I usually use a paint paddle or illustration board card. Ensure all areas are covered. Allow to sit on the glass for 20 minutes. Remove the acid and mica to a container. Mica can be reused. (It will need to be refreshed with new acid.) Rinse the glass. Remove ashphaltum with paint thinner.
Acid Embossing is done much the same way but the glass is turned face down in a vat and submerged in the same ratio acid mixture (no mica). It to is subject to a 20 minute exposure. (I typically buid a 3" deep box 1" overall bigger than my glass panel, line it with plastic, and space my glass off the bottom 1/8". I then add the acid until it just reaches the top of the edge of the glass.) Acid Embossing can also be done face up but you have to make a water tight dam around the glass.
Acid can be obtained from a local chemical supply house. Some want proof of professional business. Other items, check Mikes supply list.
Feel free to e-mail me with any addition questions. Like all other aspects of glass art, acid etching is a kick!
-TTFN ...LW
I
Raymond Chapmanhave done a little acid etching, mostly with mica. I have found that if you are using clear glass, you can use only paint-mask for your acid resist. You don't have to mess with cleaning asphaltum off the glass after. I have done this a dozen times, and not had a failure yet.
Darryl
Look Out! Robert's on the loose again.
I'm with you, Robert. I've never learned the process either, and would love to know how. Maybe another demo for June, huh?
Raymond
Tony SegaleI think we just need to go abduct Larry!....by the wayn Larry...I was the one that kept coming up to you at the conclave asking what you were doing all the time when you were working on your pewter piece displayed earlier...that turned out great!
Thanks for asking the questions, Rob & Ray
(hey, nice title for a new movie) and thanks for the respnse Larry, I immediately printed the acid etching and techniques overviews for my file.
thanks a bunch, guys.
Tony
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