White Acid

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Posted by Darryl Gomes on August 10, 2002

I have a customer that wants some broken windows replaced in a church. They are quite old and have been acid etched. They had someone else replace some previously with sandblasted glass, but the look is drastically different. Can anyone help me with a formula for "white acid"? I have heard amonnium bifluoride can be used, but I don't know how to mix it, or with what.

From what I know, you frost the whole piece first, then you clear up your pattern with hydroflouric acid. I use that for acid/mica etching. I do my acid/mica etching with paint mask, can I also clear up white acid with a paint mask resist, or do I need asphaltum? There are 28 windows with a small wallpaper pattern that would take hours to paint and peel.

Thank You

Darryl Gomes
near Toronto Canada

Aurora Ganem

I have tried this formula and works well, except on baroque blue glass. does anyone know why this could be, or if there'a a different formula to use on this kind of glass.

Steve Carter

From my research, White Acid appears to be an English term for a form of Hydroflouric etching.

I have attached several articles and formulas for your information. Hope they help.

Steve Carter

FORMULAS:

1. fluoric Acid (full strength) - 1/2 pint, carbonate of soda - 1 ½ lbs, water -1 pint.
The soda (common washing soda) must be selected, only clear crystals being used and the white powder discarded….
The above quantities may have to be modified under certain conditions, weather, for instance, having a considerable effect upon the mixture, and only an actual test upon a sample piece of glass can be taken as an indication that the mixture is in working order. It ought to produce a dense white obscure in about an hour.


2.Another recipe substitutes carbonate of ammonia for carbonate of soda, adding the carbonate to a mixture of acid and water a small lump at a time till effervescence ceases. This mixture works perfectly well, but does not produce such a dense white as the first. Its fullest effect is reached in about twenty-five minutes.


3. Soda Ash, 1 lb., Rain Water, 1/2 gallon, Fluoric Acid, 1/2 lb. - also produces a very weak effect.

Darryl Gomes

Thank you Steve.. This is a great help.

I have also been doing a little research and found that ammonium bifluoride disilved in water can do the same thing, although I have not found any recipes for the ratio of water to ammonium bifluoride. I have also learned that ammonium bifluoride is a fair bit safer to use than the hydrofluoric acid/soda mixture.

I think I will probably screen 2 coats of asphaltum resist for clearing the pattern with hydrofluoric acid.

Darryl Gomes

A Touch of Glass

Darryl

I've used the pre-mixed Armour Etch over the years for specific effects, such as getting a smooth surface on a lake in a mountain scene. Sand blast and use a diamond stylus pen for details.

White Acid was new to me, but now in my library for future reference.

Good Luck & would like to see the final project.

Steve Carter
a Touch of Glass
Cntrl Delaware

A Touch of Glass

Darryl

With 25 years of glass etching, you presented a product that I have never heard of before. White Acid?

I regularly use hydroflouric acid to achieve different effects in my designs, but White Acid is new to me. Could it be under another name due to being in Canada?

Can you provide a picture for further identification?

Steve Carter
Cntrl Delaware

A Touch of Glass

Darryl

Just remembered that there used to be a chat room on AOL for Glass Etchers. Mondays 7 - 11 PM called Glass House. Since I left AOL several years ago, I'm not sure if it is still open.

Also, I may be able to locate the list of members that were active when I was on AOL. Have not seen it for some time, but I'll check my files.

Just got another idea. One fellow glass etcher is New Brunswick - Richard Smith. I'll try to contact him to help you - Really knows his trade!

I would like to know what you find out about White Acid! Good Luck!

Steve Carter