glass cleansing

Значение термина glass cleansing в knolik

Glass Cleaner

Glass Globes

Photographic Glass Plates

1. One of the most powerful - if not, indeed, the most powerful - detergents for refractory plates is the mixture of sulphuric acid and bichromate of potash recommended by Carey Lea some years ago. It is especially useful with glasses which have been frequently used, or which from the nature of the treatment they have undergone resist the action of both acids and alkalies completely. Its utility is dependent upon the powerful action of chromic acid upon organic matter, and we have never yet met with a plate which did not succumb to its treatment. One precaution is necessary in using it, however; it must be carefully removed from the glass by copious washing as soon as possible after it has done its duty. If allowed to soak for some time, as is frequently the practice, the plates appear to absorb the solution (the penetrating power of which is extraordinary), or an insoluble compound becomes firmly attached to the surface and steadfastly refuses to be displaced. Though generally invisible, it results in a peculiar mottled appearance between the glass and the developed film which entirely ruins the picture. We recently treated a number of plates which had become useless from this cause with various detergents, including acids as well as alkalies, but to no purpose; friction with various abrading powders failed to remove the defect, and we were well-nigh compelled to give it up. Remembering, however, that cyanide of potassium has been utilised by carbon printers for the purpose of reducing the strength of overprinted proofs - which it does by virtue of its action upon the insoluble compounds of chromium - we resolved to try its efficacy on our refractory plates, when all the mottling disappeared as if by magic. Those amongst our readers who dare to fly in face of all that has been lately written upon the dangers attending cyanide and bichromate of potash have here a "wrinkle." Surely those who have dared bichromate will not fear the minor dangers of cyanide.
2. A cream of tripoli powder and spirits of wine, with a little ammonia added, is a very good solution for cleaning glass plates. Old collodion is also very good; it should be thinned down with an equal bulk of spirits of wine; add an excess of iodide of potassium, and shake till the solution is saturated. Caustic potash is very good; so is carbonate of soda. If the plates be new, and covered with little gritty particles which do not come off on the application of potash, they may be removed with nitric acid.
3. Methylated spirits, washleather, and plenty of "elbow grease."
4. Dr. Walz takes a dilute solution of permanganate of potash, and pours in enough to wet the sides of the vessel to be cleaned. A film of hydrated manganic oxide is deposited, which is then rinsed with hydrochloric acid. Chlorine is formed which acts in the nascent state on the organic matter, which becomes readily soluble. The permanganate solution can be used again and again till its oxidising power is exhausted.
5. Dissolve 15 gr. of iodide of potassium in 5 oz. of water and 5 oz. of alcohol, afterwards adding 3 gr. iodine and enough whiting or rottenstone to make a creamy paste. Rub a little of this on the glass with a rag until clean, then polish with a cloth. (J. Hughes.)

Glass Slides

Paint-Stains on Glass

1. American potash 3 parts, unslaked lime 1. Lay this on with a stick, letting it remain for some time, and it will remove either tar or paint.
2. Common washing soda dissolved in water. Let it soak awhile - if put thick on, say 30 minutes - and then wash off. If it does not remove, give it another application.

Glass Windows

1. Procure a washleather of convenient size and some "paper-hanger's " canvas. Two yards, divided into three pieces, will be a nice size to work with. Have the cut sides hemmed, and they will last a long while. When it is desired, use one; boil or soak for an hour or so in a solution of soda and water to get out the "dress"; then wring out, and rinse in as many courses of clean water as you like; then partially dry (practice will enable you to judge), fold to a convenient size, and it will be ready for use. The soda solution will now be cool enough for the leather (if too hot it will shrivel the leather); wash in the same manner, and wring superfluous moisture out; then wash the glass thoroughly with it and plenty of elbow grease, and polish off with the canvas.
2. A very effective agent in cleaning glass is a dilute solution of fluoric acid. To this is sometimes added a small quantity of some other acid, either sulphuric or hydrochloric. The glass, after being washed with this, must immediately be well washed with clean water. Fluoric acid must be carefully handled, as before dilution it will cause painful sores if allowed to come in contact with the hands and to dry on them. It corrodes glass, which causes its cleansing power, so that the strong acid should not be kept in a glass or glazed bottle or jar, but in a bottle of guttapercha or similar material.

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