Methinks the original question was; "Is Kodak Indicator stop bath the same thing as 28% acetic acid?"Originally Posted by percepts
Who's on the door in this place anyway??
Methinks the original question was; "Is Kodak Indicator stop bath the same thing as 28% acetic acid?"
Who's on the door in this place anyway??
The warning label does not say it is caustic, it only says that it "causes severe skin and eye burns". And of course, most manufacturers apply strong terms pretty liberally on those labels as a good and cheap way of avoiding lawsuits.
Chemically speaking - and we are talking chemistry here, aren't we? - the term "Caustic" generally refers to strong alkalis only and not acids (another widely misused term) or other types of reactive chemicals. Typical example would be Sodium (or Potassium) Hydroxide.
Acetic acid, on the other hand, is an acid, and a weak acid at that, again purely chemically speaking. It is corrosive, toxic, irritating and all that... but being an acid, caustic it is not.
You probably meant "corrosive", but that's another term altogether.
Then there is the other, figurative meaning of "caustic" and if I wanted to apply that meaning to this case, I would say that your reply was incomplete because even though you used bold, underline, italic and multiple exclamation marks in your reply, you forgot to apply red and blink. Aside from mishandling quotes, of course.
Which brings another point - those green toothy thingies I tend to use in messages like this and the one you were replying to are called "smileys" or "emoticons". They are supposed to convey the emotions through the strictly textual medium such as the discussion board.
This particular one denotes content strong on humor, or at least intended to be.
Actually, the original question was about making one's own stop bath out of acetic acid to avoid hazmat shipping charges. Kodak's stop bath was there just for comparison.
No need to worry about guarding the door, we may not have the council of elders or such herebut the floors are still clean and if you really want to find out who minds the door, knock hard enough and you'll quickly find out
Just to refresh everyone's memory.
It is getting harder to find 28%, I was looking for some as an albumen preservative- it's not just for stop bath.
Looking back at some old other forum posts I have, the reason given for 28% stock is that 28% is the strongest dilution obtainable from distillation. That's it. There is no reason to mix 28% solution from glacial acetic acid other than that's what everyone does. Probably because AA did it and gives a formula in his book. It's just a copy cat number that really has no significance today when you can buy 60% and dilute it to whatever you like.
The thing to work out is the working strength solution. Using AA's formula of 45ml of 28% acetic acid plus water to make 1 litre then you can work out that 12.5ml of that 45ml is 100% acetic acid and the other 32.5 is water. So having made it upto 1 litre that means that 12.5 is 1.25% of 1000ml which means AA was using a 1.25% working strength solution of acetic acid.
For myself I still have a bottle and a half of agfa 60%. I dilute some of that down to 25% in a 1 litre bottle and use that for stock.
In some old posts I have on acetic acid, there is also reference to kodak indicator stop being 51% solution but these things change so you should check that before assuming its correct. The formula is published I beleive.
But I still rekon its best (and cheapest) to buy the fuji 5 litre 60% if you can lay your hands on it from a local minilab.
this page of specs states the indicator stop bath is 85-90 % Acetic acid to make up a 1/63 working strength which if my math is correct yields a 1.56% acetic acid stop bath.
What strength is required for albumin stabilization?
http://www.tedpella.com/msds_html/26956msd.htm
Regards
Bill
I just had a look at the kodak MSDS pages and there are various kodak stop baths listed. Some indicator baths are listed at 85-90%. Others are listed at much lower strengths. Country of sale may also make a difference.
Don't know about strength for albumin.
I don't find any humor in your ignorance.The warning label does not say it is caustic, it only says that it "causes severe skin and eye burns". And of course, most manufacturers apply strong terms pretty liberally on those labels as a good and cheap way of avoiding lawsuits.
Chemically speaking - and we are talking chemistry here, aren't we? - the term "Caustic" generally refers to strong alkalis only and not acids (another widely misused term) or other types of reactive chemicals. Typical example would be Sodium (or Potassium) Hydroxide.
Acetic acid, on the other hand, is an acid, and a weak acid at that, again purely chemically speaking. It is corrosive, toxic, irritating and all that... but being an acid, caustic it is not.
You probably meant "corrosive", but that's another term altogether.
Then there is the other, figurative meaning of "caustic" and if I wanted to apply that meaning to this case, I would say that your reply was incomplete because even though you used bold, underline, italic and multiple exclamation marks in your reply, you forgot to apply red and blink. Aside from mishandling quotes, of course.
Which brings another point - those green toothy thingies I tend to use in messages like this and the one you were replying to are called "smileys" or "emoticons". They are supposed to convey the emotions through the strictly textual medium such as the discussion board.
This particular one denotes content strong on humor, or at least intended to be.
Glacial Acetic Acid
EMERGENCY OVERVIEW
Appearance: colorless liquid liquid. Flash Point: 39 deg C. Danger! Corrosive. Flammable liquid and vapor. Causes severe digestive and respiratory tract burns. Causes severe eye and skin burns. May be harmful if absorbed through the skin. Acetic acid forms ice-like solid below 62°F (17°C).
Target Organs: Teeth, eyes, skin, mucous membranes.
Potential Health Effects
Eye: Causes severe eye irritation. Contact with liquid or vapor causes severe burns and possible irreversible eye damage.
Skin: Causes skin burns. May be harmful if absorbed through the skin. Contact with the skin may cause blackening and hyperkeratosis of the skin of the hands.
Ingestion: May cause severe and permanent damage to the digestive tract. Causes severe pain, nausea, vomiting, diarrhea, and shock. May cause polyuria, oliguria and anuria. Rapidly absorbed from the gastrointestinal tract.
Inhalation: Effects may be delayed. Causes chemical burns to the respiratory tract. Exposure may lead to bronchitis, pharyngitis, and dental erosion. May be absorbed through the lungs.
Chronic: Chronic exposure to acetic acid may cause erosion of dental enamel, bronchitis, eye irritation, darkening of the skin, and chronic inflammation of the respiratory tract. Acetic acid can cause occupational asthma. One case of a delayed asthmatic response to glacial acetic acid has been reported in a person with bronchial asthma. Skin sensitization to acetic acid is rare, but has occurred.
Definition of Caustic (Merriam Webster)
Main Entry:1caus·tic
Pronunciation:\ˈkȯ-stik\
Function:adjective
: capable of destroying or eating away organic tissue and especially animal tissue by chemical action <silver nitrate and sulfuric acid are caustic agents>
It is not my fault if you are too dim to get it, no need to yell and scream at me. Especially since I wasn't talking to you in the first place.
No need to lecture me about chemistry either, I've got my degree a long time ago.
So go find someone qualified to explain some basic chemical terms to you, such as the difference between acids and alkali, what is strong or weak acid/alkali and what caustic really means.
You can start with Wikipedia, at your level it should be sufficient enough for a while.
Wow I didn't realize this was such a loaded question.
I found a source for both 28% and glacial on the web with no hazmat charges - digitaltruth.
Thanks everybody
Posting Permissions
Reply With Quote
Bookmarks