Replies

1. 
   jackplane | May 02, 2007 02:33pm | #1

   10% phosphoric acid is 10% phosphorous to 90% vehicle. As 10% saline solution is 10% salt to 90% water.

   Commercial denotes a high concentration, and for safety reasons is usually only available business-to-business, or lab supplier to lab. Not sure of the rules in your country...

   many ways to achieve an aged teak look, some being safer than others.

   Expert since 10 am.

2. 
   Cincinnati | May 02, 2007 03:33pm | #2

   Don't get hung up on the grade. I seem to recall industrial, commercial, and food grade. H3PO4 is one of the milder acids I've worked with, but still very dangerous and should be handled as such. Acids are often more corrosive and do more damage to the eyes and skin in weaker dilutions. Protect your eyes and skin. Wear a face shield over full wrap eye protection. Regular safety glasses leave too much room for a splash to get to the eyes.

   Check with your local chemical supply. I know a 15% Solution is available here. I believe the dilutions are by weight. So rather than offer calculations to make a dilution, ask the supplier for a 10 % solution. If they can't create one for you, he/she should be able to tell you how much water to add to arrive at the 10% solution. If not, post back to this thread and one of us will give you the volume of distilled water to add.

   
   

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   Edited 5/2/2007 8:34 am ET by Cincinnati

1. 
   MikeHennessy | May 02, 2007 04:33pm | #4

   " If they can't create one for you, he/she should be able to tell you how much water to add to arrive at the 10% solution."

   Not sure if it applies here, because I don't know what the user will be dealing with exactly, but I was taught NEVER to add water to acid. To dilute, always add the acid to the water. Doing it backwards can cause the water to boil explosively, splashing acid around.

   Mike HennessyPittsburgh, PA

1. 
   Cincinnati | May 03, 2007 07:49pm | #7

   You are absolutely correct: Acid to water, SLOWLY, and pour down the side of the container if possible. I didn't think to go into that detail. Thanks Mike.

3. 
   ring | May 02, 2007 04:25pm | #3

   I'm not 100% sure, but I believe the term "commercial grade" refers to the purity. Chemical supply houses sell varying degrees of purity depending on the intended use, and of course the more impurities the lower the cost.

   The highest purity is called CP (chemically pure), the next lower grade is called Analytical, and lower than that is called Commercial. Again, I'm not completely sure about this info but I believe it to be so. For finishing purposes the commercial grade is more than good enough.

   David Ring

   http://www.touchwood.co.il/?id=1&lang=e

4. 
   Dyeman | May 02, 2007 05:17pm | #5

   Phosphoric acid is the main ingredients in Marine Teak Cleaners such as this

   http://www.marinetex.com/index.htm

   I'm sure you can find a similar product in your country.

1. 
   user-141548 | May 02, 2007 08:59pm | #6

   Thank you all!

   I will take Dyeman's advise, because I'm almost treated as a criminal if I ask for concentrated Phosphoric acid and Alcohol. They look at me as if I where a bomb builder. If the main component of the marine teak cleaner is Phosphoric acid, I'm done thinking.

   Thanks again,

   Geert van der Donk