HOME FAQs BOOKS JOBS: Help Wanted Suggestions you are here: Hotline/Forum => Letter 25258
How to make up Sodium Dichromate seal
+++
I want to install a small 185 gallon Sodium Dichromate seal tank for Mil-A-8625 [link is to spec at TechStreet] MIL-A-8625 TY IB & TY II anodized parts. I have found two makeup plans, but I am uncertain as to how to calculate the amount of sodium dichromate to add to DI water. Can anyone show me the calculations?
Plan 1- Shows 56 to 64 g/l of Sodium Dichromate
Plan 2- Shows 4.0 - 6.0 percent solution by weight of Sodium Dichromate
John McGuirkMetal finisher-Mil/Aerospace - Oldsmar, FL, USA
+++
They are nearly the same. Water weighs 1 gram per ml, a liter is 1,000 ml, so 4 -6% would be 40 to 60 grams of dichromate. What ever the specification calls out is what you want to use.
James Watts- Navarre, Florida
+++
Here is my take on the calculations you need: 185 gallons * 3.785 Liters/Gallon = 700.3 liters. 56 grams/liter = 39216.87 grams / 453.59 grams/pound = 86.46 lbs of NaCr2 For 64g/liter, 98.81 lbs of NaCr2. For a 4-6% solution by weight: 185 gallons * 8.33 lbs/gal = 1541.05 lbs .04 * 1541.05 = 61.64 lbs NaCr2, .06 * 1541.05 = 92.46 lbs Na Cr2 I am not in the plating industry, just a chemical engineer looking for pot metal restoration help. These are what I would consider the correct calculations, however you might want to confirm with another source before using.
Mike JonesGovernment/ military - Crane, IN, USA