"...a good thick plastic and card board will work for a tank..." No it won't. Properly done, parkerizing involves heating the solution to 190 to 210 degrees. Phosphoric acid is one of the ingredients. No plastic, and certainly no cardboard, will work.
Spelling and grammar count!
For a Systems Engineer looks like you put your foot in your mouth and didn't do any rersearch what so ever as there are plenty of plastic materials that will work with this and cardboard is only to contain volume and as a insulator. I have allways loved goffy engineers that say it can't be done even with the right grammer. Besides with spelling and grammar you need a brain with a little common since to use with it. One thing for sure is I am not a liar and don't appreciated being called one.
Before you go around calling someone a liar you need to understand more about what you are talking about. I will explain a bit on how it's done, first the item needs to be clean and solution need's to be heated to 205 deg's and also help's to heat item being parked, put item to be parked in heavy plastic in box and leave open enough to pour solution in, purpose of box it to contain volume so it doesn't take a ton of solution and hold heat, after pouring solution in keep a eye until you get results wanted. Main thing in doing any park is you have to clean and keep clean. Yes I know it's a back yard way of doing it and I have park tank but this will work in a pinch or someone only wanting to do it one time.
I also have done the stove top version with great results before investing in SS tanks.
If you can't say something constructive try not to say anything next time, it may come back and bite ya!