Hey Ness, I had access to 55 Gal. of powdered phosphoric acid when I was still working. The large Printing plant! Boiler room had 2 5,000 gallon boilers going at the same time. I worked the receiving docks and delivered all the products thru out the plant! I had whatever they had!
They ran that through the steam and air pipes continuesly. Also 95% pure sulphuric acid for the chroming tanks for the print cylinders. That's what I used to restore my aluminum, mixed up batches of acid and tested old parts till it got nice and correct to dip and clean. I used to burn and overkill old aluminum parts for fun!
But I love Caswell sealer! That's were I buy all my buffing supplies too. They are in Lyons, NY. Close for shipping. Plus I have an account for tax free wholesale pricing.