Picked up a, new to me, Power Wheel (pictured below). The tank is in pretty bad shape inside. At first, I thought the bottom was coated with varnish but, it appears to be mostly rust. Decided so after using a long screw driver to lightly scape the bottom when my first soaking with mineral spirits didn't come out as dirty as I'd expected (soaked about 8 hours).
What did scrape out was certainly rusty scale. I've gone through several phases with rocks/drywall screws/machine screws with a bit of a DIY degreaser (super washing soda and tap water), the net result was extremely rust colored water being poured out after each cycle. However, at the rate it's going, I could be repeating this process for weeks!
So, thought I'd try some distilled white vinegar over-night. After filling the tank, noticed the label said it was diluted to 5% with water
but, not expecting to much from such a weak solution.
Now, instead of going out to buy a gallon of muriatic acid, I have some concrete floor stain left over from a previous job. Looked up the MSDS on it (Kemiko brand - cola colored) and here's what it lists as ingredients:
Ferrous chloride 7758-94-3 15 - 20%
Hydrochloric acid 7647-01-0 5 - 10%
Chromic chloride, basic 50925-66-1 1 - 5%
My guess is, the Ferrous Chloride gives it color and the Chromic Chloride is a catalyst. The Hydrochloric is what were aiming for!
So, here lies the quandary:
Are the first and third ingredients going to cause any problems? Hoping someone else may have used this type of acid in a pinch and know for sure... not being a chemist myself.
And secondly, will 5-10% Hydrochloric acid be enough? Muriatic Acid's (Crown brand @ Lowes) MSDS lists the acid content @ 25-35% mix with water.
Of course, I'm open to other suggestions for a remedy too.