I have used the phosphoric acid used here many times. Here is how to do it. Get all loose rust off by your favorite method....wire wheel or sand the easy to remove and flaky metal-rust. Wash all parts to remove any grease or oils, scrubbing well. You only need just enough phosphoric acid to wet the rust and metal surface. Be patient and let the phosphoric acid to react to the rust. Let it sit overnight or ten to twelve hours. If you have pits, wet again and agitate with a steel brush, then let it sit and react as before. A white powder means that you have an excess of the phosphoric acid. Black coating is proof that the rust has reacted with the acid and you are left with an iron phosphate coating. You can wash the white powder off with wax and grease remover or water if you use your leaf blower or compressed air to dry completely. Prime right away or be sure to keep in a dry, low humidity environment and prime as soon as possible. That gallon could probably do a car or two if you be patient and follow these directions an you don't have lots of pits. Once did a badly pitted roof using the steel brush to be sure the rust was out of the Pitts. Upol Fiberol has fiberglass in tiny strands and spreads like ordinary body fillers and sands like them...also fills in those small rust holes. Highly recommend Upol product over all fiberglass reinforced products I've used. Hope this helps.

Hello Alvin. That was neat watching the rust dissappear on time lapse. I used many methods, but I found the cheapest way was using electrolosis. Works real well. For that big of a piece, the phosphate etch and prep works wonders. George B

Alvin, Now you tell me.😮 I've never heard of concrete and metal prep. I may need to use it beneath Pearline's battery tray. Whatever lurks under there has got to be evil. Regards, John

Heya Alvin, That’s pretty interesting that it leaves a protective layer once it’s cured. That size of metal piece I would need to get a kiddie pool and do one side at a time with the white vinegar and water 😂 Keep up the great work and as always, looking forward to your next video!

When using it I find that it converts the surface layer of rust. If I sand again I find rust underneath. I found that getting rust back to the pitting and then putting on acid is more affective.

Pickle and phosphate is (or was) fairly standard with steel products. Pickling was submerging in hydrochloric or sulphuric acid (or muriatic) to remove rust and most anything else - it's prett harsh. That was washed off and the steel was then submerged in phosphoric acid. That removed any mild surface rust that formed during😂 washing and provided a short-term protection - it lasted long enough for any remaining acid to dry off. It also keys the surface well for subsequent painting. In the old days, the paint would have been red lead. Two pack epoxy primer or your favourite anti-corrosion primer are safer choices now.

I bought the 75% phosphoric acid a couple of days ago the cheapest I could find cost me $50 a gallon

I totally agree with trying a chemical approach rather than a mechanical approach for rust removal whenever possible. I can see that vinegar wouldn't work for a part that big as vinegar requires total sunersion over a long period of time. It is effective for smaller parts: Question: what's the difference between Phosphorous acid and Muriatic acid for rust repair? I've seen and purchased Muriatic acid as it's available at hardware stores around here. I didn't know if one was considered better/safer/cheaper than the other. I know little about this stuff.

Have you tried the electrolysis rust removal water and washing soda negative goes on the part other goes on a sacrificial rod to attract the rust don't get much cheaper than that

Hey Alvin, wow that stuff works very well. Is it smelly, like a chemical smell? I've never worked with it. As a matter of fact, I never used a chemical rust remover until I saw Johns videos. I just used my glass beader. Old habits die hard. The blaster metal rescue rust remover I use is just like water with no smell what so ever. It feels like water and has the same consistency as water. I like how blaster leaves a consistent derusted surface, but I guess it doesn't matter if its going to be painted anyway. Buy like you say, it is costly and does add up. I think I like using it better than the glass beader because the beader creats so much dust and is noisy. Dipping parts into a tub of fluid is so much easier. I'm glad you took the pedestal out, there is so much rust damage to repair. What about the frame piece under the floor board along the tunnel? That looks pretty bad too. Keep the great vids coming. Thanks.

Nothing beats phodphoric acid 20-40%. Spray and/or brush. You can use wall paper adhesive to thicken it a bit to apply with a brush. Expensive tho (85%). Here in Finland 49€ per litre. Ouch.

That cement etch sds says. 10.0 -30.0 % Phosphoric acid {Orthophosphoric acid} Isopropyl alcohol {sec-Propyl alcohol; IPA; 2-Propanol} 67-63-0 0.1 -1.0 % 68439-46-3 0.1 -1.0 % Alcohols, C9-11, ethoxyl

may I use this for inside a boxed frame rust? Rust sits mainly on the floor of the boxed frame. I have tried to get all the dirt and sand from the innards by washer pressure and air blasting it the best I can. Some chunks of scale rust may remain in there. The plan is to lift the front of the truck as much as possible and pour the acid in the OEM frame holes (no, there are no rust through holes). After a couple of days do the same with diluted anti corrosion paint, so it will flow and to seal everything off. It is a good plan or am I missing someting? Do I have to rinse the acid? I cannot find a way import the Eastwood inside frame spray to this country potherwise I would go that route. Thanks.

Crappy tire also has por 15 metal prep

Do you have to do any neutralizing with phosphoric acid like you do with muriatic? I have a rusty motorbike tank I need to clean and most just recommend muriatic then neutralize and then coat with oil but if this works better as the finishing then might just do that.

So did you use both on the test? I can’t tell

I washed my chassis with water after wards and now its orange 🍊 rust y again, arrrrrhh