I've been experimenting with muriatic acid for removing rust for some time now. Initially, I'd brush the product on the surface repeatedly to keep it wet and it seemed pretty effective.

I was recently turned on to a new technique of using paper towels or toilet paper soaked in acid. The toilet paper will actually cling to a vertical surface. 24 hours or less will get off strong surface rust. I thought I'd share it here as I'm amazed with the results.

Another technique I've been using is diluting the acid with water and dunking the parts. I put a couple of gallons in this covered garbage can and filled it up about halfway with water. I soaked a rusty wheel for about a week and it came out looking like new metal (except for the pitting).

These 356 parts were mostly surface rusted, so nothing heavy, but this was overnight in the diluted mixture which has been in the garbage can for a few months now:

If you do try this technique, use common sense and read the bottle for safety instructions. DO NOT use the acid indoors. I learned this when I was using it on a 356 for the first time. I came back the next day and every hammer, dolly and ferrous surface in my shop was surface rusted. I'd recommend not spraying it. I just use a chip brush and mottle it around. Save the mushed up remains in a plastic bag and use them again and again. Rinse with water. Spray on your favorite phosphoric acid based prep product, (Ospho, Metal Prep, etc...) and you're done. A gallon of the acid is about $10 and goes a long way.

COMMON SENSE..... ha

Are you planning on going with POR products?

Apple cider vinegar, evaporust, etc will do the same thing without the hazards of a strong acid.

I've used it in the past. I don't care for the product.

Clean, rust-free metal will be coated in epoxy primer with spot weld areas taped off, then coated in a weld-thru product.

I've been using these products from Summit lately and I like everything about them:

With regards to the time required, the cost involved and the results achieved, I haven't found that to be the case. The pictures don't lie. This is, by far, the best method I've found for rust removal. There's a lot of ways to get to town and none of them are wrong. I wish you success with your methods.

I don’t know that I would use muric acid, it’s hard to neutralize, whereas phosphoric acid is more mild and easier to handle.

I rinse it with water, then follow up with a phosphoric acid to prevent flash rust. By the time this panel, or any panel I would use with this process, is ready for paint, it would likely be sanded to shiny metal.

I'm needing to de-rust my 2.0 lower air cleaner housing. It has some crusty rust on the inside surfaces and several pin holes. What are the best methods to stop further rust and seal up the pin holes?

I'm mostly a 'cut out and weld in new metal' kind of guy, but I do use a product called Duraglass, made by USC. I've used it in place of lead over MIG welded repairs that I can't get to the back side of for finishing. MIG has a tendency to pinhole once ground and I'll use the Duraglass as a first swipe of filler over the welded area before any talcum based fillers. I use all filler as sparingly as possible, but apparently you could build a boat out of this stuff. From what I've seen, it's very durable. I've seen some high-end, Hot Rod shops use this stuff to set door gaps.

Duraglass cut sheet

Post a picture, if you can.

I believe you...but just what is the magic of Apple Cider Vinegar?

Its good to drink it also...to help with digestive issues, and cholesterol.

and magically it also makes rust go away?

so many companies would never want us to know these facts...

The stuff is liquid magic???

Rich

It worked for me to de-rust a bunch of hardware and the inside of two motorcycle fuel tanks. The main reason I use it is because I can soak parts in my garage and while my wife will mention the smell, she’s not annoyed by it and I know if it spills on the floor, it will not poison my dog. There are many ways to manage rust removal. Because of my lackadaisical effort towards personal safety, I tend to use products that won’t hurt me when I eventually splash them in my face.

I'm betting apple cider vinegar will NOT be nice to get in your eyes.

I'm with mepstein. I try to use the wimpiest agents that will get the job done.

Sometimes the answer is apple cider, sometimes it's muriatic acid.

The acid works much, much, faster than other things and requires further safety protocols but both have a place in the automotive world IMO.