Rust paint

[Prairie]

I have a 1910 (abouts, before John Deere bought them out) Hoover potato harvester. It is in pretty good shape, I am doing some repairs on it, but I would like to paint it when done. What kind of rust paint can I use that I can just wire brush the thing and spray on self priming rust paint in two or three coats and it will do a good job. I don't want to prime because when it eventually wears off, I don't want the primer showing.

[NCLee]

When I do something like that I use whatever Rustoleum product that best fits the bill. Usually Lowes or Home Depot will have what I need.

Here's another thought regarding primer. Match your top coat to the color of the primer coat, unless you're trying to match the original factory colors. Rustoleum's Rusty Metal Primer is a rich brown color. I used quite a bit of that when I refurbished our old 5th wheel rig.

Lee

[rAcErRicK]

Without a doubt P, there is a product called Ospho that turns rust into carbon and completely kills it. It is a clear (slightly green tint) liquid. As you said, you remove as much of the rust as you can, spray or brush it on, let it set for 24 hrs, rinse it off with water, and then paint. Your rust worries are forever over, unless of course the steel is nicked or deeply scratched. Found at homo despot, lowest, or any good hardware store. The bigger stores have their own wannabee brands which are good also and for a little less money, but if possible buy the original Ospho brand. For the protection you get it is very inexpensive. I am in a very humid and salt air environment and this IS the only way to go. I learned this from professionals. no exceptions. Good luck.

rick

[chrisser]

You may want to look at POR15 (www.por15.com). Also available retail.

It's an interesting sort of coating. It cures via the same method as super glue. Can be brushed on. It is very tenacious - if you get it on your skin and it cures (which it will quickly, just like super glue), you will have to wear it off (ask me how I know).

It's a great coating for rusty parts.

It is, however (and in my experience), a completely awful coating for bare metal, unless used with their primer.

[Franz©]

I could spend hours explaining this. Ospho is an overpriced brand of Phosphoric acid, around 5% by volume with magnesium disolved in it. You can accomplish the same process employing milk line cleaner at the same percentage. Either will convert the rust to Iron Phosphate, chemicly bonded to the good steel ONLY if full wetting of the rust layer is acheived.

No, phosphoric acid will not hurt you unless you employ incredible stupidity, it's a major ingredient in both Coke & Pepsi.

POR-15, is a polymeric coating containing phosphoric acid. It is a misuse of a coating designed for temporary repair in a marine environment. Save yourself a lot of money it falls off as the rust layer underneath grows over time.

If you have parts you want to remove the rust from go get a sack of molasses at the dairy supply mix it up in water and soak the rust off. The process is called chelation. Grab some flypaper while you're at the supplier.

[MooseToo]

a little off-topic, but, for those who want to preserve an old antique machine for display but want to keep that rust "patina", a 50/50 mix of linseed oil and diesel brushed on a couple times a year will stop new rust, shed water and give a little sheen -

franz - can you explain what a "sack of molasses" is ? is there some common substitute than can be used for small jobs ?

[Anon001]

I may not be Franz, but feed grade (not food grade) molasses comes in liquid or in a dry form in 50 pound bags. Feed stores sell it. It's purpose is as a feed additive. But, if you're going to do that, can you just buy the liquid molasses and use it?

[Franz©]

Paul pretty much nailed it.

Grocery store molasses doesn't work as well as feed grade, nor will it do as many parts, but it works.

There are a multitude of processes for rust removal ranging from electroplating rust off (electrolytic) to various acids and strong alkaline solutions.