How quick will flash rust occur?

Okay guys, I've had an exhaust manifold valve off a '50 Buick sitting in a molasses/water solution for about a month in the hopes of cleaning it up and freeing up the stuck butterfly valve inside. Well it's fermented up pretty nicely and starting to stink up my kids' bathroom. BEFORE I remove the part from it's swampy bath and have it rust back-up on me again, how quickly will it rust? AND, what is the best way to dry it so that I can throw a quick coat of high-temp paint on it to prevent it from future rust? I figure it's been submerged for like I said about a month, so not sure if the metal has absorbed moisture, or even if that's possible. Most sites show to clean it with a green scrubby and some soap but don't go into the flash rust component...I know not to paint the inside and the mechanism. I'll coat the mechanism with some acetone and graphite to keep it freed-up, if indeed my experiment worked!

 

It will rust as soon as it gets to see the air. You might not see it, but it starts. Don't leave it sit out for a couple couple of days before you paint it.

 

Take it out, wash it off and re-coat immediately. I use phosphoric acid then paint it in a few days.

 

In Houston, we watch and bet on it. Be prepared to coat it when you when you take it out.

 

I've used Evaporust on steel before, rinsed it off, then stuck it in the oven turned low for a while to dry it quickly. Preheat, scrub like hell, then pop it in the oven for a few minutes. That way I don't have to watch it rust again. Finish at your leisure.

 

In a flash!

 

But really, there's almost no way to stop it. I have used a heat gun to dry it quick and it will rust as it dries. I used a towel with alcohol to remove what I can before coating.

 

The flash rust is quick but its not like the crap you soaked off.
You can almost wipe it off.

 

You can measure it in seconds. Seriously.

 

Um, you soaked an exhaust manifold for a month in molasses in your kid's bathtub?

You ARE the king of the castle......

 

It was in a small bucket. That was then put inside the bathtub just in case of some spillover. Rather it in the tub than on the floor. Cellar is way too cold up here in Mass. this time of year. Needed the heat of the house to get the fermentation to kick in. For the other replies; thanks, I'll make sure I buy paint before I remove it from the bath! LOL

 

it depends on the humidity

 

Back in the late 60ty's a R&M Paint rep claimed that bare metal would start the rust process 7 seconds after being bared. I would suppose that would somewhat depend on the part of the country you were in but in any case pretty darn quick.

 

The last time I soaked something for a month it ruined the part. It ate away at the threads and bearing surfaces and it was junk. Before that it was a new part that had surface rust.

 

What did you soak it in ?

I soaked a quadrajet in lemon juice, was supposed to be 3 hrs but I forgot it overnight and it ate a hole in it.

Too long in vinegar (a week) removes good metal too.

 

As everyone says once you power wash or scrub of all the residue it will flash rust in a flash . Just dry it off with a heat gun and rags. Spray with a rust inhibitor such as POR 15 metal ready and the wipe down as per instructions with a slightly damp cloth and dry again As quick as you can. Then you are good to paint . Though you may not get the internals treated and clean it's a good start.

 

as you pull it out rinse it in hot , and I mean hot water and work the valve , you might want to preheat the oven to 225* and as soon as you clean the goop off and work the valve to make sure its free and keep working it breaking up the rust in the sleeves then rinse it then towel dry it as much as possible then and bake it for 2-3 hours to dry it out . and every 15 minutes or so reach in and work the valve . then paint it when it cools to room temp .

 

We used to hone cylinders to fit the pistons, and wash the blocks in the sink...and imediatly wipe down the cylinders...if you weren't real quick you could actually see the cast iron rusting before your eyes. Was hard to believe but true.

 

I found I was never quick enough then [and probably slower now!].. I found that before you even start to dry anything wipe all the machined [or any] surfaces with a lint free towel soaked with some wd40 or other light oil then you can blow most of the water off and dry..And yes its an oh sh!t when it rusts right before your eyes..

 

I don't know about that treatment for rust...but around here, if I sandblast something, or sand it with a DA, or whatever, and leave it in my shop, it will sit for years without forming visible rust.

you guys gotta move

 

This is because blasting and sanding does not remove the fine layer of protective oils.

 

I kinda doubt it.....I think it might have more to do with the difference in humidity, as well as having some insulation in my shop.

When I leave blasted stuff outside, it gets rusty. Especially in August.

 

In Kaneohe (rainy side of Oahu)...In a flash!...hence the name...I guess?

I use a lot of "Must for Rust" on bare or slightly rusted parts.
It forms this white ugly layer on it that is paintable or easy to remove later.
T

 

X2... depends entirely on relative humidity... here in the prairies with 25% humidity it's driere than a popcorn fart inside...

 

After you get all the molasses off and it is clean do a final rinse it in a solution of water and baking soda and let it dry naturally. I use 2 gallons water and 1/4 cup baking soda. I have done this plenty...a chemical reaction occurs and prevents oxidization although not permanently.

 

yep, i have had a sandblasted quarter panel for a 58 caddy hung in the hay mow of my barn for years...still looks good.

 

I usually use vinegar, but if you are using molasses, put the part out and wash it with soap and water. It won't rust then.

 

Around here flash rust can occur while you are still sandblasting.

 

Very quickly ! What a silly question ! LOL !

 

not to different from auckland, a narrow gap between coastlines = salty air, i usually end up with rusty fingerprints where ive handled the item.