Removing surface rust

First off let me just say that my idea of the at home builder and this forums members are two diffrent worlds in my book, most if not all of the work I've seen here is amazing so much talent and knowledge so let me apologize if my questions are "common knowledge" with that said I'm starting on getting some of the parts I've been collecting ready to paint and I don't really want to paint over any surface rust and was wondering if there was a way of completely removing it.....I don't have access to a air compressor to run a media blaster I'm pretty much limited to sanding right now and I'm unable to get into all the crevices and I don't see the point in leaving something 90% done I've heard of people using CLR and similar products but I am completely ignorant to how and if it works and if you can paint the suface after its been treated with it, any help would be appreciated.
A picture so you can see what I'm talking about
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Go to home depot paint department. Buy a product called metal prep.i think the manufacturer name is kleen. Its in a yellow labeled rectangular jug thats translucent. The liquid is green. Buy an industrial strenth spray bottle & chemical resistant gloves too. Hand sand any heavy rust off first. I use 40 grit. Then fill the spray bottle half way with water, top off with metal prep. Spray onto the metal & let it soak for 20 min. Go back spay again & wet sand with 240. Wipe off with a towel. You may have to do it multiple times. I did my 49' which was completely brown with heavy pitted scaly rust. She is bare steel now, has been for a couple years with no rust return. Shes stored in my garage while I gather parts to customize her. Clr is the same product only diluted. Metal prep cost 16.00 more or less per gallon. It chemically treats the metal, its phosphate acid. You will have to sand it off anywhere your going to weld when your at that point though. P.m. me & I can email pics, im using a galaxy tab & cant upload pics. Laptop died....

 

What size is the part? Soak part in molassis & water, it is easy & cheap.

 

I do this and it works.

 

Thank you to everyone who has taken the time to respond I'll let you how it goes and I'm sure I'll be back to ask a bunch more questions I should most likely already know the answers to thank you for your patience and help in advance

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I know what it's like to be in that spot. There are those crevices where you just can t get in there, usually the back side of a panel or something wedged in between two other panels. In that situation I would get rust encapsulator and have at it until the whole area turns black. Even though it doesn't fix anything it helps it from becoming a bigger problem.

 

When I am sanding and the surface has areas that just don't work well with paper sandpaper, I use the maroon scotchbrite pads.

Neal

 

Lots of good advice here. If you've got stuff that's really pitted or crusty though, blasting is much preferred. If you had a decent sized pile of stuff to get blasted, consider calling around to places that do blasting. Usually they'll have a minimum of 1 hour charge or something like that, but you'd be surprised how much a good blasting place can get done in an hour.

The piece you're showing looks well within the range of chemical treatments, though.

 

The phosphoric acid is good to spray on metal parts to keep rust from forming. I have a 37 hood that I've had outside for a year and a half. With very little surface rust. It washes off when you need it.

 

i have a media blaster and a tank full of molassas and a tank for electro. the molassas would be what i would use on that part for sure. it will remove all rust and get into spots that are haed to get to with the blaster.

 

Sorry if this is a stupid question but what is this molasses, a few diffrent people suggested that particular process but I havent the slightest as to what or how thanks again and for the curious the picture is the back side of a 61 c10 grill

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cup brushes on a grinder will clean that up nice.

 

molasses?????? dude ,your gran mother never made you molasses cookies? lol. oh my they been importing molasses since the trade routes were developed before Columbus found us. lol...REALLY not making fun of you , AM NOT....jus pointing out how times have changed. molasses is ,some sort of sugar cane type derivative... make awesome cookies, though my grandmother been gone long time, think those were the last. any how any grocery store has molasses ...mix 7 to 1.... with water. soak , any does clean rusty parts.......though the acid products work well too. good luck n get some molasses cookies or even donuts , warmed up. yuuuuumy

 

There are threads on the HAMB about using molasses. Many have used it. I have messed with it some. Go to a feed store for molasses. Cheaper than your corner grocery store.

Neal

 

Got 6gal. jug today, they sell it by the pound $15.00 mix 7 to 1, down side is, it takes time and the warmer the better, works better at 60 deg. or higher

 

Alright I would have never imagined that the molasses mentioned here and the stuff from the grocery store were same product..... the things you learn when you aren't afraid to ask the dumb questions thanks for the info I'm not sure if I'm amazed or worried that molasses will eat through rust

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Does the metal prep and/or CLR strip the paint too? I want to knock down the rust on my truck's hood and roof, but preserve the paint/patina. Can't soak the whole truck in molasses....

 

My Son and I use Oxalic Acid (wood bleach) Mix 6 oz. to a gallon of water. Put your part in and let soak overnight. Rust will be gone in the morning. My son restores old bicycles which are usually pretty rusty and the bleach works great and I have used it on old car parts, nuts and bolts ect. I recommend wearing gloves when handling it. Cleanup is easy just rinse and dry. Hope this helps.

 

I always use phosphoric acid(ospho) on any bare metal that I intend to primer/paint over. Including something fresh from the sand blaster. The phosphoric acid neutralizes the rust, etches the metal and converts it into a protective black coating that's rust proof. I helped my dad refresh this motor off his daily driver c10 and took the excess rust off with a cup wire brush on a drill. Then I spayed the motor with the acid(of course taking the proper safety precautions). Wiped off the excess with a paper towel and let it sit overnight. The next day the motor had turned gray/black and I took a red scotch brite pad to knock off the dried excess. I wiped the motor down with wax and grease remover and proceeded with the sealer/paint/clear.

 

Molasses? Hah, that's one on me!

Never would have imagined trying that, though I've heard of people using various kinds of soda pop including of course coke.

I've always used Jasco Metal Prep which is phosphoric acid, alcohol & water. This etches and de-greases prior to painting. The soft red rust becomes hard black iron phosphate. It's not steel, but it's less like chalk and more like stone. I use an etching primer on the bare metal, which will help with any microscopic rust.

I can't imagine soaking an entire truck in molasses but what if you mixed it a bit thicker and just painted it on with a brush, in sections maybe a couple feet square max, and immediately covering with saran wrap. That stuff is sticky as hell and the wrap would cling like it was glued. Go over the whole body, soak it down in the cracks as well as possible, and wrap it up. I think that as long as the molasses didn't dehydrate, it would keep etching off the rust for days.

Go back on a warm day a week later, peel off all the wrap and wash the truck down with a hot water hose and blow with an air compressor.

Does this sound far-fetched?

(EDIT: Any acid wash should be soon removed with water to stop the action. It works really fast. I usually just keep sponging it on slowly so it won't dry. If you let it dry on the surface, just make sure to wash it all off with water and dry thoroughly. The drippings from this process will stain your concrete, as will any acid BTW. I have seen parts completely disappear when left in a dip tank, so beware.)

 

Hi have you tried citric acid, once you have I bet you would dump the molassas. 24 hours in solution removes all rust.
1 kg to 40 litres

Thanks grant