acid dipping rust removal

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pishta

pishta

I know I'm right....
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I got some Rallye rims from my buddy Bob (nut4vintage) and they were in need of some "attention" so I was going to wire wheel them and shoot them argent. I had 2 gallons of 14% muriatic pool acid from my summer days and wanted to try and see if it would clean some of the rust off. Uh, yeah..IT DID! For around 8 bucks and an old trash can, I dipped half the rim for 24 hours in a 1:2 acid/water mix and then blasted it with a garden hose. The rust AND 95% of the paint practically fell off the rim leaving virgin light gray metal with no pit marks. The shots were about 10 minutes in the sun to dry and there was a little flash rust forming but it wipes off with a paper towel. So Im now dipping the entire rim in the bottom of a "Roughneck 20 gallon" trash can, a 14" Rally fits perfectly. Ill take it out tomorrow night and blast it again. I had to add about 2 more gallons of water to cover the rim (1:4) so well see if it works as good as 1:2. Remember to ALWAYS add acid to water or you could get a violent reaction from a little water dropping into alot of acid.
 

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Impressive.Beats wire brushing,don't ask me how I know.Interested in seeing your final ratio.
 
pishta said:
I got some Rallye rims from my buddy Bob (nut4vintage) and they were in need of some "attention" so I was going to wire wheel them and shoot them argent. I had 2 gallons of 14% muriatic pool acid from my summer days and wanted to try and see if it would clean some of the rust off. Uh, yeah..IT DID! For around 8 bucks and an old trash can, I dipped half the rim for 24 hours in a 1:2 acid/water mix and then blasted it with a garden hose. The rust AND 95% of the paint practically fell off the rim leaving virgin light gray metal with no pit marks. The shots were about 10 minutes in the sun to dry and there was a little flash rust forming but it wipes off with a paper towel. So Im now dipping the entire rim in the bottom of a "Roughneck 20 gallon" trash can, a 14" Rally fits perfectly. Ill take it out tomorrow night and blast it again. I had to add about 2 more gallons of water to cover the rim (1:4) so well see if it works as good as 1:2. Remember to ALWAYS add acid to water or you could get a violent reaction from a little water dropping into alot of acid.
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Makes me want to lower my whole car into a pool
 
Im going to drop my entire commando intake in next as well as a crusty hot side of a turbocharger. will update tonight.
 
I recommend neutralizing the Muriatic acid with a dip in a baking soda/water mix and then spray phosphoric acid on it as it will leave a zinc coating behind. Check it out at : http://www.eastwood.com/rust-protection-done-right

I used Muriatic acid on a boat trailer axle and after washing it off, I painted POR15 on it without neutralizing it. But the POR15 just lifted off in sheets within a year as the axle continued rusting underneath it. I think that the Muriatic acid prevented the POR15 from getting a good bond on the steel.
 
That looks good, I have used Vinegar and seen molasses work good doing this, even a battery and wires in a bucket of water, I can't remember what they called it
 
memike said:
That looks good, I have used Vinegar and seen molasses work good doing this, even a battery and wires in a bucket of water, I can't remember what they called it
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Electrolysis is the word you're looking for ;)

Going straight from the acid dip to a warm water rinse to a neutralizing solution should work best. The acid HAS to be gone from the surface, or nothing will ever stick as the acid continues to oxidize the metal. To minimize rust, the final rinse is often best if the water is hot (and the part immersed at the end of a cable/wire) so that it evaporates quickly. Blast it dry with compressed air immediately after the final rinse and let it fully dry.

A phosphoric acid solution will phosphate the part, there are solutions available for iron phosphate, manganese phosphate, and zinc phosphate. The manganese phosphate is what's used in modern plating shops since zinc as a heavy metal isn't as desirable. I prefer manganese anyway since it tends to build larger grains and works as a great primer base. A zinc bearing primer like POR15 can lend the same galvanic corrosion inhibition over a manganese phosphate, and the phosphate gives lots of 'tooth' for the paint to stick to.
 
I was going to neutralize it with a washing soda dunk. Should I rinse, blow dry and neutralize or blow dry after rinsing and neutralizing? I will be painting them after its all done.
 
I'd rinse, then neutralize, then rinse again. All rinses with new/fresh/clean water. Blow dry at the end.

If you go right from the acid to the neutralizer, you'll likely wind up with a mess ;) A pre-rinse will help get the bulk of the acid solution off. Keep the part moving in the rinse and neutralizing baths too, agitation makes things go faster.

Once the final rinse/dry is done you shouldn't get much surface rust right away - once it's 100% dry, I'd begin your painting ASAP - starting with an epoxy primer or bare metal sealer.
 
Pishta,
1. Suspend the part over the acid bath and spray rinse (hose) into the bath.
2. Immerse the part into a rinse bucket of fresh water.
3. Transfer rinsed part into a baking soda (sodium bicarbonate) neutralizing solution. Bubble formation is an indication that any acid remaining is being neutralized. I believe that powdered baking soda can be purchased at a Home Depot or pool supply store.
4. Rinse part in fresh water bucket.
5. Remove part and spray with isopropyl alcohol (rubbing alcohol).
6. Blow dry with compressed air.

The isopropyl alcohol will prevent flash rust from forming for days in a dry environment such as inside a garage.

Muriatic Acid is the common name for Hydrochloric Acid. Wear gloves and eye protection.
When you are done, add the baking soda solution in small amounts to the acid solution to neutralize the acid prior to disposal.

Art
 
DFX 340 Duster said:
Muriatic Acid is the common name for Hydrochloric Acid. Wear gloves and eye protection.
When you are done, add the baking soda solution in small amounts to the acid solution to neutralize the acid prior to disposal.

Art
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The alcohol is a great idea, helps get the water out even faster.

Also, good ventilation is very important, and you don't want those acid fumes inside or anywhere near metal. It's nasty stuff, and you don't want to breathe it either. I've seen rags that were soaked with Muriatic acid and wrung out without a proper rinse left next to a tool box, and the chrome on the tools IN the box pitted and corroded within a couple weeks.
 
I m gonna share this cause i don t want anyone to get the nasty feeling in their gut like i did from using muriatic acid. I read once something along these lines and decided to try it. We had a 37 pickup cab fresh from the media blaster, but still had a small amount of rust in a few deep pits. I tried it on a small area. BOOM!!!! It was gone. I neutralized it. All seemed well. So i did a lot more. Neutralized again with baking soda and water. Let it dry..it flash rusted a little bit, but the next morning i planned on d.a.ing all the metal down and epoxy priming.
Came in the next day....whole cab flash rusted......WTF???? So i d.a. Sand anyway. By the time i get around the cab. Its already lightly starting to flash again. WTF???. NASTY GUT FEELING
So....i talked to a friend of mine who owns a powerwash company. He sold me a product called "RUST-BAN"... Acid washed the cab. Rinsed, soda washed, rinsed again, and while it s still wet sprayed rustban solution on it liberally. Let it dry and it was fine. Scary time tho. I m sure there are other cures, but this stuff saved my butt.

When you first use it you re think holycrap this is awesome, but it can bite you.
What i didn t realize was the shear potentcy of the acid fumes. That **** is nasty and can be trcky to work with. I learned to never use it inside either. Fumes alone can flash rust every thing metal in your shop thats not coated

If you leave steel in it too long it will tear it up. I ve left bolts in too long and they look crazy when they come out. Almost like the inside of a bone in the edges.

ON THE PLUS SIDE... It works fast and is very helpful. I still use it now. I m just careful
Long story but i hope this helps
 
thanks for the war stories. This is stewing in a covered trashcan at the end of my driveway.
DFX Ill give that a shot. I have a big spray bottle Ill use to pre-rinse and some alcohol in another spray bottle to pre-dry with. Got the compressor on standby. Exciting!
 
evil 340 said:
What i didn t realize was the shear potentcy of the acid fumes. That **** is nasty and can be trcky to work with. I learned to never use it inside either. Fumes alone can flash rust every thing metal in your shop thats not coated
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Talk about learning the hard way! Yeah, the fumes, the gasses, all of it will do what it does - and acid is an oxidizer so it will MAKE rust - that's why the neutralizing step is SO important.

TSP seems to be used by folks who are using muriatic to clean knife blades of heat treat scale. The phosphate in the TSP reacts with the iron to make an iron phosphate - it would make a very good final rinse/cleanse prior to drying and should prevent the flash rust for a few days and even help prep the surface for primer.
 
verdict: Id use it again in a heartbeat. Needs a good neutralizing rinse with a basic Ph like washing soda or TSP. I spritzed it with evap-o-rust for further flash rust inhibiting. It works great on rust, not 100% on paint as it gets most off but this last rim I did had a few coats so Ill end up wire wheeling it anyway but the acid sure gets the nooks and crannies clean as well as lug nut holes and all the bare metal. They look as cast when they are clean.
 
Yep the mutiatic acid works great, but does require lots of neutralizing steps.

I read about the molasses method called chelation. Once it gets past the rust it stops once it hits bare metal. The muriatic acid does not. It keeps going and will continue to eat steel and cast iron if the parts are left in there too long.

With the molasses theres no noxious gasses to damage your lungs, or cause flash rust to everything near where your working with it since its not an acid, plus its biodegradable whereas the muriatic acid is not.

A simple hot water rinse, and blow dry is all thats needed with the molasses. One gallon of molasses to 9 gallons of water is all thats needed along with time to let it do its thing. Its not as fast as the acid, but works just as good, without the hazmat precautions, and disposal of the acid.
 
If you got the time, Molasses from a feed store does work, so does water with potatoes chopped up in it! The challenge that I found is after the fact. I recommend putting some evapo-rust in a spray bottle and spraying the part after you neutralize it and wash it down. Put it on while its still wet. I did the first one like this and it never flash rusted where as the latter 2 were yellow before I could put the hose away. I painted all 3 now so the rust issue should be taken care of. Still looking for 1 more 14" 5.5" Rallye to complete the set.
 
Did a heap of this rust removal over on the B Body forum, now sorting my Demon out.

Restoring metal parts with Muriatic Acid.

Previous owner lived one mile from the Pacific Ocean. Just did the lid and the clip:


mcbeforeacid.jpg


After an hour in the acid:

mcafteracid.jpg
 
Yup. Works great but really leaves the door open to flash rust if you don't post- treat. Even a mist of WD40 would prevent flash rust on something like the cover and clip that doesn't get handled. Looks nice. Don't know why MC's get so rusty but they always do if left raw.
 
Find some 'LPS 3' spray. It's a heavy duty corrosion preventative meant for medium term storage. It's wax-like, but won't create a sludge or anything, and shouldn't discolor or attract dirt/grit like greases/oils will.
 
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