The Stovebolt Site Forums The Shop Area Paint and Body Shop De rusting?? What to use for the best results!

What is the "best way" to de-rust chrome items. Such as grills, hub caps, etc? I have heard and read about Evapo-rust on galvanized, zinc items but does it work on chrome? What about embossed and debossed areas? I have used coke and tin foil and that works good, but man, the elbow work is outrageous! I would think that dipping or submerging items in a solution would be a good thing but am I correct? What type of solution is best? For how long? Any input would be very welcome guys.
Thanks all, as always!
CJB Chevy53

I used vinegar for small parts, you might want to check that out. Time is relative to temperature so I can't say how long to keep it submerged. I'd start with a couple days and then check every day thereafter.

Thanks Czechman! I have heard vinegar does good and will give it a try, soaking for several days.
Best regards, CJB

Here are some tips from the Archives at SBHQ.

http://www.stovebolt.com/techtips/rust/vinegar/index.htm

http://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm

http://www.stovebolt.com/techtips/rust/evaporust/index.html

http://www.stovebolt.com/techtips/rust/rust_molasses.htm

http://www.stovebolt.com/techtips/rust/zerorust/zerorust.htm

I bought a concentrated product several years ago that you mixed 10:1, in other words 1 gallon made 10 gallons of remover. It worked for a few items and then quit working and I was out about $75 for the gallon of concentrate.
I just picked up a quart of Evap-O-Rust for about $10 the other day, just to try; I'll bet it's the same stuff that I had used before. I haven’t seen any mention in any of the advertisements that address the longevity of the chems. A gallon of the Evap-O-Rust runs about $30 so to fill a tank with 10 gallons of it like I did with the other concentrate would be an expensive experiment for something that's only gonna lasts a few parts.
The other thing that is never mentioned is that it does not remove all the rust; it converts it to a black smudge, which has to be buffed off just like you have to do with the rust. The smudge comes off easier than the rust so if you have deep rust these chems might come in handy but for light surface rust where it isn’t pitted to deep I've found that just wire brushing is just as good as soaking.

Denny Graham
Sandwich, IL

For my son's science experiment, we tested Coke, Vinegar, 50/50 water and phosphoric acid, and lemon juice. We used some rusty bolts off my truck and repeated the experiment 3 times. The 50/50 phosphoric acid removed rust the best, but incredibly lemon juice was very close behind and was better than Coke or vinegar. I couldn't see using the lemon juice on larger pieces (too expensive and too much squeezing), but it was interesting.

Don't know if Phosphoric acid would cause problems with chrome, but you can get a gallon for $15 at Home Depot.

Good luck.

I do have a few gallons of Phosphoric acid that I pick up a couple of year ago at one of the big box stores. I haven't tried using it yet, I'm not a chemist and when I see the word acid on somthing it scares the bajebers out of me. I'd use it in fact I've got a couple of kits from Caswell that I'd like to try. The only hang up I have is what to do with it after I'm done with it. Never found anyone that could give me a straight answer on that one.

Denny Graham
Sandwich, IL

Denny - phosphoric acid is non toxic, it's only really corrosive in concentration, and easily diluted in water - cripes, it's even used in food and in your mouth by the dentist - inquire from these folks re disposal, laws vary by jurisdiction ... one of the good things about it is it can be reused almost indefinitely for derusting, as long as it hasn't been diluted with too much water, all you have to do is strain out particulate and move on to the next item, keeping it in a closed container between times .... it can be neutralized with sodium carbonate [the stuff you use for electrolytic derusting!], but well diluted it can really just be dumped

Bill

Look at the ingredients on the side of any soda can... Phosphoric acid. I use it quite a bit on parts here and there. I get it on my hands without any issues, though it does sting a bit if I have a cut. Pretty harmless... that is until they find it causes cancer in 10 years from now!

phosphoric acid and copper wool pad to scrub with.

I read about the electrolytic derusting here on the stovebolt sites "Tech Tips". ( http://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm ) Very interesting! Is there a limit to size that this could be taken to? Could I create a small tank (matter of defination) big enough to set the bottom of a cab into? Perhaps I could shift the cab around onto its sides, back, firewall, etc. so I can get the whole cab?

Any thoughts?

Walt Williams
La Verkin, Ut

yes you can make the tank as big as you want Walt

Bill

Okey dokey, Ya talked me into taking the plunge into the acid bath. I had three gallons of Behr #991 Concrete Etch & Rust Remover that I’d mentioned earlier. I used a Rubbermaid storage container to soak some parts in. My main confuser crashed the first of the week with half the pictures so that delayed my posting my findings. But here is some of what resulted from the experiment.
This is the sliding yoke for the drive shaft off the ‘54, 3600 as it came off the truck: http://www.pbase.com/dennygraham/image/131015814
A couple of hours in the Behr bath, a scrub up in the sink and then a light buffing on the fine wire wheel (just a couple of minutes worth) and a final paint job with Eastwood’s Extreme Chassis Black. This shows the steps and the end result: http://www.pbase.com/dennygraham/inbox


The fan blade was about as bad as the yoke.
http://www.pbase.com/dennygraham/image/131017629
But after about two hours in the bath, while I was doing some other things,
http://www.pbase.com/dennygraham/image/131017622 ,
it came out looking like a newly made part ready for paint.
http://www.pbase.com/dennygraham/image/131017617
Again, Eastwood’s Extreme Chassis Black.
http://www.pbase.com/dennygraham/image/131015821

I’m so dang excited about this now that I ran out yesterday and got me a 42x22 Sterilite 50 gallon container which is big enough to submerge the upper or lower baffles in. http://www.pbase.com/dennygraham/image/131017632/large Now all I have to do is find a reasonable source for about ten more gallons of Phosphoric Acid and put an ad in the Reporter, 'Graham's Redi-Dip', you strip it, we'll dip it!

A note on that Behr #991: http://www.pbase.com/dennygraham/image/131017826
The old black container reads “Concrete Etcher & Rust Remover” and was labeled; Caution; contains Phosphoric Acid.
The new gray container reads “Concrete & Masonry Cleaner/Etcher” and is labeled; Caution; contains Organic Salts.
Although the product #991 is the same, the new stuff in the gray jug doesn’t seem to be as strong as the old stuff in the black jug.

Denny Graham
Sandwich, IL

Denny, you been snookered, there's no phosphoric acid in it if it's not on the MSDS sheet, and it's not - no tellin what "Organic Salts" means, but in chemistry a salt is a type of compound, and I suspect in this case that would be some form of Citric Acid, a much more benign thing used in various cleaning formulas nowadays .... need to find the real deal

Bill

...So the Black jug IS better than the grey jug just as Denny suspected.

And you are absolutely correct Bill, I've been snookered. I just got off the phone with customer service at Behr in Santa Anna, CA. They took the phosphoric acid out of the formula about nine months ago and they no longer make any products that contain it.
So, like I said, "Now all I have to do is find a reasonable source for about ten more gallons of Phosphoric Acid."
And it worked so good too, good thing I didn't pour the gallon of new stuff in with the old.

In their favor, Behr is going to reimburse me for the $21.53 that I threw away on their new formula.
Denny Graham
Sandwich, IL

good on them for proper customer relations! I suspect the real deal [actually Ortho-phosphoric acid] is getting harder to find, but it is still used as a "metal prep" under various brand names

look for one called OSPHO at paint suppliers or marine supply places - and here's one [in PA] that has a 5 gallon size, and one in gallons - what you want is 75-85% acid, usually they'll say to dilute with 2 or 3 parts water .... POR15's Metal Ready is a very dilute phosphoric acid, less than 10% I think meant to not be rinsed off

Bill

I now use PPG DX520 and have used DuPont 5717s 224s for many years but they're not what you want to use for a de-rusting tank. It would cost you $1,000 to fill a 10 gallon tank up and they are usually a weak mix to begin with.

Ospho is one of those chems that contains phosphoric acid but it just converts the rust and leaves a nasty hard black crust on the metal that you can paint over. Besides, it’s about $40 a gallon in case lots.

Rust-Away is fairly expensive also at $33 a gallon. But, looking at the MSDS it says that it contains 75% phosphoric acid. So that might be a possibility.

What I’d really like to find is about 5 or 10 gallons of that Behr stuff in the old black jugs for $12 or $13 a gallon which is what I paid for it a couple of years ago.

Denny Graham
Sandwich, IL

I have used the "must for rust" from tinman tech. you can buy it other places also. the last stuff I got was kleen strip phosphoric acid and prep, from home depot or Lowes can't remember which.

Denny - OSPHO is 75%, the reason it's pricey, and like any it will act as a converter IF you use it like a paint prep - still a rust remover if you soak the part in it, and when soaking it can be diluted with at least 3 parts water, then if you return the solution to a closed container it can last as long as you'll be cleaning parts .... if you want cheap it'll always be a very dilute solution - unless it's a brand name, which will never be cheap - the DX520 is 7-13%, even DX579 is only 30-40% ... also I've heard even PPG doesn't recommend using DX520 anymore

Bill

PPG seems to be going thru a bunch of changes of late. My dealer is telling me that they are dropping a lot of the old paint systems. I liked to use Dupont years ago but their dealers got fewer and fewer so I started using PPG paints a few years ago and it looks like they are begining to loose it. I just bought some enamel for the '54 from Serwin Williams and found them quite helpfull and easy to deal with.
Yes the DX520 is a dilute acid, it's not really made to remove rust, just as a surface conversion treatment. And it works good for that. I treat all the bare metal that I shoot with it. It etches the surface slightly and turns it a soft gray while it works.
The Behr really worked great. I've been thinking seriously about ordering 5 gallons of the Rust Away to add to my three gallons of Behr stuff which isn't quite as potent. As you can see in the one picture of the upper baffle, I had about a foot of it in the tank that I was using. It not only cleared up all the rust spots around the lip and bolt holes but also took the e-coat off as well. Looking at the MSDS for the Rust-Away I see they list Hydrocloric acid also.
I still feel real uncomfortable using this stuff. Not sure just what to to with it when I'm thru with it. I've got a septic system so I can't pour it down the drain and I don't what to poison the live stock.
Denny Graham
Sandwich, IL

...mix it with your old oil and take it to the recyle center. It'll eventually get cooked off.

oil recyclers get a bit torqued about folks contaminating their used oil collection system with dirty solvents Chip, especially water based, not a good plan

it really is very water soluble and totally non-toxic in dilution, it's used in hundreds of different food and pharmaceutical products, just dilute it a lot and it won't do anything more to your septic system than the dregs of your old pepsi and dr pepper, or dump it on the lawn and watch the fertilizing effect farmers pay big bucks for ... at the same time there is no reason to 'get rid of it' unless/until you're never going to clean any metal again, just strain out large particles, keep it in a closed container and reuse as/when needed

most of the reason for brands changing their formulations is both demands of auto OEM changes and the EPA tightening up on controls of any chemicals, over a certain percent, any acid is considered 'hazardous' and is subject to shipping restrictions as well as workmans comp regulations, not to mention liability issues - when folks misuse things, for some reason it's the makers fault

Bill

Oh I’m planning on a few more trucks Bill, god willing and if the creeks don’t rise, so there’s a lot of rust in my future. That’s the only reason that I’m even thinking of putting a couple hundred bucks into chems for stripping. My only concern was that one day I may spill some or have to get rid of some for one reason or another.. I’d hate to think that one of my four legged buddy‘s got hurt because of my mishandling the chems. Don’t know if I’d buy the bit about pouring it on my lawn, this stuff is turning the news paper I’m draining it out on dark yellow. Yes it is used in the food industry but I’ll bet it’s in VERY, VERY dilute proportions. Phosphoric acid is not all that is in the formulas, the MSDS’s also list glycol and alcohol and as I mentioned, the Rust-Away lists Hydrochloric in its formula, I don’t think the lawn would like that very much.
I also agonize over antifreeze every time I drain a system. Don’t like to pour the old stuff back into fresh engines and I never know what to do with it and never heard of a workable solution. I’ve never been able to fine a recycling center around my area that will take chemical waste. Ken here has a set up for filtering and recycling it but he’s a way down near the border.

The waste oil, old gas and the kerosene that I use in my gunk tank all goes to a few oil burners in the truck shops out here. They’re glad to have it in the winter time. But your right, I wouldn’t be to welcome if I started contaminating it with antifreeze or acid.

Speaking of four legged friends, I gotta go tend to the live stock.
Thanks for the input.
Denny Graham
Sandwich, IL

I understand your concerns Denny, I use any chem sparingly and try to avoid combinations when one thing will do the job, and I favor the least problematic approach, which for de-rusting I think is the electrolytic process - partly cuz I get sodium carbonate in 20 kilo bags to use as the only additive [water softener/surfactant] in my big ol antique bottle washing machine, but also I know disposal isn't a problem .... disposal of phosphoric acid really isn't a problem either, well diluted

the hydrocloric acid in Rust Away [in parts per million] is no doubt there for it's pH adjusting quality, the same reason it's used in swimming pools and municipal waste water treatment, and in many pharma processes including the production of the ascorbic acid supplements many folks commonly ingest - not a good thing in large quantities used indiscriminantly, but not evil by name the same applies to the glycol and alcohol, very innocuous in dilution, but be suspicious of them being non-specific, glycol is closely related to alcohols, but there are many forms of both compounds [and note ethylene glycol is the toxic 'sweet' antifreeze, propylene glycol is the non-toxic one]

consider another product some folks use for de-rusting: "vinegar", strength unspecified ... the easily obtained cheap form is 5-6% acetic acid and is commonly consumed as table vinegar - it's also available in strengths up to about 25%, called 'horticultural grade', used for a variety of things [EPA controlled if labeled as a weed killer/pesticide, otherwise FDA!!] and no doubt would work better for de-rusting [de-scaling actually, like the rust stains in the coffee pot], but while the table variety wouldn't affect you much if applied to your skin, you really don't want to get much of the 25% grade on you, and latex rubber gloves are no protection against high concentrations .... low concentrations top kill weeds/grass, but the roots aren't affected and re-growth is fast, high concentrations kill the roots as well, mostly by the extreme pH effect on the soil, and regrowth is much delayed but natural flushing restores pH soon enough - acetic acid is also a very good concrete etch, as a producer of vinegar I can testify even 6-8% will dissolve the lime out of the surface of a high pressure, polished slab so is vinegar a danger? depends ...

just 'food for thought', cuz of the thread title

Bill

Denny, I sent you a PM.

I'll make the pitch for electrolysis. You most likely already have the components around the house and garage. You can find the "chemical" component already residing in your pantry or refrigerator. Or, remove rust, oil, grease, AND paint by using a sodium hydroxide (lye) solution. The lye eats the paint off, and the electrolysis steals the paint.

I have de-rusted many a part this way and will work as long as you can fit the part into the non-conductive container. My favorite success story was my radiator shutters for a 1944 B John Deere that were very rusted. The shutters work just like venetian blinds to help heat up the engine temp so that you can switch from gasoline to distillate fuel faster.

After a month of soaking with penetrating oil, no success. At my wits end and about to just throw them in the heap, I ran across this process. I dumped them in and in 3 hours, I pulled them out and was able to operate the shutters by hand! i couldn't even start to twist them with pliers before. Again, you can reuse the solution as many times as you want.

I was ageing paper for reproduction radio labels. I needed a yellow brown blotchy paper to print the labels on. I would take a quart of table grade cider vinigar and stuff a steel wool pad into it. After a few weeks the pad would desolve completely into solution and I would soak white paper in it, dry it and then iron it. Looked like it was 80 years old.
Never really gave it the rust test.

DG