uncle uncle

I subscribed to "Project Farm", as I find a lot of the experimentation done by the gentleman to be either directly connected to something that might be of use to myself, and enjoy his scientific methods he's devised. Anyway, I think I skipped this video initially, because... because I didn't think molasses would dissolve rust (actually, I'd never heard of it being used that way). Anyway, again, I happened to watch this video today, and found the muriatic acid to be of great interest to the potential job of freeing stuck bicycle parts. Why rust removal is interesting, and rust can be a problem on old bicycles, the corrosion between steel bicycle frames and aluminum bicycle parts is often stated as the likely cause for stuck parts. The oxidized aluminum "swells" and tightly sticks the part to the steel surrounding it. The muriatic acid in the video actually dissolves the rust, steel and aluminum.... I wonder if it would dissolve aluminum oxide? Anyone have experience with it?

Ex Pres 

It's good for removing mortar stains (left by my amateur bricklaying).

uncle uncle

yeah, the only muriatic acid I've been exposed to is the stuff used to clean cement (which is probably way too strong for loosening bicycle parts, but could be diluted).

Sandstrom

I have used muriatic acid to clean rust off of metal before but I wouldn't put it near anything with a paint or plated finish. If you use it please do so outside, the fumes can be quite severe. It is quite powerful in undiluted form and if not neutralized afterwards a film of rust can start to form immediately on the cleaned parts in the open air.

oneclick 

The main difficulty is loosening stuck parts is getting whatever agent you are using into the area that is stuck. Muriatic acid (HCl) removes rust, yes, but if you have a stuck cup in a shell it'll take so long to remove what matters that it might remove something (or a lot of something) else. I like heat + penetrating oil + time.

For bare steel parts HCl works good enough, but there are better ways; the best is electrolytic derusting. You can do a whole frame inside[1] and out with a windshield washer pump and a box lined with a sheet of 6-mil polyethylene. Set it up and come back whenever, when it's done the reaction stops. Moderately rusty car wheels take a day or two.

[1] well not inside of the the top tube (or any others) if it's closed at both ends.

wrk101

Muriatic acid is just a common name for hydrochloric acid. Read an MSDS on it sometime and you won’t use it.

I’m a licensed professional chemical engineer with no inherent fear of chemicals but lots of respect. Home gamers tend to not use nearly enough personal protective equipment when dealing with the more serious stuff.

Lye is another one I see people toss around (sodium hydroxide) is another to be careful with. Worst accident at a plant in my career was with lye. 29 year old employee was blinded, father of two. Life altering. He took a shortcut without prescribed PPE.

Cyclist0108

Yup. I'm just a chemist, but I concur.

desconhecido 

I know enough chemistry to know that I wouldn't want to be messing around with HCl in my garage. I don't know enough chemistry to do it safely.

dedhed

I know enough to not get it near any bleach

machinist42

Isn't that ammonia?

I recently successfully used ammonia to free up a heavily oxidized stem and a seat post too, as ammonia dissolves aluminum corrosion, but leaves steel and aluminum well enough alone. Over a week and a half I first used penetrating oils and then ammonia, and judging from the corrosion on the aluminum posts, aluminum oxide was the sticking point. I used ten and twenty pound weights as impact hammers. After a few days of ammonia, both started to move and the game was won. There was evidence on the posts of dissolved corrosion, but not of penetrating oil. (Sure, the ammonia may have rinsed it away.)

I know Sheldon suggests this but I've not read of anyone having any success with this approach.

It worked for me?



(Both the seat pillar and the stem emerged in functional condition, which really didn't matter too much as they are not of any significant interest. The frame, however, is very interesting and unscathed and so far, enigmatic and unidentified.)

desconhecido 

Either ammonia or bleach, when mixed with HCl, can release chlorine gas.

Back in the old days, we had home economic class for the girls and shop class for the boys. All the girls learned to not mix ammonia with bleach, among other things that they wouldn't tell us about. In shop class, we learned not to goose anybody with an air hose. Both items of importance.

dedhed

https://www.mcgill.ca/oss/article/en...ity/art-mixing

machinist42

Actually, though bleach mixed with HCl will produce chlorine gas, ammonia mixed with HCl will not, rather they neutralize to ammonium chloride, if memory serves?

Ammonia mixed with bleach produces chloramine, which is irritating but not as deadly as chlorine gas?

cyccommute 

Nope. When ammonia is mixed with bleach, it forms chloramine which is somewhat toxic but not as much as chlorine. Chloramine is used in water treatment and pools which gives swimming pools that characteristic odor.

Mixing ammonia and hydrogen chloride will only result in ammonium chloride which is a solid and not toxic. It’s used in baking and is used in salmiak licorice. It gives the licorice a slightly tart taste. (I wouldn’t know from personal experience as I detest licorice.)

Mixing bleach and hydrochloric acid will release chlorine.

I will agree with others that muriatic isn’t something that should be used lightly or by people who don’t know what it is. It’s a strong acid and the concentrations I’ve seen on SDSs from Home Depot say give concentrations of from 20-30%. Concentrated hydrochloric acid for laboratory use is about 35% and is considered extremely hazardous.

desconhecido 

I meant to write that mixing either bleach or HCl with ammonia would release chlorine gas. Still wrong, though.

Sandstrom

Moe Zhoost

You are correct that chloramines give pools that characteristic odor, but they are the byproduct of the disinfection process, not the agents. Having dealt with the long standing complaints of chlorine odors/irritation/and other claimed health effects from staff, patients, and other patrons at a therapeutic pool, I learned much more than I ever wanted to about chlorine odors around pools. A chlorine agent added to pool water reacts to form hypochlorous acid, a strong oxidizing agent, which then reacts to kill microbes, but also reacts with any other nitrogenous compounds present to form chloramines. The primary source of these other nitrogenous compounds is human sweat and urine. If you want to reduce the chlorine smell you have to be firm about hygiene with the pool users. The management folks for the pool that I consulted on resisted addressing this issue with their clients for fear of offending/embarrassing them. Many of these users were not agile enough to climb out of the pool to use the bathroom (and who really wants to leave a heated pool and be chilled by the room air). Many of them were incontinent to some degree. It was a tough problem to solve and I'm not sure they ever did.

There was a research group in Italy that did some work on analyzing pool water for elemental phosphorus as a bio-indicator for urine load. They presented some remarkable numbers of the average user urine contribution. I'd advise keeping one's mouth closed when in a public pool.

uncle uncle

Original poster... and, maybe I shouldn't have even brought up the potential use of muriatic acid as a bicycle part dislodging agent. I was just theorizing that the reason that aluminum parts get stuck in steel bicycle frames is that the two dissimilar metals are subject to galvanic corrosion. The corrosion, or oxidized forms of the steel and aluminum (ferrous oxide and aluminum oxide) end up squeezing the joint more tightly together, because the oxidized materials take up more physical space. So, assuming you have both of the oxidized materials present, which material is the easiest to eliminate (and thus free up the joint)?

machinist42

The trite and useless answer is that the easiest oxide to eliminate is the one which can be most easily accessed.

I use ammonia to dissolve the aluminum oxide and a variety of penetrating oils for the ferrous oxide. Combined with vibration and then impact hammer type application of force, it has worked without fatally damaging a frame or a seat or stem.

(I've been lucky I suppose?)

howie2wheels

I have heard once before that ammonia will dissolve aluminum oxide and I am glad to see this report of success with it. I have a Vintage Norco road bike that I have been bringing back from the brink that has a very stuck alloy stem. I thought that I would cut the stem to pieces and save the nice fork as a last resort. Here's hoping ammonia will do the trick.

cyccommute 

Mostly right but they are called chloramines. An amine is a derivative of ammonia where one or more of the hydrogens have been replaced by something else. They can also be part of a secondary disinfecting agent rather than just a byproduct.

dedhed

Most large drinking water systems have gone to chloramine as the secondary disinfectant due to it's longer lasting residuals and a lesser chance of forming disinfection byproducts like trihalomethanes. Usually by using chlorine as a primary disinfectant and injecting ammonia to create chloramine as it heads out into the distribution system.

unterhausen

has anyone tried an ATF and acetone mix?

wrk101

Yes.

Everything works sometimes. Nothing short of cutting out works all the time.

Moe Zhoost

Thanks for pointing out my spelling errors.