way to goo hydrochloric acid?

[coppercone2]

I want to restore a wheel barrow that is caked in cement. For shovels I usually pour a bit of HCl on them periodically and let it dissolve.  Then I wash and wire brush then sand/grind to bear metal (to remove the HCl absorbed layer). It comes off with very light brushing once its been attacked by the acid.

Because the wheel barrow is large it would take a prohibitive amount of acid solution to fill it up. Is there something you can mix it with to make a corrosive goo that can be smeared (like phosphoric acid) and then covered with some saran wrap ? (It usually takes a while).

I know I can grind/bang it off, but caked cement tends to destroy angle grinder accessories rather quickly. I would rather get it to corroded metal then clean it off. It needs to be cheap because a wheel barrow is hardly worth restoring. If I have to grind the cement off its a lost cause because it just takes too long even if I had free accessories. I also don't want to be banging on it with a chisel for 3 years. It's very old cement and from the other stuff I restored from the same 'lot' its a complete mother fucker to do with any way but HCl.

Don't care if it rusts because it will be grinded and polished afterwards.

I thought about filling it with rocks to act as a volume filler but they will probably react and degrade the acid. I also don't want to deal with a full wheel barrow of acid solution.

A solution might be to pour some acid, lay down a garbage bag and top if off with rocks like a pie crust to act as a volume reducer but its still a PITA. I would like a brushable goo. And it probably has holes that need to be welded anyway, so it will leak and make a corrosive mess once it breaks through.

[KL27x]

I know I can grind/bang it off, but caked cement tends to destroy angle grinder accessories rather quickly.

Diamond?
https://www.google.com/search?q=DEWALT+DW4772T&oq=DEWALT+DW4772T&aqs=chrome..69i57j69i60j69i61.978j0j8&sourceid=chrome&ie=UTF-8

I would fill the whole wheel barrow with as much water as it can hold and just add a little acid. Like 1 gallon acid to 20 gallons water. And let it sit for as long as it takes to weaken the cement. If it's fairly fresh, it might not take too long. Hopefully the steel doesn't spring a leak, first. 

You can buy jellied phosphoric acid by the barrel. It's called naval jelly. I don't know if that is what you want, though. I think water is the key ingredient for this. Low pH water. The acid shouldn't get used up very much. Just keep the water level high and the pH down below 3, and wait.

[SeanB]

Buy a few gallon jugs of vinegar, some Psyllum husk ( or gelatine, agar or any other cooking gel agent) and make the gel using the vinegar. Apply to the surface and cover with some plastic, and leave for a day or two. Check every day and apply more as needed, and the cement will be removed  without much work after this treatment. Acetic acid is a milder acid than HCL, but is cheap, readily available and will not degrade the gelling agent much. Will not do much damage to the steel either, and will pickle it for you as well.

[taydin]

I would use a 4" paint brush and paint the concentrated HCL on it. Then pressure wash it off.

[coppercone2]

from experience I found that it does not seem to work so good if its just 'wet', you need to have kind of a layer going on. It fully-reacts too quickly even if you use 30%. If it was small I would not mind re-coating it a whole bunch of times.. but I think you understand that the idea of restoring a wheel barrow is kinda heinous. Also using a full gallon of acid is too much! This job is worth like 5$ max.

I think I tried vinegar on the shovels before and it had little effect. I had to go out every couple of hours, scrub it a bit and pour fresh acid.

I know its hyper-low budget, but its one of those things where if I spend the money on it I will be really questioning myself later (because its functional, just looks like shit). I have a feeling if I go past 10$ + all the work, I will be thinking I should have trolled craigslist or something instead. 10$ is the cost of a bottle of acid from lowes.

Maybe I will give the gelatine/acetic acid another try, with some saran wrap on a patch. Don't think I ever tried covering it before, but I did not care too much when I used 1/2 an ounce of acid from a gallon bottle.


Can you maybe fortify the gelatine/acetic with some HCl or is it going to eat the jello?

Cost wise, this is the most irritating decision to decide how much money to put into this job.

[coppercone2]

I know I can grind/bang it off, but caked cement tends to destroy angle grinder accessories rather quickly.

Diamond?
https://www.google.com/search?q=DEWALT+DW4772T&oq=DEWALT+DW4772T&aqs=chrome..69i57j69i60j69i61.978j0j8&sourceid=chrome&ie=UTF-8

I would fill the whole wheel barrow with as much water as it can hold and just add a little acid. Like 1 gallon acid to 20 gallons water. And let it sit for as long as it takes to weaken the cement. If it's fairly fresh, it might not take too long. Hopefully the steel doesn't spring a leak, first. 

You can buy jellied phosphoric acid by the barrel. It's called naval jelly. I don't know if that is what you want, though. I think water is the key ingredient for this. Low pH water. The acid shouldn't get used up very much. Just keep the water level high and the pH down below 3, and wait.

You know I have some diamond wheels, but they are pretty expensive. I normally think of diamond as friable, and that it should not be used on masonry covering metal. I think it might get quickly destroyed because its going to be banging into steel half the time. Those cup wheels are EXPENSIVE compared to the wheelbarrow. I have planned actually kinda profitable uses for my masonry tools, I don't want to wreck them on stupid shit.

I also don't like using harbor freight accessories in a grinder, all my stuff comes from the welding stores and decent companies, so I end up having a different philosophy of use with my angle grinder then harbor freight people that are not scared of 10k rpm explosions.

I do have mixed metal/masonry capability diamond cutter wheels, but they are expensive and I reserve their use for using in jobs that are difficult to use the shield with that are an explosion hazard, for metal, rather then to wear them quickly. Like the lenox or milwakee metalmax ones.

I think unless you get good objects to restore, or use the cheapest consumables and paint, its kinda hard to stay in the green financially when it comes to home restorations.

[Peabody]

Maybe heat on the bottom from a propane torch would break it loose.

[coppercone2]

Yea thermal is an option, I will try that. I also thought to start a fire inside of it, cover it with something so it heats up and hit it with a garden hose, but I was scared the metal might break.

Any ideas about this?

Heating it from the bottom is a good idea though. To avoid the masonry insulation. I could not do it with shovels because they were coated from both sides. The wheel barrow is not so bad on the outside.

[Ian.M]

So now you want to do it on a $10 budget?   Anything that can stand up to hydrochloric acid and form a gel with it is likely to cost you far more than that in the quantities you need. Most organics are right out  -  your stomach secretes 0.5% hydrochloric acid *because* it digests them!  Your best bet is the volume reducer idea - heavy PVC sheet then put in enough gravel to hold it down, maybe with blocks of polystyrene in the middle to keep te total weight manageable.

[coppercone2]

the problem is that I am pretty sure once the concrete dissolves a little bit you will sprout a leak. My confidence is low that it will have hull integrity. I will probably have to do some filler welding.

Maybe if I can soak it into something, like old fiberglass insulation. I can neutralize it with baking soda in a barrel later.

[coppercone2]

And yes, you have to keep the costs low on this job or I will feel insane spending money and time on it

I don't know how else to appraise it. There is a cost of disposal I guess. It's kind of a wild card because I never had a nice wheel barrow before. I noticed when I restored some of the shovels and rakes etc cosmetically I was more inclined to do yard work because I felt more professional.

[taydin]

I also like the torch idea I know from experience that it works. Tried to oxy acetylene weld steel on a concrete floor and the floor exploded into my face 

[T3sl4co1l]

Yea thermal is an option, I will try that. I also thought to start a fire inside of it, cover it with something so it heats up and hit it with a garden hose, but I was scared the metal might break.

More likely it's mild steel and it'll just take one hell of a warp after that.

It's a process used by metal finishers -- heat and shock-cool a panel in a particular area, to raise or lower a bump.

Tim

[KL27x]

You know I have some diamond wheels, but they are pretty expensive. I normally think of diamond as friable, and that it should not be used on masonry covering metal. I think it might get quickly destroyed because its going to be banging into steel half the time.

Depends on the type of tool. The diamond saws and the cup grinders like these are steel embedded all the way through with large chunks of diamond. Other tools that are used for face-grinding might have just a thin surface layer.

The friability might be a concern, but I have been led to believe that the larger issue is that at a high enough temp (like what you get with the surface speed of a grinder) diamond slowly dissolves in steel, or so I have heard. And, anyhow, the steel matrix won't grind away if you are trying to cut/grind steel, so it will just load up with steel and stop cutting, and you've have to clean it off by grinding on some rocks. If I had a diamond grinder like the one I linked the pic, I would feel safe to use it for this. I wouldn't intentionally try to grind or cut steel, but incidental contact is not a big deal. They are used on hard concrete and granite, I don't think your wheel barrow steel is going to explode the diamonds.

The cost might seem high for one disc, but i you owned one, you would know. They're free compared to the elbow grease that you would use up in wearing one out. Then there's the dust masks/filters/lung health you will use up.

[Psi]

Mythbusers method to clean cement out of a cement truck.

[StuartA]

I worked for a company which made gelled nitric acid. That was done by mixing in ultra-fine silica powder to a concentration of about 5% by weight. In the US, the trade name for that silica is Cab-o-sil and it's used in huge quantities for thickening food-stuffs, cosmetics etc. Unfortunately, I think it's only sold in 10kg bags (it's so light that 10kg fills a paper sack about 4 feet high). The silica is not difficult to use but it's damn difficult to get rid of any you don't use; do not try flushing it down the toilet!

S

[coppercone2]

Oh yea cabosil. I was thinking about powdering silica gel I got.

Cabosil is fun stuff, it flows very freely in the jar when you rotate it. Just like water, if its dry enough. Weighs next to nothing for its volume. You can buy 1lb from fireworks supplier easily. It's sold for fluffing up flash powder (to counteract how 'sticky' flake aluminum is. I also think it spreads it out a bit so it burns faster.  As far as free flowing powders go, its the best I have seen.

I don't have any on hand on the moment, I always wondered what cab-o-sil would do when mixed with epoxy. Kinda like the milled fiberglass sold as a filler.

What is gelled nitric acid used for? Passivation of big things?

[StuartA]

What is gelled nitric acid used for? Passivation of big things?

Highly concentrated nitric acid was used as a rocket propellant in various old missile systems like the US Lance missile. Problem was if a round went through the propellant tank...it spoiled everyone's day. The US Army and the Brits explored the possible usage of gelled nitric acid, formulated to be thixotropic, but it never made it in to service and Lance was withdrawn in the Intermediate Nuclear Missile Treaty. But as that treaty went down the toilet last week...who knows?

I think I have seen products for both acid pickling and acid passivation formulated as gels, but I've never worked with them.

S

[coppercone2]

lol, i wonder if you can gel hydrazine

https://patents.google.com/patent/US3077072A/en

[StuartA]

The US Army was gelling monomethylhydrazine (MMH) nicely, but simple hydrazine is quite easily decomposed and pretty much anything you add to it will catalyse the decompostion. The Army was happy with that because the freezing point of hydrazine (~0'C) is much too high for use in a weapons system whereas MMH has a much lower freezing point.

The big problem the US Army had (has) is that the US Navy has vowed never again to allow liquid rocket propellants on board its ships after some bad accidents in the past, so if the Army did want to go that route, they'll need their own transport.

S

[coppercone2]

Thats interesting. Bit of checks and balances between the branches to prevent something completely insane from being implemented.

Maybe the space force will help keep space clean from particulalry bad weapons eventually. Imagine us marine controlled space command 

https://www.globalpolicy.org/component/content/article/168/37792.html

[StuartA]

Small nuclear missiles of the Lance type are really scary because they end up being controlled by very junior soldiers. Also, it's hard to keep track on them, which explains how they came to be in Cuba in '62 and nobody in the US knew about them. So, everyone's telling JFK "Invade!" and that might have gone so badly  .

S

[coppercone2]

yes all those small demolition charges and missiles are a bad idea, you need the equivalent of a medium sized office to agree to use the current weapons. If you have artillery rounds and other crap... some base could be attacked and someone can freak out and use it.