How to remove concrete residue from plastic

I have a couple of those
http://igor.chudov.com/misc/ebay/tmp/J-G-Porter/133.JPG
They have white concrete on them, some solidly stuck. How can I remove
it safely to restore the good looks. Thanks
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On Sat, 10 Dec 2011 18:39:40 -0600, Ignoramus20184

Ugh. If you're brave, muriatic acid should do it.
--
Ed Huntress

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My first approach would be diluting some phosphoric acid (etchant for automotive primer, metal-prep). Mix in a Labeled trigger spray bottle, and wet the residue, checking adhesion and re-wetting as needed.
I believe the muriatic would work, but it's a much nastier product to have around machines.
Some of those tile cleaners like lime-away (can't recall the one with 3 letters), which contain phosphoric acid may be effective, too.
When the residue begins to release, a stiff bristle brush would likely remove most of it without stripping off the epoxy? case paint.
--
WB
.........


"Ed Huntress" < snipped-for-privacy@optonline.net> wrote in message
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But don't forget the heavy rubber gloves. While muriatic acid (which is largely hydrochloric acid) isn't wildly dangerous, it will take your skin off if you let it.
And also use goggles.
Joe Gwinn
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Ignoramus20184 wrote:

(concrete saw)

The most "safe" and expensive way is to use a liquid product called "Concrete Blaster":
http://www.euclidchemical.com/product_detail.asp?id38&pselect17&cselect32&tselect07
http://www.detco.info/database/detco_products_database_view.php?editid1S1
Designed specifically to remove cured concrete from construction equipment.
Might be a bit tricky to use on your saws.
I'd soak a towel in the stuff and then wrap the towel around the saws.
That stuff is moderately expensive.
If you're more adventurous, I'd use muriatic acid (Home Despot sells it by the gallon last time I checked). Cut it 50-50 (or more) with water - and then use the towel method.
But keep it away from any shiny metal, because the acid will take the finish off.
It's best if you can remove all the plastic parts and dunk them by themselves into the acid.
Any non-shiny metal parts that have dried concrete on them can be dunked in acid - just don't let them sit in the acid for a long time (more than 10 minutes).
If you use muriatic acid, wear a good filter-mask (with cartriges) because the fumes will sting your nose.
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The MSDS says it's hydroxy acetic acid. It's been a looong time since organic chemistry, but I think the hydroxy part suggests that it's acetic acid (vinegar) that's been partially neutralized.
If any of you chemists are reading this, what's the significance of the hydroxy part of the description. I know it's an OH group, but how does it change the action of acetic acid?
RWL
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GeoLane at PTD dot NET <GeoLane at PTD dot NET> fired this volley in

It's relatively a weak acid, although concentration counts. It's generally safe to make contact with skin in _very_ diluted form, although it will slowly dissolve the epidermis. It's better known as glycolic acid, and sometimes incorrectly as "fruit acid" when used in cosmetic chemical peels. It gets this moniker from being available naturally in some acid fruits (but not citrus), like pineapples.
It's not "partially neutralized acetic acid", but can be derived from acetic acid by first neutralizing it with an hydroxide, then re- acidifying the salt.
Most any acid you can buy will slowly dissolve concrete, even though it's not a carbonate, but primarily a sulfate. Muratic acid will do, and is probably a whole lot less expensive than glycolic acid. The most common "etch" for concrete is oxalic acid, but it's dangerous, poisonous, and pretty damaging to human tissue.
LLoyd
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On 2011-12-12, Lloyd E. Sponenburgh <lloydspinsidemindspring.com> wrote:

Vinegar should work nicely, no? If so, I will just remove the panels and put them into a bucket with vinegar.
i
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yeah, but at 5% acidity, it'll take a long time.
A bottle of concentrated muratic acid, diluted in water (acid into the water, not the other way) to about 25% will work a LOT faster.
LLoyd
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Lloyd E. Sponenburgh wrote:

Yeahbut, do it outdoors and stay upwind of it.
Whoof!
--Winston
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wrote:

Yeah, takes your breath (and burns off cilia while melting mucus membrane) away even at the recommended 10%. The recommended dilution works immediately, too, so there's really no need for a stronger batch. Used on a floor @ 25%, I'm certain that it would do more damage than good.
-- Do not let your fire go out, spark by irreplacable spark.
In the hopeless swamps of the not quite, the not yet, and the not at all, do not let the hero in your soul perish and leave only frustration for the life you deserved, but never have been able to reach.
The world you desire can be won, it exists, it is real, it is possible, it is yours. -- Ayn Rand
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On Mon, 12 Dec 2011 06:45:40 -0600, "Lloyd E. Sponenburgh"

Concentrated muriatic (hydrochloric) acid is about 37%. Pure HCl is a gas. Dealt with hydrochloric quite a bit at work. Aqueous isn't that bad, although it'll sting like a bitch if you have a cut. Worst mistake I made with hydrochloric was using chlorinated solvents on my back porch with an unvented water heater in the vicinity. Had to replace ALL the stainless wire rigging on my sailboat after exposure to the resulting fumes. Mast and boom were hung on the back porch.
Nitric and sulfuric are bad and will burn skin in an instant, concentrated sulfuric wants water so bad, it'll remove water from sugar, starches, or your hide, leaving the carbon. Hydrofluoric is worse, I don't want anywhere near that stuff, although it is found in some fluxes. Worse for eyes than the normal acids are alkaline materials like lye, or worse, ethanolamines.
Be careful out there.
Pete Keillor
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correct, and by 25% dilution, I meant to cut the acid 25%/75% with water.
A roughly 10% solution of HCl is much more vigorous than a 10% acetic acid solution. Even (almost) glacial acetic acid is not all that scary to handle. Used to mix my own photo stop bath from scratch.
LLoyd
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On Sat, 10 Dec 2011 18:39:40 -0600, Ignoramus20184

Sell it to me with the nasty stuff still on it... Seriously, was in my local HD today getting prices on rentals etc of one of those.
--
William

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Ignoramus20184 wrote:

Can you get the plastic covers off? If so, just leave them in a bucket of water with a little vinegar in it. I guess a LITTLE muriatic acid would do the same. Soaking in even mild acid over time turns concrete into mush.
Jon
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Looks like a thin layer on the covers. Perhaps a few times in and out of a freezer will let the plastic and concrete expand at different rates, getting it to loosen. A few sharp taps on a concrete floor and you're done ... Maybe ...
--
Best regards
Han
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On 12/10/2011 7:39 PM, Ignoramus20184 wrote:

A wire brush, of course!
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Others have suggested acid, but thats probably not concrete that set in place. Thats a concrete wet saw, so the white stuff is just dust from old concrete that dried on. I bet warm soapy water and a nylon brush will take that right off. A little vinegar couldn't hurt.
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On Dec 10, 7:39pm, Ignoramus20184 <ignoramus20...@NOSPAM. 20184.invalid> wrote:

its a commercially used tool, it needs to look decent, but doesnt need to look brand new.......
if your reselling it you might price new covers
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Gunner Asch wrote:

Why don't you read what others have posted here on the subject before you put your foot in your mouth?
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