My goal is to assist you in looking at the elegant roads, driveways, and patios that characterize facets of hardscape design.
How to Remove Dried Concrete
Applying a concrete dissolver is one tactic used to soften old mortar on masonry tools, equipment, and vehicles. Its mild acid and foaming agent also dislodge unwanted concrete deposits from glass, metal, most plastic, painted and wood surfaces.
While preventing buildup while you work is the best defense, you cannot always do so.
Why Do I Need a Concrete Dissolver?
It's one aspect to clean masonry work and another to clean those implements used for masonry work. A concrete dissolver (CD) addresses the latter.
Start by asking the major question.
What is your problem?
- Are you in the middle of a patio project with smears of concrete and mortar all over the place? On your mason's trowel? On the tires of your wheelbarrow?
- Did your father just tile the bathroom and his pointer is filled with stiff grout?
- Are you siding a wall with stucco and finding that your floater is loaded with solid guck?
- Did your ready mix batch get poured in some unwanted spot?
- Did concrete splatter harden on your window and window frame?
- Did your new apprentice unintentionally let slop infiltrate and dry up items in your staging area?
"Use the right kind of cleaning procedures for the specific masonry materials being being cleaned."
— Portland Cement Association
What Is the Overriding Reason?
You have two choices: Throw out sound tools or clean and restore them. You invest a lot in tools and equipment. Save money by taking care of them. Clean tools work better with better results.
Masonry instructor Kreh notes: "As soon as tools and equipment are no longer being used, they should be washed off with water to remove all concrete. If left to harden, the concrete is difficult to remove and can rust or pit the metal parts." That's when a concrete dissolver helps.
How Does It Work?
After spraying the solution foams up. Chemical components break up concrete and mortar by separating the bonds that hardened it in the first place.
Given enough dwell time (15–30 minutes), simply wipe or rinse off any mushy remains. Especially caked splotches might need a second try. Repeat the process before the first attempt dries.
Where Does It Work?
It works on tools, equipment, vehicles, and non-concrete places that accidentally get smudged with concrete splashes and mortar smears. Here are some examples:
Wherever Concrete or Mortar Might Harden
Buckets, brooms, brushes, hoses
Floats, jointers, mallets, pointers
Cutting & Shaping Tools
Brick hammers, chisels, wet saws
Compactors, diggers, rakes, tampers
Measuring & Layout Tools
Levels, squares, tape measures
Aluminum, carbon steel, stainless steel
Scaffolds, tongs, tool buckets, wheelbarrows
Mortar boxes, mortar hoes, mud buggies, shovels
Glass, most plastics, rubber, wood (& painted wood)
Cars, forklifts, ready-mix trucks, trailers
Where Does It Not Work?
Since a concrete dissolver disrupts the bond property that hardens concrete, you would not want to soften areas that you want to remain strong and supportive. Therefore, do not use it directly on concrete or mortar joints between brick or block. Marble, granite, laminated, or zinc are also no-no surfaces.
CD does not work if you pre-rinse (preset). That only neutralizes it. For this reason, if you clean your tools on a concrete floor, first cover the floor with plastic or rinse it with water beforehand to nullify effectiveness.
If in doubt, check with resources. Carefully read the product label and the Safety Data Sheet (SDS). Better yet, talk to a real expert at your building supply or home improvement store.
Is a Concrete Dissolver Safe? What's in It?
Yes, it is safe for you and your instruments (tools & equipment).
The main ingredient of many CD solutions is a mild acid (from fruits and vegetables) along with trace wetting, buffering, and foaming additives. A full-dose concentrate must be diluted with water, whereas ready-made versions can be used immediately. A spray cap is an easy-to-apply option.
This restorative cleaner is also:
- Stable (Foams in place & does not run)
- VOC compliant (does not emit harmful vapors)
*It better performed against two harsh acids (phosphoric & hydrochloric) in a series of metals testing on carbon steel, stainless steel, and aluminum.
Consider These Precautions
- Read product label and manufacturer's SDS (Safety Data Sheet).
- Be aware of first-aid tips before necessary.
- Wear personal protection gear.
- Cover unwanted spray areas with plastic.
- Do not preset, which means do NOT rinse with water first.
- Test before first application. Spray on an inconspicuous area to see what happens. Just to be sure. An ounce of prevention is worth a pound of cure.
Supply List (optional*)
Container of CD (concentrated or ready-made)
Water (for concentrate see dilution proportions on label)
Safety glasses, rubber gloves
*plastic bucket, plastic sheeting, spray cap, rubber boots, stiff nylon brush, towels
Apply Concrete Dissolver in 5 Simple Steps
- Spray concrete dissolver onto concrete, mortar, grout or stucco smears.
- Let foaming action work. Dwell (to activate) no less than 15–30 minutes. Reapply if smudge is stubborn. Do not let it re-harden.
- Gently wipe off grayish paste with a towel or stiff rubber brush.
- Rinse the remainder with water using a hose nozzle or a low-impact power washer.
- Towel or air dry.
If applicable: For tools apply WD-40 to preserve metal and rub linseed oil to maintain wooden handles.
What Affects CD Results?
- Climatic conditions: Avoid rainy days that will negate activation. Avoid hot days that will heat up surfaces, possibly causing quick-drying spotty-ness.
- Curing period: Takes length of time for concrete and mortar to harden.
- Mortar type: Consider that high strength mortars Types S & M might require a second dose.
- Saturation amount: Spray on smear, do not coat other areas. If not enough, retry with more foam. Don't overdo it.
- Weather temperature: Works best in a temperate range: 70 degrees F is ideal.
The old method for cleaning stone was and still is muriatic acid. This method can be effective but is much more dangerous. It can cause tools to rust and weaken much faster. This video demos cleaning with muriatic acid.
Store and Properly Discard
In any cleanup job, you prepare, clean, store and discard.
Keep unused portions in a child-safe place, away from direct sun. Inside, in moderate 55–65 degree temperatures is preferable.
Although concrete dissolver is biodegradable, do not scatter it on your lawn or in your compost. Dispose of the (portland cement paste) residue in the job site dumpster or along with household trash.
As with leftover paint, combine the remaining used liquid in a container with cat litter to solidify it. Do not pour it down the drain, in toilets, or in waterways as it is potentially harmful to marine life.
What Brand Should I Buy?
Many CD brands are available. Most have either concrete dissolver or mortar remover in their names. The original is called speedy clean concrete dissolver.
Get a feel for holding containers when you're in a home improvement store or at a masonry supply dealer. Find out if you're getting a concentrate that you must dilute yourself or a ready-to-go product.
Do you prefer a colorful or clear liquid?
1 Gallon of Concrete Dissolver
What Size Do I Need?
That depends. The larger the area is, the more solution you'll need. A spray makes it easy to use. If you have a big expanse to cover you might want to apply with a brush and the solution in a bucket.
Here's a rule of thumb when diluting any solutions. Get in the practice of mixing the correct proportions of water and concentrate in a clean container (like a bucket). Do not combine ingredients in the product's original container.
CD comes in these sizes:
- 22 oz (spray) bottle
- 1-gallon bottle
- 5-gallon pail
- 55-gallon drum
- 272-gallon tote
- Custom order - sample kit or special request
Purchase whatever your cleaning job requires. That's reason enough to talk to someone who's knowledgeable. If you have a contractor, ask. Find out what other DIYers and masons use. Consult your masonry supplier. A reliable dealer will know about the products they sell and how to guide you every step of the way.
Learning More: Terminology to Guide You
|Masonry Term||Short Definition|
Cement and aggregate (sand & gravel) when mixed with water cures (dries) into a solid building material.
Formula that chemically activates and breaks up a solid.
Set time it takes for product effectiveness to work.
Thin mixture made of cement, sand, and water to fill joints and repair cracks.
Bond made of cement, sand, and water to join blocks, bricks, and stones.
Cement. Central component of masonry work. Powdered ingredient made from burned lime and trace minerals.
Plaster made of cement and water applied in layers to finish interior and exterior walls.
Is Cleaning Your Tools Really That Important?
Yes, it helps you COPE.
My dad and I came up with this acronym while working on a project together.
Masons and educators say so, too.
In his Masonry Skills textbook mason teacher Richard T. Kreh, Sr. states that "masons spend approximately 50% of their time working with mortar" and "tools are [they're] means of earning a living. They must be kept in good repair."
Taking care of your tools is an important matter.
Cleaning is the final step of daily masonry work
Do the least harm.
I think this three-tiered approach makes sense:
- Prevent. Carefully and skillfully applying concrete or mortar is your first line of defense. You won't end up with as much glop elsewhere either. Wash tools off as you go.
- Be As Gentle As Possible. Masonry instruments are in the middle of the mess, and people make mistakes. We do not remove smears before they harden and extraneous areas unknowingly get splashes on them—a glass window, a painted wood door, for instance. Mild concrete dissolving rather than rubbing and scratching surfaces is less harmful.
- Be Wary of Harsh Chemicals. Use strong compounds as last resort when well-advised. Some formulas will pit and rust metal and worse. I read that often contractors and engineers do not even permit muriatic acid to be on their job sites. You absolutely must wear protection.
Take care. Light exists at the end of the hardened-concrete-and-mortar-on-tools tunnel!
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
© 2016 hardscape
SolveMyMaze on February 09, 2018:
Excellent article. I've read a lot on forums before about people going for the most aggressive option first when it comes to dissolving concrete. It isn't long until they return and ask how to undo the damage that they've done. Obviously once it's done, it's done and the only way to resolve the issue is to seek professional help.
Eugene Brennan from Ireland on November 28, 2016:
A lump hammer does a great job of removing hardened concrete from tools, wheel barrows and flat metal surfaces which can survive being thumped. I've never used such a cleaning product, but it would be very useful for rough/contoured or intricately shaped surfaces which concrete clings to.
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