Red Devil 0645 Concrete Repair Patch, Cement Crack Filler, 5.5 Oz Squeeze Tube, Pre-Mixed, Pack of 1, Gray, Made in USA

A tube-based fix for everyday concrete blemishes

A squeeze tube and a putty knife were all I needed to tackle a handful of nagging concrete flaws around my home. I used the Red Devil concrete patch to fill hairline cracks along a driveway slab, seal a couple of narrow fissures around basement window wells, close up the old doorbell hole in a block wall, and even reunite a chipped garden statue with its missing piece. The promise here is simple: a premixed, water‑cleanable patch in a light-to-medium gray that stays flexible outdoors. After several weeks of use and exposure, it largely delivered on that promise, with a few caveats worth knowing before you buy.

What’s in the tube

This is a 5.5‑ounce, premixed patch in a squeeze tube. The nozzle gives you good control, especially for narrow cracks, and the material tools easily with a standard putty knife. It cures to a light-to-medium gray — squarely in the “new sidewalk” range rather than the bleached or very aged concrete many of us actually have. It’s rated for interior or exterior use and cleans up with soap and water. There’s very little odor, and working time is comfortable for small sections.

The tube format is the right choice for small, discrete repairs. If you’re planning to resurface broad areas or fill deep spalls, a tub or bagged repair mortar is more appropriate.

Surface prep and application

Concrete patching is 80% preparation. Here’s how I approached it:

• I knocked out loose material with a cold chisel and vacuumed all dust and grit.
• For hairline cracks, I slightly widened and undercut the edges with a utility knife and a carbide crack chaser to give the patch a mechanical key. A quick brush and a blast of compressed air helped clear fines.
• For one wider joint (about 3/8"), I pressed in a foam backer rod so the patch wouldn’t sink and so I wouldn’t waste material.
• I kneaded the tube for a minute, cut the nozzle to match the crack width, and applied a steady bead, slightly proud of the surface.
• I tooled the bead with a 1.5" putty knife, feathering onto the surrounding concrete. On broom‑finished areas, a lightly damp sponge added a bit of texture for a closer match.

The material spreads smoothly and doesn’t slump out of vertical surfaces if you don’t overload it. On deeper voids, I had better results building up in two thin lifts rather than trying to fill all at once. Skim coats were workable for several minutes; skinning started within an hour in mild weather.

Cleanup was genuinely easy — a damp rag took care of smears on adjacent surfaces and tools washed clean in the sink.

Performance and durability

Adhesion has been excellent so far. The patches on my driveway and walk stayed bonded after heavy rain and a couple of cold snaps, with no edge curling or flaking. The product stays slightly flexible when cured, which helps it accommodate minor movement and temperature swings without telegraphing new cracks. On the vertical block wall, the doorbell hole fill remained flush and intact.

I didn’t see noticeable shrinkage on shallow cracks. On the deeper repair (approaching half an inch in depth), I did see modest draw‑down as it cured — not dramatic, but enough to warrant a light second coat the next day to bring the patch perfectly flush. That “two‑pass” approach is typical for deeper voids with any premixed patch.

One practical win: the narrow fissures around the basement windows that would dampen during wind‑driven rain stayed dry after patching. This isn’t a substitute for a waterproofing system — and I wouldn’t rely on it to solve true foundation movement — but for sealing small surface cracks that admit moisture, it did what I hoped.

Foot traffic within a day was fine in my conditions. I waited a few days before parking a wheel near a repair, more out of habit than necessity. If you’re patching in hot sun or very cool weather, give it extra time.

Finish and color match

The cured color is light-to-medium gray. On my relatively new walkway, the match was close. On the older, sun‑bleached section of driveway and the painted garden statue, the patch read a shade darker and slightly cooler. That’s not a fault — concrete ages unpredictably — but it’s something to plan for if appearance is critical.

Two tips to improve the look:
- Texture matters. Feather edges well and use a damp stipple or a light broom to mimic the original surface.
- If the surrounding concrete is lighter, consider painting or staining. I painted the statue after the repair and the seam completely disappeared.

If you’re aiming for invisibility on very light or sand‑rich concrete, expect to do some finishing work or accept a visible repair.

Coverage, pacing, and storage

The 5.5‑ounce tube is sized for small jobs. I comfortably handled a couple of hairline cracks totaling several feet, one 3/8" void with backer rod, and the doorbell hole with a single tube, with a little left over. If you’re tackling control joints or a network of wider cracks, you’ll go through tubes quickly.

Because it’s premixed, you can cap it and come back later. I recommend wiping the nozzle clean, purging a thumbnail of air from the tube, and taping the tip before capping. Stored tip‑down in a cool spot, my partial tube was still workable a week later. Expect some skinning at the very tip; just cut back a millimeter to open fresh material.

What it does best

• Quick, clean repairs on small cracks and chips without hauling out a mixing pail.
• Vertical or overhead touch‑ups where sag can be a pain.
• Locations where flexibility helps (edges of slabs, steps that see minor thermal movement).
• Indoor fixes where a cementitious mix would be messy and overkill.

I especially liked the control the nozzle gives on narrow cracks. Caulking‑gun type crack fillers can be runny or too elastic; this patch has enough body to stay put and enough give to avoid becoming brittle.

Limitations and caveats

• Volume: 5.5 ounces disappears fast on larger work. If you have multiple deep spalls, buy larger packaging or a different product category.
• Depth: For deeper voids, plan on multiple thin lifts and/or backer rod to avoid settling.
• Color: The light-to-medium gray won’t match every slab. Plan to texture, tint, or paint if a seamless appearance matters.
• Structural issues: This is not a fix for active movement, heaving, or structural cracks. If the crack is growing, consult a pro.
• Moisture conditions: Like most patches, it wants a sound, clean, dry surface. Don’t apply to saturated or dusty concrete and expect long‑term success.

None of these are deal‑breakers; they’re the realities of using a premixed, latex‑modified patch rather than a bagged repair mortar or a self‑leveling sealant.

Practical tips for better results

• Undercut narrow cracks slightly to improve mechanical keying.
• Use backer rod for anything wider than roughly 1/4" to reduce material use and control depth.
• Feather edges thin and texture to blend; don’t leave a raised ribbon.
• Allow adequate cure time before painting or heavy use, especially in cool or humid conditions.
• For very fine hairline cracks, work the material in with a gloved finger, then smooth with a dampened putty knife.

The bottom line

For small, targeted concrete repairs, the Red Devil concrete patch is a genuinely useful, low‑mess solution. It adheres well, stays put through weather changes, and is easy to apply precisely where you need it. Water cleanup and low odor make it friendly for indoor touch‑ups, and the squeeze‑tube format encourages good technique on narrow cracks.

I recommend this tool for homeowners and pros tackling minor cracks, chips, and holes who value convenience and controlled application. It’s not the right choice for large‑scale resurfacing or structural repairs, and color matching on aged concrete will require some finesse, but within its intended scope it performs reliably and saves time. If your punch list looks like mine — a few hairlines, a small void or two, maybe a decorative repair — this tube earns a spot in the caddy.