10 ft DIY ULV Auto Injector Kit 3 for Ultra Small Cracks

10ft DIY ULV Auto-Injector Epoxy Kit — Permanent Structural Repair for Hairline & Ultra-Fine Cracks

Ultra-Low Viscosity Epoxy That Flows for 12 Hours — Penetrates Cracks Too Fine for Polyurethane, With No Tools or Manual Pumping

Cracks under 1/64 inch — too fine for standard polyurethane injection
Hairline cracks, pinholes, leaking snap-ties, and micro-voids in concrete
Flows continuously for up to 12 hours — auto-injectors hold low pressure with no manual effort
Auto-injector ports deliver 24 to 40 psi constant pressure — no gun, no compressor
Structural repair — epoxy bonds the crack and restores concrete strength
Works on dry cracks and cracks too fine to be visibly leaking
No exterior digging — full inside-wall repair
Covers approximately 10 to 15 ft of ultrafine crack — upgradable to 20 ft
Repair lasts the lifetime of the structure
Free NextStar Technical Support — 1-866-445-3984
Ships USA & Canada

Who This Is For — Cracks Too Small for Standard Polyurethane

This is the kit for the cracks the other kits cannot reach. If a crack is so fine it is barely visible — a hairline, a pinhole, a weeping snap-tie hole — polyurethane foam simply cannot get into it. This Type 3 kit uses Ultra-Low Viscosity (ULV) epoxy, thin as water and slow curing, which migrates into cracks finer than 1/64 inch and bonds them structurally. Use this kit when the crack is too fine for polyurethane, when the crack is dry rather than actively leaking, or when you need to restore the concrete's strength rather than just seal out water.

12-Hour Flow Window — How ULV Penetrates Hairline Cracks

Standard polyurethane foam expands on contact with moisture and is excellent for leaking cracks from 1/32 to 3/16 inch wide. But it cannot penetrate cracks finer than 1/64 inch — the viscosity is too high and the foam reaction happens too fast to migrate into a hairline before it sets.

ULV epoxy is the opposite by design: a near-water consistency and a deliberately slow cure. Loaded into the auto-injectors, it flows continuously under constant low pressure for up to 12 hours — long enough to creep through the full length of even the finest crack. That 12-hour flow window is the whole point of the system. A hand-pumped gun cannot hold pressure on a crack for hours; the auto-injector does it automatically, unattended, which is what lets the epoxy reach the depths of a hairline that no manual method can fill.

Auto-Injector Ports — No Tools or Manual Pumping Required

The pressure mechanism is built into each port. Once loaded with mixed ULV epoxy, the auto-injector delivers a continuous 24 to 40 psi on its own, with no gun, no compressor, and no manual pumping. For ULV epoxy this is not just a convenience — it is what makes the repair possible, because the epoxy needs sustained low pressure over many hours that no hand tool can maintain. Every tool needed for the repair is in the box.

Kit Components — ULV Epoxy Auto-Injector Kit

ULV Epoxy — 946 ml (1 Quart) Part A + 473 ml (1 Pint) Part B:
Two-component ultra-low viscosity epoxy formulated to penetrate and fill cracks too fine for polyurethane. Covers approximately 10 to 15 ft of ultrafine crack. Flows for up to 12 hours; full cure 72 hours.

Fast-Setting Epoxy Crack Seal and Port Adhesive — 2 × 300 ml (Part A & B):
For attaching injection ports to the wall and sealing the crack surface between ports.

15 Surface Ports with Auto-Injectors:
The auto-injector applies constant low pressure (24 to 40 psi) automatically for the full duration of injection — no manual effort, no compressor, no injection gun. This sustained pressure is what lets ULV epoxy fully penetrate ultrafine cracks.

Accessories:
6 wooden mixing sticks, putty knife, wire brush, 3 pairs of nitrile gloves, and safety glasses.

Complete Instructions & MSDS Safety Data

The 10 ft kit gives the DIY homeowner the same ULV epoxy system NextStar supplies to professional contractors — without the professional injection equipment. The kit can be upgraded to 20 ft at checkout. For larger projects or ongoing contractor use, call 1-866-445-3984.

Watch the full video guide →

Why ULV Epoxy, Not Polyurethane, for Ultrafine Cracks

The two materials solve different problems. Polyurethane seals leaking cracks by expanding against moisture; ULV epoxy bonds cracks structurally by penetrating and gluing the faces back together. Because cured epoxy restores tensile strength rather than just blocking water, it is the right choice for a crack that is structurally compromised, not just wet. And because epoxy cures through a Part A / Part B reaction rather than needing moisture, it works equally well on dry cracks — cracks that are not leaking at all but still need reinforcing. Polyurethane requires moisture to activate; ULV epoxy does not.

Where ULV Epoxy Is Used

Ultrafine hairline cracks and pinholes in poured concrete foundation walls, leaking snap-tie and form-tie holes, micro-cracks in concrete ceilings and vaults, gravity-feed repair of thin cracks in horizontal slabs, and reinforcement of any cracked concrete item including retaining walls, pool shells, statuary, and decorative concrete.

ULV epoxy is the standard method for sealing leaking snap-tie and form-tie holes. Because it is thin enough to flow into the void around the steel tie and cures into a solid bond, it does more than stop the leak — it encapsulates the tie and cuts off the moisture and oxygen reaching it, which stops the tie rusting further. A surface patch only hides a snap-tie leak; ULV epoxy seals it permanently and protects the embedded steel.

Installation Steps

1. Put on protective gear. Put on the supplied nitrile gloves and safety glasses before handling any materials, and wear them throughout the repair.
2. Clean the wall surface. Using the wire brush, scrub the crack and surrounding wall back to bare concrete. Remove paint, efflorescence, or loose material along the full crack path.
3. Mix the port adhesive paste. Mix a small batch of fast-setting epoxy crack seal paste (Part A + B) by hand until uniform in colour.
4. Attach surface injection ports. Using the mixed paste, attach surface ports along the crack every 8 to 10 inches. Unlike the polyurethane kit, no water pre-injection step is needed — proceed directly to injection.
5. Seal the crack surface. Apply the remaining paste over the crack between ports to seal the surface. Allow to cure until firm, approximately 1 to 2 hours.
6. Mix the ULV epoxy. Mix the two-component ULV epoxy per the instructions. Mix only what you need to start, then mix additional batches as you work up the crack.
7. Load and inject from the bottom up. Load mixed epoxy into the lowest auto-injector port. The auto-injector applies constant pressure automatically — no pumping. The epoxy migrates upward; when it reaches the next port, load that port and continue upward.
8. Allow extended flow time. ULV epoxy keeps flowing for up to 12 hours under auto-injector pressure. Leave the ports loaded and in place — the system works unattended. Full cure is 72 hours.

Tips & Notes

1. Do not skip port installation, even on a barely visible crack. The paste seal is what contains injection pressure — without it, epoxy runs down the wall face instead of into the crack.
2. No water pre-injection step. Unlike the polyurethane kit, ULV epoxy does not need moisture to cure. Skip the water priming step entirely.
3. Temperature matters. ULV epoxy flows best above 10°C (50°F). In a cold basement, let the epoxy components warm to room temperature before mixing.
4. For snap-tie holes, pack port adhesive paste over the hole opening first to create a seal, then inject epoxy to fill behind it.
5. Not sure which kit? For leaking cracks 1/32 to 3/16 inch wide, the Type 1 Polyurethane Auto-Injector Kit is the right choice. For structural repair with a professional gun and up to 60 ft of coverage, see the Pro Epoxy Injection Kit.

Common Questions About ULV Epoxy Crack Injection

Questions during your repair? Call our free technical support line at 1-866-445-3984.