How to choose an injection packer
Four decisions, in this order: section thickness, moisture, pressure, and whether you need the packer back.
1. Match the packer to the drill, not the crack
Packer size is the hole size. A 3/8" packer goes in a 3/8" hole; a 5/8" packer needs 5/8". Drill at 45° across the crack so the hole crosses it at roughly half the wall thickness, and stagger sides as you work up.
2. Length follows section thickness
Rule of thumb: the packer should reach about half-way through the section. A 4" packer covers most 8–10" walls. Once you are past 16" — mass concrete, thick foundation walls, or you want resin set behind the far face — go to a 12.75" long-reach body rather than drilling deeper and hoping.
3. Wet, ragged holes want a soft sleeve
A hard rubber sleeve needs a clean, round hole to bite. In saturated concrete, in block, or where the bit wandered and the hole is oval, a hard sleeve slips under pressure and blows the packer out. A softer poly sleeve conforms — that is the one for curtain grouting and weeping structures.
4. Hammer-in when speed beats recovery
Nylon hammer-in packers set with a hammer instead of a wrench — no nut to torque, nothing to seize. On a long production run that is minutes per hundred holes. They are single-use and get trimmed flush, and because they are non-conductive and will not rust they are safe to leave in a slab permanently. Mechanicals cost more per piece but come back out and re-sleeve.
Comparison
| SKU | Drill | Length | Body | Max pressure | Recoverable |
|---|---|---|---|---|---|
| PW-N38-AIO | 0.375" | 3" | Glass-reinforced nylon | 3,000 psi | No |
| PW-S58-BLU | 0.625" | 3" | Zinc-plated steel | 4,500 psi | Yes |
| PW-A12-1275 | 0.5" | 12.75" | Aluminium body | 3,000 psi | Yes |
| PW-S38-4 | 0.375" | 4" | Zinc-plated steel | 4,000 psi | Yes |
Hole spacing, roughly
Space packers at about half the section thickness — an 8" wall gets packers every 4–5". Tighten the spacing on fine hairline cracks and low-viscosity acrylate; open it up on thick sections with a foaming polyurethane that travels. Start injecting at the lowest packer and work up, and move on when resin appears at the next one.
General guidance only. Injection pressure, hole geometry and resin selection depend on the structure — follow your resin manufacturer's data sheet and your engineer of record.