Short answer: after wet drilling, water injection, foam use, or work in a water-bearing hole, do not park a DTH hammer wet and assume the normal oil film will protect it. Follow the hammer manufacturer's shutdown procedure: move the hammer clear of standing water, isolate the rig safely, expel residual water with clean air, distribute the approved rock-drill oil through the internal air path, protect the connections, and store the tool clean, capped, dry, and supported. For longer inactivity, the normal requirement becomes disassembly, cleaning, drying, inspection, preservation, and a controlled restart.
A DTH hammer storage procedure after wet drilling is mainly corrosion control. The piston and internal bore work with close running clearances. Water left on those surfaces can form oxidation, contaminate the lubricant, seize a sliding part, damage seals, and create small pits that remain after the visible rust is removed. The exact oil quantity, air cycle, storage interval, disassembly method, orientation, and acceptance limits are model-specific. The service manual for the exact hammer always takes precedence over generic guidance.
Why wet drilling changes the storage risk
During normal operation, compressed air transports lubricant through the hammer while the piston cycles. Wet drilling adds another fluid to that system. When work stops, water can remain in internal passages, around the piston and distributor, inside the chuck area, on splines, or in low points in the drill string. Foam and drilling additives can leave a residue after their carrier water evaporates.
The problem is not only visible red rust. Early surface oxidation can alter a sliding surface before a deep rust layer appears. Moisture trapped under contaminated oil may also be difficult to see from outside. Temperature swings in an unconditioned container can create condensation even when the tool entered storage apparently dry.
Storage begins before the hammer leaves the hole
The best preservation step happens at shutdown, not days later in the workshop. If the hammer is sitting below the water level, first use the approved drilling procedure to bring it into a position where water can be expelled. Do not leave it parked overnight under water. Do not disconnect a pressurized line, stand in front of an exhaust path, or cycle a loose hammer without the fixture and controls required by its manufacturer.
Before any handling or disassembly:
- stop rotation and feed using the rig procedure;
- raise the hammer clear of standing water where the ground and rig permit;
- shut off water, foam, or other injection in the sequence specified for the system;
- allow clean lubricated air to remove residual liquid for the documented time;
- isolate and depressurize the complete air circuit before breaking a connection; and
- restrain the hammer with suitable lifting and support equipment.
If the hammer cannot be raised, the return is blocked, the string is stuck, or the rig cannot supply controlled lubricated air, treat that as a recovery problem. Do not improvise a storage cycle while the tool remains in an unsafe hole condition.
Immediate dry-out and oil-film procedure
The objective is to replace free water in the air path with clean air, then leave an approved lubricant film on the internal steel surfaces. A generic sequence is:
- Stop the liquid injection. Follow the OEM shutdown order so that water or foam does not continue entering while the hammer is being cleared.
- Move above the water level. Where possible, position the hammer so expelled fluid can leave the exhaust path rather than flow back inside.
- Blow clear with clean air. Use the rig's controlled procedure. Observe the discharge from a protected position until free water is no longer evident.
- Introduce the approved rock-drill oil. Use the oil grade and amount specified for the hammer, ambient temperature, and intended storage period.
- Distribute the oil. Cycle only in the restrained condition and manner permitted by the manufacturer, so the lubricant reaches the piston, bore, passages, and lower assembly.
- Isolate and depressurize. Confirm zero stored pressure before removing the hammer or opening any connection.
- Clean the exterior and connections. Remove mud, wet cuttings, and contaminated grease without forcing debris into the air inlet or chuck.
Oil appearing at the exhaust provides a useful indication that lubricant has passed through the system, but it is not proof that every trapped-water pocket is dry. A hammer exposed to dirty water, corrosive additives, heavy foam, salt, or repeated wet drilling may require earlier disassembly and inspection.
Short-term vs long-term DTH hammer storage
| Storage situation | Typical preservation level | Questions before choosing it |
|---|---|---|
| Between shifts or a brief planned pause | Dry-out, internal oil film, external cleaning, protected connections, clean dry support | Was the hammer fully cleared of water? Will temperature cycling cause condensation? Does the OEM permit storage assembled? |
| Several days or weeks | Same steps plus inspection of discharge, caps, threads, splines, check valve area, storage log, and periodic condition check | Was foam or contaminated water used? Is the storage area humidity-controlled? Can the ends remain sealed and undamaged? |
| Seasonal, uncertain, or extended inactivity | Disassemble as instructed, clean, dry, inspect, preserve each part, protect threads and seals, package or cap, and log condition | What preservation product is approved? Which seals should be replaced at recommissioning? What wear measurements are required? |
| Severe wet exposure or suspected contamination | Treat as an inspection event rather than ordinary storage | Was the hammer submerged, left under water, exposed to aggressive chemistry, or operated with failed lubrication? |
Do not turn these descriptions into fixed time limits. OEM manuals use different definitions for short- and long-term storage. Exposure severity can matter more than calendar time: one contaminated wet job may justify inspection sooner than a longer period of clean, dry operation.
Long-term preservation: what must be inspected
Extended storage usually requires the hammer to be dismantled by trained personnel using the correct fixture, breakout tools, lifting method, and assembly sequence. Record component orientation and keep matched parts together. Use clean, lint-free materials and only cleaning agents compatible with the steel, seals, coatings, and preservation product.
| Area | Storage-related risk | Inspection focus |
|---|---|---|
| Piston and internal bore | Oxidation, pitting, contaminated oil, sticking | Cleanliness, free movement, scoring, corrosion marks, dimensional limits from the manual |
| Distributor and air passages | Water pockets, dried foam, blocked ports | Clear passages, deposits, erosion, cracks, correct orientation |
| Check valve and springs | Backflow contamination, sticking, loss of sealing | Clean movement, corrosion, distortion, seat and seal condition |
| Chuck, splines, and bit shank | Rust at contact faces, abrasive residue, fretting | Spline wear pattern, cracks, burrs, corrosion, retaining-part condition |
| Backhead and casing threads | Water in thread roots, galling, seized connection | Clean roots and crests, deformation, cracks, approved thread compound |
| O-rings and plastic components | Swelling, hardening, cuts, permanent set | Correct material and size, elasticity, surface damage, replacement requirement |
Polishing away a rust color does not automatically return a part to service. Pitting on a loaded or sliding surface may remain a rejection condition. Use the component drawing, service manual, and supplier acceptance criteria. If limits are unavailable, quarantine the part and request technical confirmation rather than guessing.
How to cap, support, and control the storage environment
After preservation, protect both ends from dust and moisture with clean, compatible caps. A dirty rag, adhesive tape that leaves residue, or an open connection on the workshop floor is not equivalent to a proper cap. Clean and protect the drill-pipe ends as well; contaminated rods can reintroduce water, grit, or old grease into a clean hammer during restart.
Use a dry, covered location with limited temperature fluctuation. Keep the hammer off bare soil and away from rain, washdown spray, corrosive chemicals, grinding dust, and battery-charging fumes. Follow the maker's required storage orientation. Industry guidance often describes horizontal support for preserved DTH hammers, but the correct position and support points can vary with tool design and storage fixture.
Attach a storage record showing:
- hammer identification and bit/shank family;
- last operating date and reason for removal;
- whether water, foam, polymer, or another additive was used;
- dry-out and oil procedure completed;
- inspection or disassembly status;
- preservation oil and thread compound used;
- open defects, quarantined parts, and required spares; and
- planned inspection or recommissioning date.
Restart checks after storage
A hammer that was running before storage is not automatically ready after storage. Before reconnecting it to the rig, verify the storage record and identify any missing information. Extended inactivity, uncertain preservation, visible moisture, damaged caps, or evidence of corrosion should trigger internal inspection.
- Inspect the packaging and caps. Look for water entry, condensation, dust, damaged threads, or impact during transport.
- Confirm identification and compatibility. Match the hammer, bit shank, backhead thread, drill pipe, and operating air range.
- Check external condition. Inspect the wear sleeve, backhead, chuck, splines, bit, and connections for corrosion, cracks, or damage.
- Inspect internally when required. Follow the model manual; do not reuse a pitted piston, damaged seal, blocked passage, or suspect retaining part without approval.
- Clean and relubricate. Remove incompatible preservation products if instructed, install approved seals and lubricants, and protect the threads.
- Reassemble to the documented procedure. Use the specified orientation, tooling, clearances, and torque or make-up method.
- Conduct a controlled functional check. Use a restrained setup and approved air supply. Confirm oil delivery, free operation, normal exhaust, and absence of abnormal pressure, noise, heating, or sticking before drilling.
For routine operating lubrication, see the DTH Hammer Lubrication Guide. Use the DTH Hammer Daily Inspection Checklist to reconnect storage controls with the normal pre-shift routine. If corrosion or sticking has affected the piston area, compare the evidence with the DTH Hammer Piston Wear guide.
Common storage mistakes
- Leaving the hammer in a wet hole: the tool remains exposed to water while the protective oil film is diluted or displaced.
- Blowing with unlubricated or contaminated air: free water may move, but clean steel can be left unprotected or receive more compressor moisture.
- Using an arbitrary oil: viscosity, additives, seal compatibility, and corrosion protection must suit the hammer and temperature.
- Sealing before drying: caps keep contamination out, but they also trap residual moisture inside.
- Assuming more oil fixes contamination: oil does not remove grit, dried foam, aggressive chemistry, or existing pitting.
- Restarting at full load: a stuck piston, blocked passage, wrong seal, or assembly error can turn a correctable issue into major damage.
Spare parts and records to plan before seasonal shutdown
For operations with planned downtime, procure preservation materials and likely service parts before the last hole is drilled. The list may include model-correct O-rings, check-valve components, retaining parts, approved rock-drill oil, thread compound, end caps, cleaning materials, and packaging. Do not order internal parts from diameter alone; confirm hammer model, version, shank family, backhead connection, serial or drawing reference, and part numbers.
PerfoMax currently offers an active CIR90 low-pressure DTH hammer and related DTH tooling. When requesting replacement or maintenance support, include photos of the complete tool and damaged surfaces, operating pressure and air supply, water or foam use, storage duration, and the inspection measurements required by the original manual.
Frequently asked questions
Can a DTH hammer be left in a wet hole overnight?
It should not be treated as an acceptable storage method. Where the rig and ground allow, follow the manufacturer and site procedure to raise the hammer clear of water, expel liquid, distribute approved oil, and place it in a protected condition. If the string cannot be recovered, manage it as a stuck-tool or hole-recovery event.
Is blowing with compressed air enough after water injection?
Not by itself. Clean air removes free water, but the internal steel surfaces also need the documented lubricant film. Dirty or moisture-laden compressor air can make the condition worse. Severe contamination may require disassembly and cleaning.
Should a DTH hammer be stored with the bit installed?
Different designs and procedures vary. Some guidance keeps the assembly protected; other long-term procedures require disassembly. Follow the exact hammer manual, keep all openings capped, and prevent the bit shank, chuck, foot valve, and splines from contamination or impact.
How long can a preserved hammer stay assembled?
There is no universal interval. OEM definitions of short-term and long-term storage differ, and wet exposure severity, additives, humidity, temperature cycling, and record quality all change the decision. When the storage period is extended or uncertain, internal inspection is the safer technical gate.
What should be checked first if a stored hammer will not start?
Do not keep increasing pressure. Isolate the system and check lubrication delivery, air supply, blocked passages, contamination, corrosion, piston freedom, bit movement, check valve condition, seals, and assembly. Use the model-specific troubleshooting procedure.
Technical references
- Rockmore International DTH hammer operation, service, and assembly manuals
- The Driller: Proper Hammer Storage, based on Numa hammer guidance
- Drill King International: DTH hammer cleaning, lubrication, inspection, and storage guidance
Prepare the maintenance request with the storage history
Storage problems are easier to diagnose when the supplier receives the full history. Send the exact hammer model, shank and connection, wet-drilling method, water or additive details, shutdown steps, storage period and environment, restart symptoms, and clear inspection photos. Request a quote from PerfoMax with that information to review a DTH hammer or compatible maintenance parts without relying on diameter alone.