Welds & inspection
The coating lifts off.
No tool touches the weld.
Cleaning ahead of an inspection is judged on more than how clean the surface ends up — the penetrant standards also care about what was done to get it there. Laser cleaning is non-contact, and the parameters are matched to the material and the contaminant, proven on a test area before the job runs.
Non-contact No abrasive media Test area first Designated LSO Southeast US
Before the inspection
The penetrant gets in.
Or the crack reads clean.
Penetrant testing only finds discontinuities open to the surface — the penetrant has to get into the opening to show anything at all. Magnetic particle is the more forgiving of the two: it reads a leakage field rather than needing the opening clear, and the code allows a very thin nonmagnetic coating to stay on. Both are still read through whatever is left on the metal.
ASME Section V, Article 6 for penetrant and Article 7 for magnetic particle both ask that the surface being examined — and at least an inch around it — be dry and free of scale, spatter, paint, oil and anything else that could obscure a surface opening. Ultrasonic is the softer case: it reads through thin, well-bonded coating, and what stops it is loose scale and lifting paint breaking the couplant film under the probe. Radiography reads through the material and depends on surface prep least of all.
The beam takes coating and corrosion off that band without putting a tool against the joint. Nothing is pressed, folded or dragged across the weld, so no metal gets smeared over the mouth of a crack — the masking mechanism ASTM E165 names, and the reason the penetrant standards call for an etch step when a smearing operation came first. Tightly adhered mill scale is the exception, and takes a mechanical method first.
Mechanical prep
Some take metal off.
Some fold it over.
Mechanical prep works the metal it touches, and most methods do both at once. ASTM E165 warns that smeared or peened metal can close or reduce a surface-breaking opening, and calls for an etch step to open it back up.
- Wire wheel & power brushing Takes almost no thickness off the plate — which is why it looks like the safe option. It smears a thin layer of metal instead, and that layer can close the mouth of the crack a penetrant test is there to find.
- Abrasive blasting Can smear and peen metal over a crack mouth, and leaves some media behind in the surface. Usually tolerable — but one more variable in the surface you hand the inspector, and hard to see once it is there.
- Grinding Takes sound weld and base metal along with the corrosion. Reinforcement height and undercut are measured against limits, so every pass spends margin on the geometry being judged.
- Chemical stripping A residue to rinse, and a surface that has to be dry before the penetrant goes on. The spent stripper and the rinse water are a waste stream to collect.
On site
One day.
Three surfaces.
Recorded across ninety minutes of one live on-site demonstration, on the host facility's own material — not prepared samples. Structural stock, the inside of a rail tank car, and a coated shell — same head, same operator. Cleaning only: we do not inspect or certify welds, and nothing here reports an inspection result.
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01Surface rust off structural angle -
02Cleaning inside a rail tank car -
03Coating and corrosion off steel
At the joint
What sits on the weld.
The method is the same whatever is coming off and whatever is underneath — the parameters are set to the material and the contaminant, and proven on a test area before the job runs. What comes off leaves as vapor and fine particulate, captured at the head.
- Coating / paintabsorbs — lifts off
- Rust / corrosionabsorbs — lifts off
- The parent metalnot ground, not smeared
Scope and limits
What we do.
What we do not.
LRT prepares the surface. We do not perform the examination, interpret indications, or accept or reject a weld — that stays with the certified technicians and their written, qualified procedure, against acceptance criteria the governing code and your specification already set. The standards keep no approved-methods list for cleaning; they say what condition the surface has to be in, and whether laser cleaning is accepted ahead of a given examination is that procedure's call.
Non-contact is a statement about force, not about heat. Nothing is pressed, folded or dragged across the joint, so the mechanical smearing the penetrant standards warn about is not something this process does. We do not claim the metal is left metallurgically unchanged — laser cleaning is a thermal process, and where your specification controls the surface itself, that call belongs to your engineering, on your material.
It is also not the right tool for everything. Tightly adhered mill scale, heavy grease and tar, thick elastic coatings, and anything outside the beam's line of sight are better handled another way — or handled first, then finished with the laser, in which case the smeared-metal question is back on the table and a laser pass behind it does not take that back. Where it does fit, the time comes off around the job rather than in the pass: far less to mask, no blast containment to build and strike, no media to recover, no wash-down and no dry time.
Book a demo
Tell us the material.
And the test that follows.
Tell us the material, the contaminant and the inspection that comes next, and we will tell you straight whether it is a fit. When it is, we bring the laser to your site across the Southeast and run it on your own stock. Bring your NDT people.