Every process gets oversold for a while. Laser cleaning is at that stage now, and the videos do not help, because a ten second clip of rust disappearing off a plate makes it look like the answer to everything.
We run it, we like it, and we still send plenty of jobs to the blast pot instead. Here is where it does not stack up.
It cannot create an anchor profile
This is the hard limit and it catches people out at the worst possible moment, usually at a coating hold point.
Abrasive blasting removes coating and cuts a new profile into the steel in one operation. Laser removes what is on top and leaves the surface underneath as it was. If the steel already has a sound profile from its original preparation, that is fine and you recoat over it. If the coating specification demands a stated profile depth and the steel does not have it, no amount of laser time will produce one.
Read the specification before you choose the tool. It settles the question immediately.
It is not the fast option on open bulk work
On large accessible areas where you can build containment and run a blast pot, blasting is faster per square metre and cheaper. That is simply true and nobody is served by pretending otherwise.
The laser earns its place where containment, waste, access or selectivity dominate the cost. Take those away and leave a big open steel structure in a yard, and you should be blasting it.
It cannot reach contamination that has gone deep
On porous materials, paint and staining migrate below the surface. The laser removes what is at and near the surface. Pigment that has travelled millimetres into sandstone or soft brick is beyond what the process can reach without starting to take stone with it.
The result on badly soaked masonry is a large improvement with a faint shadow left in some lights. That is usually the right outcome for a heritage asset, but it is not the same as making it invisible, and it should be said before the job starts rather than after.
It struggles with very thick build up
The process works in passes. Each pass removes a limited depth. Where a coating has been applied over and over across decades, or where there is heavy mastic or a thick bituminous layer, the number of passes required makes it uneconomic against mechanical removal.
Sensible practice on those jobs is to take the bulk off mechanically and use the laser for the final clean and the detail, rather than asking it to chew through the lot.
Reflective and heat sensitive materials fight it
The process relies on the surface absorbing energy. Highly reflective materials reflect a good deal of it, which slows things down and, on complex geometry, raises a genuine safety consideration about where that reflected energy goes.
Thin sections and heat sensitive substrates need lower energy and more passes to avoid distortion or damage, which again costs time. Some non ferrous materials need a completely different approach.
What this adds up to
Laser cleaning is a precision tool that solves specific expensive problems. Containment you cannot build. Waste you cannot cheaply dispose of. Areas you cannot shut down. Assets that cannot lose parent material. Detail work you cannot do with an indiscriminate process.
Outside those conditions there is usually a better and cheaper answer, and a contractor worth using will tell you so.
Related reading: laser cleaning or abrasive blasting and what drives laser cleaning productivity.
Talk it through
Our laser cleaning, rust and paint removal page covers what we run and where we work. Ring 02 7912 3054 and describe the job.
Perfect Remediation and Refurbishment acknowledges the Aboriginal and Torres Strait Islander people as Traditional Custodians of the country on which we live and work. We pay our respects to the Traditional Custodians and Elders past, present and future, and honour their connection to the land and ongoing contribution to society.