Blasting

Rust grades A to D and preparation grades St2, Sa2, Sa2½ and Sa3 in plain terms: what each one demands, which gets specified in practice, and why hand cleaning ends up costing more.

rticle EN Title: Blasting nozzles: how long they last and how to tell when one is worn Slug: blasting-nozzles-wear-replacement Meta description: The nozzle is the cheapest part in the installation and the least monitored. How it wears, how to measure it, and why a worn one costs you electricity. Category: Blasting A nozzle costs about

A surface can be clean to SA 2.5 and still fail to hold paint. It happens more often than it should, and the cause is almost always the same: the preparation grade was specified and the profile was forgotten. What the profile actually is Every particle that strikes the surface leaves a mark. Millions of

In dry blasting, the abrasive is accelerated by compressed air or by a wheel. In wet blasting, it is carried by a pressurised water jet. Changing the medium changes the character of the process completely. What it does differently Dust leaves the equation. Water binds the fine particles. There is no dust cloud, and therefore

Before choosing the abrasive, establish what you are using it for. There are three different purposes, and they ask for different things. Surface cleaning — removing oxides, foundry sand, burrs. The most frequent case. Cutting — applied for example to granite blocks, with special mixes of hard shot. Etching — done to increase surface adhesion

When you ask for a blasted surface, “clean” is not a specification. The preparation grade is. The standard Assessment follows ISO 8501-1, also known as the Swedish standard. The method is visual: you compare the actual surface against reference photographs. It is not an instrumental measurement. It is a comparison, made by a person, in

There are two ways to throw abrasive at a part. With a centrifugal wheel, or with compressed air through a nozzle. They do the same thing. Not at the same rate, and not for the same parts. The throughput difference A wheel propels the abrasive mechanically. The blades throw it, and the energy comes straight

Wheel blast machines differ in how the part moves in front of the wheel. Everything else follows from that: which parts you can process, and how fast. Tumble barrel Parts sit in a rotating barrel. The wheel throws the abrasive, and the parts tumble, exposing every face. For: small, robust parts in bulk. Castings, forgings,

Two families of round metallic abrasive, with different prices and different behaviour. The choice is not obvious, and in shot peening it matters more than in blasting. How they are made Cast shot is produced by atomising molten steel. The droplets solidify into spheres. Cut wire is produced from drawn wire, cut into cylinders with

Environmental requirements no longer come only from the authorities. They come from customers’ specifications, since those customers need certifications of their own. The good news is that in blasting, the environmental choice usually coincides with the economical one. The abrasive that comes back into the circuit The fundamental difference is between abrasive that recirculates and