What is etching and what is spray etching?
Etching is the process of eating away a pattern on a target material by using an etchant liquid that attacks the target material.
The most common target materials are copper and brass. The most common etchant liquids are ferric chloride, ammonium persulphate and cupric chloride
On a hobby scale it is common to submerge the target into a container filled with the etchant. This can be very slow and is often sped up by either mechanical agitation or using an aquarium / fish-tank bubbler. Even with the speed up from sloshing the container around this process can take 10-15 minutes for a PCB or over an hour for a thick brass plate.
The spray etching method uses the same etchant liquid as the submersion method, but instead sprays the liquid onto the target. This can speed up the process by an order of magnitude.
The advantages that spray etching has over the more mundane submersion method of etching is
Less manually intensive
More uniform etch
Produces sharper edges / better detail
Where are spray etchers used?
Manufacturing PCB (Printed Circuit Boards)
Etching plates for intaglio printmaking
Etching brass nameplates / plaques
Photochemical machining of mechanical parts (often used in model trains)
Etching stencils (if you can't afford a laser cutter hint hint)
Automatically generating traffic by showing friendly site logos made from brass
Why a ROTARY spray etcher?
This rotary spray etcher can be built for between $50 and $100, depending on where you need to source your material. This is a lot less than the $300 plus that other spray etching machines would cost. It is also quicker and easier to build as long as someone else has made all the errors along the way FOR you.
Well here is where I get to say "follow me on this remarkable journey of discovery"