Guys,just make a splash tank, they are mechanically simple and work very well. All you need is a dasher on the end of a stainless steel or plastic rod (depending on your etchant choice) driven by an old motor. Think of it as an inverted blender. (Hack your wife's blender for the motor) Only takes about an inch of etchant in the bottom of the tank. You do have to build an anti-splash cover seal to keep the etchant in the tank. My last one was built from fiberglassed 1/2" plywood and was a 12" cube.
Craig
--- In Homebrew_PCBs@yahoogroups.com, "rolynd33" <roland.rasch@...> wrote:
>
> What speaks against using a bernoulli type sprayer for spray erching ?
> I did a seach here but bernoulli did not yield any viable results.
>
> (In essence its just two tubes meeting at an 90° angle ,air is blown into the horizontal tube thus a vacuum is created in the vertical tube drawing up the liquid and then dispersing it in a fine spray at the top. If you dont understand what I am describing , I am not a big explainer :) - just do a quick google search)
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> It would be simple to construct, fairly large tubes can be used so no clogging of nozzles, no pump needed and no plumbing outside of the tank. All good things to me.
>
> Of cause you will need an air source that means probably a noisy compressor which is a downside. Also the fine aerosol you create must be contained so a tight seal on the tank is needed. The air you blow in must go somewhere so you need an exhaust port probably fittet with a sponge first to catch the larger paricles and then connected to a scrubber bottle to get rid of the rest of the aerosol.
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> I dont know how much pressure and volume you need but I can produce a fairly good spray just with mouth pressure.
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> Would the force of the spay cone be too much? Spray pattern too random? Not enough etchant moved?
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> The idea is simple but I guess there must be something I overlook because no one has thought of this or built one based on this principle.
>
> So, what am I missing here?
>