[copper3416]

I wish to build a spray etcher with an rv diapram pump for pcb and jewlery etching.Thinking of adding a canister filter to filter out sludge.Has anyone made a spray etcher.I am worried that I might cause damage to the pump pumping to a small orfice.WAS thingking of using a shurflow2088-422-144

[harryn]

You are right to be worried about pumping acids. As it turns out, I used to sell acid spraying tools for the semiconductor industry so perhaps you can mimick those setups.

The easiest way to deal with this is to put the acid into a tank and pressurize it instead of pumping. This technology has been in use for 100+ years with success.

Put the part into something like a 55 gallon poly drum for processing. Vent the exhaust to something which will catch the mist and nuetralize it, such as a second drum with hot baking soda solution circulating.

Atomize the spray into a fine mist (fog) with nozzle arrangment similar in concept to a air based auto paint sprayer. Run low flow rates in a single pass of the acid flow. If the acid is in very good condition, you can recyle it, but most likely you will not need to.

Just a suggestion, but consider instead to mill your pcbs. There is a section in this forum on pcb milling which shows some pretty decent results. You can search on my name for recent posts and find it.

[copper3416]

Thank you harryn for your response. Adams pcb home page will have the setup I am trying to emulate.Sorry I should have left that before.My question is how do I pump acid throught a small orfice like he did.

[3dsignco]

When I was in the Model/Movie Industry I had built my own Ghetto Etcher. Consisted of an Old 20 Gallon fish tank, Low pressure plastic Sprinkler heads. (Drip system Misters) and a Fish tank Heater, (left over from all the dead fish from he 20 gallon tank.) And a regulated Air Compressor..

Took my tank and drilled a hole in the bottom and attached a drain tube for the Ferric Chloride to drain back into the 2 gallon container of Ferric Chloride that had the Heater attached to keep the chloride warm.
Took the Misters and made small setup to spray both sides of the brass or copper at the same time. Then made a Y setup to siphon the Chloride out and adjusted my pressure on the air Regulator. Put a small t-Valve between your air supply and your siphon to eliminate any chance of back-flow.
When the ferric starts to get gunky I would do a 2 stage filter.. One through a Paint strainer to get the larger particles then through a Coffee filter.

Wallah.. Ghetto etching with very good results. Worked with this contraption for many years. Then once the Model kit went into production all Parts were made in Korea by the 1000s. Or they just got blown up in a Movie.

[copper3416]

thank you guys I think this one will be the one.http://www.prototrains.com/etch1/etch1.html.