Homebrew PCBs

Resend, was dropped..

-------- Original Message --------
Subject: Re: [Homebrew_PCBs] Re:Sprayer pressure
Date: Mon, 14 Mar 2005 09:10:13 -0500
From: uhmgawa <uhmgawa@...>
To: Homebrew_PCBs@yahoogroups.com
References: <1110754728.436.94819.m12@yahoogroups.com> <4235544F.4080809@...>

RMustakos wrote:

> As far a nozzles go, in the US, Home Despot has started carrying 1/2 and
> 1/4 inch irrigation equipment, mass produced plastic (not sure what
> kind), with all sorts of nozzles - mist, 45, 90 180 and 360 sprayers,
> all for 5 for two dollars kind of prices.  They screw right into 1/4
> inch tubing, and are made to screw into the side of 1/2 inch tube.

"A" for effort I'd say.  However these sprayers are intended
for fluid dispersion in a flat horizontal fan pattern rather
than a projectile cone.  Yet the fan nozzles found on
plastic hand-pumped bottle sprayers might be worth a try.
Garden chemical sprayers are another possibility as might be
aerosol can spray nozzles.

Speaking of which, as the fluid delivery doesn't need to be
100% continuous, has anyone given any thought to a piston
pump?  Should be easy enough to machine from plastic tube
stock.  If conventional o-rings will stand up to the etchant
that could be used as a seal.  The other possibility is a
diaphragm pump similar to those used in high-end airless
paint sprayers which does achieve 100% duty cycle.

Alternatively to avoid intricate pump components having
to withstand etchant corrosion it would be possible to
use compressed air to pressurize a container of etchant
located below board tank level.  This again is not 100%
duty cycle as the etchant must be allowed to gravity
backflow to the etchant container when said container
becomes empty.  Achieving this could be as simple as locating
a check valve in the backflow line and bleeding off the
air pressure in the etchant container.  The only thing
required to automate the process is a float switch in the
etchant container and a solenoid air valve to alternatively
pressurize/bleed air to/from the etchant container.

-- 
uhmgawa@...        www.gnu.org


-- 
uhmgawa@...        www.gnu.org