The spray manifold on the Kepro etchers are nothing more than two pieces of 1/2" CPVC pipe with a pattern of small holes spaced out over a 5 or 6 inch length.
The drilled holes are about 1/16" and drilled in a pattern something like this:
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O O O O O O
O O O O O
O O O O O O
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The manifold is made from a "T" fitting with two pieces of drilled pipe plugged into each side for an overall length of about 12". Nothing is glued except for the end caps. The pieces are press fit together so you can adjust the spray pattern. The spray manifold is spaced about 3" from the board surface.
About half way between the spray manifold and the board is a piece of fiberglass screen to break up the spray pattern for better distribution over the entire board surface. The screen has a heavy strip of PVC plastic glued to the bottom to keep it in place when the pumps are spraying.
The spray manifold is positioned closer to the top of the board so the etchant can run across the board surface as it falls back to the sump. These etching machines work pretty good and are simple to make. The main problem with the Kepro units was pump failure. Substituting a better pump is a wise thing to do or find a better way to seal the pump shaft and bearings from etchant fumes.
Tom
--- In Homebrew_PCBs@yahoogroups.com, "jcarlosmor" <jcarlosmor@...> wrote:
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> Hello Tom,
>
> I had obtained a used Kepro bench-top etcher. It is a very old machine (mid-80s I believe), but I had seen those machines in action many years ago and the performance is outstanding for fast etching of batch PCBs.
>
> The problem is that some parts are missing and/or require fixing. The two spray bars are lost. That is no problem because I can buy, cut, and cement 1/2" PVC as the originals manifolds. The problem is that I do not remember how many holes were in every spray bar. I remember that the hole size is about 1/16" ¿Am I correct?, since I used a drill bit of this size to clean of debris in the spray bars in those etchers many years ago. Do you recall how many holes, what distance between them, and the angle of up/down orientation in your Kepro etcher? I know that these details are very important to obtain the maximum performance of these units.
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> Thank you very much in advance for any help.
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> --- In Homebrew_PCBs@yahoogroups.com, "twb8899" <twb8899@> wrote:
> >
> > Grant,
> >
> > You could try using one of the Little Giant pumps. I haven't bought
> > one of these pumps in years but they used to cost about $25 from WW
> > Grainger. Kepro uses this small pump in their etchers. They modify
> > the pump by removing the metal impeller and installing one made from
> > PVC plastic. There are two pumps in the machine, one for each side.
> > The manifold is made from 1/2" CPVC pipe. The pipe has about twenty
> > or so small holes drilled to give the spray pattern. A piece of
> > plastic window screen hangs between the manifold (spray bar) and the
> > part to be etched. This screen is used to disperse the spray pattern
> > across the board for even etching. It works pretty good with 1 ounce
> > copper taking about 4 minutes to etch with ferric chloride.
> >
> > Tom
> >
>