Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@...> wrote:
>
> The other day I posted about a baffle I was trying to make.  My goal 
> was to get good agitation with good dispersion of bubbles.  Someone 
> said I had too big of holes, which weren't that way when I started.
> 
> Anyway, based on that comment I realized you can only get so much 
> power (Air) out of a tiny fish tank pump. So, like all "real men" 
> do, I opted for more power! MUCH MORE POWER!
> 
> I connected my big shop air compressor to the new baffle I made up.  
> I turned down the regulator till I could barely feel air comming out 
> of the air gun.  Then I held the baffle hose to the air gun and like 
> magic I had good bubbles and lots of them - everywhere.
> 
> Knowing that I will forget to turn down the regulator when etching a 
> board at some point, I will wait until I can hook up another 
> regulator for attachement to the etching tank.  That way, I should 
> be able to reduce the risk of having the whole tank of ferric 
> chloride sprayed about the shop.
> 
> It's still very dangerous in my opinion, but rather than buying 
> another fish tank pump, this is the next cheapest solution. 
> 
> The point of this post is, poor bubble volume and dispersion may not 
> be the problem of the baffle (Hose, stones, etc.), but rather not 
> enough volume of air going into the tank.
> 
> I suspect this will even out the etching and etch a heck of a lot 
> faster than before!
> 
> Chris


My solution to this was to use two of the larger fish tank pumps that
have two air outputs, glue all four pairs of tubing into a brass or
plastic part that had a screw type pipe on one end big enough to fit
all four tubes in (make sure you get the glue /between/ the tubes as
well) and the other end a connector to attach another tube of the same
width. I half expected the combined pressure to simply make the tubes
pop off of the pumps, but it worked, and gave enough pressure for a
good bubble stream, but I always had problems with uneven etching,
even after getting what I thought was even bubbling, so I finally gave
up on it entirely. Better than worrying about making an etchant
fountain, really...

I first started out using an air brush pump but I didn't use it very
long as I didn't want to ruin it.