On 3/23/2019 6:56 PM, Harvey White wrote:
> On Sat, 23 Mar 2019 16:29:17 -0500, you wrote:
>
>> I hafe to add my experience with aerating etching solutions.? I had a tank using ammonium persulfate.? I etched in a closet in my carport.? After a dozen or so, i looked and the heads of all the nails were missing.? Aerosolizing etchant is not a good idea and it can grt anywhere.? I use HCl + H2O2 + H20.? Ru;er gloves, rubbing the boards and 5 to 10 minutes later im done.? It takes me less than 1/4 cup of etchant to do a board.? HCl is cheap at Lowe's and 35% H2O2 is readily available from Amazon.I never liked FeCl.? Too thick and the sludge buildup kept the etchant away from the board.I woufd suggest a water pump over aeration.? I have also seen bubbles protect the copper from the etchant.Sent from my T-Mobile 4G LTE Tablet
> I'd wonder if the average water pump can handle corrosive solutions.
> I've not seen any except the peristaltic pumps, which you could make
> yourself, I suspect.
>
> FeCl I've used for a long while at the beginning of my career (in
> etching boards, that is....), and it is quite thick and sludgy...
> however, you need to heat it and keep it moving.
>
> Aeration will do that, as well as help the etchant when it turns to
> CuCl plus sludge.
>
> Harvey
>
Looks like those peristaltic pumps can be had for cheap on ebay. I don't
know what flow rate (seems like it would be small) they produce but here
is a cheap one in the US even:

https://www.ebay.com/itm/INTLLAB-Peristaltic-Liquid-Pump-Dosing-Pump-for-Aquarium-Lab-Analytical-NEW-/202608086462?_trksid=p2385738.m4383.l4275.c10

Thanks,

Dave