Hi Adam
>
>
>Markus Zingg wrote:
>> Hi Adam
>>
>> First off - let me thank you for the critical feedback. I am in fact
>> not experineced and therefore thankfull for any information.
>
>I can give tips on the acid copper plating since I have a
>bit of experience with this. I have been doing small amounts
>of copper plating for about 2 years now. I've been through
>about 3 major tanks revisions before I had something working.
Well, I will soon be able to tell wether mine works or not :-)
>> I figure I could change the setup so as all of the anodes would be
>> floded. However, I don't understand how I should avoid that copper is
>> not covered by the acid on one hand, but not having any other material
>> reach the acid on the other hand.
>
>The corrosion is due to a electrochemical reaction happening
>at the air/liquid interface. Its slow, and may take a year
>for the copper you have to completely corrode away.
>
>You hang the anode plates by pieces of PVC insulated solid
>copper wire. The wire can be attached by solder and then
>sealed with glue. The glues I've had most success with are
>PVC solvent cement or polyurethane sealant. Epoxy can lift
>over time.
>Alternatively you can drill small holes into the copper
>plates a bit larger diameter of the solid wire and use a
>center punch and hammer to crimp around the wire.
>Commercial platers use titanum mesh baskets and simply
>fill them with copper nugets. Or they might use titanium
>clamps on solid copper bars.
Thanks for the hints. I will consider them, but think it's best if I
now do experiement with what I have. Changing the way the plates are
mounted to what you propose is easy.
>> I of course do not intend to spill a drop. I may will however cover
>> the steel with a plastic film or else change to stainless steel or
>> such.
>
>Stainless is good around sulfuric acid, but do not have it
>permanently immersed. Stainless corrodes slowly when
>immersed, but is very resistant to splashes and being wet by
>the acid. It has something to do with the dissolved oxygen
>from the air maintaining the surface passivation.
>
>Every plating tank I've seen, including mine, will over time
> become surrounded by dried salts and plating chemicals
>because its very hard to completely avoid splashes and drips.
As you can see on my pages, the machine is very easy to disasemble /
assemble. So, whenever I change the solution I of course will
completely clean the tanks et all. Again, I will surely see what
happens.
>You should be agitating the plating solution by air bubbles
>or motorized PCB motion. A still solution will be limited to
>very slow plating rates due to limited copper ion diffusion
>at the surface of the PCB. An attempt to plate at normal
>current density (1 ~ 2 A/dm^2) in still solution will only
>give you rough, and "burned" deposts. Air bubbles are simple
>to setup but create fine splashes of copper electrolyte
>solution. These splashes must be stopped by some type of lid.
My setup includes motorized PCB motion. Thers an excenter wheel that
drives a frame to which the PCB holding mechnism is pluged in. Works
nicely and I even can control the speed of the motion. Adding air
bubbles to the tank would be easy also. However my friend also is
using motorized PCB motion and as mentioned his resutls are stunning.
>Happy plating.
Thank you - I will start to do some experiments now and post the
results.
Markus