So much for the heater. Now i had to make the hose for the air. The first design of the hose was a U shape with holes at both sides. It was though a bad idea. I was not sattisfied with the result. The bubles from one side interracted with the bubbles from the other, the agitation was not even inside the tank. So, i redesigned the hose. After some tests, i came to the conclusion that the hose must be in a single line with holes on both sided of it in a "V" pattern. I fixed the hose at the bottom of the base with hotmelt glue. I used also hotmelt to close the open-end.
I used an 8mm diameter (external diameter) plastic tube, like the ones used in machines with high air preassure. To bend the hose, i used the hot air gun. As for the holes, i had to calculate the total area of the holes to be the same with the hose's area. I would use 1mm drill bit, and the hose from the pump has an internal diameter of about 5mm:
Hose Area = (3.14 x 52) / 4 = 19.635
Drill Bit Area = (3.14 x 12) / 4 = 0.785
Dividing the above numbers:
n = 19.635 / 0.785 => n = 25 holes
I drilled 13 holes from one side, and 12 holes from the other side of the hose.
To bend the hose, i used a hot-air gun
I formed the hose and drilled it
With hot-melt glue, the hose was fixed on the base
The base is complete!
Here is the tank with all the accessories attached:
For those starting out making pcbs who want an out of the box solution, tank, heater, bubbler,thermometer have a look at kinsten.com.au $AU65 for the complete kit.
Look up edinborough etch - by adding citric acid to the ferric chloride solution - the copper ions are moved away from the pcb's copper surface much more efficiently than using bubbles.
Also, when I am only making a quick small board, I put the ferric chloride into a conical(erlinmyer) flask put it in a bath of boiling water from the kettle whens it's above 45C pour it into a plastic bowl & drop the board in & move the ferric chloride over the board with a brush.
@Skiwee Yes i do use it quite often indeed. As a matter of fact, this is the setup i use to make all my PCBs and never failed me.
I plan to make a bigger one, like 4 liters or maybe bigger. So i have some questions that maybe you could answer. To avoid flooding the comments board, i have open a thread in the forum. Please visit the following link:
I like the setup, you seem to use it quite often.
In the second video you agitate your etching solution. There\'s no need for that it\'s just copper sediment and waste from previous uses (it\'s best to hand this to your local hazardous waste management/company).
The solution should have a dark orange/brown \"oily\" appearance.
example image; http://upload.wikimedia.org/wikipedia/en/thumb/8/8c/Iron%28III%29_chloride.JPG/551px-Iron%28III%29_chloride.JPG
for more information on chemicals a quick MSDS search on google goes a long way.
Were did you find the air pumb and the heating resistor ... Also an other thing is about the thermistor is PTC or Ntc what you suggest!
Very nice job !! ... i Would like to build one too :-p
Welcomes from Crete!!
the bubbles accelerate the procedure. They do not stick on the PCB, and even if one bubble sticks on it, there will be another bubble to remove it within a moment. The do a great job.
I do not know if a pump could do a better job, i have not test it yet. But i do know that it would be an ugly job to clean it. Copper remains would destroy the pump if not used. It had to be cleaned regularly to keep it clean. And moreover, why risk circulating the messy etchant outside the tank, if the bubbles work that fine?
wont the bubbles stick to the PCB during the process and hence reduce the effectiveness??
since you already used a fish tank air pump, why not a water pump to circulate the solution? if a pipe with holes along the length is made and one end sealed off, that would help distribute the solution even better.
herctrap you are so right. I had totally forgotten it. I had the masters given to a friend to make the video, but he never did it and did not inform me. I forgot all about it. I will search for the masters (although i am sure that i will not find them again) or i will run a new video. thanks for noticing reminding me.
By the way, my goal was to have a video for each project or circuit (and sometimes for theories and experiments). The fact that you noticed that this page should have a video, makes me double happy. This proves 2 things for me: first that people want to see videos of the circuits and the projects (and so my efforts to make them is not useless), and second that people do know that in this site they expect find videos, and that something is going wrong if there is no video in a project. When i upload the video i will post it in the RSS. Thank you again.
At the moment, i etch without ventilation, but i have an old vacuum that i will convert to ventilator. I really had no idea that rust could occur, although now it sound normal to me! I was considering the ventilation for health reasons only. Thank you for the info Vern!