Before we explain the last part, we want to warn you that it’s
obligatory to put on a mask and a pair of gloves to work with acids.
We’ll use 110 volumes oxygenated concentrated water and hydrochloric
acid solution. First one can be found in pharmacies and the second one
in the shops of cleaning products.
We also need a test tube to make an exact measurement, and a
plastic container where we’ll put a glass fiber immersed in acid. The
mixture will be: one part of the 110 volume oxygenized water, one part
of a hydrochloric acid solution and a one part and a half of tap water.
To help you imagine the quantity, for this board (20x6 cm9 we have
used 50 cc of oxygenated water, 50 cc of hydrochloric acid solution and
75 cc of tap water. Once we make a mixture, we continue to immerse our
board in acid. Carefully, you should always wear a mask and do this in
a ventilated room, or even outside.
The vapour that comes out is very toxic. We rock gently the
recipient (left and right) so that the acid moves and attacks the whole
board evenly.
When we notice that all of the copper that wasn’t covered by toner is
consumed, we pull out the board, with the gloves put on, and we put it
under the tap for a moment.
Now when we have finished the board, the only thing left is to
remove the toner. We dip the kitchen towel in the solvent and we remove
it little by little.
The final result, as you can see, is pretty good.
The details can be seen perfectly, like our name KEMISA. The only
thing that remains is to make drill holes and weld the components.
Enjoy!
