pcb etchant solution

[Jordan]

Hi all!
Would anyone know where I can buy etchant solution in Ontario Canada! Radio Shack use to carry it but seemed to stop. I don't see it anywhere in the Digikey catalogue. Any Suggestions???

[Mr.RC-CAM]

Yes, you can buy it from the Radio Shack stores: #276-1535, $3.99 USD (http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F005%5F014%5F003%5F000&product%5Fid=276%2D1535).

Mouser: 524-22-237, $7.25 USD. (http://www.mouser.com/index.cfm?handler=productsearch._listproductsearch&criteria=etching&Precision=+All+Words&SupplierID=&categoryID=&maxrows=500&maxperpage=25)

Action Electronics: 1 gallon, $28.31 USD. (http://www.action-electronics.com/gcelect.htm)

This is just a start -- Etching solution is not that hard to find. Shipping it may be an issue (hazard mtl), so call your local electronic part and ham equip stores to see if they have any in stock.

Regards,
Mr. RC-CAM

[BMatthews]

Future or Active Electronics (one and the same but seem to use the names at different times and places) should have etchant. Not sure if they mail order though.

[DNA]

You can order the granules from this site and mix it when you need it.
http://www.allelectronics.com/cgi-bin/category.cgi?category=445&item=ER-3&type=store

I also found this formula on the web, but have never tried it myself.
Hydrochloric acid is the same as muriatic acid used for swimming pools, or can sometimes be found in paint stores. It is very dangerous being a very strong acid.

Two developers you can use, Ferric Chloride and Hydrochloric Acid/Hydrogen-peroxide.

Hydrochloric (very clean)
One part Hydrochloric Acid
One part Hydrogen Peroxide
Four parts water
NEVER store it
Etches in 3 - 5 minutes

Ferric Chloride
500gm ferric Chloride powder
500ml water
Etches in 30 - 50 minutes
(Less if you warm it a little)
Very staining

[U2Steve]

DNA- I'm curious (as always!)- Why not store the HCL/peroxide solution? Does it degenerate, or eat through the container, or lose potency, or sumthin'?

[DNA]

Dunno. As I mentioned above, I've not used that formula yet.
But since it costs only pennies to make, there shouldn't be any
reason to store it. Make it fresh each time.
Here's some more info and the original web site where I found it.

http://w1.859.telia.com/~u85920178/data/pcb2.htm

http://www.atmsite.org/contrib/Webb/pcb/

There are two etching solutions: Ferric Chloride (FeCl3) and Hydrochloric acid (HCl) + Hydrogen peroxide (H2O2). The Ferric Chloride solution is prepared by pouring 500 gr of FeCl3 into one litre of water. The other solution is prepared by mixing 200ml of HCl, 30ml of H2O2 and 770ml of water for a total of 1 litre of solution. Ferric Chloride produces more poisonous gas during chemical etching process, so the other solution (HCl+ H2O2+Water) is preferred, especially in the laboratory environment. However in any case you must etch in well-ventilated places.


The basic mix: 1 part commercial grade hydrogen peroxide (about 30% I think), 1 part fuming hydrochloric acid, AND 6 - 8 parts water with the H2O2 and Hcl separately added *slowly* to the water. This concentration gives a useful etching speed. Waste products are copper II chloride (soluble with a low pH) and water. DO's: - Ventilation when pouring the Hcl out of the bottle - A *good* impervious resist with no pinholes - Occasional agitation to release small bubbles from the surface of the board - water at hand to wash yourself if you get acid or peroxide on your hands. The peroxide in particular will attack skin very rapidly and you'll feel it.
DON'Ts: - *DO NOT* mix the undiluted acid and peroxide together. The mix will produce copious amounts of chlorine (none will be produced if the mixing directions above are followed).
- be tempted to use a strong mix to make etching much faster. A strong mix will not only etch a board bare in a matter of seconds, it will boil as well (spatter factor).
- be tempted to top up the acid and/or peroxide if the etching crawls to dead slow. Make a fresh mix instead. Too much acid gives the mix a green hue during etching and too much peroxide makes the copper appear shiny. Ideal is for an oystery sheen to cover the copper if the board is lifted out of the mix and drained. If the acid is becoming exhausted, insoluble blue deposits appear on the copper. A correct mix will give the mixture a blue colour, deepening as more copper is dissolved. The basic action seems to be that the peroxide oxidizes the copper leaving the oxide easy for the acid to deal with.

[U2Steve]

I gotcha- thanks for the info!!

Steve