A really cheap OTC way to make PCB etchant from pool chemicals - Page 1
Forum section: electronics / general

author: Beamin
author_rank: Super Contributor
timestamp: October 26, 2017, 04:06:49 pm
content: So since I don't like spending money and was appalled by the price some supplier charge for making your won PCB's I came up with a better. I'm sure someone else has thought of this but anyways.You will need:~HCl- Buy this at a pool supply store for about $6USD a gallon comes in a box of two.~Regular drug store grade H2O2 costs about 2$ a bottle~Iron nailsPour some HCl out into a plastic container you can put a lid on but one you can cap with totally sealing it. Start with 500 ml or how ever much etchant you want. Do this in the garage or outside. If you have a car tools or anything metal you don't want destroyed like cabinet hinges keep the HCl away from it. Even if you can't smell the vapor it still is concentrated enough to just destroy almost all metals turning aluminum into a thick mass of white oxide and all razor blades and stainless steel tools into rust.Add an arbitrary amount of nails to the HCl not one, but about 10-30, it will start to go through color changes. Make sure the nails are NOT galvanized; that will add zinc and you don't want that. I left the nails in for a day then took them out. Cover but don't seal the HCl as gas is produced and it will pop the container open. Its hard to go by color the HCl starts out clear then goes yellow then will turn back clear and then brown or black. This has varied every time I did this so just look for a color change. Once again make sure the fumes don't get on anything metal. Copper in HCl is usually green.Add 1 part H2O2 to 2 parts HCl solution and that's it. Should work well. You can recharge the solution indefinitely if you want to see how there are videos on youtube but it is so cheap that its not really worth it unless you are trying an experiment.The only difference in this and the ferric chloride you buy in the store is that it's not the precise ratio of ferric chloride (and some ferrous chloride) to HCl, but you make up for that by adding the H2O2 to speed things up. 3% H2O2 is practically like just bubbling o2 or even air through your solution in this context.

author: hermit
author_rank: Frequent Contributor
timestamp: October 26, 2017, 11:12:21 pm
content: I've seen steel wool used instead of nails. Pretty sure it was on this forum not too long back.

author: cdev
author_rank: Super Contributor
timestamp: October 26, 2017, 11:38:29 pm
content: A far more eco-friendly and safe way to etch the occasional PCB is to usevinegar, (I use cider vinegar)hydrogen peroxide(normal strength from the drug store for cuts is fine) and plainsalt(both table salt and rock salt work fine).It produces very little in the way of bubbles but I still would not breathe them.. I suggest doing it with windows open and a fan going for better ventilation.It takes around 15 minutes of gentle agitation to etch a PCB using toner transfer. Rock the container you etch in every minute or so. Important!: Mark the pan you use clearly so it wont be used in the future to store food..Add small amounts of salt to restart the etching action.Even so, do it in a well ventilated area and don't pour the used etchant down the sink, pour it into a glass bottle and let it evaporate in the bottom.When you are done you can use acetone or nail polish remover to clean the board

author: Beamin
author_rank: Super Contributor
timestamp: October 27, 2017, 08:18:52 pm
content: Quote from: cdev on October 26, 2017, 11:38:29 pmVinegar is acetic acid that has been diluted down. Plain white vinegar will work best as it has just acetic and water. I'm wondering the purpose of the salt is? The NaCl won't react with copper as Na is more electronegative; the Cl won't react with the copper because the Na ions balance it out in solution. Acetic acid in higher concentrations then vinegar is actually more damaging to skin then HCl as it will cause burns and irritation even with very short contact times. Steel wool will work better as it has more surface area but I only had around nails.