Buying NaOH
IamSmooth, Tue Sept 16 2014, 08:52PMI want to get pure sodium hydroxide for developing my pcb. Is food-grade pure? Any suggestions where I can get some cheaply? I've seen it on Amazon. In the past I've seen it in some stores.
Edit: I just got some from amazon
Re: Buying NaOH
Daedronus, Wed Sept 17 2014, 08:40AM
Drain cleaner in solid form is usually NaOH, check the label.
However, NaOH is usually used for stripping the etch mask, for developing normally you want Na2CO3, that is washing soda.
A simple way to make it is to get baking powder (sodium carbonate) and put it in the oven for 1..2 hours. It will decompose into Na2CO3 above 200C
Daedronus, Wed Sept 17 2014, 08:40AM
Drain cleaner in solid form is usually NaOH, check the label.
However, NaOH is usually used for stripping the etch mask, for developing normally you want Na2CO3, that is washing soda.
A simple way to make it is to get baking powder (sodium carbonate) and put it in the oven for 1..2 hours. It will decompose into Na2CO3 above 200C
Re: Buying NaOH
Shrad, Wed Sept 17 2014, 10:04AM
if I'm right, it will also generate plenty of CO2 so do it in a vented area
Shrad, Wed Sept 17 2014, 10:04AM
if I'm right, it will also generate plenty of CO2 so do it in a vented area
Re: Buying NaOH
Daedronus, Wed Sept 17 2014, 11:11AM
Yes you are, good warning.
Daedronus, Wed Sept 17 2014, 11:11AM
Yes you are, good warning.
Re: Buying NaOH
IamSmooth, Thu Sept 18 2014, 01:48AM
Na2CO3 can be used instead of ammonium persulfate? I think I misinterpreted your post. Maybe you meant it can be used to remove the photoresist.
IamSmooth, Thu Sept 18 2014, 01:48AM
Na2CO3 can be used instead of ammonium persulfate? I think I misinterpreted your post. Maybe you meant it can be used to remove the photoresist.
Re: Buying NaOH
Daedronus, Thu Sept 18 2014, 08:36AM
I'm talking about developing and stripping, not etching.
You where asking about sodium hydroxide(HaOH) , it's usually sold as drain cleaner, while small blobs, but, for negative etch masks it's bad, it's used for stripping not developing.
Sodium carbonate (No2CO3) is used for developing, and it can be made from backign soda( sodium bicarbonate, NaHCO3).
Check the manufacturer's data for the mask.
Daedronus, Thu Sept 18 2014, 08:36AM
I'm talking about developing and stripping, not etching.
You where asking about sodium hydroxide(HaOH) , it's usually sold as drain cleaner, while small blobs, but, for negative etch masks it's bad, it's used for stripping not developing.
Sodium carbonate (No2CO3) is used for developing, and it can be made from backign soda( sodium bicarbonate, NaHCO3).
Check the manufacturer's data for the mask.
Re: Buying NaOH
Conundrum, Thu Sept 18 2014, 09:19AM
Hi, you really are better off with silicate as it is much more forgiving and has a multi year shelf life.
Sodium carbonate can be made from bicarbonate by heating, also you can kludge together a basic silicate using water glass (Na2SiO3) and sodium carbonate.
Conundrum, Thu Sept 18 2014, 09:19AM
Hi, you really are better off with silicate as it is much more forgiving and has a multi year shelf life.
Sodium carbonate can be made from bicarbonate by heating, also you can kludge together a basic silicate using water glass (Na2SiO3) and sodium carbonate.
Re: Buying NaOH
Daedronus, Thu Sept 18 2014, 09:23AM
I would also like to try silicate for developing, do you have a recipe for a developing solution?
Daedronus, Thu Sept 18 2014, 09:23AM
I would also like to try silicate for developing, do you have a recipe for a developing solution?
Re: Buying NaOH
Conundrum, Thu Sept 18 2014, 10:31AM
Leave that with me, I am out at the moment but will try and check to get exact amounts.
It needs a lot of experimentation as despite silicates being kinder than NaOH it can still overdevelop if you get it wrong enough.
EDIT. from "Mikeselectricstuff.com"
"Thanks to Robin Moorshead for the following procedure to make silicate developer solution:
Take 200cc of "water glass", add 800cc of distilled water and stir. To this add 400g of sodium hydroxide (caustic soda).
Important safety precautions: The sodium hydroxide solid must NEVER be handled, use disposable gloves. When the sodium hydroxide dissolves in water it produces a great deal of heat so it must be added a little at a time and each portion allowed to dissolve before more is added. If the solution becomes very hot leave it to cool before adding more sodium hydroxide.
The solution is VERY caustic and it is particularly damaging to the eyes, use eye protection when making and handling it.
It also ruins clothing. Water glass is also known as "sodium silicate solution" and "egg preserver", It used in fire proofing fabrics, for waterproofing walls and making "chemical gardens". Caustic soda is used for clearing drains and available from any chemist. The solution cannot be made by dissolving solid sodium silicate.
This solution will be the same strength as the concentrate, and so will need diluting - about 1 part concentrate to 4 to 8 parts water, depending on the photoresist used and temperature.!"
Conundrum, Thu Sept 18 2014, 10:31AM
Leave that with me, I am out at the moment but will try and check to get exact amounts.
It needs a lot of experimentation as despite silicates being kinder than NaOH it can still overdevelop if you get it wrong enough.
EDIT. from "Mikeselectricstuff.com"
"Thanks to Robin Moorshead for the following procedure to make silicate developer solution:
Take 200cc of "water glass", add 800cc of distilled water and stir. To this add 400g of sodium hydroxide (caustic soda).
Important safety precautions: The sodium hydroxide solid must NEVER be handled, use disposable gloves. When the sodium hydroxide dissolves in water it produces a great deal of heat so it must be added a little at a time and each portion allowed to dissolve before more is added. If the solution becomes very hot leave it to cool before adding more sodium hydroxide.
The solution is VERY caustic and it is particularly damaging to the eyes, use eye protection when making and handling it.
It also ruins clothing. Water glass is also known as "sodium silicate solution" and "egg preserver", It used in fire proofing fabrics, for waterproofing walls and making "chemical gardens". Caustic soda is used for clearing drains and available from any chemist. The solution cannot be made by dissolving solid sodium silicate.
This solution will be the same strength as the concentrate, and so will need diluting - about 1 part concentrate to 4 to 8 parts water, depending on the photoresist used and temperature.!"
Re: Buying NaOH
Dago, Fri Sept 19 2014, 08:08AM
I have always used NaOH or KOH to succesfully develop my homebrew PCBs.
Not much sense in making them at home anymore though because PCBs are so cheap from China. Maybe if you're in a hurry.
Dago, Fri Sept 19 2014, 08:08AM
I have always used NaOH or KOH to succesfully develop my homebrew PCBs.
Not much sense in making them at home anymore though because PCBs are so cheap from China. Maybe if you're in a hurry.
Re: Buying NaOH
Conundrum, Sun Sept 21 2014, 11:24AM
Urgent note, please PLEASE if you are experimenting ensure you label everything.
Someone nearly got in serious trouble over here a while back because they had numerous unlabelled chemicals and it all had to be disposed of as hazardous waste because some had crystallized.
Conundrum, Sun Sept 21 2014, 11:24AM
Urgent note, please PLEASE if you are experimenting ensure you label everything.
Someone nearly got in serious trouble over here a while back because they had numerous unlabelled chemicals and it all had to be disposed of as hazardous waste because some had crystallized.
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