Photoresist: identificaiton of developer and resist remover - Page 1
Forum section: electronics / beginners

author: naut
author_rank: Contributor
timestamp: February 02, 2017, 10:59:15 pm
content: greets,I've bought a Photoresist Roll+Developer+Resist Remover kit on eBay.http://www.ebay.com/itm/262575896863The two zip baggies don't have anything written on them, so I don't know which one is the developer and which one is the resist remover. The seller from China does not seem to understand English so I was not able to get an answer from her/him. Perhaps someone can tell me which one is which from the attached photo?Thanks!

author: sleemanj
author_rank: Super Contributor
timestamp: February 03, 2017, 05:26:02 am
content: Quote from: naut on February 02, 2017, 10:59:15 pmIf it's just negative dry film photoresist, the 'developer' is probably sodium carbonate (washing soda), and the stripper sodium hydroxide (lye, caustic soda, draino). I wouldn't use what they provided if you don't know which is which, you don't want an unknown solution that might be sodium hydroxide, nasty stuff.You can use sodium carbonate or percarbonate/peroxyhydrate to both develop and strip. 30g/L room temp is about right, not too critical, develop about 3-5 mins, strip about 15mins, warming a bit for stripping helps. Have a look in your laundry, you might have some already, usually those "oxygen whitening action" powders (i use Sard Wonder Oxy Plus) are just percarbonate and a surfactant, works great. Acetone will also strip, 30 seconds in an acetone bath and the resist will all shrivel and float off.

author: Ian.M
author_rank: Super Contributor
timestamp: February 03, 2017, 06:23:59 am
content: Sodium carbonate or percarbonate will effervesce with acid producing CO2, Sodium Hydroxide wont. Take a watch glass with a few granules of the chemical and add a drop of dilute mineral acid. Its going to be exothermic so DO NOT use large quantities.

author: amyk
author_rank: Super Contributor
timestamp: February 03, 2017, 11:34:07 am
content: They do have 1 and 2 written on them, which suggests you use 1 first, then 2.That said, 1 does somewhat look likehttps://en.wikipedia.org/wiki/File:SodiumHydroxide.jpg

author: naut
author_rank: Contributor
timestamp: February 03, 2017, 07:34:43 pm
content: hey thanks guys for the info, I hope I can get around to trying this stuff in the next few days.Quoteoh, I wrote those numbers, for identification.

author: helius
author_rank: Super Contributor
timestamp: February 03, 2017, 07:42:29 pm
content: Sodium hydroxide tends to form larger, round grains, like bag #1. But I wouldn't go by that alone. You should always wear gloves and goggles when handling it, and wash your hands within 5 minutes or so after any spills even if it was diluted. It's eminently possible to handle safely, but any mistakes can be very bad.

author: knks
author_rank: Regular Contributor
timestamp: February 16, 2017, 10:46:32 pm
content: Add water to both of them, sodium hydroxide solution will be hot.Another option, sodium hydroxide can dissolve hair.

author: Unknown
author_rank: Unknown
timestamp: February 17, 2017, 09:18:23 am
content: For a quick test, cut out 2 small pieces of resist and peel of the backing. Make up a small amount of each solution and dunk one piece of resist in each. If the resist dissolves and leaves the clear plastic film then that is your stripper. If nothing happens then that is your developer.To be honest, do you want to be faffing with unknown chemistry from an unknown source in China? Resist developer is available from reputable sources and isn't expensive. You don't need a separate stripper, either leave the resist on or re-expose your etched board in your UV box and pop it back in the developer.