Etch Resist Stripping

I normally use acetone, too.... but the positive photo resist usually developed by NaOH, --- appx 14 g to the liter, can be stripped by a stronger NaOH solution, -- appx 50-60 g pr liter..
use a brush to help dissolve the resist
Often I actually use both- acetone first- because i use a chemical tin plating, and the last NaoH strips any residues sometimes left by the acetone, and preps the boards for the tin.
OTOH- at least some of the pre coated boards sold throughout europe, don't need stripping, as the resist can funtion as a solder mask and can be soldered right through.........at least that's what the PR says...
 

mzzj

Member
2005-07-02 8:17 pm
65N 25E
richie00boy said:
I . NaoH on it's own seems to leave a film behind. ... The stuff I use is drain cleaner.

Impure NaOH or something else mixed to drain cleaner?
I have used 2% NaOH and result is as clean as possible. Leave soaking for 2-15mins and rinse with hot tap water after NaOH and you should be done.

Steel wool or abrasive paper takes years to remove etch resist what we use at local univ. especially if I exposure bit longish time(paper mask for example) Maybe that resist is stronger than some others, it is also negative instead of usual? positive resist.
After drilling i use also steel wool to remove drilling burrs
 
If it is sold as "drain cleaner", it might have some other additives...
Over here we buy it at the paint shop as "caustic soda",- also used for paint stripping and heavy duty cleaning
( and beleive i t or not: to make "lutefisk"-- dried cod soaked in lye, then rinsed for a couple of days in water.... a well known norwegian delicacy, mostly used around x-mas time.... and-- it is no joke !!!!!)
 

mzzj

Member
2005-07-02 8:17 pm
65N 25E
AuroraB said:
If it is sold as "drain cleaner", it might have some other additives...
Over here we buy it at the paint shop as "caustic soda",- also used for paint stripping and heavy duty cleaning
( and beleive i t or not: to make "lutefisk"-- dried cod soaked in lye, then rinsed for a couple of days in water.... a well known norwegian delicacy, mostly used around x-mas time.... and-- it is no joke !!!!!)
We eat here that NaOH-cod also :D
but Swedish rotten herring(fermented) is absolute no-no for me

:eek: