# grind off solder mask to get down to copper

W

#### Werty

Jan 1, 1970
0
Whats the chemical to take off the

solder mask , so i can solder to tiny

PCB traces ? I guess some acid that

wont harm copper .

Im Hacking the connector on a

game box "GP2X" .

I want my own , more robust connector

where all the USB lines are heading off

board in same direction .

mail is

x-x-x-x-WERTY-x-x-x-AT-x-x-x-x-x-
x-x-x-x-S_W_I_S_S_I_N_F_O-x-x-x-x-
x-x-x-x-ORG-x-x-x-x-

BTW im also doin ARM 7 mcu's .
Ill hook up a $44 ARM7 with USB as a "peripheral" to control KB and LCD , and pass on important stuff to a central ARM7 . I test code on the first ARM 7 , so the central 7 , can't crash . Central ARM 7 can boot the other in milliseconds . I will use low cost LCD ,BW ,$10
from BG Micro .
This project is unique , because it
will never use text . There will be
icons and images on the LCD to
show you what is happening .

M

#### [email protected]

Jan 1, 1970
0
Whats the chemical to take off the

solder mask , so i can solder to tiny

PCB traces ?

I guess some acid that

wont harm copper .

no such thing

NT

A

#### Arfa Daily

Jan 1, 1970
0

no such thing

NT

I agree with meow. It is very difficult successfully hand soldering to
genuinely tiny traces, but I guess it depends what you and I define as "
tiny ". I'm talking traces of less than a half milimetre, separated by a
similar amount. I always use a scraper to remove the solder resist. I have
an Exacto scalpel with a blunt curved blade fitted for the job. I then
liberally tin the exposed copper tracks, and then solder-mop them back flat,
before soldering the new wires on, using a tiny amount of liquid flux, and
the finest gauge solder that you can get. The flux gives serious help with
getting the solder to stay *on* the tracks where you want it, rather than
flowing *between* them, where you don't ...

When I've finished, I usually put a small bead of two-part epoxy in a line
across the new conductors, back a short distance from where they are
soldered, to offer a bit of mechanical strength, as the tiny tracks will
lift if they get the slightest pull from the new wires.

Arfa

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