Positive-20 Problem. (photo)

[probert]

positiv 20

Hi,

To Sokrat : Positiv 20 can be bought at Conrad Electronic, if they exists at
Your country.
Sobakava: some day ago I could make similar pattern like You. I tried to
repair the first photoresist layer on a copper board sprayig a second layer on it, just some seconds after the first try....

Regards,
probert

 

[glenjoy]

positive20 pcb

Hi, try to use paint thinner in cleaning your board. Or polish it first with metal polish, then clean with paint thinner (industry grade).

When spraying with teh resist, try to do it in a close room, that there is no wind blowing, and not so many amount of dust to fly around, then practice, spraying with thin coating.

 

[chrismicro]

expired positive 20

Shake the spray can properly spray the board and tap it slightly in flat position on one side on a hard surface like table top until coating is even lay board flat and air dry in a dark dust free place then in an oven at 70deg C for 15 minutes and expose and etch. For a quick exposure I use bright sunlight for 50 seconds with great success. I use the top part of an old scanner (glass and lid to hold the positive down on the board)

Added after 16 minutes:

For etching I use 1 part peroxide 5 parts pool acid and 5 parts water etching time under 30 secconds

 

[rajudp]

positive20 expiry

i use dry film photoresist and giving good results.
this is a negative acting film

 

[harjeetsaini]

HI

I HAVE ALSO USED POSITIVE 20 SPRAY I HAVE ALSO VERY BAD EXPERINCE FOR THE SAME I WAS TRYING FROM LAST 7 MONTH TO GET PROPER PROCEEDER BUT I DIDNT GET IT SO ANY PLEASE HELP WHERE TO GET READY MADE PHOTO RESIST PCB.

 

[chrismicro]

Sobakava you spray it to thick, I clean my board with math-elated spirits or you can use alcohol spray the board as thin as possible and put it in a dust free horizontal position to air dry then in an oven at 70 deg C for 15 minutes the tin of positiv 20 that I'm using at the moment is about 3 years old and I have success every time with tracks as small as .245mm Sory for the poor photo but I took it with my webcam.

 

[ffddoo]

Re: uv lamp positive 20

I had the same case when holded positiv20 out of the fridge more than few months.If you put it in the fridge, (not to the icy part , but in the lower part of the doors ) you can extend its life to more than 2 years.The case on the picture is the case of bad cleaning or expired positiv20.

Greetings
Dragan

more than two years? much more? i was thinking on buying a pack of positiv 20 in order to have it for some years