Making PCB's

[audioPT]

Hi fellows!

I've just make a UV light box and want some help.

1. Do I need to turn on the lights for some time before make the exposure (so the lamps can heat a little)??
2. What is the best exposure time with pre-sensitive boards?
3. Anyone knows what are the terms, in portuguese, or the formulas of the best developer and etching liquids?

I only know caustic soda and ferric chloride. Are there better ones than those??

Thanks in advance

Pedro Martins

[grimberg]

1. Nao.

2. Depende do tipo e quantidade de lamapadas. Para duas lampadas fluorescentes de 25W cada, 8 minutos sao suficientes.

3. Percloreto de ferro e o meu favorito ja ha mais de 20 anos.

[audioPT]

Obrigado pela informação!

É bom saber que há muitos portugueses fanáticos pelo áudio por esse mundo fora! (Califórnia, hein!?!?)

For the other guys, sorry for the portuguese language in the forum.

You know, when we love our Country of Birth, we are tempted to speak our language.


Pedro Martins

[grimberg]

Pedro,

Just to clarify, I was born in Brasil. But it is the same language after all. As for the Ferric Chloride, you just have to take some simple precautions:

1) It stains any porous material. Protect all adjacent surfaces with a plastic sheet. Wear clothes that you don't mind staining in case of a spill.

2) It will react with any metal container. Use one made of glass or plastic when etching your boards.

3) Don't leave any metal objects near the place where you regularly etch the boards. The fumes may cause those objects to rust.

4) When disposing of it, make sure you dilute it before pouring it down the drain. Flush it for a couple of minutes with cold water so it won't corrode metal pipes.

[BrianL]

Ferric Chloride is a hazardous chemical. DO not pour down
your sewer!! Take it to some place where it can be safely
disposed.

Also, it's VERY bad on your skin.

[jackinnj]

just pour with a lot of water.

the Ferric chloride plus water plus copper yields, among other things, hydrogen gas.

[audioPT]

Please, don't be afraid!

I also buy a bottle with some kind of 'process inverter' to dilute with the Ferric Chloride. It neutralises the corrosive action of the Ferric Chloride.

I also have finished the equipment: UV box, Developer and etching. The last ones are made of glass. I also use a air pump (from aquaruim) to accelerate the process and it worked out! 15min.

Soon I'll put here some pics.

Thanks for the replyes.

P.S. Well, for an brasilian guy, you write very well portuguese from Portugal

[masood]

dear all reader,
good morning. i am new. making electronics gadgest is my top hobby. i want to etch my pcb so i purchase 12 inch 8 watt uv tube light i expose it through posetive image on copper clad for 30 mins.after 30 mins i saw copper clad there was not a single line .please help me to how can i get sharp image on clad to etch .thanking you yours ever masood

[dangus]

The best way to determine exposure time is to do a test strip. Use a long narrow piece of sensitized circuit board, lay your artwork on it and cover with glass, then cover all but a portion of it with a book or something that is light-proof. Expose for 5 minutes, then move the cover to expose more. Repeat until the last part of the strip has been exposed for 5 minutes. Then develop, and see which exposure time gave the best results.

This is the same technique used in photo darkrooms. Making a test strip

[masood]

Originally Posted by dangus

The best way to determine exposure time is to do a test strip. Use a long narrow piece of sensitized circuit board, lay your artwork on it and cover with glass, then cover all but a portion of it with a book or something that is light-proof. Expose for 5 minutes, then move the cover to expose more. Repeat until the last part of the strip has been exposed for 5 minutes. Then develop, and see which exposure time gave the best results.

This is the same technique used in photo darkrooms. Making a test strip

dear dangus,
thanks reply i will try this method
your ever