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DIY pcb anyone?

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John Rudd:
Just tried to knock off a couple of boards but its all gone PT....

Firstly my developer was too strong.....

...but I'm not sure if my exposure time is too short ...around 3 mins...
Any tips or pointers?

awemawson:
John,

Before I moved (about 6 years ago) I had a full development  lab pcb production line set up, with developing tank, rinsing,etching tank, washing, and tin plating - it was one of the things that got sold to reduce volume for storage. About 18 months ago another similar one flitted by me on eBay and I reached out and grabbed it - its like this one:

http://www.megauk.com/pcb_labstation.php

I've installed it, plumbed it in, replaced a faulty heater, and got all the chemicals but not yet filled it up. I used pre-coated boards, exposed through overhead slide film printed on my laser printer, developed using mega developer, and etched with ferric chloride. I would let the developer tank temperature stabilise for a while, then put the board in and examine it every 30 seconds or so until it looked right. Actual time of course varies with the strength of the developer and and its temperature.

Lots of hints and tips on the Mega site

Bluechip:

--- Quote from: John Rudd on September 08, 2013, 10:46:08 AM ---Just tried to knock off a couple of boards but its all gone PT....

Firstly my developer was too strong.....

...but I'm not sure if my exposure time is too short ...around 3 mins...
Any tips or pointers?

--- End quote ---

PT in what way , John ???
 
I have a MEGA UV unit. I only expose for 2 mins ... UV tubes are little used though, so I suppose they are fairly good emission. Need to be warmed up first for 10 mins as MEGA recommend.
 
Dave BC
 
 

John Rudd:
Dave,
I'm using pre coated board with ohp films and a 4 tube uv unit.
I exposed the board for 3 mins,then developed using a proprietary solution.
The board appears to develope ok but then etches poorly...Fresh ferric chloride solution used...
Not sure if the board is past it's sell by date tbh....(I've had the board for a umber of years stored in a cool dry environment)
My methodology has been fine uptil now.....

I'm thinking the board isn't exposed long enough......?

Bluechip:
John
 
I assume it's not removing the copper in places. ??
 
I only use MEGA stuff, odd bods I know who do pcb's warned me about 'pick 'n mix'  sometimes not working properly, but if you've used it all before that should not be an issue.
 
Could be the board, I believe it does have a shelf life.
 
I get mine from CPC, I think it is MEGA sourced.
 
Only time I got  other than MEGA was some board off an ebay seller .... cheap ... and not without good reason it turned out...  :bang:
 
All the resist had the 'spray' lines across it ... utter rubbish. Fortunately I only got 2 A5-ish sheets to see what it was like. 
 
I reckon I could put the resist on better myself with a stick ... :(
 
Dave BC
 
 
 

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