Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

----- Original Message -----
From: "Bryan Pope" <bryan.pope@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, March 23, 2007 2:50 PM
Subject: Re: [Homebrew_PCBs] Velleman PCB Etching Tank ET-20


> Leon Heller wrote:
>> I've just etched a small board (ARM JTAG interface) using the new tank
>> and it looks very nice. The instructions suggest two minutes to warm
>> the solution after switching the heater on; I used about five minutes,
>> and at least 20 minutes is probably about right. Because of the low
>> temperature etching took about 15 minutes.
>>
>> I used my usual photo-etch technique with artwork produced on an HP
>> DeskJet 5940 inkjet printer using Premium JetStar film. The text on
>> this board had the default 5 mils line width, and came out perfectly.
>> Narrowest track size was 12 mils, though.
>>
>> Here is a photo of the PCB:
>>
>> http://www.leonheller.com/pcb.jpg
>>
>>
> That looks ∗really∗ good! What process do you use for the photo-etch
> technique? I searched the web and found that UV is the conventional way
> to develop the resist but was looking through my Jameco catalog
> yesterday and they offer a positive photo-etch package from Datak that
> is supposed to only need a 100-watt incandescent to develop the
> resist.. Has anyone used this product before and if so, what were your
> results?

As I said in my earlier post, I use an HP 5940 printer and JetStar Premium
film to create the transparency. I then expose the PCB (precoated positive
resist) in a home-made UV unit, and develop in sodium hydroxide solution.

Leon