Re: MAKING YOUR OWN PC BOARDS [1 Attachment]


davemrtn
 

.016 if more than reasonable when using a PCB House to make your boards.


Years ago I used the tape and mylar method for very complex boards, usually laying out the boards, with solder mask and silkscreen and all mylars were a minimum of 2x, if not 4x, requiring photo reduction prior to the film being shipped to the fab house.

�The iron I use for smt I purchased from radio shack when they still had a store here.� If you search there website for cat # 6400215, you will see a photo of the iron.


More than the size of the iron, the diameter of the solder used will have the greatest impact on your success while soldering smt components, if you are using a roll of solder.


David Martin - NA1MH - Mountain Home, Ar. -----------------------------------------

On 2/22/2017 16:26, Bry Carling wrote:

0.016" traces are quite reasonable.


We used to make PC boards designed with Tape and Light tables in the mid 1970s

and the traces were often as narrow as 0.010" or 0.015" although 0.020" was preferable as a minimum.


THAT being said, I would not want to try to solder to traces that small and that close together., Very challenging!� What kind of IRON and TIP did you use?


Thanks - Bry AF4K


From: 4sqrp@... <4sqrp@...> on behalf of David Martin davemrtn@... [4sqrp] <4sqrp@...>
Sent: Wednesday, February 22, 2017 3:15 PM
To: 4sqrp@...; n5ib@...
Subject: Re: [4sqrp] Re: MAKING YOUR OWN PC BOARDS [1 Attachment]
�
�

Jim,

��� You mentioned minimum trace width.

��� Playing around making a smt board for an oscilator I made this board with 0.016" (16mil) traces, and fortunately the even narrower spaces between (near the chips) did etch out ok.

The worst thing was dealing with solder bridges, so use of solder wick was required from time to time.




David Martin - NA1MH - Mountain Home, Ar. -----------------------------------------
On 2/22/2017 12:57, n5ib@... [4sqrp] wrote:
�

I've tried out Chucks's suggested paper, and a couple of other re-purposed alternatives. they certainly work, but it took a while to soak off, and I always had trouble cleaning off the paper residue that remains stuck. For a while even I tried working with the "Press'N Peel Blue" plastic transfer film (more costly, but at the time it was on the boss's nickel). But I was convinced on the spot the first time I used the Pulsar paper stuff and saw it just float off the board in about a minute, leaving nothing but toner and clean copper behind - ready to pop directly into the etch bath.

The raw deposited� toner has some porosity and pitting can be seen under magnification. Not nearly enough to be damaging unless traces are really thin. Recently I've started using the"Toner Reactive Foil" product as well and find a much cleaner surface to the un-etched copper and ability to get consistent traces down under 10 mils.� The foil pretty much eliminates the pitting.

Now, for DIY, I just about never use traces smaller than 15 mils, but some of the text legends and such that I'll etch for ID will have lines of 6 or 8 mils, and they usually come out clean.

If you were going to do a "mini mass production" of maybe a few dozen boards (I did that once for a club kit - never again, the drilling was a drudge - hi), a more economical alternative paper is not a bad idea.� But nowadays my DIY boards are just about always one-off, Then if it turns out to be a useful project that others might have interest in, off it goes to a fab house. Nick and I will talk about the "gotchas" for that process. There aren't many, but they are important..... ask me how I know�� :^))

If you like Pittsburg style, or SMT, where drilling can be mostly avoided, the DIY route is really attractive, even for modest quantities.

Jim, N5IB



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