To PCB or not to PCB...

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kheston
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To PCB or not to PCB...

Post by kheston » Sun Mar 22, 2009 1:46 pm

I have two circuits MrAl and Bigglez designed for me that I've had bread-boarded for about a year and use regularly. I'm thinking they're full-proof and that I can commit them to their own custom boards.

They're small enough for the free version of Eagle to lay out and I'm looking forward to using the very-specific photo-paper mentioned in another thread to transfer the traces using a laser printer.

My question is about how to get started with my own little etching station. But, I haven't used one since my high school electronics class (RIP Mr. Rigby). I remember it being murderous on clothing (unremovable green stains), but otherwise as relatively safe. There's a kit with a tank (heated, I think), some chemicals, and a sizable PCB at the local Fry's for ~$60 that I almost bought last week. However, I've never seen anyone review such a kit so I hesitated.

Suggestions?
Kurt - SF Bay

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Lenp
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Re: To PCB or not to PCB...

Post by Lenp » Sun Mar 22, 2009 7:17 pm

Kheston,

If you'll search this forum for Blue Transfer Paper, (Mr Al was the original poster), there is much info.
I have great success with a vertical tank, aquarium heater and nitrogen bubbles. An aquarium pump also works well. With fresh amonium persulfate etching time can be as short as 15 minutes for the thinner clad boards. I got away from ferric chloride years ago, way too messy!

Hint: If you are stuck on FeCl, oxalic acid, a wood bleach available from woodworker's and paint suppliers, will usually remove much of the iodine color stains you are sure to get!

If you need more info, shout it out!
Len
Len

“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)

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MrAl
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Re: To PCB or not to PCB...

Post by MrAl » Sun Mar 22, 2009 7:54 pm

Hello,


If you really want to get cheap there are very cheap ways to make PCB's if you dont mind drawing the lines
out yourself with a pen. The black Sharpies work very well for resisting Ferric Cl. etchant but dont use the
other colors as they dont seem to work as well.
Dry transfers also work well for the ic pins. You can then draw lines to the chip pads and go from there.
To etch, buy a bottle of FeCl and pour some into a plastic tray or glass cooking pan that is clear.
You only have to pour in to a depth of 1/2 inch or so, not the whole bottle.
The white plastic trays you get with meat at the local supermarket work just as well as any other
once they are cleaned thoroughly with soap and water.
The reason white or clear plastic or glass is used is so that you can see the pattern emerge while
the board is etching...not absolutely necessary, but nice to be able to keep an eye on the progress.

A trick to use that doesnt require a pump or agitation is to float the board on the top surface of
the etchant solution. You do this by holding the board above the surface with one end slightly
lower than the other, and then letting go of the board so that one end hits the surface before
the other. The board naturally floats on top. The lower end of the board hits the surface first,
and as the board falls the surface forces all the air bubbles out from under the board from one
end to the other, thus eliminating air bubbles which will mess up the pattern.
I do move mine around a little after about 10 minutes or so, with a toothpick, moving it around
like a little boat on the top of the solution back and forth a few times. Soon you can start
to see traces on the board bottom start to form because the light passes through most boards.
If not, hold a flashlight on the side of the tray and shine under the board.
Of course if the board isnt translucent you wont see anything, in which case you have to take
the board out and check it. If it's not done, simply refloat and wait a bit longer.
If there happens to be one stubborn area just use a Dremel to separate the traces later.
When the board is done, wash it with water for a minute or so. Carefully pour the tray
solution back into the bottle using a funnel if needed. Wash the tray carefully
by first filling it up with water to dilute the solution before pouring it down the drain.
Let the water run for about two minutes to make sure the solution down the drain
is diluted and harmless. There will be very little waste solution here.

Good luck, and let us know how you make out with the boards if you can.
LEDs vs Bulbs, LEDs are winning.

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Re: To PCB or not to PCB...

Post by Engineer1138 » Wed Mar 25, 2009 8:51 am

Kurt:
This may be heresy on this board, but for the $60 cost of that kit, you can get a few PCBs professionally made and the quality will be light years ahead of anything you can do at home.

Some folks like expresspcb.com, others use batchpcb.com and there are tons more if you just google cheap PCB.

Not to put down the DIY method: I did it for years, but now that my spare time is really limited and all my boards are surface mount, getting 5-10 boards for just a bit over $50 is a more attractive proposition.

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Re: To PCB or not to PCB...

Post by Bigglez » Thu Mar 26, 2009 12:35 pm

Engineer1138 wrote:Kurt:
This may be heresy on this board, but for the $60 cost of that kit, you can get a few PCBs professionally made and the quality will be light years ahead of anything you can do at home.

Some folks like expresspcb.com, others use batchpcb.com and there are tons more if you just google cheap PCB.

Not to put down the DIY method: I did it for years, but now that my spare time is really limited and all my boards are surface mount, getting 5-10 boards for just a bit over $50 is a more attractive proposition.
I share Lyndon's view. Put your time into learning CAD/CAM tools,
it will pay back hansomely. There is a world wide surplus of wet
PCB fabs falling over themselves for your hobby business.

Be aware that ExpressPCB is a closed system. Use their 'free'
CAD/CAM tools and you must use their shop. Using any tools
that generate industry standard Excellon/Gerber files and you
can shop around for the lowest prices or best turn around times.

I did make my own PCBs in the basement(*) for a while, it's
little more than a time filler for kids.

*Before I moved to California, where few homes have basements.

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Lenp
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Re: To PCB or not to PCB...

Post by Lenp » Sun Mar 29, 2009 8:51 pm

More about DIY Boards...
I agree that a double sided board, with fine line artwork, screens and plated through holes is beyond the DIYer in most cases. But, not all boards need that complexity! If you need just one board for evaluation, the board does not have file line artwork, you need it today, not next week, are not sure the layout is 'perfect' and the board is a relatively simple single sided design then It's hard to justify not doing it yourself if you have the basic skills and material.

Maybe some of the posters are 'perfect' and are able to do 'perfect' board layout and circuitry the first time. My experience is that usually that's not the case unless there is a lot of prior experience, both in fabrication.software and evolved skills.

The DIY'er can make a board, test it, find the errors, correct the artwork and do another board long before the board house schedules the production. We've actually done several revisions in the same workday!

As a bonus, the cost may be less than the typical setup and shipping costs. Then after all is said and done, they can send their now 'perfect' artwork out for professional quantity fabrication if necessary.

Len
Len

“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)

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MrAl
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Re: To PCB or not to PCB...

Post by MrAl » Sun Mar 29, 2009 9:38 pm

Lenp wrote:More about DIY Boards...
I agree that a double sided board, with fine line artwork, screens and plated through holes is beyond the DIYer in most cases. But, not all boards need that complexity! If you need just one board for evaluation, the board does not have file line artwork, you need it today, not next week, are not sure the layout is 'perfect' and the board is a relatively simple single sided design then It's hard to justify not doing it yourself if you have the basic skills and material.

Maybe some of the posters are 'perfect' and are able to do 'perfect' board layout and circuitry the first time. My experience is that usually that's not the case unless there is a lot of prior experience, both in fabrication.software and evolved skills.

The DIY'er can make a board, test it, find the errors, correct the artwork and do another board long before the board house schedules the production. We've actually done several revisions in the same workday!

As a bonus, the cost may be less than the typical setup and shipping costs. Then after all is said and done, they can send their now 'perfect' artwork out for professional quantity fabrication if necessary.

Len
Hi,

Well said Len!

For many simpler layouts you cant beat the DIY method. I think everyone should at least try it a few times
even if just for the experience alone.
Cost?
Single sided boards can be had for less than 2 dollars US, etchant around 5 bucks, Sharpie $1.19 for one, ruler $1.00 or less.
The dry transfer patterns will run a little higher, maybe 4 bucks for a set which will have quite a few patterns.
A kit with all of the above will run around 10 dollars US (minus Sharpie and ruler).

Granted i would not want to have to make every single board that i've ever used in the past or that i will
use in the future, but it sure is cool to be able to make a board now and then yourself and not have to
wait for a PC board company to do it. As you said, it's great when you want to try out a board first
before ordering a bunch from a company just to see if it really works right.

I can not say the same however when it comes to the tiny tiny SO patterns (smaller than 0.05 inch pitch)
as these are a bit hard to make even with a laser printer. People have done it however.
LEDs vs Bulbs, LEDs are winning.

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kheston
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Re: To PCB or not to PCB...

Post by kheston » Mon Mar 30, 2009 11:16 am

MrAl,

The instant gratification factor of being able to etch my own PCBs right when I want them will have me buying some FeCl and a board or two next time I'm at the elec. store.

Biggelz/Engineer1138/LenP,

There is definitely some wisdom in paying someone to do what they do best, especially when the finished price competes with the cost of the materials and one's time is involved. I have a small number of hours in any week to dedicate to pretending to know something about electronics and one can get a lot of programming done in their day job while their PCB travels via mail...

I'll be using a hybrid model with mail ordering when I'm feeling patient and FeCl in a glass dish when I'm not.

Thanks for the suggestions!
Kurt - SF Bay

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Re: To PCB or not to PCB...

Post by Bigglez » Mon Mar 30, 2009 11:41 am

MrAl wrote:I can not say the same however when it comes to the tiny tiny SO patterns (smaller than 0.05 inch pitch)
as these are a bit hard to make even with a laser printer. People have done it however.
The whole point of double sides PCBs with solder masks for a
hobby project is that new components are only available in
SMD/SMT format, and typically have fine pitch pads.

Visit SFE (sparkfun Electronics) to see the various break out
boards they offer to adapt hot new ICs and modules to SBB
experimentation. They have over 100 styles!

Etching a hobby board from scratch for parts that could already
fit on a SBB or RS Proto Board is limited to bragging that
the hobbyist made the PCB
. Only in rare cases would a PCB
be a critical part of a circuit (An RF amplifier or microwave patch
antenna for example).

When PCB design is done with CAD/CAM tools the design is 100%
reproducible, and easily copied and modded for another project.
The CAD/CAM tools include error checking that is easy to do
on a computer but very hard for the average human to spot
(violation of clearances, track widths, wrong drill sizes, orphan
polygons, open traces, mirrored pinouts, etc.)

Double sided plated through holes are required on some SO
power packages, and even if only TH parts are used in the PCB
double side layouts greatly reduces the PCB area.

Locally I can get one day turns on proto PCBs, and I can go over
there in my SUV, and don't wait for UPS or FedEx to swing by my
home.

Personal satisfaction seems to be the only remaining "plus"
to home wet chemistry.

I got pretty good at two-sided PCBs using real photo tools
made from 2X mylar and tape artwork created on a light table,
using Bishop sticky tapes and donuts, and a lot of fine work
with a sharp X-Acto blade. I even got a local wedding invitation
printing shop to photo reduce the artwork and make working
negatives for my homebrew vacuum frame.

BUT After countless hours of shoshing nasty chemical
around in our basement(*), I gave up!

(*) When I lived in the mid-west where everyone had a basement.

Having said that I think every hobbyist should make at least
one PCB of their own design from scratch to have the full experience
of the hobby.

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philba
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Re: To PCB or not to PCB...

Post by philba » Mon Mar 30, 2009 11:55 am

There are definitely differences of opinion. I'm not fortunate enough to have a local 24 hr turn PCB house so I am either forced to pay big bucks for 3 day turn or do it myself in a few hours. Doing it myself is pretty easy. And, I can do double sided no problem. You have to factor in the lack of plated through holes and populate the vias yourself but it's not hard at all. And with SMT, you don't have to drill many holes (the absolutely biggest PITA of home production).

I do agree that there is no reason to draw the layout by hand.

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MrAl
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Re: To PCB or not to PCB...

Post by MrAl » Tue Mar 31, 2009 10:19 pm

Hi again,


You know what is really strange is that it is actually cheaper for me to make a small (relatively simple
like with dip packages) board around 2x3 inches rather than buy an experimenters board at Radio
Shack. I can get 4x3 for about $1.50 USD which makes two boards. Plus, then it doesnt have wires
running all over it which make it harder to troubleshoot and the reliability is a bit higher too.
LEDs vs Bulbs, LEDs are winning.

Bigglez
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Re: To PCB or not to PCB...

Post by Bigglez » Tue Mar 31, 2009 10:42 pm

MrAl wrote:it is actually cheaper for me to make a small (relatively simple
like with dip packages) board around 2x3 inches rather than buy an experimenters board at Radio
Shack.
What is the state mandated min wages in your locale?
Did you factor in your time (even at min wages)?

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MrAl
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Re: To PCB or not to PCB...

Post by MrAl » Wed Apr 01, 2009 6:29 am

Bigglez wrote:
MrAl wrote:it is actually cheaper for me to make a small (relatively simple
like with dip packages) board around 2x3 inches rather than buy an experimenters board at Radio
Shack.
What is the state mandated min wages in your locale?
Did you factor in your time (even at min wages)?
Hello,

If i factored in my time for my own personal projects i could not afford to build anything, small or large,
using ANY pc board making technology.
LEDs vs Bulbs, LEDs are winning.

Bigglez
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Re: To PCB or not to PCB...

Post by Bigglez » Wed Apr 01, 2009 6:38 am

MrAl wrote:If i factored in my time for my own personal projects i could not afford to build anything, small or large,
using ANY pc board making technology.
What is the state mandated min wages in your locale?
Did you factor in your time (even at min wages)?


While that may be true, I asked a different question
for a different reason. For comparison purposes,
what is your time worth? Min wages by state seems to be
a fair measure, agreed?

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Re: To PCB or not to PCB...

Post by rolerbe » Wed Apr 01, 2009 4:58 pm

I have had good luck with the Pulsar http://www.pcbfx.com/ approach. One can make very professional looking boards very quickly and cheaply after the initial outlay (~$100). Their 'tankless' method (basically rubbing the FeCl onto the board with a sponge) works very well -- very quick and uses almost no etchant. Also, I like DipTrace's http://www.diptrace.com/ schematic capture and pcb layout tools pretty well. Have built some pretty complicated boards still under the limits of their freeware trial program.

Pulsar's claim of a board in 15 minutes is pushing it a bit, particularly as most of your time will be spent in layout and drilling if not smt, but from ink transfer to ready to populate in under an hour is very realistic.

The one thing I have yet to do is via's. Haven't figured out how to fill the via and connect the layers yet (open to suggestions)

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