Homebrew_PCBs

Hi guys
I am using UV exposure method on clear acetate

15 secs exposure caustic soda developer about a 60 secs

hydrochloric acid / peroxide etchant no bubbler just sloshing about but the problem is the protective layer is coming off after a few minuets of etching

hydrochloric is 30%
peroxide is 9%

Any advice please
Dave

On 12/05/2013 15:07, dave_donlan wrote:

> Hi guys
> I am using UV exposure method on clear acetate
>
> 15 secs exposure caustic soda developer about a 60 secs
>
> hydrochloric acid / peroxide etchant no bubbler just sloshing about but
> the problem is the protective layer is coming off after a few minuets of
> etching
>
> hydrochloric is 30%
> peroxide is 9%

Use a test strip with a range of exposure times to get the correct exposure.

Leon
--
Leon Heller
G1HSM

On Sun, 12 May 2013 14:07:11 -0000, you wrote:

>Hi guys
>I am using UV exposure method on clear acetate
>
>15 secs exposure caustic soda developer about a 60 secs

UV photo stuff exposes from the top down, you may not have exposed the
resist enough.

Did you do a test series of exposures, either through a variable
filter or by progressively uncovering the board?

>
>hydrochloric acid / peroxide etchant no bubbler just sloshing about but the problem is the protective layer is coming off after a few minuets of etching
>
>hydrochloric is 30%
>peroxide is 9%

Proportion is about 1 part HCL to 3 or 4 parts H2O2 (assuming drug
store strength peroxide)?

Harvey

>
>Any advice please
>Dave

> dave wrote:
>
> I am using UV exposure method on clear acetate
> 15 secs exposure caustic soda developer about
> a 60 secs

As other have said, if you have not done a test
strip you should.

Is it positive or negative acting and what brand
photopolymer?

Most of them recommend stripping in lye and
developing in sodium silicate or sodium
carbonate.

> hydrochloric acid / peroxide etchant no bubbler
> just sloshing about but the problem is the
> protective layer is coming off after a few
> minuets of etching
>
> hydrochloric is 30%
> peroxide is 9%
>
> Any advice please

It's probably nothing to do with the etchant.

Most likely under exposed if it is negative
acting resist. Negative resist can be hard
on top and soft underneath.

Could be the sodium hydroxide soaking in and
continuing to weaken if it is positive resist.
Acid/stopbath it or switch to sodium silicate.

All this is assuming that the boards are pre
coated professionally and not being coated
or laminated by yourself. If you are doing
the lamination by yourself there are a whole
range of other problems it could be.

Dave

It does of course depend on the UV source and the photo board but 15s
sounds far too short.

Using laser printed art work on acetate, with my UV box (2 x 8W tubes)
and using pre coated board (usually from Mega Electronics) I need about
3 minutes.

But as folk have suggested try a test strip.

http://www.piclist.com/tecHREF/piclist/biketut/chapter3.html#zzee_link_9_1019487419

Paul

On 12/05/2013 15:07, dave_donlan wrote:
>
> Hi guys
> I am using UV exposure method on clear acetate
>
> 15 secs exposure caustic soda developer about a 60 secs
>
> hydrochloric acid / peroxide etchant no bubbler just sloshing about
> but the problem is the protective layer is coming off after a few
> minuets of etching
>
> hydrochloric is 30%
> peroxide is 9%
>
> Any advice please
> Dave
>
>
>
> No virus found in this message.
> Checked by AVG - www.avg.com <http://www.avg.com>
> Version: 2013.0.2904 / Virus Database: 3162/6317 - Release Date: 05/11/13
>



[Non-text portions of this message have been removed]

Totally agree. 15 seconds seems very short. With a bunch of fairly standard UV LEDs my Chinese eBay resist takes about 6-7 minutes to expose well.

I also let it cure in the dark for a few minutes after exposing.

I also do another few minutes under UV and let it cure again after developing, before etching.

I have had the resist come off before in the developer when it was under-developed or the developer was too hot. But if it stands up to that, I have not yet had a problem with it falling off during etching.

--- In Homebrew_PCBs@yahoogroups.com, Paul <paul@...> wrote:
>
> Dave
>
> It does of course depend on the UV source and the photo board but 15s
> sounds far too short.
>
> Using laser printed art work on acetate, with my UV box (2 x 8W tubes)
> and using pre coated board (usually from Mega Electronics) I need about
> 3 minutes.
>
> But as folk have suggested try a test strip.
>
> http://www.piclist.com/tecHREF/piclist/biketut/chapter3.html#zzee_link_9_1019487419
>
> Paul
>
> On 12/05/2013 15:07, dave_donlan wrote:
> >
> > Hi guys
> > I am using UV exposure method on clear acetate
> >
> > 15 secs exposure caustic soda developer about a 60 secs
> >
> > hydrochloric acid / peroxide etchant no bubbler just sloshing about
> > but the problem is the protective layer is coming off after a few
> > minuets of etching
> >
> > hydrochloric is 30%
> > peroxide is 9%
> >
> > Any advice please
> > Dave
> >
> >
> >
> > No virus found in this message.
> > Checked by AVG - www.avg.com <http://www.avg.com>
> > Version: 2013.0.2904 / Virus Database: 3162/6317 - Release Date: 05/11/13
> >
>
>
>
> [Non-text portions of this message have been removed]
>

--- In Homebrew_PCBs@yahoogroups.com, Paul <paul@...> wrote:

> It does of course depend on the UV source and the photo board but 15s sounds
> far too short.

I also agree. Back in the 70s, I used an old arc-light unit--complete with
carbon rods--that put out blinding light . . . I mean, really, really
bright, and because it was from an arc, it was super rich in UV--of all
kinds. Still, with that powerhouse exposure unit, it took at lest 90
seconds for an acceptable PCB exposure with pretty-much the same type of
emulsions used today. If there weren't any fine lines on the board, I'd
give it another 30 seconds.

I'm not even sure 15 seconds of direct exposure to the sun would be enough.
In fact, I think per square centimeter that old arc light was brighter than
the sun.

Best
,

Todd
------------------------------------------------------------------------------------
K7TFC / Medford, Oregon, USA / CN82ni / UTC-8
------------------------------------------------------------------------------------
QRP (CW & SSB) / EmComm / SOTA / Homebrew / Design


[Non-text portions of this message have been removed]

I'll assume you're using the cheap readily available negative exposure
dry film.

As others have said, 15 seconds, sounds too short. I use about 2m30s
with doubled tracing paper and UV leds, I think last time I used the sun
(too big a board for my box) I put it out for about 5 minutes.

You should be using Washing Soda (Sodium Carbonate) to develop somewhere
in the region of 20g/Litre - 5 minutes and a bit of a rub. In fact I
use it to strip as well (just warm up a stronger solution for stripping,
soak 1/2 an hour, and the resist will float away), it takes longer but
it's safer in all respects. Sodium Carbonate is available at your
nearest supermarket, look in the laundry aisle for "natural" products,
read the label, there'll be one there that is probably 100% Sodium
Carbonate for sure.

For hobbiest purposes, there is piles of lee-way with long exposures, if
your artwork is sufficiently high contrast. When exposed, the traces
are clearly visible. I'd suggest doing some small test pieces
(something that has traces about as thin and closely spaced as you would
want to use, like a SO16 breakout or something) to see how long an
exposure you can get away with before you start seeing trouble. You're
a hobbiest right so no need to be crazy precise, mark-one-eyeball it.
Start with say 3 minutes, if it looks too-far-gone, try the next one 2
minutes, if it looks ok, try one at 4 minutes. I think you'll be
surprised just how long an exposure you can "get away with".

Also, try using the doubled-tracing paper artwork. Way cheaper than
acetate.

On 13/05/13 02:07, dave_donlan wrote:
>
> Hi guys
> I am using UV exposure method on clear acetate
>
> 15 secs exposure caustic soda developer about a 60 secs
>
> hydrochloric acid / peroxide etchant no bubbler just sloshing about
> but the problem is the protective layer is coming off after a few
> minuets of etching
>
> hydrochloric is 30%
> peroxide is 9%
>



[Non-text portions of this message have been removed]

On Mon, 13 May 2013 13:50:15 +1200, you wrote:

>I'll assume you're using the cheap readily available negative exposure
>dry film.
>
>As others have said, 15 seconds, sounds too short. I use about 2m30s
>with doubled tracing paper and UV leds, I think last time I used the sun
>(too big a board for my box) I put it out for about 5 minutes.

Take a strip of board, use a file or knife to score the board at about
half inch intervals. Put your image on top. Put a piece of cardboard
or something guaranteed opaque on top of the board covering all but
the last piece as marked by the scoring on the board.

Expose for half a minute. Move the cardboard over a notch, expose for
half a minute. Do this until you have the last notch on the board
exposed for half a minute. Each successive notch will be exposed for
30 seconds more.

You should get an idea of what the best exposure is fairly easily.
There's a piece of special film made for enlarging photographs with a
pie pattern on it. Each segment is a different shade of gray, letting
in progressively less light. One long exposure with that would do the
trick as well. Make sure you have detail as fine as you want for the
process.

Harvey

>
>You should be using Washing Soda (Sodium Carbonate) to develop somewhere
>in the region of 20g/Litre - 5 minutes and a bit of a rub. In fact I
>use it to strip as well (just warm up a stronger solution for stripping,
>soak 1/2 an hour, and the resist will float away), it takes longer but
>it's safer in all respects. Sodium Carbonate is available at your
>nearest supermarket, look in the laundry aisle for "natural" products,
>read the label, there'll be one there that is probably 100% Sodium
>Carbonate for sure.
>
>For hobbiest purposes, there is piles of lee-way with long exposures, if
>your artwork is sufficiently high contrast. When exposed, the traces
>are clearly visible. I'd suggest doing some small test pieces
>(something that has traces about as thin and closely spaced as you would
>want to use, like a SO16 breakout or something) to see how long an
>exposure you can get away with before you start seeing trouble. You're
>a hobbiest right so no need to be crazy precise, mark-one-eyeball it.
>Start with say 3 minutes, if it looks too-far-gone, try the next one 2
>minutes, if it looks ok, try one at 4 minutes. I think you'll be
>surprised just how long an exposure you can "get away with".
>
>Also, try using the doubled-tracing paper artwork. Way cheaper than
>acetate.
>
>
>
>On 13/05/13 02:07, dave_donlan wrote:
>>
>> Hi guys
>> I am using UV exposure method on clear acetate
>>
>> 15 secs exposure caustic soda developer about a 60 secs
>>
>> hydrochloric acid / peroxide etchant no bubbler just sloshing about
>> but the problem is the protective layer is coming off after a few
>> minuets of etching
>>
>> hydrochloric is 30%
>> peroxide is 9%
>>
>
>
>
>[Non-text portions of this message have been removed]

One thing not mentioned so far is to cure the image after exposure-development.

After the image is developed on the board, some recommend to cure the remaining resist by exposing the image to harden the image. Some resist may not be compatible with this step so check first.

Another issue is resist adhesion. Lots of discussion on this too. I always wear rubber glove to keep the board free of oil from my hand and to keep chemicals off my hand. Some even have recommended to mildly pre-etch the blank then apply the resist. And so on...

If you want to be accurate with exposure, you might want to use Stouffer's 21 step exposure guide. do a google search if you want one.

cheers for the advice I will try another test strip but go over longer time.
The uv box is a converted scanner with four UV 9W tubes from a nail curing unit
The boards are positive photo from Maplins
it is clear acetate lazer printer. I print 2 images to double up the thickness
Dave

--- In Homebrew_PCBs@yahoogroups.com, "smilingcat90254" <smilingcat@...> wrote:
>
> One thing not mentioned so far is to cure the image after exposure-development.
>
> After the image is developed on the board, some recommend to cure the remaining resist by exposing the image to harden the image. Some resist may not be compatible with this step so check first.
>
> Another issue is resist adhesion. Lots of discussion on this too. I always wear rubber glove to keep the board free of oil from my hand and to keep chemicals off my hand. Some even have recommended to mildly pre-etch the blank then apply the resist. And so on...
>
> If you want to be accurate with exposure, you might want to use Stouffer's 21 step exposure guide. do a google search if you want one.
>

> dave wrote:
> <SNIP>
> The boards are positive photo from Maplins
> <SNIP>

Well in that case def. do not use lye.

Maplins might recomend it on the web page, but
the manufacturer recomends sodium silicate on
the package of the pre sensitized boards.

Sodium silicate is a lot more fogriving.
With lye if you have the temp. too high the
entire thing will just strip instantly.

If you under exposed positive resist then
EVERY thing should have stayed on.

As everyone has said 15s is probably too short.
Too short an exposure with positive and you
will get a completly covered board.

Hi Dave

Maplin board! I nearly mentioned that when I replied before. I have had
terrible problems with some batches from the local branch. I think some
of it may sit on the shelf for a long time. I only go and buy it as a
last resort if I really have nothing left in stock and need some board
in a hurry.

I have found that Maplin board needs even longer exposure times. One
batch needed 8 minutes here.

The Mega Electronics pre-sensitised board has always been consistent &
reliable.
http://www.megauk.com/pcb_laminates.php

Never bothered printing double. LaserStar (from Mega) works really well.
http://www.megauk.com/artwork_films.php

But since work scrapped all their overhead projectors some time ago I
have quite a bit of OHP transparency film which I use for less critical
boards.

Regards

Paul

On 13/05/2013 19:36, dave_donlan wrote:
>
> cheers for the advice I will try another test strip but go over longer
> time.
> The uv box is a converted scanner with four UV 9W tubes from a nail
> curing unit
> The boards are positive photo from Maplins
> it is clear acetate lazer printer. I print 2 images to double up the
> thickness
> Dave
>
> --- In Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>, "smilingcat90254"
> <smilingcat@...> wrote:
> >
> > One thing not mentioned so far is to cure the image after
> exposure-development.
> >
> > After the image is developed on the board, some recommend to cure
> the remaining resist by exposing the image to harden the image. Some
> resist may not be compatible with this step so check first.
> >
> > Another issue is resist adhesion. Lots of discussion on this too. I
> always wear rubber glove to keep the board free of oil from my hand
> and to keep chemicals off my hand. Some even have recommended to
> mildly pre-etch the blank then apply the resist. And so on...
> >
> > If you want to be accurate with exposure, you might want to use
> Stouffer's 21 step exposure guide. do a google search if you want one.
> >
>
>
>
> No virus found in this message.
> Checked by AVG - www.avg.com <http://www.avg.com>
> Version: 2013.0.2904 / Virus Database: 3162/6319 - Release Date: 05/12/13
>



[Non-text portions of this message have been removed]

On Mon, 13 May 2013 18:36:03 -0000, you wrote:

>cheers for the advice I will try another test strip but go over longer time.
>The uv box is a converted scanner with four UV 9W tubes from a nail curing unit
>The boards are positive photo from Maplins
>it is clear acetate lazer printer. I print 2 images to double up the thickness

As a complete guess on the exposure, look for a good exposure to be 3
to 4 minutes. This is based on my own experiences, different
photoresist, more UV light (perhaps).

I do think that 15 seconds is way too small.

Positive photoresist is a polymer (long chain molecules). It is
damaged (read unlinked, read broken apart) by UV light. This happens
from the top down to the board surface. The mask prevents that from
happening.

Under UV light, the top down starts to change into a form that can be
dissolved. Note that the stripper is just a more concentrated
solution, so we're dealing with degrees, not absolutes.

Underexpose, and with too strong a developer, you tend to strip the
board. That very thin layer of photoresist may not work to keep the
etchant away.

You may want to check the strength of your developer. IIRC, it took
very little time (15 to 30 seconds) to "develop" photoresist.

Harvey

>Dave
>
>--- In Homebrew_PCBs@yahoogroups.com, "smilingcat90254" <smilingcat@...> wrote:
>>
>> One thing not mentioned so far is to cure the image after exposure-development.
>>
>> After the image is developed on the board, some recommend to cure the remaining resist by exposing the image to harden the image. Some resist may not be compatible with this step so check first.
>>
>> Another issue is resist adhesion. Lots of discussion on this too. I always wear rubber glove to keep the board free of oil from my hand and to keep chemicals off my hand. Some even have recommended to mildly pre-etch the blank then apply the resist. And so on...
>>
>> If you want to be accurate with exposure, you might want to use Stouffer's 21 step exposure guide. do a google search if you want one.
>>
>

On Tue, May 14, 2013 at 2:36 AM, dave_donlan <dhd01@...> wrote:

> cheers for the advice I will try another test strip but go over longer time.
>
> it is clear acetate lazer printer. I print 2 images to double up the thickness

My 2c: When making boards at home I print onto drafting paper. 8mil
is no problem:

http://capnstech.blogspot.com/2011/05/playpause-making-pcbs-at-home.html

Drafting paper is transparent to UV, and I worry less when it goes
through the printer.

(And now my plug: I supply pro-quality PCBs, double sided everything,
10 boards for USD19 inc worldwide delivery.
http://tinyurl.com/hvpcbfaq)

Mitch.

Do you mean $19 per board when 10 boards are ordered ($190 total)? What is
the cost for one or two boards?



Jeff

_____

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of Mitch Davis
Sent: Monday, May 13, 2013 10:56 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] Re: photo layer coming off





On Tue, May 14, 2013 at 2:36 AM, dave_donlan <dhd01@...
<mailto:dhd01%40live.co.uk> > wrote:

> cheers for the advice I will try another test strip but go over longer

time.

>
> it is clear acetate lazer printer. I print 2 images to double up the

thickness

My 2c: When making boards at home I print onto drafting paper. 8mil
is no problem:

http://capnstech.blogspot.com/2011/05/playpause-making-pcbs-at-home.html

Drafting paper is transparent to UV, and I worry less when it goes
through the printer.

(And now my plug: I supply pro-quality PCBs, double sided everything,
10 boards for USD19 inc worldwide delivery.
http://tinyurl.com/hvpcbfaq)

Mitch.





[Non-text portions of this message have been removed]

Hello Jeff, hello homebrewing PCB folks.

First, something on-topic: When I was getting started with home
etching, I also made a test strip. I used my CAD program (KiCad) to
place 10 SOIC-14 footprints at 1-inch intervals, and wired each chip
to its neighbours with traces of various thicknesses. After printing
(see the blog entry from my last group email), I made marks at 1-inch
intervals on the back of the blank board. Then I got two pieces of
card, and slipped the blank between them with only the last inch
hanging out. Off to my UV light, and I started a timer. Every thirty
seconds I pulled out another inch, so that after about five minutes,
I'd exposed all of the strip. I then developed and etched it. What I
found was that for my UV light setup, and the blank I was using, 2½-3
minutes was fine. I was able to get reliable 8mil traces through
drafting paper with only one run through the printer. (I should point
out that my making of boards at home is entirely unconnected to the
professional PCBs I supply to customers)

On Tue, May 14, 2013 at 11:39 AM, Jeff Heiss <jeff.heiss@...> wrote:
>
> Do you mean $19 per board when 10 boards are ordered ($190 total)?

Haha, oh goodness no! I wouldn't do any business! That's USD19 total
for 10 boards.

As an example, this customer paid me the Australian equivalent of
USD19 for these boards:

http://nanibox.com/2013/03/kurobox-prototype/

He also paid USD3 for registered shipping, but that's it. (He and I
are both Australian so it was easier for us this way).

According to my records, for his order, I checked and processed his
order same day, board manufacture took 3 days, and shipping was 7
days.

There are some other important details: That's the up-to-5x5cm price,
and for Paypal it's +5%. For more info, read my guide:

http://tinyurl.com/hvpcbfaq

> What is the cost for one or two boards?

I have a 10-for-5 offer for boards that are up to 5x5cm (USD19), and
10-for-5 on up to 10x10cm (USD36, but smaller sizes are cheaper.
Also, thinner is cheaper). If you're really only after one or two, 'm
very happy to make 5 and throw 3 or 4 away before shipping them to
you. Or you can give them to budding engineers or use them for SMT
soldering practice.

Oh, and here's another happy customer:

http://electronics.ozonejunkie.com/2012/11/pcb-manufacture/

His boards were also USD19, but he also paid me USD25 for DHL.

If you're greedy, you can visit these too:

http://dangerousprototypes.com/forum/viewtopic.php?f=2&t=4722
http://dangerousprototypes.com/2012/12/06/workshop-video-interview-with-mitch-from-hackvana/

Talking to my customers is the highlight of my day. I have a 24-hour
live chatroom where several dozen of my customers hang out and talk
about electronics, give feedback to each other on their PCB designs,
and generally have a good time. You're all welcome to join (see my
guide).

Like most of you I'm an engineer and a tinkerer. I love making stuff,
and I get a buzz out of helping others to make stuff.

Lest I wear out my welcome here, if you'd like to know more, please
send me a private email, or come chat with me and other customers in
the chat room.

Regards,

Mitch.

Hi Mitch

More power to you, it's a really great idea to have someone on the
ground as an "interface" between Europe/USA and the Chinese PCB makers
although I do have a great Chinese friend in HK who is into specialist
electronics manufacturing and who helps me out.

A couple of questions

How about a sideline in supplying some PCB materials for us homebrew
hackers? Pre-sensitised board is expensive here and solder resist
laminate film is expensive and very difficult to find in small quantities.

What kind of costs for a solder paste mask? (I saw somewhere you can
supply them)

Do you miss the Fosters?

Ooops that's three questions.....

Regards

Paul

On 14/05/2013 05:44, Mitch Davis wrote:
>
> Hello Jeff, hello homebrewing PCB folks.
>
>
>
> On Tue, May 14, 2013 at 11:39 AM, Jeff Heiss <jeff.heiss@...
> <mailto:jeff.heiss%40comcast.net>> wrote:
> >
> > Do you mean $19 per board when 10 boards are ordered ($190 total)?
>
> Haha, oh goodness no! I wouldn't do any business! That's USD19 total
> for 10 boards.
>



[Non-text portions of this message have been removed]

On Tue, May 14, 2013 at 2:11 PM, Paul <paul@...> wrote:

>
> More power to you, it's a really great idea to have someone on the
> ground as an "interface" between Europe/USA and the Chinese PCB makers
> although

That's what I do. I speak Chinese so you don't have to. I check
boards thoroughly and give a report on each one. This saves you a lot
of time and money. And I'm there to make sure the fabs do a great job
every time.

>I do have a great Chinese friend in HK who is into specialist
> electronics manufacturing and who helps me out.

I'd be interested in talking to him, as I don't have good contacts for assembly.

> How about a sideline in supplying some PCB materials for us homebrew
> hackers? Pre-sensitised board is expensive here and solder resist
> laminate film is expensive and very difficult to find in small quantities.

I'd really love to. One issue is freight. Fibreglass is extremely
heavy. Freight for a few boards can often end up more than for the
boards. For another issue, see below.

> What kind of costs for a solder paste mask? (I saw somewhere you can
> supply them)

I was selling laser-cut stainless frameless solderpaste stencils of up
to A4 in size for USD25. I have stopped doing that for the moment
though, as I really really have to concentrate on getting web ordering
of PCBs going. (And 90% of that is the back-end processing, not the
customer-facing stuff).

If you'd like to make your own solderpaste stencils, it's not hard:

http://lowpowerlab.com/blog/2013/02/11/diy-smd-metal-stencils-the-definitive-tutorial/

I think everyone should try that. (Felix is another customer of mine :-) )

> Do you miss the Fosters?

LOL, Fosters is megaswill, I never drink it. I brew my own beer :-)
That's what this group is for eh, making your own?

Mitch.

On Tue, May 14, 2013 at 2:26 PM, Mitch Davis <mjd@...> wrote:

>
> I check boards thoroughly and give a report on each one.

I should clarify that I check the design. Here's a recent report for a
customer:

- No board outline file. Please see attached. The purple lines should
be a rectangle enclosing the whole board. You can have right angle or arc
corners. In particular, please pay close attention to the shape of the
board in the area of the four RJ45 connectors (or whatever they are).

- Be aware of PCB manufacture limitations if your final board outline
has sharp angled concave corners near the RJ45s. It's not possible to
faithfully reproduce sharp angled concave corners. The mill bit is 0.8mm,
and therefore the smallest radius of curvature of the arc you'll get on
concave corners is 0.4mm. Please let me know that this is ok.

- The fab will "pull back" copper very slightly so there's no copper
right at the very edge of the board. There will be a very thin copperless
margin right around the board. If you don't want the fab to do pullback
(for example, if your design had SMA connectors) then please tell me and
I'll tell the fab.

- Many packages use .dri for drill files, but Eagle wants to put drill
holes into .txt files. That's ok, but the files to include in your .zip
are the .txt files. (Also, with our .cam file, we can't find a way to stop
Eagle from generating useless .gpi files, sigh).

- On the top you have silkscreen across the pads. What will happen is
that the soldermask will be used to mask the silkscreen - silkcreen will be
omitted where it crosses pads. This is not a fatal problem, but if you're
expecting to get back boards where the silk looks just as you designed it,
this can be a bit of a shock. The easiest solution to this is to redefine
your footprints so no silk crosses the pads, but you'll still need to
carefully review every part of your board if you want a total remedy.

- The "XYZ" text is covering up "ABC".

- No silkscreen on the bottom layer (that's ok, but please tell me it's
intentional).

My chat channel is also a very good place to get a review.

Mitch.


[Non-text portions of this message have been removed]

On 14/05/2013 07:26, Mitch Davis wrote:

>
>
>
> > Do you miss the Fosters?
>
> LOL, Fosters is megaswill, I never drink it. I brew my own beer :-)
> That's what this group is for eh, making your own?
>
> Mitch.
>
> _

But they keep telling us on the TV ads that it is amber nectar! You
imply they are telling porkie pies? :-) Real ale myself... proper Brit
stuff. I do brew although none on the go at the moment.

Paul


[Non-text portions of this message have been removed]

On Tue, May 14, 2013 at 3:45 PM, Paul <paul@...> wrote:

>
> But they keep telling us on the TV ads that it is amber nectar!

That it was an ad should be enough of a giveaway, that it was also on
the TV means it's incredible.

Desperate attempt to stay on topic: How long does presensitised board
last when the bag is sealed? How about once it's been opened but then
sealed up? (Not talking about what the manufacturer recommends, which
is probably going to be "after using your 2x2cm square, throw the rest
of the board away" but what folks have found for themselves...)

Cheers,

Mitch.

In article
<CA+KzSgJHRQsZ3gojr0ij=1UkLBWx-MdtbHRscDmzLUKbLxarHQ@...>,
Mitch Davis <mjd@...> wrote:

> > Do you miss the Fosters?

> LOL, Fosters is megaswill, I never drink it. I brew my own beer :-)

Thank God for that.

--
Stuart Winsor

Midlands RISC OS and Raspberry pi show, 13th July 2013

http://www.mug.riscos.org/show13/MUGshow.html

In article <51914A6B.9000102@...>,
Paul <paul@...> wrote:

> Maplin board!

Maplin - Arrgh

Bought some board from them once, they had to order it because they had
none in stock at the local shop. That was usual. I would go in with a list
and if I was lucky they might have two of the items I wanted - must have
cost them a fortune in postage because they would send direct from head
office post free.

When it turned up it seemed to be covered in scratches, which I judged
would have gone right through the protective film and the photo-resist. I
complained and they sent me a replacement piece that looked worse than the
first - looked like somebody had been kicking and scuffing it around on
the floor. I was in a hurry and desperate so I had to use it - broken
tracks everywhere where the scratches had removed the resist.

One would have thought that because I had complained they would have
checked the replacement over before sending it out.

--
Stuart Winsor

Midlands RISC OS and Raspberry pi show, 13th July 2013

http://www.mug.riscos.org/show13/MUGshow.html