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Static Electricity and Ferric Chloride (argh!)

P

Puckdropper

Jan 1, 1970
0
I'm a little upset right now, so please consider that when reading. If
you don't care, feel free to go to the next thread.

I was working on etching a circuit board, and wasn't too happy with the
progress of the etching process. Since warm etchant works better than
cold etchant, I picked up the etching container (a little 4 oz container)
and walked towards the garage heater (oil filled radiator type). After
walking the grand total of 6 feet, I move to hold the etchant container
closer to the heater and get shocked!

On reflex, I jerk back from the heater, scattering and spilling the
contents of the etchant container. The etchant gets all over my hands,
the floor, my coat, and the heater. Luckily, I was able to avoid serious
injury and minimize staining, but I can't trust that heater any more. I
think the FeCl just ate through the paint before stopping, but I can't be
sure.

Next time I get an idea like this, I'm either going to be more patient,
or if I want to move the etchant container, I'll put the lid on first.
Either one would have prevented the whole situation, and at the worst I'd
be disappointed by a bad board. They're a lot cheaper than a heater.

Puckdropper
 
C

Chris

Jan 1, 1970
0
I'm a little upset right now, so please consider that when reading. If
you don't care, feel free to go to the next thread.

I was working on etching a circuit board, and wasn't too happy with the
progress of the etching process. Since warm etchant works better than
cold etchant, I picked up the etching container (a little 4 oz container)
and walked towards the garage heater (oil filled radiator type). After
walking the grand total of 6 feet, I move to hold the etchant container
closer to the heater and get shocked!

On reflex, I jerk back from the heater, scattering and spilling the
contents of the etchant container. The etchant gets all over my hands,
the floor, my coat, and the heater. Luckily, I was able to avoid serious
injury and minimize staining, but I can't trust that heater any more. I
think the FeCl just ate through the paint before stopping, but I can't be
sure.

Next time I get an idea like this, I'm either going to be more patient,
or if I want to move the etchant container, I'll put the lid on first.
Either one would have prevented the whole situation, and at the worst I'd
be disappointed by a bad board. They're a lot cheaper than a heater.

Puckdropper


Sorry for your troubles. I was once using ferric chloride with the GC
"Professional Etching Kit" (before they started including an O-ring to
keep the heater from contacting the plastic tank). Combination of
circumstances, the heater was touching the wall of the tank when I
plugged it in to warm up and melted through just as the solution was
reaching temperature. I was in another part of the plant.

By the time I came back to check if the etchant was up to temp most of
the contents of the tank had poured out on the floor and had seeped
into many different places in the lab. No fun to clean.

Oh, well. DIY etching is a lot of trouble. And always use the
included O-ring. ;-)

Cheers
Chris
 
B

Bob Masta

Jan 1, 1970
0
I'm a little upset right now, so please consider that when reading. If
you don't care, feel free to go to the next thread.

I was working on etching a circuit board, and wasn't too happy with the
progress of the etching process. Since warm etchant works better than
cold etchant, I picked up the etching container (a little 4 oz container)
and walked towards the garage heater (oil filled radiator type). After
walking the grand total of 6 feet, I move to hold the etchant container
closer to the heater and get shocked!

Besides heat, the other thing you might want to check is to
make sure that your ferric chloride is not too concentrated.
Yes, you read that right: Believe it or not, above a certain
concentration etching slows down to a near-standstill.
You not only need to attend to this when you buy
new etchant (which is sometimes supplied at too-high
concentration), but also as it ages. You'll need to ask
a chemist for the explanation... it's something to do
with site competition (or something equally unintuitive).
But in the lab where I used to work, it was standard practice
when the etchant started to slow down (after some number
of boards were etched), to dilute it a little to bring it back up to
speed. I wouldn't have thought that usage would have
provoked a concentration increase, though it might have
been due to evaporation.

If you want the details on the proper concentration, see
www.daqarta.com/lptxh.htm

Best regards,




Bob Masta

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Signal Generator
Science with your sound card!
 
A

Aly

Jan 1, 1970
0
Puckdropper said:
I'm a little upset right now, so please consider that when reading. If
<SNIP>

Nasty old stuff that. Lately most the of the things I've been doing seem to
revolve around the cooker in the kitchen. From using the oven at 250oC for
SMD components, to using a saucepan on the stove with a sealable sandwich
box floating in a pan of water. That's where the etching gets done. All
very technical and high tech.

A sandwich box I've found is the most brilliant thing for etching, and at
50p each in the local supermarket too. Just stick it in a saucepan of hot
water. As for storing unused ferric cloride I use an airtight coffee jar
(glass being non reactive) stored under the sink in the dark.

I once tipped my mixed solution down a stainless steel sink.... Don't do
that.

All experience and memorable though. :)
 
I'm a little upset right now, so please consider that when reading. If

<SNIP>

Nasty old stuff that. Lately most the of the things I've been doing seem to
revolve around the cooker in the kitchen. From using the oven at 250oC for
SMD components, to using a saucepan on the stove with a sealable sandwich
box floating in a pan of water. That's where the etching gets done. All
very technical and high tech.

A sandwich box I've found is the most brilliant thing for etching, and at
50p each in the local supermarket too. Just stick it in a saucepan of hot
water. As for storing unused ferric cloride I use an airtight coffee jar
(glass being non reactive) stored under the sink in the dark.

I once tipped my mixed solution down a stainless steel sink.... Don't do
that.

All experience and memorable though. :)

GAWWWWWWD!!!!, Does you mom know you're doing that in her kitchen?
 
C

Chris Jones

Jan 1, 1970
0
Aly said:
<SNIP>

Nasty old stuff that. Lately most the of the things I've been doing seem
to
revolve around the cooker in the kitchen. From using the oven at 250oC
for SMD components, to using a saucepan on the stove with a sealable
sandwich
box floating in a pan of water. That's where the etching gets done. All
very technical and high tech.

A sandwich box I've found is the most brilliant thing for etching, and at
50p each in the local supermarket too. Just stick it in a saucepan of hot
water. As for storing unused ferric cloride I use an airtight coffee jar
(glass being non reactive) stored under the sink in the dark.

I once tipped my mixed solution down a stainless steel sink.... Don't do
that.

All experience and memorable though. :)

If you ever go to using Ammonium Persulfate etchant, then don't put it in an
airtight container. I learnt that the hard way. It makes some kind of gas
and my bottle exploded unexpectedly, distributing etchant all over the
place.

Chris
 
R

Rich Grise

Jan 1, 1970
0
<SNIP>

Nasty old stuff that. Lately most the of the things I've been doing seem to
revolve around the cooker in the kitchen. From using the oven at 250oC for
SMD components, to using a saucepan on the stove with a sealable sandwich
box floating in a pan of water. That's where the etching gets done. All
very technical and high tech.

A sandwich box I've found is the most brilliant thing for etching, and at
50p each in the local supermarket too. Just stick it in a saucepan of hot
water. As for storing unused ferric cloride I use an airtight coffee jar
(glass being non reactive) stored under the sink in the dark.

I once tipped my mixed solution down a stainless steel sink.... Don't do
that.

All experience and memorable though. :)

I etched a board with I think RS FeCL3; after I did the board, I dumped
about a pint of the stuff down the storm drain.

I wonder if I killed any fish? (this was about 5 miles from the ocean).

Thanks,
Rich
 
N

none none

Jan 1, 1970
0
Aly said:
<SNIP>

Nasty old stuff that. Lately most the of the things I've been doing seem
to
revolve around the cooker in the kitchen. From using the oven at 250oC
for
SMD components, to using a saucepan on the stove with a sealable sandwich
box floating in a pan of water. That's where the etching gets done. All
very technical and high tech.

A sandwich box I've found is the most brilliant thing for etching, and at
50p each in the local supermarket too. Just stick it in a saucepan of hot
water. As for storing unused ferric cloride I use an airtight coffee jar
(glass being non reactive) stored under the sink in the dark.

I once tipped my mixed solution down a stainless steel sink.... Don't do
that.

All experience and memorable though. :)
I ended up getting a 2.2gallon fish tank from petsmart and used an aquarium
heater and aerator for the tank. I also drilled a hole in the bottom of the
tank (it's a cheap tank, all plastic) and have a pump hooked up to pump the
solution into a holding tank(only when using ferric Chloride) there is a
valve on the bottom of the tank which allows me to drain the solution after
os many uses
but it helps being able to use the pump to both empty and fill the etching
tank :p Don't use Ammonium Persulphate though in that setup unless your
gonna drain teh tank after each use, that stuff doesn't keep very well.
 
P

Puckdropper

Jan 1, 1970
0
[email protected] (Bob Masta) wrote in
Besides heat, the other thing you might want to check is to
make sure that your ferric chloride is not too concentrated.
Yes, you read that right: Believe it or not, above a certain
concentration etching slows down to a near-standstill.
You not only need to attend to this when you buy
new etchant (which is sometimes supplied at too-high
concentration), but also as it ages. You'll need to ask
a chemist for the explanation... it's something to do
with site competition (or something equally unintuitive).
But in the lab where I used to work, it was standard practice
when the etchant started to slow down (after some number
of boards were etched), to dilute it a little to bring it back up to
speed. I wouldn't have thought that usage would have
provoked a concentration increase, though it might have
been due to evaporation.

If you want the details on the proper concentration, see
www.daqarta.com/lptxh.htm

Best regards,




Bob Masta

I read that somewhere. You may have posted it yourself on Usenet
previously. The Google Searches turned up quite a bit of good
information before I even started.

Puckdropper
 
A

amdx

Jan 1, 1970
0
On reflex, I jerk back from the heater, scattering and spilling the
contents of the etchant container. The etchant gets all over my hands,
the floor, my coat, and the heater. Luckily, I was able to avoid serious
injury and minimize staining, but I can't trust that heater any more. I
think the FeCl just ate through the paint before stopping, but I can't be
sure.

Next time I get an idea like this, I'm either going to be more patient,
or if I want to move the etchant container, I'll put the lid on first.
Either one would have prevented the whole situation, and at the worst I'd
be disappointed by a bad board. They're a lot cheaper than a heater.

Ok, my ferric chloride story, I'm etchimg pcbs in a ¼" glass tray I made

Using silicone to stick sides to a 12"x12" bottom. Working on my wife's NEW

stove that has stainless steel burner covers. To heat the solution I
decided to leave

the cover on the burner and set the burner on the lowest setting. So, I'm
etching

along just fine until I notice a little etchent on the porcelain, the bottom
piece of

glass developed a crack. Now the etchant leaked on to the stainless steel
burner

cover and onto the stove top, down the front and into the burner hole.

After a major clean up, the only real damage was to the stainless burner
cover,

It has a deep etched line where the crack in the glass was.

I had used this method 5 or 6 times before the heated glass became a
problem.

BTW the best trick I learned about etching is to float the pcb on top of
the

etchant. Apply a piece of tape to the back side of the pcb to make a little
grab

point and just float it on top of the etchant. Etching goes much faster, I'll
let

others explain why.



Mike
 
E

ehsjr

Jan 1, 1970
0
Puckdropper said:
I'm a little upset right now, so please consider that when reading. If
you don't care, feel free to go to the next thread.

I was working on etching a circuit board, and wasn't too happy with the
progress of the etching process. Since warm etchant works better than
cold etchant, I picked up the etching container (a little 4 oz container)
and walked towards the garage heater (oil filled radiator type). After
walking the grand total of 6 feet, I move to hold the etchant container
closer to the heater and get shocked!

On reflex, I jerk back from the heater, scattering and spilling the
contents of the etchant container. The etchant gets all over my hands,
the floor, my coat, and the heater. Luckily, I was able to avoid serious
injury and minimize staining, but I can't trust that heater any more. I
think the FeCl just ate through the paint before stopping, but I can't be
sure.

Next time I get an idea like this, I'm either going to be more patient,
or if I want to move the etchant container, I'll put the lid on first.
Either one would have prevented the whole situation, and at the worst I'd
be disappointed by a bad board. They're a lot cheaper than a heater.

Puckdropper

A sort of Rube-Goldberg method for heating the etchant
is to use a hot plate. There are better methods, but
this one is cost free for most people.

Ed
 
B

Bob Masta

Jan 1, 1970
0
A sort of Rube-Goldberg method for heating the etchant
is to use a hot plate. There are better methods, but
this one is cost free for most people.

The method I use for heating is just to set the plastic
etching tray on a waterproof (plastic coated) heating pad.
This is the standard commercial home-use pad, with the
fabric cover slipped off. It doesn't get anywhere near as
hot as a hotplate, but that's a virtue... never boils over, etc.

Best regards,


Bob Masta

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Signal Generator
Science with your sound card!
 
R

Rich Grise

Jan 1, 1970
0
Ok, my ferric chloride story, I'm etchimg pcbs in a ¼" glass tray I made

Using silicone to stick sides to a 12"x12" bottom. Working on my wife's
NEW
stove that has stainless steel burner covers. To heat the solution I
decided to leave
the cover on the burner and set the burner on the lowest setting. So, I'm
etching
along just fine until I notice a little etchent on the porcelain, the
bottom piece of
glass developed a crack. Now the etchant leaked on to the stainless
steel burner
cover and onto the stove top, down the front and into the burner hole.
After a major clean up, the only real damage was to the stainless
burner
cover,

Go to the grocery and get a glass baking dish. :)

Cheers!
Rich
 
L

Lars Torben Wilson

Jan 1, 1970
0
The method I use for heating is just to set the plastic
etching tray on a waterproof (plastic coated) heating pad.
This is the standard commercial home-use pad, with the
fabric cover slipped off. It doesn't get anywhere near as
hot as a hotplate, but that's a virtue... never boils over, etc.

Best regards,


Bob Masta

I've only done a few boards so far, but I've found that floating the
etchant tank (hahaha--it's a plastic sandwich box) in hot water does
the trick nicely. No chance to overheat; spills go only into water,
etc.



Torben
 
E

ehsjr

Jan 1, 1970
0
Bob said:
The method I use for heating is just to set the plastic
etching tray on a waterproof (plastic coated) heating pad.
This is the standard commercial home-use pad, with the
fabric cover slipped off. It doesn't get anywhere near as
hot as a hotplate, but that's a virtue... never boils over, etc.

Best regards,


Bob Masta

Good idea - I just tried the heating pad method tonite,
and I like it better than the hot plate. Thanks!

Ed
 
L

Lionel

Jan 1, 1970
0
I've only done a few boards so far, but I've found that floating the
etchant tank (hahaha--it's a plastic sandwich box) in hot water does
the trick nicely. No chance to overheat; spills go only into water,
etc.

That's the same method I used to use. The only drawback I found was
that it is easy to get careless when agitating the inner tray, &
splash water or etchant everywhere.
 
L

Lars Torben Wilson

Jan 1, 1970
0
That's the same method I used to use. The only drawback I found was
that it is easy to get careless when agitating the inner tray, &
splash water or etchant everywhere.

Oh man. I don't do the etching in the sink. Got a pregnant woman in
the house. :)

I go out to the porch on an old wood bench, with a cube heater blowing
warm air over the pre-warmed etchant with the board in it. I use a cotton
ball to rub etchant on the soldering side. I also like to float the board
in the etchant on the component side for a while first, to give it a head
start in dissolving before I start on the soldering side. I can usually do
a pretty good 4cm by (say) 6cm board in 5 to 10 minutes.


Torben
 
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