Photo-Etching

[unittrain]

I was looking into photo etching I found some info http://www.prototrains.com/etch1/etch1.html here
what I was wondering is if this type of pump would provide enough pressure to etch rivets in N scale
and if not what specs would I be looking for. Also on the resist developing frame is it necessary to
create a vacuum in between the brass and the art for better developing?

[Chris333]

Anything that circulates the etchant will help. Randy Gustafson showed me a Lego based battery powered  propeller that would hang down into the container. Any agitation will help.

Bob would know more about using pressure.

I don't think you need vacuum for the artwork. With the Micro Mark kit you clamp in between 2 squares of plexi and this works fine. At work we do use vacuum, but this is more of a speed thing because we might expose 150 newspaper plates an hour. A clamp would work, but not for 150 times over and over.

Just draw on a piece of brass with a Sharpie then soak in Ferric Chloride and watch what happens. It is self training.

[diezmon]

keep in mind the etching is done chemically, not by pressure.. or force of moving the echant.  circulation helps a lot though.  I have a simple fish tank air pump, and a tube at the bottom of my etch tank with holes.. kind of like a sprinkler.   Just to keep things moving.

Some guys simply hold the part in the etchant, and move it around my hand.

Although, I haven't done anything with rivets yet. 

[randgust]

The Micro-mark kit is good, not great, but everybody has to start somewhere.

You can etch with it, Chris has done a great job.  I learned everything I learned from Chris, and a whole lotta expirimentation and do-overs.  Chris will verify I did everything wrong at least once.

The biggest advantage is that when I started to shop stuff around for commercial etching, they wanted a sample.  Well, the Micro-Mark set and the home-brew methods can do that. I made about eight sets of 70-tonner parts before I got a perfect set.

If there's a fatal flaw (other than the fact this has to be the most dirty, dangerous and toxic 'hobby' activity I've tried yet) it is that the fish-tank aerator doesn't do an adequate job of stirring the Ferric Chloride to etch evenly.  It really doesn't.  The bubbler has a 'zone' it etches in, and even small parts are chewed up in some areas and not etched in others, even if you flip and wash every five minutes.   My teenage sons solution to use Lego and K'nex parts to come up with a stirrer/circulator was downright revolutionary.

[kiwi_al]

Hi Randy,
Did you try using a fish tank heater to heat the Ferric Chloride? Used to use this method of etching Printed Circuit Boards - tank , bubbler and heater to get really good single sided boards way way back in the day .

[Chris333]

I think Randy is using a heater, I am as well.

For best results you need to get the whole sheet to etch evenly. The idea of bubbles is to continuously wash the surface and let fresh etchant to clean metal.  Really the only way this works well is if you have a billion bubbles with lots of force. If you could get that you would probably get a big foamy head that would leak out the top of the container.

I think professional equipment is contained and pressurized. The etchant is constantly circulated with pumps and jets spraying the etchant directly to the sheets, even if this all happens submerged. The pressure would help the etchant evenly eat away metal as well.

My best results are to slosh the etchant container around vigorously while the etchant is working. Sometimes this takes 10 minutes and I do get tired!  Randy's idea does this for you, you don't have to sit right there and put in effort during the whole process.

Besides all the stuff and time it takes to get sheets ready, you need more time to etch the sheets. This is why you won't see me trying to make a hundred etches of something to sell. For making a few pieces for a project, well yeah that is worth my time.

[randgust]

Yeah, I put in a heater.  Actually, in the spirit of 'do it wrong the first time' I used two; the first one cracked and shorted out!

Here's the stirrer in the Micro-Mark tank; that's all K'nex on the motor, driveshaft, and removable bracing; with a Lego propellor jammed on the shaft.  That really worked well.  There's a quick disconnect on the motor so you could pop it off and leave the shaft/stirrer intact.



The challenge was to come up with something that the ferric chloride wouldn't destroy, and that's not easy!  It did finally embrittle the K'nex, but I've got boxes of the stuff, so no big deal. 

[Walkercolt]

When I worked for "Fish-Finder's", the PC board etcher used ultrasonic "spray nozzles" to etch the boards. Remember, they were doing multi-layer, both sides of the boards too. Took the boards about five minutes to move thru the tank. You had to have a haz-mat suit and positive pressure respirator to go in to the room too...nasty. Then the high-dollar "marine" series stuff was gold plated for corriosion resistance...another nasty room. Wish I coulda got to the rolls of gold leaf!

[Chris333]

Hey check out this guys 1/700th scale layout with just about everything etched:
http://forum.larsenal.com/viewtopic.php?t=440

[diezmon]

Hey check out this guys 1/700th scale layout with just about everything etched:
http://forum.larsenal.com/viewtopic.php?t=440

je ne pas parle Francais...

http://64.233.179.104/translate_c?hl=en&sl=fr&tl=en&u=http://forum.larsenal.com/viewtopic.php%3Ft%3D440&usg=ALkJrhgUKuNlkt7ulH2dmYMqnccRVeBMHg

[John]

awesome

[kiwi_al]

A 44 tonner in 1/700th scale - that's awesome!

[DKS]

Oh... my... god... I've just $hit my pants. That guy crams more detail into 1:700 than I've seen in some 1:87 models. The crane at the bottom of page 1 and on to page 2, for instance. Just incredible.

[up1950s]

Just what I needed , more reason to feel inadequate . :-[

[womblenz]

Just what I needed , more reason to feel inadequate . :-[

I couldn't agree more

Cheers Warren