PROJECT: PCB Etching Tank  - Page 1
Forum section: electronics / projects

author: Spawn
author_rank: Frequent Contributor
timestamp: March 26, 2012, 07:57:28 pm
content: For a while I am in search for a good etching tank, but the good ones are expensive and cheap ones are crap.For example the Velleman model or the Taiwan model are known to fail, they start to leak after a while and not even on the glued pieces but on the material they use. There are some examples on the Dutch electronics forum. These models cost around 70 euro till 90 euro.Before I start, this is not going to be a Tupperware or whatsoever tank, I want nice solid and fast etching tank.After reading those stories about leaking I decided to go with a glass tank, but the problem was finding right size tank, I don’t need to etch big PCB’s the standard 16cmx10cm (6.2”x3.9”) is more than enough for me. I was in hunt for a glass tank around this measurements: 40cm (15”) high, 30cm (12”) wide and with 15cm (6”) depth. I want the height for the 500Watt heating element which I will explain why so much power.The only option for such tank was a battery jar (also known as glass battery box), no glues or silicone kits whatsoever, a nice solid tank, I didn’t want to get some aquarium tank because of the silicone joints. After a long search in the garden stores I was about to give up, the biggest problem was the height, most tanks where around 15 to 20 cmToday my wife ask me to pick up something in a garden store, I never checked this store before because it was in another city and my wife saw something in a add. While I was walking in that store I was also looking for a battery jar and I found one!Not the exact measurements I want but it was close enough for me, this thing was pretty cheap too, it was on discount and it cost me 15 euroMeasurements are 30cm (12”) high, 20cm (7.8”) wide and deep, it’s little bit wider than I want but I am still happy with it.Before we go in to the materials:I will post every update including pictures and videos in this start post.The idea is having a tank which heats up in no time and etches pretty fast.The tank:it looks pretty solid and has 5mm thick glass:Almost all materials below are from this ebay store:Aquarium HQThe heater:I ordered 2x 300Watt aquarium heaters (P0w4H in the house), like I said I want a fast etching tank, the idea is to get around 45C to 50C (113F to 122F) in no time and stay there, but most aquarium heaters are limited till 35C like this one below, so I have to open it up and hack it in some way to make it go till desired temperature, if that won’t work I just take out the thermostat and short it, there are digital aquarium temperature controllers if needed, these are not that expensive.This is the only decent priced 300W with this length btw:If anyone wants to buy a heater don’t buy chrome ones, we want as much possible glass made material in our tankThe air pump:I took a pump with high rating and because of the rating I wanted a adjustable pump, we don’t want our PCB’s flying around the room after all. The pump is rated at 192liter air/hour (50gallon air/hour) There are some dual outlet pumps out there but I want minimize the tubing.The bubble maker:I didn’t want to drill holes in some tubes and see if the bubbles get all over the tank so I went for a aquarium bubble air wall, which has the right length for the tank, I ordered 2 air walls and they will be attached at the bottom of the tank:A old fashion good trusty glassthermometer:Last but not least, small materials like T-pieces, small knees, tube, suction pads for the tube and most important a check valve, we don’t want the aggressive etching material in our pump when it is sitting next to the tank.That’s all I can think of to get, I ordered them all and when these arrive I will keep this topic updated with the test and finishing it.Price tag till now is still reasonable with 64EUR or 85USD or 81AUD or 54GBPPS: If you find any typo’s or bad English grammar, you can keep it

author: Simon
author_rank: Unknown
timestamp: March 26, 2012, 08:36:49 pm
content: yes I have not yet found a decent container for etching and a "cheap" one off ebay just fell apart on me....

author: Zad
author_rank: Super Contributor
timestamp: March 26, 2012, 08:44:42 pm
content: I think I would be paranoid that localised heat would crack the glass, as 5mm isn't very thick.

author: Simon
author_rank: Unknown
timestamp: March 26, 2012, 08:47:30 pm
content: Quote from: Zad on March 26, 2012, 08:44:42 pmit would be a sudden temp jump that would crack the glass, if the heater is kept away from the side it will be ok

author: Spawn
author_rank: Frequent Contributor
timestamp: March 26, 2012, 08:55:03 pm
content: Because of my work I tested a lot proto type machines in the past and wrote up testing protocols.This is not industrial of course, but when the bubbler and the heaters arrive I will do a long term test, like from room temperature water till around 45C and try to keep it there for hour or two with the heaters attachedon the glass, if it cracks bad luck we start over again

author: george graves
author_rank: Super Contributor
timestamp: March 26, 2012, 09:11:41 pm
content: What the typical use of the "battery boxes" ? (so the store clerk didn't look at me strange!)

author: IanB
author_rank: Super Contributor
timestamp: March 26, 2012, 09:21:49 pm
content: Quote from: george graves on March 26, 2012, 09:11:41 pmThey are usually antiques in their original form. You would fill the glass jar with acid and suspend lead plates in it from the top to make a lead-acid accumulator. Typically you would not find one made for that purpose since the 1920's.Today I think they are probably just decorative glass items, perhaps to be used as a small fish tank or display case for aquaculture? I suspect "battery box" is just a name carried over and no longer describes the true function.

author: Spawn
author_rank: Frequent Contributor
timestamp: March 26, 2012, 09:27:14 pm
content: Here a nice history:QuoteInformation is taken from:Allaboutbatteries.comBut near history of it was indeed in 20’s at railroad companies and more.The jars we use these days are made for putting flowers in them or for decoration.

author: Spawn
author_rank: Frequent Contributor
timestamp: March 27, 2012, 12:13:14 am
content: The first addition to the tankWaiting on those orders to finish will take long time lolI had some lexan tube laying around, I made 2 PCB holders.Made a flat side, to prevent rolling on the tank:

author: M. András
author_rank: Super Contributor
timestamp: March 30, 2012, 07:22:14 pm
content: the liquid will constantly move by the constant air bubbles this will prevent the localized heat buildup at point of the glass? by simply stiring the etching solution.

author: Spawn
author_rank: Frequent Contributor
timestamp: March 30, 2012, 07:41:16 pm
content: Yes indeed, and bubbles are actually for the sodium persulphate because if it gets heated more than 50 Celsius it will looses the etching effect, so bubbles will move the heat around to prevent that.I received the air pump today, but it is weird because I ordered almost everything from same seller.

author: Spawn
author_rank: Frequent Contributor
timestamp: April 03, 2012, 06:33:48 pm
content: Received all items I ordered from the seller above today, 7 days is great I have seen worse like a month even more.Unfortunately I ordered the air wall stone from another seller so I can’t test the tank yet.It looks like I don’t have to modify the heating elements, the temperature knob can be turned further than the max 35 Celsius so I think 40 is possible without any tweak.To be honest I start to worry about this tank sizeIt needs at least 10 or 11 liters etching stuff that’s a lot, to stock this it would be problem, there are smaller battery jars but I can’t find one.Another option is the tank from PRO-MA, they build good quality etching tanks but it’s not from glass, the tank takes 1,75 liters and that’s really good . The tank from PRO-MA looks like this:http://www2.conrad.nl/goto.php?artikel=530360The tank is for this machine:http://www2.conrad.nl/goto.php?artikel=530328The PRO-MA tank:Here a photo of the knob from the heater, as you can see the temperature can be set more than the marks on it:A photo with heating elements in the tank, it looks like these are made for this tank

author: kripton2035
author_rank: Super Contributor
timestamp: April 03, 2012, 07:01:24 pm
content: this pro-ma tank has really bad review on the conrad web site ...

author: TerminalJack505
author_rank: Super Contributor
timestamp: April 03, 2012, 07:10:48 pm
content: That looks like a fun project. You must plan on doing a lot of boards.I'll stick to the cheapskate method: a foam brush. Toss the board in the etchant (ferric chloride) and scrub the board with a foam brush. It's a pretty quick and effective way to etch boards.

author: Spawn
author_rank: Frequent Contributor
timestamp: April 03, 2012, 07:20:29 pm
content: Quote from: TerminalJack505 on April 03, 2012, 07:10:48 pmLol it's more for the fun part than making a lot boardsQuote from: kripton2035 on April 03, 2012, 07:01:24 pmYeah seen it just a minut ago, people say they leak out of the box, nice to have a water tank which leaks out of the box...

author: IanB
author_rank: Super Contributor
timestamp: April 03, 2012, 09:22:51 pm
content: Have you thought about making your own tank?http://youtu.be/hT6Ow_cBTpsAcrylic plastic appears to be resistant to most aqueous solutions including ferric chloride, with the only exception I can see being chromic acid.If you have access to some workshop tools you could make a tank to your exact requirements.

author: T4P
author_rank: Super Contributor
timestamp: April 03, 2012, 09:46:16 pm
content: Quote from: IanB on April 03, 2012, 09:22:51 pmI never really had the idea but then , a circular saw should do the job

author: Spawn
author_rank: Frequent Contributor
timestamp: April 03, 2012, 11:20:33 pm
content: Thanks for heads upIanB, in fact I did use lexan and glued (welded) together where I worked for a medical factory 10 years ago, for some reason they ended up letting loose the “welded” parts when physically abused or higher temperature exposure, I used almost same liquid from that video.You could say “you just suck at welding lexan”but it was not only my work my coworkers had same issue.Besides that, I know a company from those days which I have good contact with and I can let them make a tank from lexan with minimum welding like making a U shape and then weld 2 pieces to open sides, and choose a thickness till 25mm and I believe that could work, because the piece you weld has really big surface, but the price would be too much, but you never know with me, if I can’t find any solution I might ask them for a price. They did vacuum tanks for us to test the blisters on leakage and they worked perfect, but then again they used 25mm thick lexan.Dave.Sits best to use a table saw with certain speed and cutting (pushing through) speed, if you go too fast the piece you cut start to smelt and gets really messy. You also can use a electric jigsaw by using mask tape on your piece but you need really steady hands because of the piece you cut needs to be welded.Since I wrote the last piece here I was looking for another solution for the tank, and I came up with a square glass vase 25 cm high and 10cm each side, inner side would be around 9cm x 9cm and the water will be filled till 22cm and that makes only 1.78 liters of etching liquid which is perfect, with this vase I can use a standard EU PCB in this tank because 9cm square has approx 12,5cm distance between diagonal corners.This would cost me more money, because the heaters I got are too big for that and i need a new one, but like the title says it’s a project, if it works fine for me total costs of this tank will be even lower than the current one and that might help other people to get a idea.

author: T4P
author_rank: Super Contributor
timestamp: April 03, 2012, 11:41:20 pm
content: Quote from: Spawn on April 03, 2012, 11:20:33 pmCertainly , i know about that . I would never use a circular saw for cutting acrylic to perfect straights , but sometimes helps to keep tool costs down ...Maybe .I saw those proxxon bench saws and my first thought is they are too smallIn the end i must really go to a proper tool shop and take a look at the bench saws .

author: Spawn
author_rank: Frequent Contributor
timestamp: April 03, 2012, 11:51:53 pm
content: Lol, smallest proxxon table saw is even too small for bigger size PCB's

author: T4P
author_rank: Super Contributor
timestamp: April 04, 2012, 05:23:22 am
content: Quote from: Spawn on April 03, 2012, 11:51:53 pmAnd there's only one size

author: Spawn
author_rank: Frequent Contributor
timestamp: April 04, 2012, 07:39:25 am
content: Quote from: Dave.S on April 04, 2012, 05:23:22 amYou think so?http://www.proxxon.com/eng/html/27070.phphttp://www.proxxon.com/eng/html/28070.phphttp://www.proxxon.com/eng/html/27006.phpBut we are going off topic again Dave.S

author: T4P
author_rank: Super Contributor
timestamp: April 04, 2012, 12:20:42 pm
content: Quote from: Spawn on April 04, 2012, 07:39:25 amI know , but on element14 there's only 1 size .

author: Spawn
author_rank: Frequent Contributor
timestamp: April 04, 2012, 01:14:23 pm
content: Dave.S what do I have to do with element14? Let me ask it different way: Who cares what element14 sells? I can buy all 3 sizes here…

author: Spawn
author_rank: Frequent Contributor
timestamp: April 04, 2012, 01:15:50 pm
content: Still no bubble wall stone, but I was in a hunt for another tank today, and came home with a round vase, it is 300mm high and 115mm round inside, good enough for a EU size standard PCB. And it only takes 2.5 liters, I can choose to fill till 2 liters with another heating element which I already ordered.This is still 10 liters lower than the first tank option.When the bubbler arrives I will take a video about the temperature, to see how fast it goes to 45 Celsius from room temperature.Here is a photo with a standard size PCB and the 300W heating element.I probably use the first tank as safety tank when the small one explodes on me

author: Psi
author_rank: Super Contributor
timestamp: April 04, 2012, 01:25:23 pm
content: I've always put my dish of FeCl into an old microwave for a few minutes, gets it nice and hot.FeCl has quite a high boiling point, at least 280C.I dunno how safe it is to microwave the stuff but it's never given me any problems.I imagine if it did boil the fumes wouldn't be good for the microwave

author: Spawn
author_rank: Frequent Contributor
timestamp: April 04, 2012, 03:33:23 pm
content: Lol Psi, my wife would killed me if i used the microwave for thisLike always I couldn’t wait so I went to a pet shop and got a bubble stone which fits in the tank.And run a test, from 20 Celsius till 45 Celsius it took 17 minutes, I keep it running to test the durability of the tank after 22 minutes it was at 51 Celsius and couple minutes it reached till 53 Celsius and stayed there for a hour and tank is still okThe heater is 300W and max temperature is 35 Celcuis on it's scale, but you can turn it further on so no mods needed.Don’t have some etching stuff so I need to order those to test the working.Below a photo and a video of the tank running.After 17 minutes at 45 Celsius:Video at 51 Celcuis after 22 minutes:

author: sonicj
author_rank: Frequent Contributor
timestamp: April 04, 2012, 05:52:07 pm
content: nice timerthats the smallest drill press evarr!i was thinking one of those outdoor real estate literature holders would make a good tank....-sj

author: Spawn
author_rank: Frequent Contributor
timestamp: April 04, 2012, 09:02:06 pm
content: Yeah that was the only timer with big digitsand that poor drill press stood in its box for months because I had small bench, I got bigger bench now and it is already full I had everything stacked up in a wardrobe, 5 power supplies take a lot room, also my UV light case is big too. Waiting on some panel meters to finish the bench now.Those literature holders are looking good but they need to be glued and till now every glued tank I seen on the net had leakage problems soon or later. Besides the second one on the picture takes almost 4 liters liquid and I think the first one is even bigger.I was busy for hours to get the temperature right, finally I got it working nicely between 41 Celsius and 46 Celsius, when it hits 46 Celsius it takes a while before it drops to 41 Celsius.I am planing to take a hour long video to see its exact behavior, water is cooling down right now.

author: codeboy2k
author_rank: Super Contributor
timestamp: April 06, 2012, 07:27:48 am
content: I used to make my own boards at home, years ago.. but in my opinion it's just not cost effective anymore. The blanks are expensive in small quantities, so you have to buy large sheets and cut it yourself. Then you have to sensitize it with a photo-resist, and you might not get that coating even, it takes a long time to get expert at it. I always did darkroom boards, never iron-on anything.Then it's nearly impossible to make anything more than a 4 layer board, and you don't get plated through holes, unless you buy another chemical... and oh, the chemicals. Theyhave become unreasonably expensive these days for home use quantities. Plus, there's the issue of disposal. I can go on and on....With the numerous PCB houses online these days, and fast turnaround for small runs, you get a better board with solder mask, silkscreen, PTH, it's often fully tested, and routing, you can even get gold plating.. it's just too cheap to make it at home anymore.The only reason to do it, as was already said here, is for the fun and experience.

author: Spawn
author_rank: Frequent Contributor
timestamp: April 06, 2012, 08:06:12 am
content: Quote from: codeboy2k on April 06, 2012, 07:27:48 amExactlywith the money spend here I can order PCB’s for a decade I think, because I don’t make that much PCB’s. It is just for the fun and hobby part of it, as we all know hobby needs some afford.One or two PCB’s I make a year when I have some idea or see something on the web which gets me triggered is enough for me to make PCB’s at home. I don’t want to wait 3 till 7 days I just want to spend time on same day and make it for the fun part of it.

author: nctnico
author_rank: Super Contributor
timestamp: April 07, 2012, 07:31:15 pm
content: I agree it has become very affordable to have PCBs made. OTOH etching a PCB yourself gets you a PCB real quick.I've been etching PCBs since I was 13. Mostly using submersion etching. When I was a few years older I've build myself a big submersion etching machine. It worked but etching was slow. When I got kids I threw it away because I didn't like the idea of having so much chemicals around. But... having PCBs made every time is not practical especially when I need to make a quick prototype for a customer. So I decided to get myself an etching machine again. Since I've always used Ferric Chloride I choose to use that again. I stumbled across a simple spray etching machine which is nice for euro-card sized PCBs (and slightly bigger). The first time I used it I wanted to hit myself on the head with a big hammer. I should have got it 25 years ago! Etching is so amazingly fast you can see the copper disappearing.This picture is very similar to the one I have although mine can only do single sided while the one in the picture can etch double sided boards:http://www.electronics.gompy.net/etsbak/etsbak10.JPGIts basically an aquarium with a plastic lid and a false bottom. In the middle of the lid there is a small DC motor with a tube attached. The tube has holes and the end of the tube extends into the etchant. When the motor turns around the etchant is sucked into the tube and exits through the holes. Its amazingly simple!This page describes how to build one (its in Dutch but the pictures speak for themselves):http://www.electronics.gompy.net/etsbak/index.html

author: Spawn
author_rank: Frequent Contributor
timestamp: April 09, 2012, 09:29:24 pm
content: Nice one there nctnico, spray etching is really fast indeed could look in to that later but like I mentioned before I don’t etch that much to have one of those. But project wise its good thing to build I guess, I can use the first tank in this topic for this I guess, still no silicone joints and such.

author: poorchava
author_rank: Super Contributor
timestamp: April 12, 2012, 03:30:32 pm
content: I'm using an ordinary food container.I've tried to make my own out of acrylic glass, but eventually the the seams would always break. I've tried all kinds of stuff from ordinary silicone to epoxy glue and they all failed. This one contains about 3-3.5 liter of solution.

author: Spawn
author_rank: Frequent Contributor
timestamp: April 26, 2012, 12:06:29 pm
content: Bad news for the project and good news for myself, I just won a Foam etching machine from a local auction site.I did spend some time and money in to this project but some things where still bugging me, I want a compact solid etching tank/device, but with the project setup I had too much things hanging around like wires, hoses to the pump and I like neat clean looking stuff.I hope no one gets disappointed with this, I know someone was looking forward to see if the aquarium stones will survive long enough after a lot usages but I can’t test this anymore, I am 100% sure this setup will work but I can’t prove if it lasts long (which was my intention).Sorry about this, but I like I said I need a solid and neat etching device, if I knew I came across a tank beforehand it would save me a lot money, in fact the whole tank I have is cheaper than I spend till now on this project, and it is barely used.For the interested, this will be my new etching device: