Suggestions for an etching tank? - Page 1
Forum section: electronics / general

author: Dago
author_rank: Frequent Contributor
timestamp: October 27, 2009, 11:04:46 pm
content: I was drooling on an etching tank (with a heater and an airpump) which costs around 125$ until I sortof realised it's just an aquarium heater + aquarium air pump and a transparent tank. I checked on aquarium heater and air pump prices and the pump + heater cost considerably less, the best deal I was able to find was around 26$ for a 100W heater and an air pump. Now I'd just need to find a suitable tank (transparent) which could fit euro sized pcbs (160x100mm). Making one from plexiglass or something would be pretty easy too but I don't really have tools for that. Any ideas or suggestions where I could find something suitable?Or I could just continue etching my PCBs in a tupperware container but it's just so damn slow (takes an hour or more) and you have to move the board around every once in a while.Heres a pic of the commercial one:

author: EEVblog
author_rank: Unknown
timestamp: October 28, 2009, 12:10:27 am
content: Spring a bit more money and get this nice one!:http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/PCB-Equipment/Etching/PCB-Etch-tank/29472Nothing worse than etching boards in the old tupperware container, so do anything you can to avoid it!Dave.

author: KuchateK
author_rank: Regular Contributor
timestamp: October 28, 2009, 12:33:46 am
content: Stuff used for etching is usually aggressive to silicone or glues and home made container or even professionally made aquarium can leak pretty quickly.I'm using plastic cereal containers. I paid for them 4 & 6 dollars (medium and big). I was able to find containers with covers sealed with rubber gaskets, so when I'm not using solution nothing evaporates even after few months. Covers have additional smaller windows that can be used to put air tubes or heater cable inside and there is still nice splash protection. Drawback is that they are over twice the thickness of regular etchers and it takes one liter to fill medium and over three for the big one. But one piece plastic part will never leak and that sealed cover is really good.I'm not using heater right now and I'm experimenting with agitation by PC fan blades on long plastic tube and small electric motor from toy. I'm not making a lot of PCBs so little more time to etch is not a big deal for me.Edit: I've found exactly what I have:http://img163.imageshack.us/img163/3922/41n1zb2rnulaa400.jpg

author: Dago
author_rank: Frequent Contributor
timestamp: October 28, 2009, 01:28:04 am
content: Quote from: KuchateK on October 28, 2009, 12:33:46 amCereal containers actually sound PERFECT!! I gotta try to find some.QuoteWell, I've been exposing my PCBs with a 11W fluorescent light (the regular kind) and etching them in a tupperware container and it has been working pretty well, just takes a long timeExample PCB with a µMAX package ic (0,65mm lead pitch):Ordering PCBs from a manufacturer (like pcbcart) is always possible as well and not THAT expensive but usually I do not have the patience to wait for them (I guess you people are the same with projects, once you start doing something you gotta get it done FAST before you lose interest) and usually you can't be sure the first design is 100% correct so its easier to do multiple revisions at home.

author: Simon
author_rank: Unknown
timestamp: October 28, 2009, 07:58:36 am
content: use a vertical food box, these are normally sold as breakfast cereal boxes, they are thinner and taller, not perfect but as close as you will get to what you want for a fiva, you can (carefully) drill a hole in the side to pass the air pump pipe through, they come with lids which is handy

author: Dago
author_rank: Frequent Contributor
timestamp: October 28, 2009, 07:00:19 pm
content: Bought this today, it should be pretty good. It's a tad big (three liters) but it has a good base and feels stable so it shouldn't tip over or anything. I've been looking at aquarium heaters and they start to seem like a bad idea. Mainly because they are usually long and narrow (and need to be fully submerged, so I'd basically need three liters of etching liquid.. with a shorter heating element I could use like a liter) and the thermostat usually goes only up to 32C. Any other ideas for a heating element? It might be possible to put a power resistor in a big glass test tube, put in some oil (to transfer the heat) and then plug the thing up and use it as a makeshift heating element but....

author: KuchateK
author_rank: Regular Contributor
timestamp: October 28, 2009, 07:41:17 pm
content: Check different stores. Aquarium heaters about 20cm (~8in) should be available off the shelf. In typical cereal box can be mounted diagonally and covered with one liter. Tetra has models starting at about 5 3/4" (~15cm).http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=16756http://www.amazon.com/Tetra-26447-Submersible-50-Watt-Heater/dp/B000OQO69Q/ref=sr_1_1?ie=UTF8&s=home-garden&qid=1256757755&sr=8-1The built in thermostat should be easy to disable. Heaters with rubber cap on top can be easily opened for various hacks (I was making long units shorter long time ago and to compensate short heating element I've connected two in parallel).As for replacement thermostat LM35, potentiometer, comparator (like LM393) and relay/triac is a decent start. You can also make fancy unit with LCD, microcontroller, timer, buzzer and PID library (Arduino has one) for precise regulation for about $10-15 in parts.

author: BlackCow
author_rank: Newbie
timestamp: November 06, 2009, 11:06:29 pm
content: I feel ghetto, I use a Tupperware and the toner transfer method printing with the library's laser jet printer XDAnd to speed things up some I hold the Tupperware over the stove top. I have a thermometer in it though to make sure it doesn't get too hot.