Solder pot for tinning wires and component leads. - Page 1
Forum section: electronics / general

author: elcomtel
author_rank: Regular Contributor
timestamp: October 16, 2013, 12:46:55 am
content: I have to admit that I have never used a solder pot to tin wires and component leads.So I was wondering if people could give me their ideas and tips.I'm particularly concerned about how the solder maintains it quality. Doesn't it deteriorate after time and become contaminated?To start with I bought one of these Solder Pots on Aliexpress to introduce myself into the art:http://www.aliexpress.com/item/New-Solder-Pot-Soldering-Desoldering-Bath-50mm-220V-150W-ST21C-ST-21C-Silver-freeshipping/800076568.htmlThe next thing I need is some solder, so I intend to buy the following from my local hardware:Sn 60% Pb 40% Solder Bar 250gmhttp://www.bunnings.com.au/consolidated-alloys-60-40-soft-solder-stick-_p5060304(I intend to use 60/40 as this is what I traditionally use (or 63/37 depending on the application).But there are also other Sn/Pb (inc. Cu) ratios available.Sn 50% Pb 50% Solder Bar 250gmhttp://www.bunnings.com.au/consolidated-alloys-50-50-soft-solder-stick-_p5060061Sn 40% Pb 60% Solder Bar 250gmhttp://www.bunnings.com.au/consolidated-alloys-40-60-soft-solder-stick-_p5060299Sn ??% Cu??% Pb Free Solder (Which looks like it could be used for electronics lead free soldering)http://www.bunnings.com.au/consolidated-alloys-120g-aquasafe-solder-stick_p5060443Is it plausible to consider the other solder bars I have listed for what ever other reasons?I also have to assume that I need to dip my wires and component leads into rosin flux before I dip into the solder pot. Is there any other flux that I could use or use it (such as pouring a little into the solder pot, given that normal rosin flux would smoke profusely, so I'm suggesting a non organic flux similar to sulfuric acid) in such a way that would keep the solder 'bath' clean?What about the temperature setting of the solder pot? Would I set it to 300degC as my soldering iron for 60/40 solder? What temperature should I set the solder pot if I was to use Pb free (not that I want to....I simply ask this for academic reasons)?Given that I have no practical experience with using a solder pot, is there anything I should know before I attempt to use one?Rather that learning by trial and error I thought I'd put this question out to the EEVblog community.My reason for asking this question is my interest in setting up a small scale electronics production line and I suspect that a solder pot is the better way to tin wires and components.--------------------------------------------------------------------------------------------------------------------------Further on my thoughts about the use of a 'Solder Pot' I am contemplating a poor man's wave soldering device. I would manually dip the PCB into the molten solder to make all the solder joints.Prior to this I would apply rosin flux to the whole solder side.I know that people are using electric frypans to reflow SMD PCBs.http://www.sparkfun.com/tutorials/59So why not 'wave solder' with an electric frypan?A popular $150 USD stainless steel frypan sold on the Australian market.http://www.sunbeam.com.au/Cooking/Frypans-and-Skillets/FP8910-Ellise-Stainless-Banquet.aspxDoes anyone think there is merit to my 'wave soldering' idea given that electric frypans are used successfully for SMT work?Many thanks in advance.

author: nanofrog
author_rank: Super Contributor
timestamp: October 16, 2013, 02:16:58 am
content: You will get oxides on the surface, so you'll have to skim the surface to remove it before dipping the wire in. So in a way, there is "deterioration", but it's not that difficult to deal with IMHO.If you mean to stick to lead based solder, stay with 60/40 (tin & lead respectively) or 63/37. The other types are meant for other applications, not electrical work (i.e. plumbing & auto body; melting temps rise with increased lead content as well).Dip the wire in the flux, then into the pot. Do not add flux to the pot, as it will cook off and make a mess that you'd have to scrape off the top (also increases your consumables costs).As per wave soldering, how do you intend to generate the wave/jet? Or do you mean to have a large surface area for dip soldering?You might want to look at some solder pot vids on YT (https://www.youtube.com/results?search_query=solder+pot&oq=solder+pot&gs_l=youtube.3..0l2j0i5l2.21853.23271.0.23520.10.8.0.0.0.0.229.924.2j4j1.7.0...0.0...1ac.1.11.youtube.vbrPOwekgKw).Hope this helps.

author: amyk
author_rank: Super Contributor
timestamp: October 16, 2013, 12:12:36 pm
content: You should also give it a wide berth and put something nonflammable and heat resistant e.g. refractory tile under it.

author: MacAttak
author_rank: Unknown
timestamp: October 16, 2013, 10:34:52 pm
content: And something capable of catching the molten solder should you manage to tip it over

author: envisionelec
author_rank: Frequent Contributor
timestamp: October 16, 2013, 10:50:37 pm
content: Quote from: nanofrog on October 16, 2013, 02:16:58 amI think he was asking to dip the entire PCB into the pot.I've done this...it works for very small boards. Kinda.

author: edavid
author_rank: Super Contributor
timestamp: October 16, 2013, 11:19:02 pm
content: I thought this was a good tutorial:http://www.piclist.com/techref/solderpots.htmNote that if you try to dip solder boards without solder mask, you are likely to get some bridges.

author: Bored@Work
author_rank: Super Contributor
timestamp: October 16, 2013, 11:39:01 pm
content: Quote from: envisionelec on October 16, 2013, 10:50:37 pmIt even "works" for larger boards. See 1 min into this videoBut well, voluntarily doing it this way at home is a bad idea. A really bad idea.I have never felt the need for a soldering pot, small or large in decades. I don't have to tin heaps of wires or component leads. Not even when through-hole was still all the rage.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: October 17, 2013, 12:13:25 am
content: A good resource to ask would be firearm enthusiasts who cast their own bullets. They should have good recommendations for lead melters (which easily exceed the temperatures needed for Pb/Sn solder), tools for skimming and other tasks, safety, etc.

author: elcomtel
author_rank: Regular Contributor
timestamp: October 17, 2013, 12:20:01 am
content: Quote from: Bored@Work on October 16, 2013, 11:39:01 pmPre-tinning of wires and component leads is a normal part of good soldering practice. Most people take for granted that component leads are pre-tinned during manufacture.Sure an amateur hobbyist will 'just solder' and never concern themselves with pre-tinning, but if you work in aerospace, defence or medical electronics then soldering becomes an artform.You shouldalways pre-tin wiresbefore you begin to solder unless you intend to produce crap.This is more work at the end of the day and why I was interested in a solder pot. I simply wanted to speed up the process over using a hand soldering iron.ALWAYS CORRECTLY PRE-TIN YOUR WIRES BEFORE YOU SOLDER

author: elcomtel
author_rank: Regular Contributor
timestamp: October 17, 2013, 12:23:41 am
content: Quote from: Phaedrus on October 17, 2013, 12:13:25 am@Phaedrus you are a very clever man !!! I respect people enormously who can think outside the square.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: October 17, 2013, 12:43:21 am
content: No problem. My first exposure to working with molten metal, before I took up EE and soldering, was my dad's lead melter which he used for casting bullets for muzzle loading muskets.Safety:1. Wear eye protection2. Wear flame-resistant, temperature insulating gloves3. Triple check to make sure the device is off when you're done4. Keep the area well-ventilated5. Use a tool to manipulate objects you're dipping; don't put your fingers closer than 8-10cm to the molten metal6. Ensure the tools you use are rated for the temperatures you are dealing with7. Do not lean over the pot; consider wearing a headband to absorb sweat. Sweat droplets can fall into the pot and explode to steam, spraying drops of molten metal8. Do not set the temperature higher than it needs to be; 10 degrees C over the melting point is more than sufficient9. KEEP A FIRE EXTINGUISHER HANDY10. Use common senseYou will need to skim oxides constantly; every couple of minutes. Have a disposable steel or ceramic container you can dump the slag into.

author: Bored@Work
author_rank: Super Contributor
timestamp: October 17, 2013, 12:44:08 am
content: Quote from: elcomtel on October 17, 2013, 12:20:01 amAs if you work in any of these industries ... Ha, ha, ha. If you would, you wouldn't have to ask for the right solder alloy to start with. Or wouldn't have babbled about "wave soldering". Hey, you wouldn't have to ask if you would work in any kind of electronic industry.QuoteSo to tin that one wire you want to plug into your arduino you are now willing to wait ten or 15 minutes until the soldering pot has heated up. Instead of quickly touching it up with the soldering iron. Yes, I can clearly see how using a soldering pot is less work at the end of the day. And don't tell me you have to tin hundreds of wires every day, each day of the week. Because then we are back to square one - that people doing that usually know their solder alloy.QuoteBla, bla, bla.

author: nanofrog
author_rank: Super Contributor
timestamp: October 17, 2013, 02:22:42 am
content: Quote from: envisionelec on October 16, 2013, 10:50:37 pmMy suspicion as well, but figured clarification couldn't hurt. Particularly given the differences the two processes (when to use which).DIY wave equipment seems rather ambitious and overkill for a hobbyist IMHO, or even shop that does the occasional small production run. Other options would make better sense, such as reflow for in-house production, or outsourcing production to a PCB & assembly facility.Quote from: Phaedrus on October 17, 2013, 12:43:21 amSubstitute sinkers for bullets, and you're brining back similar memories for me.Quote from: elcomtel on October 17, 2013, 12:20:01 amHow did you arrive at the first part of your first statement?I do agree that pre-tinning a wire is good practice, and required for MIL-Spec/NASA standards. But if someone is in a hurry and it's a one-off experiment, it may not be as critical (or something they still need to learn).Now I get that you're interested in a pot to save time, and that's all well and good.But have you considered alternatives, such as using a PCB mounted wire connector, and make (or have made) the accompanying wire harnesses using crimp connectors instead of soldering?I ask, as a properly executed crimp connector has equal or better electrical characteristics than a soldered joint (look up cold weld), or the issues associated with solder wicking up the wire under the insulation (reliability, particularly under vibration),and is faster. There's a reason these things came to exist, and it's not just the result of bean counters.

author: Noize
author_rank: Regular Contributor
timestamp: October 17, 2013, 10:53:25 pm
content: No! Always have pot before you solder.