--- a question of thin leadless solder and good flux --- - Page 1
Forum section: electronics / projects

author: 3roomlab
author_rank: Frequent Contributor
timestamp: April 02, 2013, 08:58:46 pm
content: i have been working around my bench using ASAHI 1.0mm 60/40 CF-10 RA.previously i didnt really care much about what i use, but as i get to do more and more work, i seem to notice i need something more.first of all i work in an enclosed room, i made an air extractor to spot extract fumes, but i think that is not enough as i can still smell it. so i turned on more power to the air sucker lol.so question is, for health issues, i like to look for a solder that is something leadless, i know there has been alot of talk about pros and cons about leaded and leadless. but does anyone have any recommendation for this in the 0.3-0.5mm range?then there is also the question of fluxes, as i do more work, i realize that i use more and more flux, as the work gets more tricky, and the obsession with nice shiny and lean blobs. i also notice that even with my iron at 280degrees, the flux that i use "GOOT BS-10" just vaporizes really fast! isit me or is my 280degrees too hot for it? does anyone have an idea what is a better flux, in the sense that it does not vaporize so rapidly (or at all?).under this forum search i have read much about the SMD side of soldering, and i wish to "migrate" over to the SMD side of things using 0.3-0.5mm solder, and hopefully not use paste at all. thin solder coupled with a new good fine tip, you think 0603 SMD will be doable?do give me some advice, much appreciated... cheers

author: mariush
author_rank: Super Contributor
timestamp: April 02, 2013, 09:16:53 pm
content: QuoteYou assume that there is a health risk because you can still smell the fumes and somehow you think the problem is Lead in the solder wire/paste. Wrong. The fumes are almost 100% burnt flux, there's no lead in it (well, there's maybe a few particles of lead but for you can safely say there's no lead).Lead doesn't turn into smoke at the temperatures used to solder.Flux smoke can be bad for your health, it can cause asthma, it affects your lungs in time.Solders without lead usually have to use stronger fluxes as you generally need higher temperatures to solder with such solder wires or pastes, therefore the flux may have less time to attack the surface and clean it for the solder. So the fluxes in these solder wires/pastes with no lead can actually be even worse for your health.So if you want to be healthy, it certainly seems sticking with lead based solder wire/paste is more healthy.And I seriously suggest you do some research on types of fluxes and pick something that's suitable for pcb and electronics.You mentioned Goot BS-10 :http://www.goot.co.jp/e/detail.htmlQuote

author: mariush
author_rank: Super Contributor
timestamp: April 03, 2013, 01:39:13 pm
content: I bought a 50ml bottle of no-clean flux made by a company in Poland from a local store for about 3$ :http://www.termopasty.pl/pg_176_172_3_3_1_topnik_tk83.html(the smallest bottle in the picture, use Google Translate if you care to see the ingredients)I then bought a syringe and some needles from the pharmacy and took 2-3 ml in the syringe, and just put a few drops on boards when needed. When I'm done, I just make sure the needle isn't filled with flux otherwise the flux evaporates and becomes solid inside the needle, blocking the flow.It works great as a flux, it's no clean, the only downside is that the fumes smell bad (but with ventilation it's no issue)The flux you bought didn't evaporate so fast because of the formula, it evaporated probably because your tip had too high temperature.Lead solder melts at 180-183c, so 250-300c should be enough to solder. Unleaded solder melts at 217c so you kinda need about 350-400c to solder efficiently. But remember, the flux has to become liquid BEFORE the solder melts and makes contact with the surfaces, so it's natural for the flux to pour out the solder wire as soon as you touch the solder wire to a hot tip.And if the flux is on the board, it will start working as soon as you heat up the surfaces and will boil fast and attack the copper so that when you put the solder to the copper, the solder will interact properly and form a connection.In Singapore, you should have Farnell, branded as element14 but it's Farnell. They're not the cheapest fluxes but they're good quality:http://sg.element14.com/fluxThe cheapest pen there at about 8 dollars is the "83-1000-0951 951 Low Solids No-Clean" model :http://sg.element14.com/kester-solder/83-1000-0951/chemicals-solder/dp/1925200http://www.farnell.com/datasheets/660654.pdf(see page 13)It's a good flux, you don't have to clean it off the boards after you're done, but it will leave a bit of remains when it evaporates. if that bothers you, you can use some acetone or isopropyl alcohol to wipe those off the board after soldering. This one is about 10 ml of flux.More expensive but more value for money (20$ for 40 ml, the previous one was 8$ for 10ml so it's like you get a fourth pen free with this one) , you have this flux.http://sg.element14.com/itw-chemtronics/cw8300/water-soluble-flux-pen/dp/1663183datasheet:http://www.farnell.com/datasheets/85578.pdfThis is water based, which is a bit worse than no-clean. It's more strong, attacks at lower temps, might be more smelly and - you willHAVE TOclean the flux really well after soldering with some wipes dabbed in water, and then maybe also use some isopropyl alcohol for a second wipe. If you don't clean the flux, it will keep corroding the copper and weaken the solder joints.Read the datasheet and pay attention to what it says if you plan to buy it.

author: mariush
author_rank: Super Contributor
timestamp: April 04, 2013, 02:37:05 pm
content: Why would you search for Asahi solder on element14?The software couldn't find "Asahi" and they recommended "Ass" because it's short for "Assorted" and there's lots of products in store that have the words "Assorted colors" or something like that.Element14 sells some other brands and they have plenty of good solder wire from good manufacturers : Multicore , Stannol, these are very good brands. They also have their own brand "Multicomp" and those solder wires are made by various companies they work with, so while they may be cheaper than Multicore, you have no guarantee that the quality is consistent or not. Multicore and Stannol are well known brandsFor example they have this multicore for 28$ singapore dollars (250g / 1/2 Lb ) :http://sg.element14.com/multicore-solder/3096525-m/solder-wire-60-40-180-deg-250g/dp/5090787Thin wire, excellent for electronics, rosin flux (wipe it off with acetone/isopropyl alcohol after you're done soldering)If you don't mind bigger diameter (0.7mm is still reasonably small), you can get the 60/40 variety with a no-clean flux for 20$ (250g) :http://sg.element14.com/multicore-solder/610008/solder-wire-crystal-511-0-71mm/dp/610008and plenty of 500g solder wires for around 45-50$ , only the flux inside varies (and you can read the datasheet to see how the flux behaves and what you should do after soldering, if it needs cleaning or not)http://sg.element14.com/multicore-solder/d620505/solder-wire-crystal-505-0-71mm/dp/3294158http://sg.element14.com/multicore-solder/610021/solder-wire-crystal-511-0-71mm/dp/610021http://sg.element14.com/multicore-solder/609985/solder-wire-crystal-400-0-71mm/dp/609985Any quality soldering station will have temperature sensor near the tip and self adjust to maintain the temperature.Fluxes are inside the solder wire, and when the solder wire approaches the tip that's one the copper pad or wire that needs to be soldered, it has to become liquid and attack the surface to remove oxides before the solder melts and pours down. So pretty much any flux will go liquid and boil and do its work under the melting temperature of the solder, about 180-183c for 60/40 and 63/37 , 210c and up for unleaded solderEvaporation on liquid fluxes happens because the actual flux is combined with alcohol so that it can flow easily where you want to put it.There are some flux creams or thick pastes that remain more solid for longer time, but they're not designed for soldering using your iron, they're more like "put a layer of flux on the bottom of the board then move the board through wave soldering machine" like in the video below.I believe more recently the machines have liquid flux right at the beginning of the process or foam flux ( farnell has both in 5 liter bottles) that gets sprayed on the board from below, giving the flux a few seconds to clean the surfaces before the wave of solder comes to solder everything.The machine in the video uses foam flux as far as I can tell, and you can see the flux smoking as it evaporates when the solder in the wave solders everything.later edit: I see those asahi wires for 5$ for 0.5 lbs ... look man, good things cost money. A quality solder wire will have flux inside the wire at a reasonable amount... multicore may have 2.2-3% flux while your cheapie solder may only have 1% and the percentage may vary inside the solder due to poorer quality control ... the multicore brand also is supposedly using 5 strands of flux inside the solder wire, so the flux may work better ... you're paying a bit extra for the quality.A 250g - 500g spool should last you a very long time, so save some money and get some quality stuff.

author: Randall W. Lott
author_rank: Regular Contributor
timestamp: April 04, 2013, 02:58:57 pm
content: Lead doesn't atomize until very high temperatures, so you're just breathing in flux fumes. There's really not big of a health risk if you wash your hands very thoroughly.

author: img
author_rank: Regular Contributor
timestamp: April 04, 2013, 07:56:22 pm
content: @ mariushHow bad is the smell of the Topnik, and how good is it as a flux? Compared, say, to Edsyn FL22.

author: mariush
author_rank: Super Contributor
timestamp: April 04, 2013, 08:36:28 pm
content: I really couldn't say how it compares to others, as I haven't use many fluxes. Haven't used Edsyn at all.I use it with Multicore no-clean solder, when I have more oxidized surfaces. It's a bit sticky, it boils nicely, doesn't evaporate fast, it just works...How could I explain it...In the bottle it smells more or less like isopropyl alcohol, a bit less pronounced.If you have some fan on the desk and maybe an open window and your nose is 1 meter or so away from the solder point, it actually smells nice when soldering and it's not bothersomeHowever, if I actually stand above the solder point as if I'd watch through a magnifying glass and pull a bunch of flux smoke straight in my nose, it's almost like an acid, it smells bad and I feel like I want to cough it out, like when your throat is really dry, it makes me want to cough.Naturally, you're not supposed to do that, and I leave a computer fan 20-40 cm away from boards when I solder with my face so closely to the board to blow away the smoke and not cool down the solder iron tip at the same time.

author: img
author_rank: Regular Contributor
timestamp: April 04, 2013, 09:26:16 pm
content: Thank you, this is useful.Now I need to find a way of buying some of this flux in the UK.I have Thermopasty solid rosin I think, and it's good, but have never seen your flux for sale in the UK.

author: mariush
author_rank: Super Contributor
timestamp: April 04, 2013, 09:30:45 pm
content: If you want, I can go in town when I have some time, but one or two bottles and mail them to you.I'll just have to check if the store I bought the bottle from still has them, I got my last bottle a couple of months ago and if I remember correctly they were 13.5 RON (3 euro/2.5 pounds)You can paypal me the money when you get the package, if you're interested pm me.Otherwise, I've seen them here and at 8 zlots and that's quite cheap (I think that works out at under 1 pounds):http://www.hotair.pl/pl/sklep/akcesoria-do-lutowania/topnik-tk83-50ml.htmlBut I'm not sure if they ship outside Poland and I'm too busy now to go with Google Translate to find out their shipping terms.

author: Monkeh
author_rank: Super Contributor
timestamp: April 04, 2013, 09:31:16 pm
content: Kinda sounds like rosin dissolved in isopropyl alcohol. Works great, easy to make.

author: img
author_rank: Regular Contributor
timestamp: April 04, 2013, 09:45:17 pm
content: Quote from: mariush on April 04, 2013, 09:30:45 pmThank you very much for the kind offer.The shipping to the UK from this shop is around 14GBP for an item that costs 3GBP. If shipping from your location is as expensive, then there is no point in inconveniencing you. I'll try to get the Polish flux seller here in the UK to supply the flux and see what he says.

author: mariush
author_rank: Super Contributor
timestamp: April 04, 2013, 10:21:28 pm
content: No, it shouldn't be that much, should be less than 3-4 euro for postage, it's lightweight.Give me a message with your address if you're still interested and If I can still find this flux in the store tomorrow, I'll mail it to you tomorrow (Friday)

author: img
author_rank: Regular Contributor
timestamp: April 07, 2013, 04:44:15 pm
content: A quick update:This good man, called ciufek on eBay has got TK83 and other good things from Poland:http://stores.ebay.co.uk/ciufeks-soldering-solutionsI am working up the courage to request the H036 gel flux from him.