Best tips for cleaning a soldering iron from lead-free solder - Page 1
Forum section: electronics / beginners

author: Write_to_Smokegenerator
author_rank: Regular Contributor
timestamp: March 23, 2012, 10:04:04 pm
content: HelloI know that's a quite common question.I wanted to do some soldering today for a project and i realized my iron is not working, I took a closer look and bingo, tip is full of leftovers of lead free solder.http://www.flickr.com/photos/77940640@N04/6863342980/#in/photostreamI did measure the heat, instead of 300° it displayed 150° i looked in the net for some hints.I tried to get it off with a wet piece of cotton,steel wool and i tried it with a little mechanic help of my tweezers (gentle).None did show any results, a friend says I can at least bring the tip back to working but I'm out of ideas.Anyone got some usefull hints?cheers.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 23, 2012, 10:25:25 pm
content: Quoteyour iron is not working.

author: Write_to_Smokegenerator
author_rank: Regular Contributor
timestamp: March 23, 2012, 10:36:35 pm
content: the iron is working quite fine, i measured the heat a a little behind the tip did read 270° or so (the accuaracy is not that well +- 3 Digits at this range)The Problem is as i described the solder I may did not clean during work enough so a little solder was left on the tip and the flux burned so it's like an isolating layer and the heat can't get through.I still would appreciate some tips to clean the tip, i don't want to buy a new one because this tip was only used 1 time or so (also I would love to do the soldering this weekend and i can't go to a shop this WE to buy a new one)cheers.

author: TerminalJack505
author_rank: Super Contributor
timestamp: March 23, 2012, 10:37:21 pm
content: Sometime all you need to do is just use some 60/40 RA or RMA solder to clean the tip. Try turning the heat up until it will melt 60/40 rosin core solder (350C or so) and use the solder and a wet sponge until the tip will finally wet properly.

author: sonicj
author_rank: Frequent Contributor
timestamp: March 23, 2012, 10:38:50 pm
content: keep applying rosin cored solder to the tip until the contaminants are removed by the rosin flux. you local electronics shop should have tip tinning products which do the same thing, but with a more aggressive flux. if repeated attempts to re-tin the tip are not working, you can remove the contaminants by mechanical means. ie: lightly sand it with 800 grit, scrape lightly with hobby knife, use a polishing bar, etc.-sj

author: Write_to_Smokegenerator
author_rank: Regular Contributor
timestamp: March 23, 2012, 10:45:07 pm
content: That sounds useful.Quote from: sonicj on March 23, 2012, 10:38:50 pmIf i do it mechanical f.e with a 800 grit isn't that to harmfull for the tip?by the way thx for the tips.

author: IanB
author_rank: Super Contributor
timestamp: March 23, 2012, 11:02:01 pm
content: Yes, mechanical or abrasive cleaning can remove the iron plating from the tip and therefore damage it. But really the proper solution is to get a new tip and reserve it for lead/tin solder.To clean an existing tip there is no better way than to heat it up until the solder melts, then successively apply flux, a wet sponge, and more solder until it is clean and shiny again. If necessary some of the tip tinning/cleaning compound can help, but it is not essential. It just speeds up the process.

author: Ajahn Lambda
author_rank: Regular Contributor
timestamp: March 24, 2012, 12:48:43 pm
content: I've used Ruby Fluid, a zinc-chloride solution, with reasonable success, in the same 'wet-and-wipe' method that's been described here. Keeping the iron hot is probably the biggest challenge, because every time you're applying flux or wiping it with a wet sponge, it's losing a large amount of heat. And as you've probably figured out, cold flux and/or solder don't work as well.

author: G7PSK
author_rank: Super Contributor
timestamp: March 24, 2012, 06:41:08 pm
content: From the photograph I would say that the tip has oxidized, most oxides are refractory compounds. It may be that you will need to apply heat with a blow torch or hot air gun while applying flux and fresh solder, But in all probability the tip is scrap and needs replacing as the tin oxide will combine with the iron plating and with that compromised the tin in lead free solder will start to dissolve the copper body of the tip.

author: Neilm
author_rank: Super Contributor
timestamp: March 24, 2012, 07:59:14 pm
content: I always thought that once you have used lead free, you couldn't recover it. Especially if the tip was not made for lead free.Neil

author: IanB
author_rank: Super Contributor
timestamp: March 24, 2012, 08:12:16 pm
content: Quote from: Neilm on March 24, 2012, 07:59:14 pmI can't imagine it being much of a problem outside of an industrial environment. Lead free solder is mostly tin, and normal tin/lead solder will mix with it perfectly well. So if you "wash" the tip with enough new solder it will eventually be cleaned of all traces of the old composition.

author: Write_to_Smokegenerator
author_rank: Regular Contributor
timestamp: March 24, 2012, 10:53:41 pm
content: The Tip was used only once so it's a pity but I will get a new one soonI but I think I won't use the lead free further, because a friend of mine did some PCB's with the lead free and is completely pissed off.Only thing to keep in mind is to wash your hands, and don't eat while soldering.I did try to use some put some solder on the tip and quickly removed it (I don't have flux at home right now)I did bring it back to shine somewhat.Did measure the heat with my Multimeter and 210°C (300°C should be) still not good enough for SMD soldering -.-thx for repliescheers.

author: IanB
author_rank: Super Contributor
timestamp: March 25, 2012, 01:12:17 am
content: A good tip when soldering is always to make sure the tip is shiny when you switch the iron off to put it away. It will then then be clean next time you come to use it.The essential step is to clean the tip on a damp sponge to bring out the shine, cover the tip with fresh solder, then switch it off. Next time you switch on the iron bring it up to temperature, wipe it on a damp sponge and re-tin it, and it will be ready to use.

author: Ajahn Lambda
author_rank: Regular Contributor
timestamp: March 26, 2012, 01:22:56 am
content: Quote from: IanB on March 25, 2012, 01:12:17 amTotally agree.You don't have to go through too many EE classes to see what really eats tips up, and what makes them painful to use later, but cleanliness == godliness here.QuoteThat's one way, definitely. I try to keep my tip (heh) away from a wet spongewhenever possiblewith my Hakko, ever since getting one of those brass brillo pad tip cleaner-thingies with it:The reason being that there won't be as nearly as much thermal shock to the tip, which is important once you realize that the tip has a very thin coating made from a different metal than the core. I do admit that there are times that a sponge will get the flux off much faster and easier than the tip cleaner, though.You might find these documents from Hakko to be informative on the topic at hand:http://www.hakkousa.com/AHPDirect/download/tn/TN00000026.pdf<-- Why do tips wear out so fast?http://www.hakkousa.com/AHPDirect/download/tn/TN00000027.pdf<-- Happy Tip Tips, a detailed look at tip construction & care.http://www.hakkousa.com/AHPDirect/download/tn/TN00000030.pdf<-- Flux residues and what to do about them.FWIW, I've been using lead-free and lead/tin solders for quite some time, and haven't run into any serious issues. The only 'difficulty' was when I first started using lead-free solder and didn't fully understand the different temperature requirements (approximately 30°C higher, but it depends upon the specific alloys used). Since then, it's merely been a matter of dialing the temperature to the correct setting.One other caveat with lead-free solders I've found: they don't seem to haveas gooda resistance to cracking under flexure/stress, versus the old 63/37 tin/lead alloy. I've heard this referred to as creep deformation, but IME, creep is not the same phenomenon. For some applications, this might be an issue, but it can be alleviated with proper mechanical considerations during the design process.

author: sonicj
author_rank: Frequent Contributor
timestamp: March 26, 2012, 01:43:27 am
content: Quote from: SigEpBlue on March 26, 2012, 01:22:56 amcreep deformation is movement due to pressure + time + heat. i think what you're referring to might be better described as shear strength??-sj

author: Ajahn Lambda
author_rank: Regular Contributor
timestamp: March 26, 2012, 02:20:10 am
content: Quote from: sonicj on March 26, 2012, 01:43:27 amHmm.... Shear strength is typically a defined value for a material, past which a material will fail in that particular mode, IIRC, as in a steel shear pin holding two components together, such as a trailer to a vehicle. I knew creep wasn't the right term, but I'll be damned if I can remember the proper one.I have the dumb today.I think a better, if not general, term might be fatigue. Most of the lead-free joints I've seen that have had some mechanical failure look like the metal was 'torn', as in a stress failure, much like when you try to bend a steel rod around a tight radius. You see a flaking, or opening of the surface, on the outside of the bend.Itsort oflooks like this picture at the failure:

author: clonecrp
author_rank: Regular Contributor
timestamp: March 26, 2012, 02:22:46 am
content: Hi:Have you tried Solid SAL Ammoniac ? =>Been using it for years 40+ ...Let me know how it worked...Thanks !Doug

author: G7PSK
author_rank: Super Contributor
timestamp: March 26, 2012, 11:19:42 am
content: Quote from: SigEpBlue on March 26, 2012, 02:20:10 amWhat you are describing is hot shortness where at certain cooling rates the contraction of forces as the metal cools is greater than the tensile strength of the alloy, ie. it was cooled down to fast some alloys are particularly susceptible to hot shortness.

author: Kozmyk
author_rank: Regular Contributor
timestamp: March 26, 2012, 06:19:17 pm
content: Back in the Days I worked at a Sony TV factory, there were these yellow glue sticks that you melted with a soldering iron. We called it Magic Solder. Apart from it's adhesive properties it left the bits beautifully clean after it was wiped off.Re cleaning the tip. I believe that it's best to leave a good layer of solder on the tip before switching off. This protects the plated area from oxidation and ensures good wetting the next time the iron is used. On next switch on, the old stuff can be wiped off and the tip retinned with fresh solder.