Cheap solder leaving strange residue? - Page 1
Forum section: electronics / beginners

author: Jay112
author_rank: Regular Contributor
timestamp: May 13, 2016, 07:59:47 pm
content: A roll of lead solder I recently bought from ebay seems to be having some strange problems that I've never seen into before with other solders. Every once in a while when I'm soldering there will be a strange plastic-like string that hands down from the tip of the solder, almost like as if there was a thin line of burnt plastic inside the solder. I feel pretty certain that it's not because I'm accidentally burning any nearby plastic pieces.Have you ever seen anything like this? Do you know what it's from?

author: Fsck
author_rank: Super Contributor
timestamp: May 13, 2016, 08:07:58 pm
content: is it some unknown brand that substituted something in for flux?

author: Jay112
author_rank: Regular Contributor
timestamp: May 13, 2016, 08:12:56 pm
content: I don't know enough about solder to know which are the popular brands.This was the title of the solder: "A roll of 0.5mm 100g Tin Lead Rosin Core Solder Soldering Wire"And this is the ebay link:http://www.ebay.com/itm/A-roll-of-0-5mm-100g-Tin-Lead-Rosin-Core-Solder-Soldering-Wire-/172180016673

author: Cubdriver
author_rank: Unknown
timestamp: May 13, 2016, 08:15:31 pm
content: Some sort of contamination in the rosin core would be my guess. Does the smell of the rosin smoke change at all when you get this plastic-y thread?-Pat

author: Fsck
author_rank: Super Contributor
timestamp: May 13, 2016, 08:17:19 pm
content: well, the rosin core flux is a solid and will be plasticy when melted.is it actually like burnt plastic? (charred, smokey, etc?) or just melted plastic?

author: rstofer
author_rank: Super Contributor
timestamp: May 13, 2016, 08:26:55 pm
content: Buy some decent solder:http://www.specialized.net/Specialized/Multicore-MM00992-Solder-Sn60Pb40-02522AWG-RosinFlux-5Core-683.aspxhttp://www.alliedelec.com/kester-solder-24-6040-0061/70177924/?utm_source=bing&utm_medium=cpc&utm_campaign=Product%20Ads&mkwid=6kTPp5T7&pcrid={creative}I try to buy the Multicore when I can but it takes about 15 years to use up a roll. I just don't tend to do a lot of hand soldering.Considering all the time and effort that goes into designing circuits and PCBs plus the cost of the PCBs and components, cheap solder is a really bad idea.There will be rosin left on the board even with the best of solders. I don't tend to remove it but you can if you wish.

author: Jay112
author_rank: Regular Contributor
timestamp: May 13, 2016, 08:33:49 pm
content: Thanks for the replies, everyone!I think it's more like melted plastic than burnt plastic, and I don't think it smells like burnt plastic. It doesn't create any smoke either.A unique thing with this solder is that it's the thinnest solder I've ever used. Do you think maybe that's related?@rstofer: Thanks for the links! That's great advice about not going cheap with the solder.

author: Fsck
author_rank: Super Contributor
timestamp: May 13, 2016, 08:47:12 pm
content: thin solder will probably have a higher flux:solder ratio, so maybe.if it's amberish in colour, it'll probably just be the rosin flux residue (normal). I use kester 44 and just leave it on there. I prefer the 63/37 eutectic over 60/40 though.I think I'd probably clean an unknown brand's rosin flux residue though.

author: Jay112
author_rank: Regular Contributor
timestamp: May 13, 2016, 08:49:31 pm
content: Quote from: Fsck on May 13, 2016, 08:47:12 pmThanks for the advice.If I coat a board with conformal coating, do you think that prevents the damage from the flux? Or should the board be cleaned before applying the coating?

author: KL27x
author_rank: Super Contributor
timestamp: May 13, 2016, 09:01:19 pm
content: I get rosin strings a lot when using external RA. I've never seen a flux core solder have that high a flux content, but this is a good thing.The residue is usually completely harmless to the electronics. But if you are going to do a conformal coat, remove the residue, first! Alcohol works fine. A mix of 91-95% alcohol + acetone is really effective.

author: Bud
author_rank: Super Contributor
timestamp: May 13, 2016, 10:10:00 pm
content: "High quality Best made in China"Yes, this instills a lot of confidence.

author: Audioguru
author_rank: Super Contributor
timestamp: May 13, 2016, 11:13:52 pm
content: Quote from: Bud on May 13, 2016, 10:10:00 pmThey cannot put their sewage (there islotsof it) in the ocean because they drink the sea water so they ship it in the solder they export. I bought some cheap Chinese stripboards that used sewage to poorly and loosely stick the copper to the phenolic. I think the phenolic was made of used toilet paper.https://www.eevblog.com/forum/Smileys/default/rolleyes.gif

author: Jay112
author_rank: Regular Contributor
timestamp: May 13, 2016, 11:38:17 pm
content: Quote from: Audioguru on May 13, 2016, 11:13:52 pmI actually did receive 100% garbage from ebay once.They sent me a package that contained an empty toy bag. Has that ever happened to you guys? It seemed strange to me, because I had ordered 4 items from that seller, and he had shipped out 2 of them, but then I received the empty bag instead of receiving the other 2.The strange thing is that if he was trying to scam me, I would've expected the entire order to be a scam. Why would he only ship half of it?I think that was the 2nd time I was scammed on ebay (I've only started using it about 6 months ago, probably placed a few dozen orders since then). For the first scam I ordered "100% solid copper" wire, only to receive copper-clad steel. There's a thread on this forum where you guys helped me with that.

author: nanofrog
author_rank: Super Contributor
timestamp: May 14, 2016, 07:35:39 am
content: FWIW, therewasis such a thing as plastic core solder (type R)*.As previously mentioned, definitely spend a little extra for quality supplies (solder, flux, desolder wick), as it's actually cheaper in the end.Not only does it cause less damage to boards, you get better results (better flow, & reduced time on joints). And then there's the reduced aggravation as a free bonus.*I found a sheet on it (here). Still available by special order it seems (Kester P/N = 24-6040-1809, which is 60/40, .031", 58 core size ).

author: Jay112
author_rank: Regular Contributor
timestamp: May 14, 2016, 01:51:26 pm
content: Quote from: nanofrog on May 14, 2016, 07:35:39 amInteresting. Do you know why anyone would need plastic core solder? The only thing I could think of was maybe the plastic has a high melting point, giving the solder the ability to be melted into various shapes?

author: nanofrog
author_rank: Super Contributor
timestamp: May 15, 2016, 08:34:06 am
content: Quote from: Jay112 on May 14, 2016, 01:51:26 pmOff-hand, I can't think of anything that would require plastic R vs. R liquid or paste that's ROL0 compliant, but suspect it's for some rather particular MilSpec application (something to do with fungal growth?).As per casting, you typically use bars or slips, not solder wire.

author: Fsck
author_rank: Super Contributor
timestamp: May 16, 2016, 06:03:50 am
content: Quote from: Jay112 on May 13, 2016, 08:49:31 pmalways clean first.

author: macboy
author_rank: Super Contributor
timestamp: May 16, 2016, 03:30:26 pm
content: Quote from: nanofrog on May 14, 2016, 07:35:39 amIt's a bit of a misnomer, as there is no "plastic" (i.e. synthetic polymers) present. It is a pure, non-activated rosin core. This is a rather special product only used where the activating agents normally added to the rosin can't be used. Kester "285" is their RMA (Rosin, Mildly Activated) and "44" is their RA (Rosin, Activated). I really like soldering with Kester 44, but I also have some 285 and it is also nice since the residues are water clear rather than amber colored.

author: nanofrog
author_rank: Super Contributor
timestamp: May 16, 2016, 04:10:42 pm
content: Quote from: macboy on May 16, 2016, 03:30:26 pmI'd seen it in person, but never used it (did know it was R at least). I took the use of the wordplasticliterally however, as I don't recall any other roll of R from other manufacturers using the term.FWIW, I keep 44 on my personal bench (familiar with 285 & 48 too), as well as 186 and 1544 liquid flux. Some other stuff too (Multicore, Alpha Metals, and even some ancient RadioShack). And Chemtronics for wick.Learned the value of good quality consumables a long time ago (had the fortune of some excellent mentors when I was a kid).

author: Cubdriver
author_rank: Unknown
timestamp: May 16, 2016, 08:49:26 pm
content: Kester 44 63/37 is my main go to as well. I also have a spool of the 331 organic core that gets used on PC boards that can have a bath immediately after assembly, but (as I learned the hard way at a previous job when someone DIDN'T give the boards a bath after soldering them), it's hygroscopic and corrosive if not cleaned off. There's also a spool of the silver bearing Kester floating around here somewhere, but I haven't had occasion to use that yet.My inclination with things like solder is the use the good stuff. It's notthatmuch more $$, and this is definitely one place where crap can cause you no end of headaches between making assembly needlessly difficult, causing overheating of components trying to get them to wet and later potentially causing troubleshooting misery due to bad joints.-Pat

author: sleemanj
author_rank: Super Contributor
timestamp: May 16, 2016, 10:27:03 pm
content: FWIW, my main roll of solder at the moment is BEST 0.4mm, and it pretty much lives up to it's name of the various Chinese solders I've used over the years, goes on well, good flux content, produces a good looking joint. No complaints.I did once have a roll of "San He" 0.6mm which wasn't half bad either.I didn't particularly like the Synhonty 0.6 from eBay, and the PPDESD 0.3mm also from eBay was a bit iffy on the flux consistency (probably to be expected at 0.3mm)But of course, like anything from China, just because I got a good roll of BEST today, doesn't mean that you will tomorrow.

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: May 16, 2016, 10:39:12 pm
content: Some cheap generic brand solder I've used came with an adhesive sticker attached to the roll, contacting the first layer of solder - every ~100mm or so there would be a small amount of adhesive residue on the outside of the solder, and produced what OP describes

author: Jay112
author_rank: Regular Contributor
timestamp: May 16, 2016, 10:49:18 pm
content: Quote from: RobertHolcombe on May 16, 2016, 10:39:12 pmWow! This definitely might be it! There was a sticker that seemed to leave some residue on the outside of the roll!I guess the way to tell if this was the case is if the residue stops appearing once I get past the first layers. But if it continues appearing through the rest of the roll, then I'll just assume it was either the flux or some other cheap thing they put in there.

author: sleemanj
author_rank: Super Contributor
timestamp: May 16, 2016, 11:28:41 pm
content: Quote from: Jay112 on May 16, 2016, 10:49:18 pmI guess this is a good reason for the avionics solder-ers wiping down the solder before they use it :-)https://youtu.be/Vynb_HdEIDU?t=7m4sOf course, I'm hoping they aren't sending satellites to space with eBay chinese solder :-)

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: May 17, 2016, 12:08:17 am
content: Unless the reel is coming sealed from the manufacturer you never know what has been in contact with the outer layer so would be good practice to at least clean the outer layer with IPA when you buy it, only takes 5 seconds

author: Jay112
author_rank: Regular Contributor
timestamp: May 17, 2016, 07:54:58 pm
content: Quote from: sleemanj on May 16, 2016, 10:27:03 pmI just realized that the roll I was talking about is of the brand name BEST! I randomly ran into it when I was cleaning.Mine is .5mm. I'm surprised they even make solders in smaller diameters! Also it says the flux content is 2.25%.

author: Jay112
author_rank: Regular Contributor
timestamp: May 18, 2016, 06:30:21 pm
content: If someone found an old used unmarked roll of solder, is there any way to determine if it's plumber's vs electrical solder?

author: Cubdriver
author_rank: Unknown
timestamp: May 19, 2016, 12:10:24 am
content: Well, for what it's worth, in my experience plumbers wire solder is typically much thicker (like 1/10"ish diameter), and usually solid rather than flux cored, so that's at least something that might help to distinguish the different types. Plumbers solder also (again in my experience) tended to be 50/50 rather than the 60/40 or 63/37 electronic stuff - the plumbers WANT it to stay in a plastic state longer as it cools so that they can wipe and smooth the joints, as opposed to us electronics types who what it to solidify as quickly as possible to reduce the chances of a cold joint in wiring.-Pat

author: Jay112
author_rank: Regular Contributor
timestamp: May 19, 2016, 12:26:17 am
content: Quote from: Cubdriver on May 19, 2016, 12:10:24 amThanks for responding, Pat! The diameter was thinner than the plumbers solder I'm used to, but thicker than the electrical solder I'm familiar with.One feature I forgot to mention is that it's in a roll shaped like the one in the following picture, only about twice as long and the roll diameter is about 3 times larger than the following (I have one of the following):Do you know if plumbers solders ever come in rolls like that?

author: Cubdriver
author_rank: Unknown
timestamp: May 19, 2016, 04:24:21 am
content: Hi Jay -The electrical solder I usually use is 0.031" (0.8mm). I've also seen (and, in the past, used) thicker electrical solder - about 0.062" dia. I've never seen plumbing solder in a dispenser pack like you describe, but that doesn't mean it doesn't exist.Is it solid, or flux cored? A quick glance at McMaster-Carr shows solid 50/50 solder in 0.062 and 0.125" diameters. Cored doesn't rule out it being non-electronic - they do make acid core solder, but non cored (solid wire) pretty much rules it out as being an electronic solder (again, in my experience).Could you post a photo of the solder and package in question?Do you have a temperature controlled iron? The 50/50 melts at a temp about 45*F hotter than the 60/40 does (420*F vs 375 for 60/40 and 360 for 63/37). If you have a temp controlled iron, try setting it for 390-400*F. If the mystery solder doesn't melt, it's likely 50/50.If you don't have access to a temp controlled iron, melt a blob of 60/40 and a similarly sized blob of the mystery stuff on something you don't care about scorching (a piece of wood or PC board scrap, for instance). Heat each in turn to molten (try to heat for about the same amount of time, and note that if the mystery solder takes longer to melt it's likely 50/50), then stir with a piece of wire or the like as they cool and solidify. The 60/40 should go from liquid to solid relatively quickly, while 50/50 would still seem mushy and moveable for a longer period.That's about all I can suggest off the top of my head.-Pat

author: Jay112
author_rank: Regular Contributor
timestamp: May 19, 2016, 05:49:31 pm
content: Quote from: Cubdriver on May 19, 2016, 04:24:21 amThanks Pat! I think you helped me figure it out! I've never noticed a "flux core" on solders before, but when looking closely at a cross section of this solder it looks like there's a separate core inside! I tried to capture it in the 2nd picture below.I have a temp-controlled iron, and I could've done that other test you mentioned, but I bet the flux core alone will be a good indicator. I just didn't realize it would be so prominent.

author: Jay112
author_rank: Regular Contributor
timestamp: May 19, 2016, 05:50:53 pm
content: Ugh, nevermind. I guess I didn't understand that plumbing solder can also have a flux core. I re-read your post and then I realized my error. I got overly excited from noticing a flux core for my first time.Maybe I'll be able to do that temperature test you had mentioned!

author: Cubdriver
author_rank: Unknown
timestamp: May 19, 2016, 06:14:15 pm
content: That could be old Rat Shack solder that's long ago lost its label. They used to sell it in those packages back in the day. Try melting a bit and sniff to see if the flux smoke has that distinctive rosin scent. (I'm not sure what the acid core would be like, but probably more of an acrid, unpleasant smell based on the plumbing I've done.) Obviously, don't take a huge snort of it, just a slight whiff.-Pat

author: Jay112
author_rank: Regular Contributor
timestamp: May 20, 2016, 10:13:21 pm
content: Quote from: Cubdriver on May 19, 2016, 06:14:15 pmThanks again, Pat! That's interesting that it looks like an old Rat Shack solder!I'll do the temperature tests you had mentioned once I become less busy.Speaking of the Shack... I ordered some cheap stripboards recently from ebay, and on the top of each one was printed the words: "Radio Shaek", like in the following picture:http://www.ebay.com/itm/322004567483I wonder why someone would print that at the top of the boards. It seemed strange to me.

author: nanofrog
author_rank: Super Contributor
timestamp: May 20, 2016, 10:52:04 pm
content: Quote from: Jay112 on May 20, 2016, 10:13:21 pmPerhaps because they copied their2760150protoboard pattern, and is the closest they could get away with regarding the name?Regarding the RadioShack P/N, it seems the latest version of their website no longer uses the dashes.FWIW, there's another photo of one that's been posted on Adafruit with Radio Shaek 1 etched at the bottom (here).

author: Cubdriver
author_rank: Unknown
timestamp: May 21, 2016, 02:13:46 am
content: Does this look familiar?I happened to find it tonight while searching through some old stuff digging for a terminal strip. I can't imagine that it's from any later than the mid 80s, so it's got to be around 40 years old. (And no, I don't see me using it any time soon - it looks pretty cruddy!)-Pat

author: Jay112
author_rank: Regular Contributor
timestamp: May 21, 2016, 02:00:12 pm
content: Quote from: Cubdriver on May 21, 2016, 02:13:46 amWow, Pat, the cap looks exactly the same! I bet the chances are pretty low that a plumbing solder would come in the same container with the same cap!