Why do some brands of 63/37 solder appear shiny and others dull? - Page 1
Forum section: electronics / beginners

author: salil
author_rank: Regular Contributor
timestamp: June 01, 2015, 11:44:01 pm
content: I recently ran out of 63/37 solder (can't remember what brand) so I purchased some more solder - one made by MG Chemicals and the other by a company called Kaina. Pictured below I have two 20 awg wires sloppily tinned. It may be hard to tell from the lighting in the picture, but the red wire came out substantially more shiny. I used the same temperature, technique, length of time, etc. for both wires - the only thing that changed was the brand of 63/37 solder. Any idea why the black one (Kaina) is so dull in appearance while the red one (MG Chemicals) is very shiny? (beyond the fact that the MG Chemicals one is just more expensive)

author: dacman
author_rank: Frequent Contributor
timestamp: June 02, 2015, 12:07:14 am
content: http://www.dipmicro.com/store/SOLDER08170

author: Monkeh
author_rank: Super Contributor
timestamp: June 02, 2015, 12:08:56 am
content: As mentioned above, the crap you bought is not 63/37.Throw it in the bin and buy some real solder.

author: zapta
author_rank: Super Contributor
timestamp: June 02, 2015, 12:16:44 am
content: What happens if you add flux, does the cheap one become shiny?

author: Monkeh
author_rank: Super Contributor
timestamp: June 02, 2015, 12:21:50 am
content: Quote from: zapta on June 02, 2015, 12:16:44 amNo. I actually have some of that junk around, it simply is not 63/37. It's not even close. Normal lead-free alloys are nicer.

author: salil
author_rank: Regular Contributor
timestamp: June 02, 2015, 12:30:09 am
content: Quote from: zapta on June 02, 2015, 12:16:44 amJust tested this, it doesn't.Is there any REAL 63/37 solder in China?

author: Monkeh
author_rank: Super Contributor
timestamp: June 02, 2015, 12:30:44 am
content: Probably, but you'll have to pay actual money for it..

author: salil
author_rank: Regular Contributor
timestamp: June 02, 2015, 12:32:58 am
content: Quote from: Monkeh on June 02, 2015, 12:30:44 amIs any of the solder coming from China on eBay actually 63/37? Can anyone confirm?

author: dacman
author_rank: Frequent Contributor
timestamp: June 02, 2015, 12:41:00 am
content: Why don't you buy some Kester?

author: Monkeh
author_rank: Super Contributor
timestamp: June 02, 2015, 12:41:33 am
content: Quote from: salil on June 02, 2015, 12:32:58 amProbably not.Why don't you just go buy a roll of decent stuff locally and be done with it?

author: Muttley Snickers
author_rank: Unknown
timestamp: June 02, 2015, 12:55:35 am
content: Off Topic.I've only recently started to store solder in air tight plastic bags after noticing that some older spools stored out in the workshop have oxidised, the area is prone to condensation and hoping that it may help, these are larger Multicore spools.Muttley

author: djQUAN
author_rank: Frequent Contributor
timestamp: June 02, 2015, 02:58:30 am
content: Yeah, cheap solder is crap. I just suck it up and buy pricier stuff. It saves you the hassle.I once bought a fine strand solder (0.3mm IIRC) from an unknown brand and was said to have flux core but there are parts that do have flux and some do not. Can't remember if it did feel like 63/37 eutectic alloy. I still have that small roll almost unused after >15yrs somewhere in the junk bin.If you really want really good stuff, get the Cardas quad eutectic solder used by audiophools. It is pricey but the flux and alloy solder wets really really well even on heavily oxidized parts.For general soldering, I use Alpha metals 63/37 solder but it is about to run out and guess what, the new spool I bought is an MG Chemicals 63/37 #22 and as you found it, it works well.

author: zerorisers
author_rank: Regular Contributor
timestamp: June 02, 2015, 03:44:22 pm
content: go to fry's. I found that stuff from MG chemicals there is really cheap. a normal $20 bottle of rubber renue is $8 there! works great!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 02, 2015, 05:48:00 pm
content: It doesn't look like you heated the black wire for nearly as long, or nearly as hot. So the flux was not activated, and the solder did not have time to flow.Timing a hand soldering application, tinning wires, wouldn't seem a very reliable method:It takes time for the iron to heat up some strands.Then you have to reliably apply solder to those strands so they begin to tin.Then you have to add enough solder that it fills in the bundle, without taking heat out and slowing the process.Then you have to stroke iron and solder along the joint to fully saturate and tin all surfaces, and push off excess flux or dirt that has oozed out of the bundle.Finally, dragging or shaking off excess solder.Solderability is better defined by specific test conditions, like heating a cleaned copper plate and analyzing how the solder and flux tins and flows over the plate, and what finish it leaves when it freezes. (I don't know the actual standards, but they are out there, in ANSI/ISO/MIL/etc.)Tim

author: salil
author_rank: Regular Contributor
timestamp: June 02, 2015, 09:51:30 pm
content: Quote from: T3sl4co1l on June 02, 2015, 05:48:00 pmI realize it's not the most accurate test, but I timed it and used the same technique as best I could by hand. Also, I did the same test several times and got the same result.

author: Ian.M
author_rank: Super Contributor
timestamp: June 02, 2015, 10:21:19 pm
content: 63Sn/37Pb solder is an eutectic alloy. When it cools it freezes all at the same temperature. Other alloys don't, and precipitate crystals that have a higher concentration of whichever component is in excess of the eutectic ratio as they cool, lowering the freezing point of the remaining liquid towards the eutectic melting point.If you melt a small pool of the suspect alloy on a heat resistant non-metallic surface and stir it with a wooden toothpick as it cools, it is very easy to tell the difference between a eutectic and a significantly non-eutectic alloy.There is a small market for 37Sn/63Pb solder for some types of craft work, and as lead is much cheaper than tin, it is remotely possible you may encounter some from unscrupulous sellers!

author: zapta
author_rank: Super Contributor
timestamp: June 03, 2015, 05:13:20 am
content: Quote from: Ian.M on June 02, 2015, 10:21:19 pmDoes eutectic impliy shiny solder joints and vice versa?

author: johansen
author_rank: Super Contributor
timestamp: June 03, 2015, 05:18:11 am
content: if you want shiny solder, find the stuff that is 3% silver.its amazing.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: June 03, 2015, 06:50:20 am
content: Check out my similar threadhttps://www.eevblog.com/forum/reviews/solder-quality/

author: Refrigerator
author_rank: Super Contributor
timestamp: June 03, 2015, 08:06:02 am
content: I've tried chinese solder once but it was crap as hell ( now i buy solder locally ) and only now did i notice that the solder might be just what ever the crap they suck off PCBs when they remove components.