I was under the impression hobbyists are still fine to use leaded solder, and thought leaded solder was easier to work with than lead-free (told to me by engineers and techs). Surprised to hear that lead-free is being used.
For the size, I was thinking .040 might be too big as well, but actually it's been working out great for me.
ImA4Wheelr - please post how the eBay sourced solder worked out, if well, please post the link. Thanks.
Just wanted to comment on the “Solder paste” Mechanic, that Fast Tech sells. I have used it for three years and the stuff works great! I have also used Kester and it works also! As far as the solder wire from Fast Tech that is a totally different beast.
I will say that the mechanic solder paste flows very well. The issue i find is lack of experience and know how in how much paste people apply which is a learning curve. In other instances individuals have not Stored (refrigerated) the product properly. Keep in mind that there is a shelf life on solder paste and if not stored properly it will deteriorate quicker. I have used the mechanics solder paste that Fast Tech and hundreds of other places sell that is over a year and was stored properly without any problems! Is there better paste out there certainly but for the jobs most do here it ( mechanics brand Solder) is more than adequate for their projects.
Just because one or two had a bad experience does not make it a bad product. Practice with it like you need too with any paste and get to know the product you are working with!
There is also some paste that does not need cold storage but it does have a shelf life you need to be aware of.
Nobody here is trashing Mechanic solder, so please don't confuse what is being discussed. In the beginning I used it quite a bit and it works well and is a great value. I also sell it in my store, which is something I wouldn't do if I didn't think it was good.
For wire I don't waste my time with the no-name stuff. A lot of those wire positive reviews are similar to the "1200 lumens" 400 lumens lights where the person writing the review hasn't actually used the good stuff so they don't know what they're missing.
The thread was about” solder wire” from Fast Tech, then their “Mechanic Solder paste” was drawn into the thread and misrepresented by those that have not used it! This sort of misinformation does not benefit the hobby and prevents hobbyists from using a fine product! The quoted comments above are what prompted the response to reassure individuals that they are false statements and to dismiss them. (trashing before they even used). Too funny, Sometimes we forget how impressionable people are?
As far as the rest of the Thread dealing with “solder wire” no problems.
Note that on FT’s page for the two kinds of solder that gave such bad results, there’ s only glowing reviews.
Would anyone who’s actually bought the stuff — and so is allowed to post on the product page —- and found it lacking care to try putting a review at FT to warn people off, and also post it here?
It’s always interesting to test whether honest bad reviews get posted on a site.
Short answer: “Nope. They don’t.”
I’m one of those who never refrigerate my Mechanic’s soldering paste. Yeah, it gets a bit thick. I’ll usually thin it with some flux, but typically, a tub lasts me for a year or longer before it gets too thick to use. By that time, I’ve used half the tub or more, and will just buy a second tub. Works out to less than a penny a day. Then it gives me an excuse to order some more when it’s dried out:
“I need to order more soldering paste; I might as well put a couple of spare emitters on the order. I’ll just get a couple of spare XM-Ls. I might need a spare XP-G2 (or two) as well, they’re cheap. A couple of XP-Ls would be good… I might need a handful of DTP PCBs too, better get some 16mm and 20mm to be on the safe side. Hmmmm… need some new drivers to use with these new emitters…. Just a couple of Q-Lites… and maybe a FET driver. Hey! That’s a new color Convoy host! I better stick that on the order as well…”
$250 later… :Sp
Way back when I bought the solder and I did post some reviews and neither of them showed up.
I use this solder, it works well
https://www.fasttech.com/p/1443502
I also use a q-tip to dab flux from a big ole tub of flux as well…I guess I was taught it’s easier to clean up the flux than try to fix bad solder joints (plus I kinda like the smell of rubbing alcohol)
Speaking of which…I need to get more…I’m almost out!
Tom E wrote:
ImA4Wheelr - please post how the eBay sourced solder worked out, if well, please post the link. Thanks.
I bought 15ft from vendor howudoin60 and it works better than any solder I ever used. So it could be the real thing. Here is a relist of the product I bought:
I liked it so much that I bought a whole roll, but from a different vendor due to price. The roll has arrived, but I have not tried it yet. It sure looks like the real packaging and it does not appear to be tampered with. So, I think it's legit.
Thank you Tom E for recommending this solder. I really like it.
I’ve been unhappy with the way my radio shack 60/40 has been working for me the last few weeks. I’m not sure if it got contaminated or what, but it almost seems like the rosin has gone bad. I ordered a couple of the 15’ Kester rolls you linked. I hope to be impressed with how much better it works.
For all this linked Kester premium solder wire there are no shipping options to EU.
Question for EU guys here. Do we have equivalent premium solder to Kester that can be ordered from EU? Where could we find it?
Stannol brand comes from Wuppertaal,Germany in the Ruhr Valley.Led4power,who designs and builds the LD2 CC drivers,sells it but I don’t know if that is only with driver orders.Good price too.If not,just search Stannol on e-bay.
Ok we have Stannol and after some researching I found Mundorf M-solder silver/gold
This looks like ultra premium stuff but unfortunately it also costs small fortune :)
Now that I’ve been around here a while, I’ve seen many different solder jobs here from different users and the range. I wonder if some simply have horrible solder, or if they are using the completely wrong methods/ideas for soldering. Reflow vs wire joints are two different worlds of soldering, of course—so I’m going to talk about joint soldering briefly.
In one thread I explained that the heat often soldered at to achieve good bonds on denser metals like copper (metals with higher heat conductivity) typically will oxidize solder blends very quickly because the heat is higher. Solder placed on the tip of an iron to aid heat transfer is already becoming highly oxidized typically after 10-15 seconds only, without any further inflow of new solder into the mix. 10-15 seconds I would say is probably as long as my longest joints take to fully solder. That would be time from fully pre-heated tip touch-down on the joint, fresh wire feed-in to the joint, and pull away for the set. With the oxidation factor in mind, soldering of joints should be done as quickly as possible, with as much pressure/contact-area as the user can apply from the iron tip, to allow it to be done quickly in this manner. I watched one person solder and reviewed it, and it appears the “speediness” factor is not being picked up on—which if used, will almost always give you perfect looking “mirror” joints. I think the problem some face based on watching a couple friends while teaching, is they don’t have a setup or jig to hold things in place correctly while adding the tip pressure, so they take time being careful to hold the wire down lightly with the tip, and the result is very slow heating, non-uniform heating, burnt insulation because the copper wire keeps pulling heat down the wire the longer the iron is on there, and finally “crackly”, or “blobby” (stacks of blobs) looking joints.
Soldering should be heat passed into the joint of the intended connection as fast as possible, then a rosin core fed into the joint itself, NOT the iron tip. The iron tip is only to pass heat with. If you are flowing solder right into the joint, you guarantee that the heat needed in the joint is there. We know the heat will be fine at the iron tip, so that is not the best place to add solder.
I stopped using flux altogether, after I realized rosin core solder simply gives the best joints you could ever ask for, and the flux amount is consistent with the solder applied. So yes, I only use rosin core solder for lights and will never look back. I use 0.022” inch diameter (62:36:2 ratio, silver-bearing) on everything now. Luckily, I managed to stock up on the RadioShack stuff before they closed down, of this spec. It is probably out there for sale I imagine everywhere still online. Small wire is just better for what we do, IMO. Thicker solder wire adds too much mass as I feed it, at too high a rate for my tastes to maintain control over the pool and pool temperature.
So here is an example of a joint I did, 18AWG. Notice, the wire is fully bonded into the pool, the pool is shiny showing little oxidation, and the joint is consistent overall, showing that the temperature was high enough everywhere to bond fully in the fluid-state. This type of joint (with rosin core) requires no pre-tinning either, because what is occurring is a tinning and a joint creation at the same time. Tinning is really unneeded if the surfaces are clean and rosin core is used, unless the joints become very large, and you are trying to obtain a semi-reflow to occur (such as on a spring base).
KKW, this is the same exact solder you tried out on the same wire/joint/iron in IL…I could help you with your technique to get them looking like that^ photo every time. 
It just needs a slight tweaking and you’ll be good to go forever; I promise you this. 
The thing I have been seeing going around is extreme spatter in photos. I ditched the bad flux long ago, and away went the spatter, I hate that crap and it really shouldn’t happen. Get one tiny spatter on a bare die and you’ll have a black spot there and ruined emitter projection.
Hello!
I gave away to my friend my “1 or two USD multicore solder” and bought a new one:
https://www.fasttech.com/p/3494000
AVOID!!!
Terrible stuff.
Does not melt almost at all, does not flow anywhere, just barely could make two joints with this to get one led soldered…