Tinning tips with fluxfree solder? - Page 1
Forum section: electronics / beginners

author: hirada
author_rank: Regular Contributor
timestamp: January 11, 2021, 03:24:31 pm
content: Hi,just wondering, since flux has a reputation of being more or less aggressive, would it not be a good idea to tinning the tips with pure Sn(Pb) solder without any flux core?Or is it to the contrary the flux that avoids oxidation of the tip?Any thoughts?

author: tooki
author_rank: Super Contributor
timestamp: January 11, 2021, 06:19:39 pm
content: Without flux, you'd never be able to tin the tip, since it would oxidize and you'd have no way to eliminate the oxides.Edit: to be clear, the function of flux is toget rid of oxides. It does this both on the tip and on the items to be joined. The flux isn'tcausingoxidation, it's getting rid of it!

author: tooki
author_rank: Super Contributor
timestamp: January 11, 2021, 06:20:58 pm
content: What prevents oxidation of the tip is making sure it's ALWAYS properly tinned. Above all, this means tinning it frequently and generously when working, and DO NOT wipe off the tip when returning it to the stand — if anything, tin itmoreright before putting it away.

author: rstofer
author_rank: Super Contributor
timestamp: January 11, 2021, 08:12:37 pm
content: Tips are expendable items, they don't last forever. Plan on replacing them from time to time if the plating is eroding.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: January 11, 2021, 08:27:46 pm
content: Don't worry. The flux burns off. When it's cold it's not active unless you have fully active flux, but there shouldn't be any left. It is now smoke.As noted above, you *will need some* flux to even tin the tip.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 11, 2021, 08:43:28 pm
content: As said before, without flux there is just no soldering. (for normal applications).But there is a lot of variety of flux. Some are quite agressive and have to be cleaned after soldering, others only leave non-agressive residues and do not have t be cleaned.Some are soluble in water, others need other solvents. I've used IPA, but it tends to leave a whitish powdery residue.It is possible to solder without flux if you have all process parameters under control, but you need to solder in an oxigen free environment, such as flooding a wave solder machine with nitrogen. But even then a bit of flux is usually used to improve the soldering quality.

author: hirada
author_rank: Regular Contributor
timestamp: January 11, 2021, 08:49:02 pm
content: Due to some unhealthy bargain - blackout combination I've gotten hold of some massive 3mm 50/50 fluxfree solder and now have no idea, what to do with it. So my plan was to use it for tinning. But now I've learned, that is not a good idea. Thanks to all of you!

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 12, 2021, 06:58:48 pm
content: Those 50/50 solid bars are regularly used for soldering stuff like zinc roof gutters, but always with extra flux.

author: hirada
author_rank: Regular Contributor
timestamp: January 12, 2021, 09:02:46 pm
content: Great. I do have the solder, now I just need a roof! Thanks for clarifying. It was a bargain, and we'll see, wether I ever will have any use for it. 3mm diameter is quite hefty.

author: uli12us
author_rank: Contributor
timestamp: January 27, 2021, 10:36:39 pm
content: You can use the solder but need to apply extra flux to the parts. Only the big diametre isn't really good.If you have a jewellers Rolling Mill like this, you can reduce the size in several steps.https://www.amazon.com/dp/B01ITYJH20?tag=ganoksingen-20&linkCode=ogi&th=1&psc=1

author: Ian.M
author_rank: Super Contributor
timestamp: January 27, 2021, 11:27:51 pm
content: @hirada,Add 35% extra tin by weight to it, and you'd have very close to Sn63Pb37 eutectic solder to fill a solder pot.Otherwise Sn50Pb50 alloy was historically used for tinsmithing before the dangers of ingesting lead compounds were realized. Its also used for assembling stained glass panels in North America. Unless you want to explore tinsmithing, only making objects that will never be used for food or drink or growing edible plants I don't expect you'll find much use for it unless you need to build large RF screening cans.If you were in the USA and cast your own bullets, it might have come in handy as a more convenient way to add small proportions of tin to your bullet alloy.