Soldering fluxes for home use - Page 1
Forum section: electronics / beginners

author: pcm81
author_rank: Regular Contributor
timestamp: August 17, 2025, 11:24:12 pm
content: This thread is building on top of my other flux thread, but since it has a slightly different topic i decided to branch out to new thread.Anyhow, the basic question is: is there any reason to use anything other than the most aggressive flux in a home/hobby environment?There seem to be 2 dominant categories of fluxes no-clean resin fluxes and water soluble organic acid fluxes. Each one of these general categories has a range of activity.Since the no-clean resin fluxes are only no-clean when fully heated, and in hobby shop environment there is bound to be left some residue that did not get fully burned off then the whole "no-clean" goes out of the window.So the question becomes, why even bother with anything other than the more aggressive fluxes like ORH0 or ORH1?

author: Analog Kid
author_rank: Super Contributor
timestamp: August 17, 2025, 11:28:59 pm
content: You do mean solderingwiring, not sheet metal or something else, right?My own experience is only using standard rosin-core solder, which has always served me well for all kinds of wiring projects.I've never felt the need to clean it off a board.Your experience may be different, and I'm curious to hear other points of view on this.

author: pcm81
author_rank: Regular Contributor
timestamp: August 17, 2025, 11:32:52 pm
content: Quote from: Analog Kid on August 17, 2025, 11:28:59 pmWiring/PCBs etc but in a hobby environment (soldering iron / hot air station), not in a reflow oven.

author: pcm81
author_rank: Regular Contributor
timestamp: August 26, 2025, 10:03:31 pm
content: so, I decided to do a test to answer my owwn quetion as posted above.Here is a picture of copper plate 30 minutes after i applied kester 186 and kester 2331 to it. Both fluxes we applied and left on the plate cold, no heating or soldering, to show the difference of corrosion by unreacted flux

author: thm_w
author_rank: Super Contributor
timestamp: August 27, 2025, 12:36:46 am
content: Quote from: pcm81 on August 17, 2025, 11:24:12 pmThe no clean stuff I use is very mild, if I leave it on bare copper without heating, no corrosion was seen. I'm not too worried about a small amount of residue on the top of the PCB, especially when its on top of soldermask, nothing is going to react.The citriflow mentioned here is probably minimally reactive as well:https://www.eevblog.com/forum/other-blog-specific/nanofix-youtube-flux-comparison/Your demo shows that water soluble flux must be washed off. You haven't tested no-clean.

author: d-el
author_rank: Regular Contributor
timestamp: August 27, 2025, 12:45:17 am
content: I recommend FluxPlus 7019074 (6-412-A).Excellent soldering quality of SMD components.I wash it off with either pure kerosene (Jet fuel or aviation turbine fuel) or a kerosene/ethanol solution in a 1:1 ratio.

author: pcm81
author_rank: Regular Contributor
timestamp: August 27, 2025, 02:06:24 am
content: Quote from: thm_w on August 27, 2025, 12:36:46 amYou are correct. I bought Kester 184 because it is ROL0. so most mild and i had 2331 which is ORH1, which is most aggressive. The idea was to use 184 for things i can't clean or guarantee full heating, like in stranded wires. I started this thread being concerned about the things i cannot clean, hence the no clean flux, but ended up buying ROL0 because was worried about places i cannot clean or heat up fully and wanted to test most mild flux.

author: pcm81
author_rank: Regular Contributor
timestamp: August 27, 2025, 03:46:13 am
content: Just found this:https://www.idc-online.com/technical_references/pdfs/mechanical_engineering/Fluxes_for_Soldering.pdfInteresting read for those who care.