General > General Technical Chat

Good solder wick (for german market)

<< < (4/5) > >>

madires:
From my experience I don't need to clean pads after using the Felder solder wick. What would the purpose of that (unless you deal with some highly sensitive circuit, extremely low leakage and guard traces)? If you replace an SMD you'll even add more flux and clean everything after soldering anyway. The cheap solder wick you have must be really bad if even additional flux doesn't help.

Traceless:
@tooki: Okay great I'm gonna try the Felder then as well. For stubborn residues I've got a bottle of Kontakt WL here, do I have any advantage using Kontakt LR over WL for flux removal?

@madires: Yes for SMD replacements I use lots of flux but I make sure that it is all declared no-clean so I don't need to worry about corrosion in cases where I don't/can't clean up perfectly. And yes the cheap wick was absolute rubbish. Mostly I work on PC parts (mainboard, GPU), power supplies (ATX and bricks for notebooks, screens) and also occasionally on fun projects or my own appliances. I don't do this for a living just as a hobby, to learn and also because I think that it is absolutely stupid to throw away perfectly good electronics just because a 30 cent component died.

madires:
Maybe I'm wrong, but I think that the term "no-clean" is trying to sell the obvious, i.e. standard flux meant for electronics isn't corrosive anyway. There are corrosive fluxes for special purposes, like for hard to solder metals, and things like plumbing, but you have to especially look for them.

PS: I'm also supporting the idea of repairing stuff. The big project I'm working on is the Transistortester.

tooki:

--- Quote from: Traceless on October 20, 2021, 09:06:12 am ---@tooki: Okay great I'm gonna try the Felder then as well. For stubborn residues I've got a bottle of Kontakt WL here, do I have any advantage using Kontakt LR over WL for flux removal?

--- End quote ---
I honestly don’t know. I actually have both here, but I’m about to head out so I can’t test it right away.

I know I looked at the ingredients long ago, and Kontakt LR, WL, and LS are all very similar. (LS is the more unusual one, because it comes in a larger can with much higher pressure.)


--- Quote from: madires on October 20, 2021, 10:29:22 am ---Maybe I'm wrong, but It think that the term "no-clean" is trying to sell the obvious, i.e. standard flux meant for electronics isn't corrosive anyway.

--- End quote ---
I’d say half right. Indeed, standard RMA flux does not need to be cleaned for most applications.

No-clean liquid fluxes tend to have far less solids content than liquid rosin fluxes: most have under 5% (often under 2%), versus the 10-30% typical of liquid rosin flux. The no-clean liquids in turn have more non-rosin agents.
The low resin content makes any residues practically invisible.

For the flux core in wire solders, as well as in pastes/gels, no-clean usually has paler residues than traditional rosin. The amount of flux is also usually slightly less.

Paste/gel and liquid no-clean also can only be considered no-clean when used for full-board reflow soldering. These fluxes must be heated to a particular temperature to neutralize the fluxing agent, and in hand soldering, it’s very common for part of the flux (at the edges) to get heated enough to activate the fluxing agents, but not hot enough to neutralize them! That leaves them in an active, corrosive state. So always thoroughly clean such fluxes when hand-soldering. (That problem doesn’t affect no-clean flux cores, since the flux is heated sufficiently by the molten solder.)


I don’t know this for sure, but my hunch is that no-clean really became more important with lead free solder, because the higher temperatures required end up burning a lot of traditional rosin fluxes. (Burnt flux could well be conductive, and it is unsightly.) It seems to me that no-clean is mostly used in a sense to indicate fluxes that can handle higher temperatures better.

But for sure, there’s a ton of overlap, and the terminology chosen sucks.

Also, corrosive fluxes are actually common in electronics manufacturing: most water-washable fluxes are highly corrosive and need to be removed flawlessly. (And must not be used whatsoever for anything the flux wicks into, especially stranded wire.) The stringent cleaning requirements are why such fluxes are best avoided for hobbyist use.

Some traditional electronics rosin flux types (like RA) do require cleaning, because the residues are conductive and/or corrosive.

madires:
Interesting topic! I only "manufacture" a few PCBs at home, nothing fancy, and repair a lot of stuff. So far I haven't had any problems with standard solder with RMA flux. For decades I'm using Kontakt Lötlack SK 10 (basically rosin) for protecting my home made PCBs and it works well. I've used some no-clean flux pen for SMD work but ended up making my own flux (rosin dissolved in IPA). Sometimes I stumble across some vintage electronics with really crusty old flux residue (residue is an understatement in this case) and the traces and pads are still fine while the soldering looks horrible.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod