Looking for a "greasy" solder paste

[ledtester]

Years ago I found some solder paste at my local surplus store that very much resembled Vaseline/petroleum jelly. See below for what it looks like on a wire. I like it because you can easily apply it to wires with something like a toothpick and years later it is still as soft/greasy as it always has been.

Supposedly SRA Flux #135 is also supposed to be soft as shown in this video:

https://youtu.be/SVhkHgP1Gvs

but the puck I bought was already hard and others report that it tends to dry out/crystalize over time.

Does anyone have an idea of where I can more greasy flux paste?

[BillyO]

Are you looking for solder paste (flux with tiny solder balls in it), or flux paste (just flux)?

[ledtester]

Just flux paste.

[BillyO]

The oldest stuff I have is rosin based and it is still "greasy", but that could only be because I kept it well sealed and have not opened it in years (until now).  I have since switched over to the flux in plunger tubes.  That stuff, both the rosin based and the resin based are kind of "greasy" and I have never had any of it harden up before using it all.

I mostly buy from MG Chemicals.

[thm_w]

https://blog.sra-solder.com/knowledge-base/sra-135-rosin-flux-paste-user-guide

The consistency of the flux should not be gooey or hard to puncture. In other words it should be solid but also easy to dip wires and applicators into.

3. If the Rosin flux becomes dry is there anything you can do to return it to more of a paste? You would want to gently heat it until it softens up, but you need to be careful not to heat it up too quickly or at too high of a temperature.

I guess what they mean is, heat it and it will temporarily soften, but will harden again. The SDS doesn't say what solvent is in there that evaporated. Could try mixing a small amount with IPA or ethanol.

Maybe just find somewhere that can guarantee a "fresh" jar, or ask them if they'll exchange it for one. Because they are advertising it as easy to dip.

[pcprogrammer]

In 2018 I bought some paste from Aliexpress, but the links are dead now. The paste came in a tin and, when kept at room temperature, stays smooth for a long time. I still have a bit left over and it is still good. Only after heating the rosin crystalizes and separates from the grease. It is a bit to firm to be used in a syringe though.

Maybe this stuff is similar, but I have not ordered it. https://www.aliexpress.com/item/1005009188346974.html

I'm waiting for this https://www.aliexpress.com/item/1005009828390639.html to arrive. When it does, in a couple of days, I can share my findings.

[tooki]

Years ago I found some solder paste at my local surplus store that very much resembled Vaseline/petroleum jelly. See below for what it looks like on a wire.

Just flux paste.

FYI:
For historical reasons, flux pastes from the plumbing and sheet metal worlds are referred to as soldering paste.

In the electronics world, that terminology was originally used but died out, with the name “flux paste” becoming common. When solder paste — that is, solder powder suspended in tacky paste — came out, it was called “solder cream” before everyone settled on “solder paste”.

Note that in electronics, we mostly differentiate between flux paste and tacky flux. Flux paste is the classic stuff in jars or cans, and it’s usually very stiff. Tacky flux is designed to be sticky, but with very defined viscosity characteristics so that it can be stenciled on (as part of solder paste). They’re usually thixotropic and flow easily but then retain their shape. Flux paste and tacky flux also have very different vehicles (paste is usually petroleum jelly, while tacky flux is usually polyalcohols).

[ledtester]

FWIW, here's a video of using the paste to tin a wire.

https://imgur.com/a/ZVuKqjA

(link doesn't work)

I like this paste because it easily sticks to the wire and it takes only one hit with the iron to tin it all around.

Another characteristic is that creates a little bead of residue when you heat it up as you can see at the end.

[tooki]

FWIW, here's a video of using the paste to tin a wire.

https://imgur.com/a/ZVuKqjA

”The requested page could not be found.”

[ledtester]

Yeah - my imgur uploads seem to get deleted. I'll have to find another way to share the video.

[nonius_]

In the Netherlands we have 'Purine', a product from Bison/Griffon (Perfecta Chemie Goes).

It's a pasty flux, but normally used more for soldering steel and metal, not electronics.

https://www.werkenmetmerken.nl/docs/S-39_UNIVERSAL_PURINE.pdf

Cheap soldering irons often also came with a tiny bit of cheap/nasty solder and a little orange/red cup of yellowish solder paste.

Just stumbled upon this product too, from Weller: https://www.bol.com/nl/nl/p/weller-soldeervet-lf25-20-gr/9200000065996035/?cid=1775163107052-4199593166106

Seems a bit expensive to me but is otherwise what you're looking for, I think. Or this stuff: https://www.amazon.nl/-/en/Solder-Soldering-Machinery-Cleaning-Protecting/dp/B0BQCHSQLB/ref=pd_day0_d_sccl_2_5/259-7502592-2036547?pd_rd_w=31SbW&content-id=amzn1.sym.5f2c4c18-0e1d-4c1f-bb1b-f034669e60c3&pf_rd_p=5f2c4c18-0e1d-4c1f-bb1b-f034669e60c3&pf_rd_r=TVMAHK0WSCR0CZWXR52Y&pd_rd_wg=a1Skl&pd_rd_r=381b6997-d6b9-45fd-a19f-813c6b09e2c2&pd_rd_i=B0BQCHSQLB&psc=1

Or searching for 'colophonium' may give you other suitable products. You could even make your own paste from colophonium-resin and a solvent (IPA?).

BTW, verify if your paste is conductive, because mine is. It needs careful cleaning in high-impedance (CMOS e.g.) or high-voltage circuits.

[BillyO]

Yeah - my imgur uploads seem to get deleted. I'll have to find another way to share the video.

YouTube works.

[tooki]

In the Netherlands we have 'Purine', a product from Bison/Griffon (Perfecta Chemie Goes).

It's a pasty flux, but normally used more for soldering steel and metal, not electronics.

https://www.werkenmetmerken.nl/docs/S-39_UNIVERSAL_PURINE.pdf

Cheap soldering irons often also came with a tiny bit of cheap/nasty solder and a little orange/red cup of yellowish solder paste.

Just stumbled upon this product too, from Weller: https://www.bol.com/nl/nl/p/weller-soldeervet-lf25-20-gr/9200000065996035/?cid=1775163107052-4199593166106

Seems a bit expensive to me but is otherwise what you're looking for, I think. Or this stuff: https://www.amazon.nl/-/en/Solder-Soldering-Machinery-Cleaning-Protecting/dp/B0BQCHSQLB/ref=pd_day0_d_sccl_2_5/259-7502592-2036547?pd_rd_w=31SbW&content-id=amzn1.sym.5f2c4c18-0e1d-4c1f-bb1b-f034669e60c3&pf_rd_p=5f2c4c18-0e1d-4c1f-bb1b-f034669e60c3&pf_rd_r=TVMAHK0WSCR0CZWXR52Y&pd_rd_wg=a1Skl&pd_rd_r=381b6997-d6b9-45fd-a19f-813c6b09e2c2&pd_rd_i=B0BQCHSQLB&psc=1

Or searching for 'colophonium' may give you other suitable products. You could even make your own paste from colophonium-resin and a solvent (IPA?).

BTW, verify if your paste is conductive, because mine is. It needs careful cleaning in high-impedance (CMOS e.g.) or high-voltage circuits.

The Purine and Weller are both for general soldering, not for electronics.

The one on Amazon is insanely expensive for being no-name.


Why are people so reluctant to order real brand-name products from electronics distributors like Mouser and Digikey?!? It’s no more expensive than the Amazon stuff, but you’re not taking a gamble on whether the no-name stuff is good or junk. You can get, for example, SRA, ChipQuik, or Caig fluxes for far less money than the Amazon no-name.


FYI, the standard English word is “rosin”. (“Colophonium” is an obsolete word in English.)

[BillyO]

If you want REAL flux, look for products from Kester or MG Chemicals.  It would not surprise me if the hobby brands like SRA or ChipQuick are either rebranded from the big guys or are substandard.  I mostly use MG Chemicals because it's a Canadian company, but I have also used Kester.  These companies supply the large production houses with barrels of flux.  If it's good enough for them, it's good enough for me.


The ones I use are:
MG Chemicals 8341 No-Clean Soldering Flux Paste
Kester RF550 Rework Flux

They both have other formulations, but these work well for me.

[tooki]

If you want REAL flux, look for products from Kester or MG Chemicals.  It would not surprise me if the hobby brands like SRA or ChipQuick are either rebranded from the big guys or are substandard.  I mostly use MG Chemicals because it's a Canadian company, but I have also used Kester.  These companies supply the large production houses with barrels of flux.  If it's good enough for them, it's good enough for me.

I’m pretty sure SRA and ChipQuik (as well as many other companies) source their fluxes from flux manufacturers that are smaller than the “big guys” like Kester, precisely because the big guys have no need to do OEM work. I can’t remember the name of the company that makes some of the SRA and ChipQuik stuff, but I came across some very strong clues. (Like product numbers matching up!) They certainly aren’t “substandard” as you suggest.

I don’t think MG makes all its products, either, since some are made in Canada and some are made in USA.


As for Kester: they’re huge in North America, but Kester products are all but impossible to find in Europe. Sure, they’re available to order from some distributors, but only if you’re ordering a whole case. General-purpose distributors like DK and Mouser carry Kester solder, but the fluxes and cleaning products aren’t available from them.


And clearly, ChipQuik and SRA supply at least some non-hobby customers, since they sell solder paste and flux in containers far too big for hobby use.

[BillyO]

By substandard, I meant compared to the big guys, not in product quality.  I guess I should have said smaller suppliers.

The OP is in the US, that's why I included Kester.  I believe MG Chemical is available in the EU and UK, but I don't know which products they send there.

[nonius_]

Tooki: I see 4 posts of you in this thread, none of which address the question of OP. Instead, you criticize every suggestion and go in to irrelevant details.

Why not make your 5th post answer the OP? I.e. post a link (or a specific article number from a brand you deem acceptable) to a product that YOU think is suitable for him, for electronics, at a competitive price, of a good quality, etc.

Now THAT would be helpful. All the rest is just waffle.

[tooki]

Tooki: I see 4 posts of you in this thread, none of which address the question of OP. Instead, you criticize every suggestion and go in to irrelevant details.
…
 All the rest is just waffle.

It is not “just waffle.” Correcting misinformation is important here: the wrong fluxes (like the first two you suggested, and most any flux labeled “soldering paste”) can be damaging to electronics and thus are not safe to use.

The “irrelevant” details are explanations of why, so that I’m not just some asshole who says “WRONG!!” and then backs it up with nothing.

Why not make your 5th post answer the OP? I.e. post a link (or a specific article number from a brand you deem acceptable) to a product that YOU think is suitable for him, for electronics, at a competitive price, of a good quality, etc.

I did mention some good brands and suppliers.

Why are people so reluctant to order real brand-name products from electronics distributors like Mouser and Digikey?!? It’s no more expensive than the Amazon stuff, but you’re not taking a gamble on whether the no-name stuff is good or junk. You can get, for example, SRA, ChipQuik, or Caig fluxes for far less money than the Amazon no-name.

But I was waiting to make a specific recommendation until OP could post the video they wanted to share. Since they have a specific texture they’re after, I’d rather see it first and then suggest something, assuming I know one that is just like it.

[nonius_]

can be damaging to electronics and thus are not safe to use.

As I mentioned before, they may require proper cleaning afterwards. Something I've been doing my entire life.

To LEDtester: I've been using a similar pasty flux for the past 45 years, even though it may not have been intended for electronics, it certainly works very well, for (pre-)tinning components, wires, etc., and I also occasionally use it in actual soldering of components on PCBs. But, as I mentioned before, in that case it's important to properly remove the residue as it's pretty conductive. When not properly removed it'll play havoc with high-Z circuits, and in one case it caused carbonization of a pertinax (phenolpaper) board of a valve radio with 300Vdc over tracks that were close together. So be aware of that, hence why I stressed in my previous post to verify whether the paste you get is (slightly) conductive.

The tin in the picture below sits permanently on my desk next to the soldering iron and rolls of solder. It's an integral part of my soldering process. This is one the 4 tins I bought at the local hardware store as it was going on sale (50 cents per tin; I bought their entire remaining stock )

So take people's remarks that you can't/shouldn't use it in electronics with a grain of salt, I've been doing exactly that for 45 years. In fact, it's how I was taught.

Let us know which product you end up buying and how it performs!

[tooki]

Or just avoid all that uncertainty and risk and buy a flux intended for electronics. (Note that many non-electronics fluxes, particularly ones with chlorides (ammonium chloride and zinc chloride being classics), leave ionic residue that embeds itself in the PCB material, resisting cleaning. So you think you’ve washed it off, but there’s still stuff there that can cause problems.)

[pcprogrammer]

And another thing to add to this use of not really for electronics solder paste (soldeervet as per the tin lid) even if it is acid free, might be bad for the long life tip of your soldering iron.

The stuff in the picture provided by nonius_ is intended for tubes and plates and most likely to be used with a torch.

I have similar paste, but only use it for the intended materials like zinc for gutters or copper pipes for pluming, not for electronics.

[pcprogrammer]

I received the soldering flux I ordered and it is a clear paste and fluid enough to push through a syringe, but still tacky enough to stick to a wire. When heated with the soldering iron it produces a lot of smoke, so an extraction fan is needed. It then becomes a clear liquid that does not evaporate. A solid copper wire was easily tinned.

Have to do some proper soldering on a PCB to see what it does.

For me the jar holds some very sound advice though. 
See the last line on the label in the last picture attached. 

[TizianoHV]

I am very happy witth AMTECH RMA-223 (made in usa!). It comes in a siringe and it is gel like.
Be careful with clones, the last aliexpress flux was total garbage.

[ledtester]

Ok, I uploaded my video to youtube:

https://youtu.be/dgkrwQQyzE4

What I like about it:

- it's very "soft" and pliable -- much more than the stuff that comes in tins
- one hit is enough to tin the wire all away around - it seems to spread very well even when applied to just one side

What I don't like about it:

- it gives off an odor that suggests you shouldn't be inhaling it

Here are some more pastes I tried:

SRA No. 135:  https://youtube.com/shorts/w7TNMxmCb9M

Bojacks: https://youtube.com/shorts/xqXPqPAevE4

Thermotronics: https://youtube.com/shorts/Ep6Dn2_eI_8

The SRA has a hard upper crust... you have to dig under it to get to softer stuff.

The Bojacks and Termitronics are similar in consistency.

[Brumby]

It's a pasty flux, but normally used more for soldering steel and metal, not electronics.

This comment sent shivers down my spine.  It reminded me of the very first introduction to flux by my grandfather - an event which occurred when I was in primary school, well before I slid into the world of electronics.  This was a home made flux called "killed spirits".  The process was extremely simple, the result was very effective but the residue would DESTROY electrical work if appropriate neutralisation and cleaning efforts were not performed (and even then you would wonder about any hidden pockets of death).  It would straight out devour electronics.

In those days, you would soon learn (if not already educated) about the risks and appropriate courses of action - BUT these days, there are so many options that consideration of acidic effects doesn't really feature in the minds of many, especially for some of hobbyist background or those with limited experience in wielding a soldering iron.  What may have been crucial knowledge and essential practices 45 years ago has been largely made redundant by technological advances.  Certainly, flux manufacturers have made more options available and while the lessons on chemistry have evolved, they are less prominent in the thinking of users.  There is still the responsibility to choose appropriately, but that often falls to reading the label.
 
As such, I see cautions and warnings of the utmost importance - with the explanation of WHY a statement was made frequently more useful than the original statement.  Understanding is far and away more valuable than simple knowledge.

This is where the EEVblog shines brightest (IMHO).  We have members of a global community which offer their time, counsel and experience willingly, freely and often enthusiastically for no other purpose than to assist others. 

I am often amazed at the wealth of knowledge that finds its way onto these pages.  It is truly humbling.