Electronics > Repair
Restoring dried solder flux paste
<< < (6/12) > >>
tooki:
I tried various ratios, stirring while cooling vs. leaving it still, nothing made any difference. Nothing at all like the old Kester 44 rosin flux paste I have a tin of, which is clearly a true dissolved mixture, since it can be remelted without any kind of separation, so it's not a suspension or emulsion. From the (many, many) flux MSDSs I looked at, and a few other sources, it's pretty clear that for liquid fluxes, unprocessed rosin can be dissolved in solvent, but that for petroleum jelly based paste fluxes, the rosin is processed first.
SilverSolder:

Are all paste fluxes based on petroleum jelly, or only some of them?
jpanhalt:
@tooki

I just bought a pound of gum rosin.  That's about 8X the amount of paste flux I have used in 50 years.  Should last me awhile. :)

My hypothesis is that your mixture is all wrong.  I suspect something like 1% to 5% petroleum jelly is what is needed, maybe even less.

Should arrive later this week, but an unusually strong Winter storm is brewing, and shipping may be delayed (i'm in a very remote area).  Will test and report.

John
tooki:

--- Quote from: SilverSolder on February 15, 2021, 09:57:14 pm ---
Are all paste fluxes based on petroleum jelly, or only some of them?

--- End quote ---
No, not all are. Newer flux formulations tend to use other things.


--- Quote from: jpanhalt on February 15, 2021, 10:00:22 pm ---@tooki

I just bought a pound of gum rosin.  That's about 8X the amount of paste flux I have used in 50 years.  Should last me awhile. :)

--- End quote ---
I should think so! :D


--- Quote from: jpanhalt on February 15, 2021, 10:00:22 pm ---My hypothesis is that your mixture is all wrong.  I suspect something like 1% to 5% petroleum jelly is what is needed, maybe even less.

--- End quote ---
Not a chance. A 99% rosin concoction, provided you found a way to make a stable mixture, would be a solid, not a paste.

Kester SP-44 was 25-50% rosin according to the MSDS. (The MSDS doesn't list petroleum jelly, but other sources say that's what its base was.)

MG Chemicals 8342 rosin flux paste's MSDS says it's just 5% rosin, 10% paraffin oils (which could overlap with petroleum jelly, that being such a loosely defined term), a few % acids, with the balance unspecified.

SRA #135 rosin flux paste's MSDS says it's 30-50% rosin, 20-40% petroleum jelly, and the balance "non-hazardous stabilizers, and water". (That paste has the most similar appearance to the Kester SP-44 of all the still-available rosin paste fluxes I've seen.)


--- Quote from: jpanhalt on February 15, 2021, 10:00:22 pm ---Should arrive later this week, but an unusually strong Winter storm is brewing, and shipping may be delayed (i'm in a very remote area).  Will test and report.

--- End quote ---
Please do!!! If you do find a way to make a functional rosin flux paste, I think many people would be curious.

(I've seen a few youtube videos claiming to do so, but I am quite certain they're fake, in that they claim to add a small amount of IPA to solid gum rosin to make a paste, but then when they demo the paste, it's a very pale yellow paste, not the dark amber the rosin would be.)
jpanhalt:
One experiment is worth 1000 expert opinions or TDS's.  Why do you think ChipQuik's TDS's are so vague?  (PS: ChipQuik's use of bismuth in its low-melting solder is a matter of marketing.)

Will report back as weather and the USPS allows.
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod