| Electronics > Repair |
| Restoring dried solder flux paste |
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| helius:
SP-44 is the paste form of Kester 44 flux (the liquid form is 1544). It is IPC class ROM1 (rosin, medium activation, detectable halides). The name "44" comes from its halide portion, 0.44% by weight. This is an important part of the formula that is missing in the homebrew test. Note that this would be an organic bromide, not an inorganic type. Where can a person get alkyl bromides? One source is oddly in degreaser cans. 1-bromopropane (NPB) is a solvent used in some flux removers (which I do not recommend for that purpose as it has been associated with peripheral neuropathy). If someone else wants to experiment with it, I will pay close attention. |
| jpanhalt:
My purpose was not to replicate SP-44 (which apparently is no longer available) but to show that rosin and petroleum jelly do mix and remain a stable jell. I would never consider making, rather than buying a flux. |
| T3sl4co1l:
--- Quote from: helius on February 26, 2021, 09:35:05 pm ---Where can a person get alkyl bromides? --- End quote --- Just call up Max Gergel, obviously. :P (Passed author of _Excuse Me Sir, Would You Like To Buy a Kilo of Isopropyl Bromide?_, a not-too-bad telling of the swashbuckling time that was chemical manufacturing during the uh, 40s to 60s I think it was. Given the title, I don't think we'd have any trouble in this regard...) Tim |
| tooki:
--- Quote from: jpanhalt on February 26, 2021, 09:50:02 pm ---My purpose was not to replicate SP-44 (which apparently is no longer available) but to show that rosin and petroleum jelly do mix and remain a stable jell. I would never consider making, rather than buying a flux. --- End quote --- I wonder what the deal is with my rosin, since it didn’t end up looking anything like that, and just congealed in a layer under the PJ. |
| helius:
--- Quote from: T3sl4co1l on February 26, 2021, 11:41:02 pm ---Just call up Max Gergel, obviously. :P (Passed author of Excuse Me Sir, Would You Like To Buy a Kilo of Isopropyl Bromide? --- End quote --- Thanks for that, I hadn't thought of that book in nearly a week :) It's full of crazy anecdotes, the best perhaps being when the salesman demonstrates the gentleness of a tile cleaner by gargling with it. Unbeknownst to him, the chemist who mixed the cleaner substituted trisodium phosphate for sodium pyrophosphate, completely changing the pH of the product. I was so interested in this story that I tracked down the detergent ingredient he mentions, DuPont MP-189. The only information I was able to find is that it is a type of hydrocarbon sodium sulfonate, which is entirely unsurprising given the narrative description. |
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