I have seen a few videos of people using acid flux on 18650s. They seem to get really fast wicking with out the need for surface prep. My question is: is this an ok idea? I am considering it for my next build but I don’t know if I should. Acid flux is not recommended for electronics and needs cleanup. Is it ok for 18650 soldering? Also, can I neutralize it with baking soda to ensure that’s it’s deactivated after soldering?
-
Howdy! we're looking for donations to finish custom knowledgebase software for this forum. Please see our Funding drive thread
Acid flux on 18650s
- Thread starter john2364
- Start date
eee291
100 kW
I would recommend you to spot weld 18650s, but if you really want to solder then you can just use regular soldering flux.
You don't need acid based flux since the 18650 can is made from Nickel plated Steel. Just make sure you have a high powered Iron something like a 150W one works really well.
You don't need acid based flux since the 18650 can is made from Nickel plated Steel. Just make sure you have a high powered Iron something like a 150W one works really well.
Yea, this is not my first and I am pretty good at soldering. I also have a good iron. I can do a joint in about 1 second or less with my hakko station and large chisel tip. To get a fast joint you have to remove the oxide layer on the can first. Rosin flux does not become acidic until it’s heated so it does not start working on the oxide layer until your already heating the cell. With just solder and rosin flux it takes too long and the cell can get hot. To get it to wick fast, I previously had to give a very light sanding to the terminal first. Acid flux would take care of this problem and it would do a better job than a light sanding. I have seen some really fast videos where people used it. The problem is that it stays active after it cools and I guess that is where it causes problems. I guess it could be too caustic to begin with as well. So while it would really help the initial joint it could cause massive problems down the line. I just was wondering if there was a method to avoid this and if it’s just generally a bad practice to use it at all. It sounds like no one recommends acid flux even for batteries so I think that I will stick to my old method.
Jan-Erik-86
100 W
- Joined
- Jan 23, 2019
- Messages
- 110
When i was building my pack I first tried with a 30W iron (practicing on dead batteries), and not unexpected it did not flow the solder even after a few sec (even after sanding). Adding rosin flux didn't help. However, adding a drop of acid flux made it flow perfectly even with my 30W iron in less then a sec.
Upgrading to a 100W iron and the solder would flow perfectly and instantly without any additional flux (flux core solder though) or surface prep.
As for the acid flux part, i noticed that the flux would easily go into spots where you couldn't clean it up, and after seeing a video on youtube where one guy had accidentally used acid flux instead of rosin flux on one of the packs, i quickly abandoned the acid flux option. I couldn't find it right now, but on the video he showed that the acid flux had totally corroded and eaten up the batteries in only about a year or so, and it was clear that only pure luck saved him from the pack shorting out. Multiple cells were already dead or shorted.
So with enough heat there was no need for any additional flux in my case at least, but even though i used flux core solder for electronics i cleaned off what i could as i don't know what flux it is (high quality solder, but from the 80's), and I'll probably unwrap and check my pack in a year or so just to be on the safe side (especially as i didn't fuse each cell).
Upgrading to a 100W iron and the solder would flow perfectly and instantly without any additional flux (flux core solder though) or surface prep.
As for the acid flux part, i noticed that the flux would easily go into spots where you couldn't clean it up, and after seeing a video on youtube where one guy had accidentally used acid flux instead of rosin flux on one of the packs, i quickly abandoned the acid flux option. I couldn't find it right now, but on the video he showed that the acid flux had totally corroded and eaten up the batteries in only about a year or so, and it was clear that only pure luck saved him from the pack shorting out. Multiple cells were already dead or shorted.
So with enough heat there was no need for any additional flux in my case at least, but even though i used flux core solder for electronics i cleaned off what i could as i don't know what flux it is (high quality solder, but from the 80's), and I'll probably unwrap and check my pack in a year or so just to be on the safe side (especially as i didn't fuse each cell).
X2flier
10 W
- Joined
- Jun 25, 2018
- Messages
- 79
There is a good soldering flux (paste) which is entirely non-acid: LA-CO. The website can find sellers near you; just scroll down to Resources there, or buy it on-line.
https://markal.com/collections/soldering-fluxes/products/regular-flux-paste?variant=9204786757679
You can buy a two ounce (~56gr), four ounce (~113gr), or one pound (~450gr) container. You can solder almost any metals using this flux, even most stainless steels. After soldering, this flux cleans up with plain water; no baking soda or alcohol needed. Safe for drinking water pipes. I have not tried it on batteries, yet.
https://markal.com/collections/soldering-fluxes/products/regular-flux-paste?variant=9204786757679
You can buy a two ounce (~56gr), four ounce (~113gr), or one pound (~450gr) container. You can solder almost any metals using this flux, even most stainless steels. After soldering, this flux cleans up with plain water; no baking soda or alcohol needed. Safe for drinking water pipes. I have not tried it on batteries, yet.
Similar threads
