Do we have any tools/equipment in the electronics lab that make it very easy to solder to heavier-gauge stranded enameled wire?
At home, I haven’t had luck using heat to burn/melt off the enamel, either from just sending my soldering iron (Pinecil) up past 400C or trying to use a blue flame lighter (just chars it, and apparently also oxidizes copper which is apparently not good for a solder joint). So far, the best I’ve been able to do is use sandpaper to abrade the enamel off, exposing the raw copper wire, but that does result in loss of some strands or risking damage, and is just really tedious, especially when I have to do this for a lot of brushless motors.
I actually just tried acetone 30 minutes ago, didn’t really have any effect. Haven’t messed with other solvents really, the ones I have at my disposal at home though are
Acetone (both hardware-store stuff and scented nail polish remover)
Acetone-free nail polish remover
Kleen-Strip premium stripper (SDS says it has Dimethyl carbonate, Xylene, Methyl Sulfoxide, Ethylbenzene, and Methanol in significant quantities)
Mineral spirits
Vinegar
The chemical route still seems as messy (especially to set up a dipping rig and in case of accidental spills) than scraping/sanding though.
I just popped into the electronics lab, couldn’t find anything that looked like a soldering pot. Didn’t do a deep search though. I’ll be buying a cheap one for myself, might request a higher quality one under the tools request system if I find it a very useful tool.
Unrelated, I did see a box of random microcontroller programmers, just taking a little note for myself about that.
Interestingly, we just got an email about electronics donations that included a solder pot. Good to know our current inventory on that and that it’s something that could be valuable to members!
Of all of those solvents, the paint stripper will be your best/most likely bet. It’s still a bit of a toss up if it will work though, it’ll just depend on the actual composition of the stripper and the type of insulation on the wire.
Unfortunately, for the most part the solvents that could easily dissolve common insulators (polyester, polyurethane, polyamide, polyamide-imide) aren’t readily accessible to consumers (usually for good reasons). You can probably find one or some combination of hardware store solvents that would work well enough to get the insulation off even if not fully dissolved, but you’ll have to deal with solvent waste if you go down that route since you won’t (shouldn’t) be letting them evaporate off. PM me if you decide to go down the solvent route. There is one out there that you’d be able to find that would work, but there are some non-standard safety things to consider with it.
If you’re trying to pump a LOT of heat into something, I’d reach for either a solder gun or an actual torch–butane, propane, acetylene.
There are a couple issues with a solder pot:
It takes FOREVER to heat up–they’re meant to be run for hours on end and not turned on and off.
In our space, the solder gets contaminated with whatever random stuff people are mucking with so you will never know what is in it.
At some point, you have to dispose of a bunch of solder with toxic gorp in it and replace all the solder.
Side note: enameled wire is generally magnet wire and not heavy gauge, multiple strands. Are you sure you have enameled wire? In addition, the enameling should melt about 400C, I think the new soldering irons should get there, but you may need one of the Thermaltronics 800 Series (800F–420C) tips to do so. I suspect we only have the 700 series in the lab.
Thanks for letting me know the drawbacks of a solder pot- the continuously-heated nature of it may not make it appropriate for a makerspace then, at least a larger one.
To be honest, I’m not too familiar with different types of wire. The picture I posted above of the three wires coming out of the brushless motor, the stripped ends are what I have been trying to tin (and only have been successful by sanding it off, twisting it a bit, sanding more, twisting again, and sanding more). I can tell you that for brushless motors that are difficult to tin the wires for (which must be done to shorten wire lengths or change connectors, both of which are necessary for my use case) are often ones where the wires coming out of the motor are additional lengths of the same wire wound up in the motor stator if this is what you’re talking about @buzmeg
My home soldering iron is a Pinecil, it does get up past 400C (or at least, claims to) but I think it might just be too small to sustain that heat?
My solder pot arrives today so I’ll start to try that out at home and see what success I have.
Okay, so the connections you are trying to work with are like the DC brushless stuff from RC racing. That’s definitely not enameled.
What the sanding is doing is scraping off junk–oxides, organics, etc. You can do the same thing with a good flux and it’s much less work. I believe we have a couple of syringes of very nice paste flux in the elab. Use it liberally.
Since those wires are capable of carrying away so much heat, you definitely need a soldering iron that can pump out a lot of power or has a lot of thermal mass. That is the benefit of a soldering pot–it has a massive thermal mass relative to the wire you are soldering.
Looks like I bought the right tool for the job then! It actually just arrived earlier today.
And yes, they are the exact same BLDC motors used in RC drones (I don’t know if RC cars use outrunners, I thought they mostly use inrunners?). Dys/FlashHobby/Turnigy D2836 if you’re interested in confirming it’s specs. This specific project is for combat robots (like BattleBots), I’m prepping a lot of spare weapon motors since my bot likes to burn them out in battles.
This also reminds me that I should really pick up some good flux paste for my home setup, I usually prefer flux marker but it’s not appropriate for this use case. The freebie flux paste I have doesn’t make a dent in whatever is coating these wires. Is there a specific flavor (brand and product name) of flux paste that’s really good for cutting through this stuff? And should I use BOTH flux paste AND a soldering pot?
Yes and no. A solder pot is certainly going to do a better job tinning them.
However, if you’re really doing BattleBots-type stuff, you probably want to get a good tool and do crimping instead. Crimping is a stronger mechnical bond than standard Tin-Lead solder joints. In addition, BattleBots stuff can throw around ENORMOUS bursts of energy which will can heat things up enough for solder to melt.
Do a good read through the NASA workmanship standards. There’s a LOT of good information in there: index
The weight class I’m competing in (3lb), soldering XT30/XT60 and bullet connectors and keeping decent slack, shock-mounting, and strain relief is more than enough to handle the current and mechanical stresses (given you’re doing proper soldering joints, anyway) assuming your bot is still together. Crimps do see a higher amount of use in the upper weight classes though.
Since the bots only operate for a maximum of 3 minutes and because weight/space efficiency is so important, we tend to skirt the lines of maximum current ratings that would definitely melt joints and connectors if operated at full power for 30 minutes straight. But still, making sure that the wires and ESCs are to-spec that the currents we operate at won’t put the solder melting in danger is key. Not really any way to avoid solder joints since the ESCs don’t have crimp connection points at all.
I’m going to email you. It sounds like you’d be a great addition to the electronics stewards helping with this stuff.
that would definitely melt joints and connectors if operated at full power for 30 minutes straight. But still, making sure that the wires and ESCs are to-spec that the currents we operate at won’t put the solder melting in danger is key. Not really any way to avoid solder joints since the ESCs don’t have crimp connection points at all.