Soldering questions

[vsefiream]

Soldering is similar and as much an art form as welding is. Both require patience, a little skill and proper prep.
I am an electrical-mechanical technician by trade and I have been soldering for 30+ years. I always manage to learn a new trick here or there so I thought I'd pass a few along here.
A couple things to keep in mind for prep.
IRONS:
Have a few irons, one is not right for all jobs. I like Weller but Ungars have proven to be just as good! I have a Weller 8200 gun for the heavy stuff like heavy gauge wire to motors or caps to a stock can. I have an Ungar Iron with a flat broad tip that I believe to be around a 45 or higher watt unit. I 'll dbl check that one when I get home, as it's been a pit box standby until I had to use it a little while back. I was very surprised with it and it's a great iron! Lastly I have a Weller 30watt pencil tip base unit used for small jobs. These three units were a very small investment but the right tool for the job is the first rule! Always have a damp sponge near by to clean the tips, just wipe the hot tip across the wet sponge to clean and it's like new. I always use a 60-40 rosin core solder for 99% of all jobs, I prefer Kester.
TOOLS:
I have a few other very handy tools;
- First - the above mentioned sponge, use it every time to clean the tip often. Always keep the tip and working surfaces clean
- Second - a tube of flux paste, I use Radio Shack stuff. I always dip anything bigger than a ~18 gauge wire in flux and then tin it, this is especially necessary on silver wire, copper wire is usually much more forgiving and will tin more easily. Make sure to fully tin the end and DO NOT BREATH IN THE FUMES!! Flux and solder fumes are dangerous.
- Third - a good solder sucker is very helpfull. A bulb is OK but the spring loaded syringe style are great. Keep them clean too as they tend to clog up over time. Along the same lines is a roll of copper braid. It's used to wick up left over solder like a sponge.
- Fourth - a good set of small tools consisting of small sharp tipped pliers, small wire cutters and a set of good wire strippers
- Lastly and not necessary is shrink wrap and a heat gun. I have become a fan of liquid electrical tape as of late. It works well and has a ton of uses, I even mix it with graphite to create traces to fix rear defrosters in the car and to make flexible circuit board traces!

So here are a few tips;
- Always clean and tin both surfaces to be joined. Remove all old solder and wire bits, use the solder sucker follwed by the copper braid.
- The surface will remain tinned but will need an application of new solder to make the joint. Heat the surface with the tip and apply a small amt of solder slowly to the tip/surface junction to promote heat transfer. Next, put solder to the surface until it melts on it, only a small amount is needed
- When joining only heat one surface, ie a motor tab, place the tinned wire on the tab and apply heat to the wire, it will melt and tranfer heat to the tab, then add a slight amount of solder to complete the joint, it should be a smooth, shiney, fully engaged joint. The solder should form a fillet from the wire to the tab. ie wire to wire, I usuallt lap joint as well, I lay both wires against each other on a suitable surface. I apply heat to both ends at the same time and let them flow together. This is always strong and conductive.
- When soldering to a motor can, file the surface first, apply flux to the site and tin with a high wattage gun. This will establish a solder joint to anchor the caps to. Solder the caps to the tabs using a smaller iron then twist the ends together and solder the ends to the can with the high wattage gun.

I hope this helps and FWIW I still cannot weld very well

[treystoys]

I had posted this over in the vintage electronics section as a reply, but it may get more visits here...more of the same really, but just my view point.

And this hits home too! lol

I hope this helps and FWIW I still cannot weld very well

I'v had a machine for 7 or 8 years now and have yet to master it


Edit post Reply with quote

Post Re: Tips for soldering wires onto used motors

I realize this is an older thread, but figured I'd give my input.

First, as the other guys have said, a higher wattage iron along with steady hands will end in a better joint. The main thing you want to really worry about too much heat on is circuit boards and battery cells, but since this is a basic motor rewire we'll leave that info as is I use a vintage Ungar UTC 300 (made by weller) 60 watt iron with a mid sized 3/16 tip to get the heat where I want it. I also forgo all the cleaning items such as wire brush and solvents and just use fresh rosin core solder and a little heat to remove anything old and gritty. If your re-soldering a factory joint, the likely hood of it being contaminated is slim unless you know it has gotten grease or oil on it.

That being said, I always solder over a non flammable surface, if not available, a few layers of aluminum foil works for a temp area.

To remove the old joint and solder, I hold the motor so the working joint is on an angle to drip off away from the motor after its heated. Pre tin your tip, and wipe that away either on a damp sponge or damp paper towel folded into a bout a 2" square. Also use small amounts of solder to test the tips heat before attempting to solder or de-solder anything (that's going to keep unwanted heat off the joint and keep it from soaking up into the rest of the component) with a good 4-6"s of solder (I use the thinner stuff) unwound I'll apply solder to the tip and when it will melt the instant it touches the tip no sooner then its ready to work. Now back again to the motor, if de-soldering, and the motor is in a jig or held firmly in place (the handles of a small needle nose pliers work well here, cradle the motor between them and put a rubber band around the open end, trust me you don't want a motor with the endbell heated to 500 degrees to land in your lap! lol) Ok sorry, hold the heated tip firmly against the joint, within 2-4 second the solder should start melting. If you've angled the joint down, you can basically scrape the solder and wire off after its started melting. When its off, you can keep the motor in that position and dab some solder on the joint to pre tin the area, at the same time if it looks dirty then use the solder like a cleaner and hold heat at one end of the joint and let the solder wick to the other side and fall off the tab until you have a nice layer of shiny solder on the tab.

Your ready to add a new wire now. For handling the tinning of and soldering wires, a piece of silicone fuel tubing an inch or so long that has a slit down one side can be put over the wire as an insulator to allow you to hold the wire with your fingers without melting your finger prints off I usually set the solder spool so that the solder is extended facing me and pull it up and make it into an arc so its one less thing to handle. This leaves the wire in one hand and the iron in the other. I remove only the amount of wire insulation needed to solder that particular joint. No need to have uncovered wire exposed anywhere not needed. Anyhow with the wire stripped, I always twist the exposed wire end to keep it from fraying I hold the exposed wire to the top of the iron (hot air rises ) touch the solder to the side or top of the wire and let the solder soak into it. After the tinning process inspect your work and make sure the solder has soaked through entirely. If not re-tin using the step above. If you find you are unable to get the wire tined completely, it may be contaminated or old and handled too much, replace it with a new wire and try again.

Once tined through and through its time to make the connection. Some guys use a jig with small alligator clips to hold things in place, but I use my fingers and if needed the fuel tube to insulate a little. So holding the wire on the tinned motor tab, apply heat to the tinned wire with pressure enough to melt solder and push the joints together. Once melted its very important to keep the cooling joint perfectly still. A cold joint will look very dull and brittle and will very likely fail once current (heat) is flowing through. A good joint will "appear" solid and shinny, and will hold heat up too the melting point of the solder used.

I am new here, however I've been actively involved in rc for probably 30 years, most of those soldering I hope I wasn't too long, however I wanted to be as detailed as possible for the guys attempting to solder for the first time.

Thanks for reading!!

Trey