I am building a robot arm, but I have i'm not that good at soldering and I need some tips

Question

If there are any tips that will help me, or at least make it easier for me that would be great. I'm only 14, but having many problems with my soldering. I don't know what it is, but I can never solder right.

PLEASE, if you have any tips reply back ASAP it would be great.

jw0752 · Accepted Answer

Hi Slayton,

It is difficult to know what to tell you without more information. Perhaps you can send a picture of your work that you feel is bad and we can give you some suggestions based on what we see. In general I would say that you should frequently clean and re-tin the tip. I use a wire brush that I always brush away from myself as it will throw little blobs of solder. After it is clean I put on a new coat of solder. Next I place the tip on the joint to be soldered and apply a little solder by directing the solder into the space between the iron tip and the joint. Once the solder flows into the joint I remove the solder wire and a second later I remove the solder iron tip from the joint. If you have had success the solder joint will look like a little mountain with the wire coming out the top. It should also appear fairly shiny if you are using lead solder and it may be a little dull if you are using lead free. Send a picture and you may get some better advice from the other guys on the forum. Keep trying!

John

jw0752 · Answer

Hi Slayton,

For light applications I use a solder iron with a tip temp of about 270 C. For larger connections I use 310 C. If you solder iron doesn't have settings try to find one that has 25 Watts as this should put you in the comfort zone. For a beginner I would use a good quality lead solder as opposed to the lead free. It melts at a lower temp and in my opinion just works better. Of course I am an old guy and set in my ways and it will be difficult for them to pry my lead solder 60/40 away from me. Hopefully some of the other guys will chime in here with better and more current suggestions to help you.

John

brotherbob · Answer

Hi Slayton, A couple more points for consideration... 1) The solder iron tip is very important, crappy ones just don't work (and may cause serious heart burn). A good solder tip has a copper, core solder eats copper for breakfast so the copper should be surrounded by iron for durability. Solder doesn't like iron, so the last little part of the iron tip is coated with chromium or other stuff that liquid solder will stick to. When buying tips its difficult to tell what you're getting, but the no brainer is to go with "Weller" tips, they are all good. The shape and size of the tip along with the power of the soldering iron are also important but there are too many options to go into here. For electronics a simple starting point is a soldering iron around 50 watts and a tip shaped like a sharpened pencil. 2) When making a solder joint there are at least three things that make contact, the two things to be joined and the soldering iron tip, not counting the solder wire in your hand. All three should be coated with just the right amount of solder before you attempt to join them. This coating process is called "tinning". Some components and Printed Circuit Boards (PCB) come already tinned. It is often useful to add more solder to the pre-tinned components as it is too thin, designed to inhibit corrosion rather than facilitate soldering. Before tinning the parts you need to make sure they are clean, bare copper or shinny tin (copper corrodes all by itself depending on ambient conditions and this needs to be removed, it is very hard to tell by eye ball when it needs to be cleaned). For cleaning you can use abrasion or chemicals. Pre tinned stuff usually does not need to be cleaned. 3) To make a good solder joint all three parts must be above the melting point of solder, if not its called a "cold solder joint" and you're in trouble, it looks good to the untrained eye, but does not perform well electrically and breaks easily. Cold solder joints occur when the solder melts but the parts weren't above melting temperature or not properly cleaned. 4) Good electronic soldering wire. Electronic solder wire is hollow where the hollow contains rosin that serves to clean the joint and make the liquid solder flow better. Solder wire too thin is better than too thick. The solder should be less than half as thick as the solder tip point (assuming that by some magic you have just the right sized tip, only someone with too much money has all the right sized and shaped tips). 5) Fan to gently blow away the "poisonous" smoke from the burning rosin (Good idea to vent outside, until your neighbours complain). 6) Eye protection is useful as rosin sometimes causes spitting (It doesn't matter if the burning rosin gets on your hands, you're a tough guy, right?). 7) Squeeze Bottle of water to extinguish the fires that your mother will never know about. A good soldering process guarantees that a good joint is made (famous last words). 8) A simple process, tin all parts to be joined. Place tinned parts to be joined so they are touching and held in place (requires a good imagination without spending the money on a third hand). Soldering iron up to temperature (test by swiping solder wire across the tip and observe instant melting). Clean tip with wet sponge, tin tip. Solder wire in other hand, place iron tip on both parts simultaneously and observe that the tinning on both parts melt. Touch solder wire to one of the parts close to where the tip is making contact but do not touch the tip. Observe that solder wire melts (This almost guarantees that all parts are up to temperature and you won't get a cold solder joint). Remove solder wire and tip and observe solder joint changing from liquid to solid. The rosin from the hollow core solder wire will leave nasty looking black patches on your joint this may be sort of cleaned with water but rosin cleaner works best but most people don't clean the joints unless some quality assurance inspector is looking over their shoulder. Most electronics are damaged by excess heat from soldering, so speed in moderation is a good thing. Soldering is almost an art form, so most importantly, have fun. And if you don't, at least leave some good burn marks in the table so they will know you were there...

Sean_Miller · Answer

Dad thought: Doing this at 14 will make you an amazing adult. Keep it up.

There are a lot of good tutorials on YouTube. So, I'd spend a little time there.

My thoughts are little repetitive to other posters, but here's my tips and tricks:

Look at your tip right now and assess if it has chunks missing out of it or looks generally worse for wear. If so, get a new tip to start your habits fresh.
Make sure you are soldering on the correct side of the board. Some boards have copper soldering pads only on one side. You should be soldering on the side that has little copper circles showing.
Get soldering iron tinning compound. It comes in a small tin container the size of a quarter. It readily puts an even coat of solder on the tip (aka tins the tip) just by dipping in it once your iron is hot.
Use a wet sponge to wipe the tip after each soldered joint to get any globs of solder off.
Get a soldering iron tip cleaner for under $5. It looks like a little dome container with strands of brass balled up in it. I quickly stab my solder tip in it repeatedly after a session to clean it up to prevent oxides from forming.
This is the big one when you think you've done it all correctly: if you suspect you do not have a very hot iron, cut your component leads short (no more than 1/4 should remain sticking out the side your soldering) prior to soldering. For example, if you let 2 inches of a resistor's leads hang out in the air, the heat from the iron will dissipate down the wire resulting in it hard to get the joint up to temperature. The smaller the lead, the quicker the joint heats which is preferred.
My actual application of solder is hard to describe, but I'll try: Place the tip on the pad and wire at the same time and then bring solder to the opposite side of the iron within a second. If it doesn't melt, I often cheat and quickly touch the solder wire to the solder tip and quickly move it around to the opposite side of the wire. It will suck in fast, so lift the solder wire off followed by the tip quickly. It's just a love tap while the solder is still touching the pad and wire. If you leave the iron on the copper too long, you burn off the solder mask and it can then get a little goofy. Here is a video of me doing it - start at 2:49. You may need to slow down the video.
Sometimes ugly is better than perfection. If I have continuity, but it doesn't look like a perfect silver Hershey's kiss, I move on. Typically, if I try to perfect it, all the flux has burned out of the original solder, I'll burn up the solder mask, the solder wants to stick to the tip more than it does the board, and the copper solder pad will separate from the board. Then it's real ugly. So, if the previous step doesn't look perfect, accept it if it has continuity and respect that your board has true grit and character.

brotherbob · Answer

Hi Sean, I like that " re-tinned pre-tinned" sounds like a lyric from a song. There are a couple of possible reasons for re-tinning pre-tinned components: 1) The pre-tinned is dirty or corroded, here in North America this really doesn't happen, but exposure to high humidity, in say the tropics will cause nasty tinning corrosion in no time at all, and a compromised supply chain can easily make it dirty. So the worst of both worlds would be to buy from some mom and pop shop in the tropics where you would almost be guaranteed of dirt and corrosion. 2) My favourite reason belongs in the art of the solder technique. When you first touch your tinned solder tip to the two components to be soldered, you want to be able to see the pre-tinning on all three items flow together (confirming that a good joint has formed) just before you add the final dollop of solder wire to the mix just for good measure.

Sean_Miller · Answer

The Arduino is probably the most popular small prototyping board that's been around about a decade. It has a huge community base with prewritten code libraries to talk to just about every sensor you can think of. Go to Arduino.cc to learn all about it. The Arduino is coded with the C programming language. The Netduino has the same pins as the Arduino. It just has more speed and ram and is programmed with C# instead. I prefer it for things like R2D2 where I need multiple code threads interrogating sensors at the same time. However, it does not have the user community that Arduino does. You definitely should get an Arduino. It will be able to be the brains behind your robot arm (and legs and head if you add them). See ya', Sean

mcb1 · Answer

This probably the best guide I've seen on the internet. https://learn.adafruit.com/adafruit-guide-excellent-soldering/preparation Don't worry about the actual soldering iron they use, however a lower wattage as has been suggested with a good clean tip is essential. It's a art and when done right can look very easy, but practice and it will come. The next advice is be able to identify the difference between a good joint, and a poor one, and try to understand why. Once you can understand the why, you'll avoid making the bad joints. Mark

Sean_Miller · Answer

Up until I hit 40, I only soldered to connect car stereo speakers at best. I got into the hobby when my son (6 at the time) got it in my head to build an R2D2. Since R2D2, we've had some neat things: Dadbot -a PVC robot that allows you to control the robot over the internet. Uses a Netduino 3 Wifi Tennis Ball Pitch Machine - this does just what it says. 3D printed parts. Mobile phone garage door opener - uses a web IP camera to look at the garage door and open or close it by your mobile phone. Uses an adafruit trinket Door alarm - device that when a door is opened, it sends an alert to my cell phone. Uses the EPS8266 Car Backup Camera on a turrent - just finished this one. It is a backup camera that can be rotated to help see down the lanes of a parking lot. It uses an adafruit trinket. Raising Awesome Alexa Skill: this was software only. I wanted to learn how to make an Amazon Echo Skill so we made one for our YouTube channel. You can follow our builds on " Raising Awesome " channel of YouTube. See ya, Sean

brotherbob · Answer

Yes pre-tin everything before making a solder joint. Tinning is also used to reduce the effect over time of corrosion. I suspect you might be referring to inserting a component into a socket and then soldering the component in the socket. If doing that, you can't pre-tin the socket and pre-tinning the component will change the dimensions of the component leads to the point where it may not properly fit in the socket. On the other hand can't figure why use solder in a socket. I have a hard time recollecting seeing a "proper" component or PCB that didn't come already pre-tinned. I have seen cheap below consumer grade PCB (non fiberglass) that weren't pre-tinned (always assumed they were from some fly by night mom and pop jobber shop in China under contract to some bozo that knows their customers have no recourse when the product fails). Can't recall ever seeing a fiberglass PCB that wasn't pre-tinned and usually with solder mask. Its also a joy to work with pre-tinned copper wire with teflon insulation. I have always assumed that the pre-tinned stuff was applied using electro-plating tech, on inspection it sure looks like it. When handled properly (low humidity and no touching) the electro-plated stuff stays clean enough that you can go directly to soldering. I have always assumed that wave soldering machines required pre-tinned components and have never knowingly ordered a component that wasn't pre-tinned. You have to have a high tolerance for re-work (re-work is the term used when fixing something that failed final test) to chance using anything that isn't pre-tinned. The problem with re-work, is not the fixing time and hassle, its the time and delay to debug and fault isolate to the bad solder joint. Besides joint integrity, another major advantage of pre-tinning, is that on heat sensitive components (think pretty much all integrated circuits) it is the best way to avoid overheating when making the final solder joint. The final joint can be made faster when pre-tinned thus reducing heat transfer to the heat sensitive component. Tinning by hand can also reduce heat transfer on each component individually and will also reduce heat transfer compared to soldering with all components not pre-tinned. I'm wondering what issues you've had using pre-tinned components?

Sean_Miller · Answer

Sorry, reading my post again, I see I wasn't too clear. I took your step 2 as instructing to re-tin the pre-tinned components. I have never manually re-tinned pre-tinned components. I also haven't pre-tinned brass headers or socket pins. The only thing I have ever pre-tinned is wire. I don't disagree with the recommendation of re-tinning pre-tinning. I just didn't learn to do so and have not had any issues with my joints. Sorry, Slayton, if I've caused confusion. -Sean

I am building a robot arm, but I have i'm not that good at soldering and I need some tips

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