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

     Thanks again for the help.

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

     When you sent the video early I went to it and watched a few videos. And yes, I subscribed. You and your son have made some awesome stuff. Do you know what an Arduino is? If you do, can you give some tips on programming, because I don't know anything about programming. I see that you use the Netduino, but I don't know what that is.

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

     Thank you for telling me about the website. I already had the Arduino, but I have know Idea how to program it. Is there an easier way to know how to program the Arduino.

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...

Hi Bob,

This is an awesome addition to this thread with lots of good advice.

John

Thank you, you were very helpful and funny. And yes I'm a tough guy. I have a weird mix of hobbies like football, math, science, engineering, etc.

Are you saying just pretinning resistors and capacitors, or are you saying to pre-tin your chips and socket pins as well?

I've never done that without issue.  I actually do not pre-tin anything except for wire since it is typically very long and not as quick to get up to temp.

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?