Soldering Help

[wv2win]

I have a 40 watt Weller soldering iron. I'm practicing my soldering using 24 gauge wire on a radio shack grid-style PC board: Grid-Style PC Board with 371 Holes - RadioShack.com. I'm using .032 60/40 Rosin-Core-Solder. I'm using the needle tip on the soldering iron which I've cleaned on the water dampened sponge as well as dipping it in Lenox Tinning Flux. I also dip the ends of the wire in the tinning flux.

I've been told to not put the solder on the iron but instead put the tip of the iron on the wire for a 4-5 seconds and then touch the solder to the wire. When I do this it doesn't melt the solder. When I tried a second wire I had set up, I believe I touched the soldering iron as much on the PC board than the wire and the solder seemed to melt better. Now I am a little confused on where exactly to hold the tip of the iron and for how long and where to apply the solder so it will melt properly.

Thanks for any advice.

 

[squirrel64]

Hey WV,, Pretty good video here explaining tip placement... YouTube - How and WHY to Solder Correctly

 

[Throat hit]

I have never not tinned the tip and if the wire is good clean stuff just strip it and tin it right away. Ie put some solder on the tip quite a bit and flick it off with a quick snap of the wrist not on the sponge. The tip is tinned now get on it and put tip solder and wire togther in a second or to the wire should take run tip and solder down the wire to tin the length you want and bingo. If the solder is good quality you wont need extra flux. Tin your wires first and then stuff the board. Tin the tip again and solder the tinned wire to the pcb using more solder. The small amount of solder on the tip transfers heat between it and the object being heated a dry tip is very hard work and not good practice IMHO. Regards Rob Ex electronics/antenna developer and radio ham.

 

[wv2win]

Thank you for the video, very informative. And thanks for the tips, Thoat hit. Some told me to use this tinning flux: LENOX | TINNING FLUX . Is this the same as "tinning" the iron tip with solder as well as the wire ends before you solder?

 

[AttyPops]

Don't get too hung up on the tinning flux right now....you tinned the tip with solder. It's good to have flux but like TH said, it's mostly about heat. Your solder has flux. Many parts are actually pre-tinned. The iron can be tinned with the solder.

You have to heat the parts, and melt to solder onto the parts. Another way to say that... the parts melt the solder, the iron heats the parts. No cold joints that way.

A bit of solder on the iron tip helps the heat transfer to the parts. Flux is used to prep the metal and remove oxides (invisible) from the metal. The rosin core solder will help clean the parts - the rosin is a flux.

That flux is plumbing flux I think..... now, in general, plumbing and electronics use different fluxes.... plumbing uses acid flux, electronics rosin flux. So...IDK about that flux. I think it has some solder in it too. Best to do some research on it.

Now, tinning in general just refers to pre-coating the parts with solder. Use the solder to pre-coat the heated parts if you wish. Often, I don't even tin the wires... kind of depends on the joint. Heating, say, a button and a wire connection, and applying flux/solder once is all it often takes. As long as you don't eat a greasy slice of pizza, wipe the grease on the wire and try to solder it )) you'll be fine. You also have to be careful that you don't over-heat the PCB or the little copper pads will lift off.

For what it's worth: I recommend lead-free solder, but that's me. Leaded solder is somewhat easier to work with, but is bad for the environment. Wash your hands, and use a fan so as to not breath lead-vapor. Don't smoke around lead solder also, it's known to combine with lead fumes and produce even more nasty stuff. I have some and use it on occasion for particularly nasty joints, but in general I avoid it.

 

[AC0J]

I tend to like a higher wattage solder iron except for very delicate parts. I also prefer the flat tips over the pointed ones. It heats the surfaces better. Most solder has a flux core, so the use of additional flux is not needed. Lead free solder is NOT perfected yet. It tends to make a lot of "cold" solder joints. Look at the X-boxes common lead free solder failures. Practice makes perfect. get the tip "wet" with a little solder, hold it to the parts until you see it start to flow into the wire and touch your solder to the connection. Keep the heat there until it flows evenly. If you take the Iron away to quick, you will have a dull look to the connection and have a weak joint. A proper solder connection will be bright and shiney.

 

[AttyPops]

I would have thought x-boxes where flow-soldered (or hot air, or whatever they use now).... Anyway, I think the trade-off between not having nasty lead fumes around is a good one. But I'm hand soldering. Like I said, if you do use lead solder, just take the precautions. I still suggest lead-free solder for these types of things. AC0J is correct about the shiny result as one visual test.. that will ensure that you get the solder hot enough (lead-free needs a little more heat). A 40W iron s/b more than enough. I usually work around 30ish watts.

P.S. How many more holes left on that 371 hole board? Keep practicing!

 

[Throat hit]

I used to make boards up every day, day In day out and soldering is like riding a bike . Well I had not used an Iron for a bit and tried to solder a 10 mm cable to a lug. I failed so tried some solder with lead in and it worked as normal. The lead free needs a bit more heat and I dont think you are supposed to mix lead and lead free if fixing older boards. It sets and looks like dry joints half the time to. Sorry to witter on but it is what I do best.

 

[wv2win]

Thanks guys for the tips! I especially appreciate the part about how the solder should look when done correctly (shiney).

Another questions if you all don't mind. I have some 20 gauge solid wire that I have practiced with along with the 22 gauge stranded wire. In making a 5 volt box mod, could I use the 20 gauge wire instead of the stranded wire? It seems easier to solder and stay in place.

 

[DaveP]

In addition to what everyone said, a mechanical contact is necessary to transfer heat. You can't just touch and get good heat transfer. Press the iron to the pad and the component lead with enough pressure to ensure that the parts get hot (it should only take 2 or 3 seconds) before you push the wire into the point where the iron meets the junction of all the parts.

Unless this is a practice board, I'd practice on two wires twisted together. Lay them down on something you can use as a backboard and solder them together. You want to learn on something you can discard afterward! Then you can work on the expensive parts.

 

[AC0J]

I would have thought x-boxes where flow-soldered (or hot air, or whatever they use now).... Anyway, I think the trade-off between not having nasty lead fumes around is a good one. But I'm hand soldering. Like I said, if you do use lead solder, just take the precautions. I still suggest lead-free solder for these types of things. AC0J is correct about the shiny result as one visual test.. that will ensure that you get the solder hot enough (lead-free needs a little more heat). A 40W iron s/b more than enough. I usually work around 30ish watts.

P.S. How many more holes left on that 371 hole board? Keep practicing!

They probably are flow soldered, BUT the lead free solder doesnt stand up to the temperature changes and eventually cracks. This happens to a lot of electronics that are made with lead free solder.

 

[Throat hit]

get an old circuit from a scrap item Take some parts off the board you will soon learn about the time you have to be on there(dwell time) and how hard to press. Lead free joints can look dull even when good so check your solder to see which type it is as you may be being hard on yourself.

 

[WillyB]

For things like PCB boards and the atty connector shells a little cleaning with steel wool helps.

 

[rannox]

A cool trick for tinning wire, wrap thin solder around the wire u want to tin, hold tip on the wire for a sec, solder melts, wire is fully tinned.

 

[wv2win]

Thanks for all the help. I got the 5 volt box mod together and ....it doesn't work! Now I have to try and figure out where the weak link is. I have a multi-meter, I just have to figure out how to test each connection with it to figure out which one is the problem.