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Topic: Soldering Temp / Fixing Trace (Read 10548 times) previous topic - next topic

adele

Hello,

I have been having a problem learning to solder correctly. I have an Elenco kit and it tells me that the solder included with the kit should be 700F. I set my soldering station to 375C.

I have a lot of problems getting the solder to flow correctly. The solder never melts unless I actually touch it to the tip of the soldering iron. The Elenco book tells me not to do that.

Once I get the part soldered it's not very stable. I just soldered a switch to the board a little bit ago, and the round silver area that I'm supposed to solder to, came right off of the board. Now it just looks brown and won't hold solder anymore.

I've watched a lot of YouTube videos but I'm clearly still doing something wrong.

Also, is there anyway to fix the board that I have, or is it just junk now?

I also think that I might be using the wrong type of soldering station. I tried using one of those small soldering irons from Radio Shack but it was not melting the solder. I thought it wasn't getting hot enough for lead free solder.

So I am using this soldering station, but it's still not working well for me. I think the amps might be too high on it.

Thanks!

ghlawrence2000

#1
Dec 02, 2014, 05:26 am Last Edit: Dec 02, 2014, 05:37 am by ghlawrence2000
If you are using a tiny pencil tip, there will be a significant initial drop in temperature when you touch the iron to the area to be soldered. The smaller the tip, the bigger the drop in temperature.

It is not that you should not touch the tip of the iron with solder, but ideally, you will have enough solder on the tip of your iron to form a thermal bond with the area you wish to solder. This will allow heat transfer into the joint, which you then apply the solder to. If the temperature is well matched to the melting point of your solder, and size of tip is large enough to supply enough heat to the body of metal you are trying to solder, the solder will melt and spread(flow).

There are several things that can cause you problems, dirt, insufficient heat transfer, mismatched iron/solder temperatures.

I suspect you are new to soldering, and you have asked a sensible question! You summarised that your solder is 700F = 371C  so chose a setting on your soldering iron of 375C. That would seem absolutely logical in theory.

You have not said exactly which Elenco soldering station you have, or exactly which solder you have, as such there are many potential points to address here.

Using the Amazon iron as an example, of the 5 tips included with that iron, my feeling is that the 2.4D tip (Number 4) would be the most suitable choice, based on it is big enough to enable heat transfer but small enough to not be too large if soldering IC legs for example. I would have a better idea of which to recommend to you if I saw the tips in my hand, it may be that number 3 is suitable also, and would achieve a higher heat transfer. If number 3 is not too big for what you are trying to solder, try that one. Tips 1 and 2 are simply too small for general purpose electronic soldering, as heat loss is too high, and transfer too low.

Quality and type of solder varies tremendously and has a dramatic effect on the soldered joint. Everybody has gone 'lead free' mad, but lead free is not as easy for a beginner as traditional lead solder. I have had a soldering iron in my hand for about 40 years, and I am still using the same solder. It is the choice of professionals.  Expensive, but ease and quality of finished joint speaks for itself. The solder I am referring to is Ersin multicore 60/40 activated rosin flux. http://www.easyflip.co.uk/Farnell_element14_2013_UK/ebook.html?page=3620
The 60/40 505 No-Clean Flux or 60/40 511 No-Clean Flux types would be my recommendation.

Now we have identified a good quality suitable solder, let me draw your attention to some of the important points. Specifically for the 511. "High wetting ability - good spread on copper, brass and nickel - for fast soldering". You can just watch it spread almost instantly! The main point I wish to draw your attention to though, is the melting point of the solder, and the suggested iron temperature!! Then you will see why your initial guess at setting you iron was WAY OFF the mark...... For the 511 multicore solder the melting point is 180C with an iron tip temperature recommendation of 308C.

So I think now you can see, as is typical with these bundled irons and solders they are a good price and a good introduction to general purpose soldering, but some refinement will make your experience so much better. I could not see an actual specification for the solder Elenco supply, and you didn't specify which particular model of Elenco kit you had. So my recommendation would be get some good quality solder such as that I mentioned, (activated rosin cored 60/40 leaded solder) not necessarily ersin multicore brand. And get the largest possible tip size suitable for the style of soldering you are planning to work on.

Flux, can compensate for some dirtiness, but most important with soldering, is cleanliness of the joint!

What concerns me most about your statement of 700F solder, you run the risk of damaging IC's, transistors, Arduinos!, anything really if you are working at those sorts of temperatures. My main recommendation to you, get some suitable solder.

Regards,

Graham
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adele

#2
Dec 02, 2014, 05:53 am Last Edit: Dec 02, 2014, 05:56 am by adele
Thanks for your in-depth reply. I am looking at the solder page you gave me. I have to buy my products from Mouser.com. Can you recommend any solder product from their Web site that would work?

Lastly, is there any way to fix the board that I have, or do I just need to buy a new one? I guess the soldering iron was too hot and it caused the metal on the board to fall off, so now there is nothing for me to solder the switch to.

EDIT: One other question. Is there a way for me to clean the board before I start soldering to make sure that the solder will stick? I saw some people on YouTube using alcohol. Is that okay to use?

DVDdoug

#3
Dec 02, 2014, 06:02 am Last Edit: Dec 02, 2014, 06:13 am by DVDdoug
I assume you are using flux-core solder, but some additional flux will often help.

Where I work, we use water soluble flux and lead-free solder.   It isn't as easy to work with as regular-old tin/lead solder and rosin-flux.    I don't have much experience with no-clean flux.

Quote
Lastly, is there any way to fix the board that I have, or do I just need to buy a new one?
Sometimes you can replace a trace with wire.    But, that won't mechanically hold the switch and it's ugly.    If it's just a small break in a trace, you can often bridge the break with a piece of small-gauge bus wire, or wire-wrap wire.    If the pad is damaged or missing the repair is more messy.

Quote
One other question. Is there a way for me to clean the board before soldering...?
Alcohol won't hurt but it's not that effective.  The flux has some "cleaning action" when heated, but if there is some corrosion you may need to mechanically scrape the copper with an X-Acto knife or maybe steel wool.   

ghlawrence2000

I guess the soldering iron was too hot and it caused the metal on the board to fall off, so now there is nothing for me to solder the switch to.
:( Without knowing what board, and how much damage, I cannot comment whether any part of it is salvageable, but almost certainly excess heat would not have helped you.

I cannot get on with the mouser website, and being forced to the UK site which I suspect is not where you are from.

You need, Multicore, activated Rosin flux (2 or 3 %) 60/40 tin/lead, I would suggest 0.8 -1.0mm ( no idea what that is in inches!) I could only see 1lb rolls on mouser which is a HUGE amount of solder to buy as a trial and error exercise. Can you not order a smaller quantity from Amazon? Such as.... http://www.amazon.com/Kester-Pocket-Pack-Solder-0-031/dp/B00068IJNQ/ref=sr_1_4?ie=UTF8&qid=1417497043&sr=8-4&keywords=60+40+solder+rosin+core

Once you have found a product that is suitable and you can get on with it, then you can buy a larger quantity.  :) Sorry I couldn't help further. My preference is the ersin multicore, I cannot really comment on what is available in your country. Although you don't need to go for the most expensive, definitely don't go for the cheapest (chinese) brands.... It is false economy!

Good luck.

Regards,

Graham
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KenF

I'd suggest you avoid the lead free solder.  The leaded solder is far easier to work with and unless you eat the stuff it's not going to poison you.

Foggiest

I'd suggest you avoid the lead free solder.  The leaded solder is far easier to work with and unless you eat the stuff it's not going to poison you.
Seconded loudly!

Get some rosin multicore solder, get 63/37 mix.

Then practice on junk stuff until your technique is right.
Pads coming off can be too high temperature, but it can also be heavy handed or taking too long on the pads.

Get some flux too (flux pen or gel syringe), and some isopropyl alcohol.

Sooo
Clean board in the IPA, pads should be nice and shiny with no grease or oil residues.
Place component, apply extra flux (flux pen).
Clean the tip of iron on a dry tissue, then wet it with fresh solder.(be quick)
Place the tip so that the blob of solder touches both the pad and the component.(be quick)
Push fresh solder into the molten blob and then onto the pad... it should flow quickly.(be quick but thorough and observant)
Lift iron, rinse and repeat until it becomes second nature!

The joint should be shiny and clean, with some flux on, not burnt offerings!(no brown or black scum and dry powdery dull solder).

NOTE! Start the iron too low 150C, and slowly work out at what temp reading the solder starts to melt.
This will help identify solder melting temp, and any offset that the station has (once you know the correct temp you are fine!)
The solder ratio I stated earlier is for a eutectic mix, this has a lower temp and will alloy and lower the temp of other solders too... can go surprisingly low 230C should be around the mark.


You keep stating Mouser as point of purchase, no idea where and what, if in Europe, TME have genuine products and are supersonic fast delivery... just take your time on the website as it is like some browser based puzzle game!

CrossRoads

Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

adele

Thanks everyone. I am going to try all of these tips and see what happens.

I thought it was the fumes of the leaded solder that you had to worry about? I have stayed away from it because people keep saying its really bad.

Also, when I said the traces were damaged, I think I used the wrong term. I looked online and it appears what happened is that the soldering pad lifted off of the board. I could post a picture but it's really tiny and really won't show what I'm talking about.

So I am wondering if the solder pad that lifted off of the board, can be fixed, so I can re-solder the switch back onto the board.

Thanks for providing me with so many useful tips.

larryd

Quote
So I am wondering if the solder pad that lifted off of the board, can be fixed
Tack a pad off a scrap PCB using extra heat.
Move it to the place you want to repair and carefully solder it in place.
Make sure you have continuity from the pad to all traces top and bottom.
Use some pre-tinned wire to make continuity if there is none. (I have use stripped 30AWG wire used for wire wrapping)
Clean the result with alcohol and a Q tip.
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polymorph

Lead does not go to vapor at soldering temperatures. The smoke from soldering is the flux. You do NOT want to breath it in, so don't.

I am going to pile on and say, get some 63/37 leaded solder. Forget lead free, it is very touchy. You must use a lot of extra flux for lead free solder.

700F is NOT going to burn up your boards! I've been working on electronics professionally for many years, and for through-hole components I almost exclusively used 800F. I use lower temps with surface mount, but I'm still up around 700F.

If you lower the tip temperature too much, you end up spending a lot more time applying heat, and  are then more likely to damage the parts or the PCB.

You may be able to simply clean off the brown stuff from the trace. Isopropyl was mentioned. If the pad around the hole is actually torn off, you may find that you can just bend the component lead over onto the trace.
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Tkrain

If you've got the part secured (with joints on the other pads, with superglue, with some ugly kludge, whatever) but still don't have continuity on the lead/pad that you lifted, you can often follow the trace to find what that connection leads to on the board and run a small gauge wire from the lead to the next connection point.  Just be sure that your new "trace" doesn't bridge to other pads/locations that it isn't supposed to.  Pulled pads are something that even the most experienced solderers encounter from time to time. We've had some boards at our facility that get pads pulled just because you looked at them funny.  

As has been mentioned before, the big things here are time and temperature.  Both should be as low as possible to achieve the joint.   Too high of a temperature or too long holding the iron to the joint can burn out LEDs, ruin ICs, etc, not to mention what you've already discovered: detach pads from their trace connections.

The fumes you mentioned are bad for you regardless of whether you are using conventional leaded solder or lead-free.  You don't want to be breathing either solder mixture's fumes ever.  Get a small fan (some people wire PC cooling fans, we mostly use little personal fans) pointed away from where you are soldering.  You don't want a strong breeze, just a little draft that can pull the solder fumes away from you.  You don't want to cool the solder, just draw away the fumes.  

At our facility, we usually bake the boards at fairly low temperature, and make sure we keep our hands clean before handling them.  Most PCBs can be cleaned with hot water before soldering (but they need to be completely dry before soldering!!!!!).  If we do pre-clean the boards, we blow the water off with compressed air and bake them for an hour in a circulating oven.  

When you're first learning to solder, flux is your friend!  You should be using a solder with a flux core, but it usually never hurts to apply a little flux to the lead and pad before soldering.  That being said, most flux solutions are corrosive over time, so you need to clean the board afterwards to get rid of it.   There are "no clean" fluxes (both liquid and in some solder cores) that eliminate the need to clean the board.  

adele

Thanks.

I ordered 2 parts:

http://www.mouser.com/Search/ProductDetail.aspx?R=835-Pvirtualkey59020000virtualkey590-835-P

http://www.mouser.com/Search/ProductDetail.aspx?R=4884-227Gvirtualkey59020000virtualkey590-4884-227G

I am still going to use the lead-free solder to practice with because I have a lot of it. I was also able to get 1,000 0 Ohm resistors for $8 so I am going to use those to practice with. So I have something to solder.

I'm also going to use a bigger tip on my soldering iron. The tip I am using is very tiny. It actually fits right into the socket on a breadboard. It's like a small pin, so it sounds like that is another reason why my soldering is failing.

I have a fume extractor setup on my desk already. I can put it right on top of my PC board, so almost all of the smoke goes directly up and into it.

The switch is still attached to the board, and it still works. It just wobbles back and forth because the pads lifted. I was going to try using a hot glue gun over the solder to see if it will stick back onto the board. I don't know if that will damage anything. I don't think hot glue is conductive.

I don't like the idea of using lead solder but I am going to try it... Since that it what everyone recommends.

larryd

Quote
It just wobbles back and forth
5 Minute Epoxy
No technical PMs.
If you are asked a question, please respond with an answer.
If you are asked for more information, please supply it.
If you need clarification, ask for help.

ghlawrence2000

#14
Dec 03, 2014, 02:50 am Last Edit: Dec 03, 2014, 03:05 am by ghlawrence2000
I don't like the idea of using lead solder but I am going to try it... Since that it what everyone recommends.
There is a very good reason everyone recommends it........... The lead free stuff is Sh** and a REAL nightmare to use compared to leaded and that is for people that have been soldering all their lives. Lol.

What is your main reason why you don't you like the idea? If you live in a house with plumbing older than 1986, your drinking water pipes were almost certainly soldered with leaded solder, remember that every time you have a drink ;)

Regards,

Graham

Edit, for a less biased opinion, read the following article (which sounds great the way it is written!), and then read the user comments below  ;)  :smiley-roll-blue: How to go green with lead free solder
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