Soldering How-To

[and_]

Re: Soldering How-To

hello
i have 220v solder. if i heat it up and unplugg it can i use it to recap my mobo or there is still a risk to burn it down (electric charge) ?

[willawake]

Re: Soldering How-To

what is the watts of your iron? i understand that 220V is the mains voltage of your iron.

[Rainbow]

Re: Soldering How-To

I use AC powered 25W soldering iron - the tip is grounded so that should be safe. There's no temperature control, but who cares if it works fine anyway? I even use a 75W "pistol" type iron - for mosfets which need lots of heat - that one is not grounded but never killed anything.

[willawake]

Re: Soldering How-To

25W is quite small my friend, your tip must be quite efficient. sometimes i have difficulty with my 60w on some boards.

[Jay_EE]

Re: DE-Soldering How-To

Okay, I'm going to give my tips on desoldering in here. I'll give you the 'What has always worked best for me' tips. Being an Electronics Engineer gives me a little insight into this, you could say.

First off, TRY NOT TO SCRAPE THE HOLES CLEAN WITH AN EXACTO KNIFE. you could very easily damage one of the leads on the INSIDE OF THE VIA for the thru-hole component. Some components can connect to multiple layers of the board (there are more layers than just the top and bottom surfaces) You do not want to damage one of those inner layers, because there is NO CHANCE of fixing that kind of mistake unless you have a detailed diagram of the boards etches.

Now, for the tips:

First, I suggest you remove the leads from the capacitor. Capacitors in general have weak leads that go into the case. Sometimes you can just pull a capacitor off the board leaving just the leads left on the board. This makes removal somewhat easier, as you can now grab the lead with a pair of needle nose plyers, one at a time. Pull the capacitor straight upwards and it should lose its leads. If it is taking too much force (it should not be strenuous), then just leave it be and we'll deal with the whole capacitor at once. I like to remove the caps by pulling them off their leads because I have found that sometimes rocking a capacitor can break nearby components (ie, traces, small surface mount objects, like resitors, caps, transistors, etc).

Moderator comment : i dont like this method, each to his own though.

Now, for the desoldering. Usually I just use a solder-wick, and apply that to the underside of the board then put heat directly over the wick (with lead still attached). If you heat and reheat solder, some of the softer metals will actually vaporize, and it will also start to oxidize, both of which will make it harder for the solder to flow. Keep the solder wick on top of the trace, and apply the heat until the lead comes free of the hole. Then keep applying heat until you do not see the solder flowing into the wick any more. Move the wick to a dry area (ie, no solder visible on the wick), and repeat once more. This should take anywhere from 3-10 seconds. The longer you apply heat, the more likely you are to peel a trace from the board, so try to keep it on the shorter side. This process SHOULD remove the solder and part in one sweep. IF you do not get all the solder out of the hole in that pass, APPLY MORE SODLER TO FILL THE HOLE COMPLETLY ONCE AGAIN, then repeat the removal with the solder wick. Do not try to wick a hole that is half empty, or you will just overheat the board. Between each try of removal, let the board rest/cool for some amount of time before you try again. Remember, heat is the enemy of the epoxy board substrate. Although it is made to withstand heat, it is not made to withstand high heat for prolonged amounts of time.

Patience and a little insight and all your holes will be clear!

ps: If you so desire to use the solder bulb/solder sucker, I suggest removing the cap like above, so the leads are left, then cutting the lead close to the board on the component side of the board (the side where the cap was sitting on). Then, suck the lead out as you heat the hole with lead and solder all attached. Once in a while you will get a lead that gets stuck because it is bent or something, then you can use your soldering iron to push it out, and then grab it while the solder is wet with a pair of needle nose plyers..

Hopefully this all makes sense and helps some of you.

Note, I usually set my iron to about 430 degrees F. That is hot enough to melt the solder, but not so hot to vaporize the flux in the solder instantly. You may need to increase the heat a little if the components you are soldering have a large heatsink source attached (ie, large metal component). Some motherboards have their caps attached to an internal ground plane, and therefore carry the heat away very quickly. You may need to increase the heat some to compensate.

Good luck!

Jay Kramer

[and_]

Re: Soldering How-To

what is the watts of your iron? i understand that 220V is the mains voltage of your iron.

I think it's 50watts
and yes, 220V is main voltage
its type is зтп-1

[Rainbow]

Re: Soldering How-To

25W is quite small my friend, your tip must be quite efficient. sometimes i have difficulty with my 60w on some boards.

It's Velleman VTS25:

Believe it or not - it works for most caps. If there's a large plane on the board, I just add solder to improve heat transfer from the tip.

[willawake]

Re: Soldering How-To

I think it's 50watts
and yes, 220V is main voltage
its type is зтп-1

50w is ok, there is concern about using solder iron gun type which are like 200w+ too hot. I cant see much in your photo but the mains cable looks poor. it is necessary for the iron to be grounded for ESD reasons. does the plug have grounding point or pin? unplug the iron and check with multimeter from the grounding point of plug to tip of iron. should read about 1 ohm.

if you work with the iron unplugged then it will cool down while you are working. not recommended to work like that. not recommended to use non grounded iron either.

[willawake]

Re: Soldering How-To

Velleman VTS25

gotta be the bargain of the year if it works fine. 10 euro on the web?????? great find

[Rainbow]

Re: Soldering How-To

I bought it in a local shop, don't remember the price anymore. I also bought a stand - it's a must. I plug it in and let heat up for a while - if the remainings of old solder on the tip can be cleaned using wet sponge, it's ready to work.
The tip is replaceable - might be compatible with tips for the more expensive temperature controlled irons - but I still use the original one (it's not very sharp anymore but it doesn't matter for caps).
That yellow part is rubber - good for handling but it slowly moves down the handle during work which is annoying. Glue would surely fix this

[willawake]

Re: Soldering How-To

The tip is replaceable - might be compatible with tips for the more expensive temperature controlled irons

i was thinking it looked like Goot ones

[and_]

Re: Soldering How-To

it has only two wires and stays hot quite long time (made in good old CCCP ) so i think i should heat it up, unplugg, desold a cap, plug it in and let it to heat up again .. it takes time but right now i don't want to waste money on newer solder that i only use once a year

thank you, willawake, for your answers

[willawake]

Re: Soldering How-To

it is going to take time that way. if it has two wires then yes dont use it on the board plugged in.

[Rainbow]

Re: Soldering How-To

Found out recently that my 25W iron can even solder/desolder TO-252 and also TO-263 components! It can do it even better than 75W soldering gun, provided that correct technique is used. There are two keys to success:
1. add some solder
2. lie the tip as flat to the component's tab as possible
This maximizes heat transfer between the iron and the component, desoldering it in a couple of seconds.

[tazwegion]

Re: Soldering How-To

I usually alternate between 25w & 40w irons, and while a vacuum-tube solder sucker is good, I still need to use a sewing needle (mounted in a hobbyist's knife handle w/ vice tip) to clear those PCB holes on occassion, while heating from opposite side