soldering iron question...

learpilot2

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I am doing some pcb repairs, and wondered what watt soldering iron works best. I have one that is selectable to either 15 watts or 30 watts. 30 watts heats things up real fast, and needs contact only 3-4 seconds to solder. On 15 watts, it is tamer, but requires heating up the componets for 7-8 seconds to solder. Is it better to have 30 watts of heat for a short time or 15 watts for a long time? I am worried the 30 watts of heat for even short times might damages the pcb. Any ideas? Also I use 63/37 solder. Is that really better on pcbs than 60/40?

thanks,

rick
 
Personally I have an adjustable temperature station. I would recommend that over a plain ol' plug it right into the wall and wait for it to heat up iron. When I had one of those it was a 30 watt and I generally did okay with it.
 
A hot iron that allows you to solder faster will transfer less heat into the component (and soldering pad!) than a cooler one...

The idea is to get the iron on the component and solder quickly.

My temperature controlled iron is kept at 650 degrees F.
 
some thoughts

I use Hakko soldering tools - good quality and priced well too. You can solder with just about anything, but I've never regretted spending $50 on a "nice" soldering station.

No matter what you use, get a stand and a sponge for the iron. both will help keep the tip clean, which is 50% of efficient soldering ("half cleaned is half soldered" :)

Components are tougher than they look (and usually tougher than they're spec'ed). for ICs, I always use sockets, so I can heat those to my heart's content :)

If you use rosin core solder, make sure to clean that up with some alcohol when you're done. You don't want a sticky yellow mess all over your PCBs.
 
Also,

If you need solder, Fry's has some on clearance for dirt cheap... Unavailable in stores, you'll have to order over the web.

.050 60/40 Rosin core:
http://www.frys.com/product/4811340

.062 60/40 Rosin core:
http://www.frys.com/product/4811360

They are on clearance for $1.90 for a 1/2 pound spool. :)

They have less than 10 left of the .050. I tried to order 20 spools but it said "call" so I put in an order for 10 and it went through.

5lbs of solder should last me another 3 or 4 years though.

RJ
 
They have less than 10 left of the .050. I tried to order 20 spools but it said "call" so I put in an order for 10 and it went through.

I got "call" for 5 of the .050, so I bought 20 rolls of .062 for the hell of it... it's good for doing connectors anyway... I hate burning through my .031 and .020 on those....
Thanks for the heads up.

Fucking radio shack wants $12.99 a roll for .062 these days.
 
Hey Mark,

Glad to help out another KLOVer where I can.

I figured $1.90 a roll for a 1/2lb of solder was kick ass. :)
 
For what I need to do and my repairs, I have a 15 & 30 watt adjustable iron. Its a basic iron that works just fine, I also use a pencil tip.

As other members said... Some joints you have to use 30 watt, if theres a lot of solder to heat, the 15 watt setting will only heat some of it. Other joints have a metal sleeve that goes through the other side of the board like for an IC socket and 30 watt again works perfect. Hit the joint quick with the heat and it flows nicely to the opposite side.

Now if I'm doing close small joints and small one sided pads or traces, I turn it down to 15 watts.
 
Solder is in!

Qualitek International, Inc - http://www.qualitek.com/
60/40 solder with 3.3% rosin core flux.

That was the first time I ever ordered from frys.com. I usually go into the stores.

They also have 2 different SKUs of silver bearing solder on clearance for $4.90 for a 1/2lb roll, but I don't use that.

Frys # 4811370
Frys # 4811390

RJ
 
While we're on the topic, can someone explain why "cold solder joints" are called just that?

I have never understood the logic behind it.
 
Cold solder joint is a name... just a name...

It refers to when a solder joint looks grey and grainy which gives it a 'cold' appearance. It can be from overheating the solder when you put it on the joint... not heating it up enough to boil out the flux... or from it overheating in circuit.

An example of overheating is those pesky diodes on Pac Man/Ms. Pac/Pac Plus boards. The board turns brown around those diodes and the solder on them looks like hell.

You can remove/add new or you can dab a little rosin flux on top and reheat it to make it good again.
 
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