Dumbest soldering question

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MaskdBagel

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Dumbest soldering question
« on: 17 Jul 2010, 07:47 am »
OK, this is really more of a general technique question than a question related to a specific kit (I hope!), but you guys have been awesome so far, and I've gotten a lot of good guidance here.
So.
I'm putting together a Cornet2. After much wrestling, I got all the terminals and resistors onto the board, and they all check out well according to my trusty multimeter. But the process was WAY way tougher than it should have been for one big reason: I can't get the traces to heat up enough to take my solder. I eventually got every point so far in good shape, but I just can't figure out what in the world I'm doing wrong that almost every point gives me trouble.
My iron is plenty hot enough to tin quickly and easily. I'm using exactly the same technique on the points that work out like they should as I am on the ones that never heat up. And the same technique I used to hot rod a made-from-scratch Telecaster a few years ago. I'm not an old pro with the soldering iron, but I'm not bad.
I find I'm putting the iron on the board and the lead for 20 seconds or more, poking the solder at the trace across from where I have the iron, and it's not even leaving any of the core. And then some points, I'm heated, soldered, and off in five seconds.
I'm super frustrated, and I figure taking some time out to humbly ask for some troubleshooting was a lot better than having a board full of cold points. Does anyone have any ideas? I'm happy to admit that I'm too much of a newbie to figure this one out, but I sure don't want to be out several hundred bucks and end up with something fried or unusable. Any help would be VERY MUCH appreciated. Thanks so much.

Kent

srb

Re: Dumbest soldering question
« Reply #1 on: 17 Jul 2010, 08:11 am »
Before soldering each joint, wipe the tip off on a damp sponge and tin with just enough solder to coat and leave a small solder bead on the tip.
 
It may be that the tip is not of a proper shape to allow enough contact to the trace and component lead.  Sometimes very pointed tips or flat chisel tips don't provide enough contact area.  I prefer to use a pointed tip that has four angled flats on it, giving the ability to get more contact area by angling the tip.
 
Also too large of a gauge of solder can make it more difficult, so maybe try a thinner gauge solder.
 
Steve

timind

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Re: Dumbest soldering question
« Reply #2 on: 17 Jul 2010, 10:29 am »
Make sure the tip is securely fastened in the iron for optimum heat transfer. I know, dumb answer, but I've been caught by this several times and have learned to check this frequently.

Niteshade

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Re: Dumbest soldering question
« Reply #3 on: 17 Jul 2010, 11:59 am »
With a clean soldering tip, make sure the tip is touching both the eye and wire at the same time. I use a screwdriver tip (medium). Never liked the pointed ones.



The one labeled "Piatta" (meaning flat)  and third down most closely resembles what I use.

poty

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Re: Dumbest soldering question
« Reply #4 on: 17 Jul 2010, 01:48 pm »
Do you use some sort of soldering flux? Maybe the problem is not with heating, but with oxides covering plates and leads?

Clive

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Re: Dumbest soldering question
« Reply #5 on: 17 Jul 2010, 02:37 pm »
What wattage iron do you have?  Soldering the many connections that go to the ground plane need considerable heat.  A 15W tor 18W iron would not be up to it.  I'm guessing but I believe you'll need 25W to 40W.

WGH

Re: Dumbest soldering question
« Reply #6 on: 17 Jul 2010, 03:11 pm »
Lightly polishing the connection points on the board with 0000 steel wool to remove any oxidation will help too.

avahifi

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Re: Dumbest soldering question
« Reply #7 on: 17 Jul 2010, 03:34 pm »
What brand of solder and type are you using?

It MUST be a rosin core solder.  Good old Kester 44 works fine in most cases.

It should take no longer than 2-3 seconds or so to make a good connection from a circuit board trace to a parts lead.

Call me at 651-330-9871 if you need more help with this.

Best regards,

Frank Van Alstine

Ericus Rex

Re: Dumbest soldering question
« Reply #8 on: 17 Jul 2010, 04:55 pm »
If there's dirt and/or grease/oil the solder won't flow into the joint.  Be sure board and leads are all clean.  If dirty, clean with alcohol.

MaskdBagel

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Re: Dumbest soldering question
« Reply #9 on: 17 Jul 2010, 05:43 pm »
Thanks so much for the replies, everyone. I'll try and answer everything here...
My supplies are 63-35-2 .022" rosin core solder from Radio Shack (I know, I know), a small pointy tip, and  a 15W iron. I also have a little thing of flux that I've tried on stubborn traces, but it doesn't really make a difference. I did need to tighten the tip once, so thanks for that one, it wasn't a dumb thing at all. My issue isn't that the solder isn't flowing everywhere it should or beading up on anything. It's that it actually just won't melt when held against the trace and the lead. (Which makes me wonder how much difference steeel wool/flux should be making, but I'm not super knowledgeable here, obviously.  :?) The iron is plenty hot enough to melt it, so I'm pretty puzzled. I'll go track down a piatta tip and see how much difference that makes.
Any other suggestions are very welcome, and I'll report back on the new tip.

Thanks!!

srb

Re: Dumbest soldering question
« Reply #10 on: 17 Jul 2010, 06:03 pm »
Hopefully a tip with more contact area will make a difference, but it may be that the RS 15W iron is too small.  Any low wattage iron will directly melt solder, but when the tip is in contact with a larger trace or component leg, heat will be drawn away lowering the tip temperature at the solder junction.
 
Steve

bregez

Re: Dumbest soldering question
« Reply #11 on: 17 Jul 2010, 06:44 pm »

My supplies are 63-35-2 .022" rosin core solder from Radio Shack

I believe that is silver-bearing solder which also requires additional heat to flow.  I agree with the others in that your 15W iron may be the problem.

MaskdBagel

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Re: Dumbest soldering question
« Reply #12 on: 18 Jul 2010, 04:00 am »
Thanks again, you guys. You make an adventurous novice feel like journeying on! And just when I was getting discouraged... I picked up a little 25W Weller iron today, and I was on and off every point in about five seconds a piece. I'm less scared of fried components now, and I feel a lot better about the quality of my connections, too. Now I have to wait until Tuesday for my next batch of parts to arrive. You guys rock, and I think I'm back on track. :)
The next time any of you are in Seattle, I owe you a donut. Seriously.

Richr

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Re: Dumbest soldering question
« Reply #13 on: 18 Jul 2010, 05:44 am »
All good tips. Another one: if you are having trouble making good contact between the iron and the joint, you can use the iron to directly melt a small amount of solder into the joint. Assuming this gets the joint heated sufficiently, you can then complete the soldering job normally. 

Niteshade

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Re: Dumbest soldering question
« Reply #14 on: 18 Jul 2010, 10:53 am »
It sounds like the iron heat is not transferring. A screwdriver tip will most likely help. Pointy tips with a low thermal mass are not nice to work with. Remember that the iron has to touch both surfaces you're soldering. A common mistake is people "grinding" the tip in to try and make better contact. Don't do this since you will damage the eye.

Iron temperature. If it's too high, solder oxidizes and will not work right. Too low and heat will not transfer to the components being soldered. I made myself a soldering station with a light dimmer from Lowe's. It works on any iron and was very inexpensive to make. (Note: Get a steel junction box large enough to place a wall socket next to the dimmer and get the appropriate finish plate to put on the front.)

Oxidation: Is everything shiny? Oxidized metal will not solder.

Thanks so much for the replies, everyone. I'll try and answer everything here...
My supplies are 63-35-2 .022" rosin core solder from Radio Shack (I know, I know), a small pointy tip, and  a 15W iron. I also have a little thing of flux that I've tried on stubborn traces, but it doesn't really make a difference. I did need to tighten the tip once, so thanks for that one, it wasn't a dumb thing at all. My issue isn't that the solder isn't flowing everywhere it should or beading up on anything. It's that it actually just won't melt when held against the trace and the lead. (Which makes me wonder how much difference steeel wool/flux should be making, but I'm not super knowledgeable here, obviously.  :?) The iron is plenty hot enough to melt it, so I'm pretty puzzled. I'll go track down a piatta tip and see how much difference that makes.
Any other suggestions are very welcome, and I'll report back on the new tip.

Thanks!!