[llmobll]

Well I'm about to start this project, yet there is one thing i'm not 100% sure about. What is the right way to solder components onto the PCB board??

I was under the impression that you always do it from the bottom. With the board upside down you bend the leads to hold the component in place and solder. Like this:

Yet when I look at peoples boards it looks as if they have applied the solder from the top. Like this:

Is this right, or can you do it both ways? Which way is better? Someone set me straight.

 

[beamrider]

I could be way off base here, but you solder from the underside of the board, unless it's a SMD component. The neat little solder joint on the top is from solder wicking along the component lead thru capilary (sp?) action.

 

[llmobll]

Thats what I thought, that it was just solder leaking through, if this is the case, then I guess these pictures show what using a little to much solder can do.

However the reason I asked was because I've seen pictures that looked very bad. The joints showed clear soldering from the top (round solder drop), and I wanted to know if there was any point to soldering on top.

Another quick question, with some of the heavier components (Capacitors), how do you keep them close to the board? When the board is upside down it is hard to solder without them moving.

 

[Voodoochile]

Quote:

Originally Posted by llmobll Another quick question with some of the heavier components (Capacitors) how do you keep them close to the board when the board is upside down? I find this to be the harded part of soldering.

A few ways:
The third hand thing works for some people (though not good for caps per se).

Masking tape (bleh)

Place the cap, flip the board over so the cap is on the bench, and tack one lead with a speck of solder. The pick up the board with one hand and place your finger on top of the component, applying gentle pressure. Reheat the spot with the iron, and the cap will click in tight to the board. Then solder the second lead, finally come back and complete soldering the fist lead.

I like the third option. Sounds very cumbersome, but after a time or two, you don't even think about it... takes no time at all.

 

[llmobll]

Quote:

Originally Posted by Voodoochile I like the third option. Sounds very cumbersome, but after a time or two, you don't even think about it... takes no time at all.

mmmm... that does make alot of sense. I think i will try that with the really big caps. Thanks!

-Dan

 

[tangent]

Quote:

I guess these pictures show what using a little to much solder can do.

Too much solder bunches up on the backside of the board a lot quicker than on the front side. I point this out because I don't want you to judge the quality of your joints by what you see on the top side of the board. Depending on the amount of spacing between the hole and the lead -- which varies between builders because they use different parts with different lead thicknesses -- you will get more or less solder on the top of the board.

You should get some solder on the top side, as it indicates that the solder was flowing well when you made the joint. Yet, I've made good joints where no solder made it to the top side.

Quote:

When the board is upside down it is hard to solder without them moving.

I put the board in a "helping hands" device so that it is holding the board just off of vertical, so that the leads' friction in the hole is all that's holding the parts from falling out. (You could make it straight vertical, but it doesn't really help, and it makes it harder to see what you're soldering.) Then I apply solder to the upper lead, drop the solder wire, and use my now-free hand to quickly push the component down. Then I remove the iron and let the joint cool.

This usually only has to be done with big components, so there's no danger of getting burned by the heated part. The only tricky one is chip sockets, where you have to be careful to push only on the N-1 pins that aren't being heated.

The main trick to pulling this off is that you have to work quickly enough that the flux doesn't burn away while you're shifting your hand from holding the solder to pushing on the component. But if it does burn away, solder another lead, then come back and add some more liquid flux or solder to the first joint to make sure it didn't become a "cold" joint.