Questions regarding "bridged joints" ?

[Henry89789]

I read in a book that  when soldering in new components one must be careful to avoid "bridged joints" where the solder spills over to a solder joint next to it because the solder might touch something it is not supposed to thereby causing a malfunction.

I am finding that some joints are so close it is extremely difficult to avoid a bridged joint. So the questions are :

If you have a bridged joint and the pedal works: 

Does that mean that it was okay to have the bridged joint at that location?     

Or can you have a bridged joint where the pedal works but without the benefit of the sound improvement that that particular component change  was supposed to give the pedal?   
In other words,  yeah, the pedal works  but you haven't improved it because the bridged joint cancelled out or negated the improvement that the component change was supposed to give the pedal?

Is it all or nothing with bridged joints?  If the pedal works with a bridged joint do you always get the full improvement that the component change was supposed to give the pedal?

How can you tell, in advance,  which joints should not be bridged because if they are bridged the pedal will malfunction?

Thanks in advance for for replies to these questions.

[iccaros]

Does that mean that it was okay to have the bridged joint at that location?

don't know, what is connected there in the schematic?
you can have a short and things still work, they may not work as well or you may not get a specific tone, it could cause things to go bad later in the build.

you stop solder bridges, by
using flux
using the lest amount of solder

the only way you can tell if a bridged joint is bad is read the schematic.  what are you bypassing? what are you shorting?

[Henry89789]

I am talking about bridged joints when modifying pedals. So lets say I am changing a capacitor or a resistor which is right next to another one and the solder form the cap being changed bridges to a joint from a cap or resistor right next to it.  A couple of times when this has happened the pedal has worked and the mod seems to taken "effect".

[Willybomb]

I've bridged a number of joints in a couple of current pedal builds (accidentally) just to find no effect at all when I switch it in... so if your effect works as advertised after the mod, it's probably just luck.

[LucifersTrip]

The bottom line is that the circuit was designed a specific way and it would be rare that a random bridged connection would be an improvement. Additionally, you may not notice any sound difference immediately, but somewhere down the line, something could happen...like an overheated and blown pedal. Remember, not all components are there to change the sound.

It is impossible to answer your question about "which joints should not be bridged" until we see exactly what was done.
If you accidentally bridged a connection and don't understand the ramifications, I'd unbridge it.

Using too much solder is a rookie error. You really don't need as much as you initially thought. Try to use less solder, use a pencil point tip,  and you'll rarely have problems with bridging.

[flintstoned]

I've made solder bridges intentionally when modding sometimes, when I've lost a pad during desoldering. On some boards you can see the traces and see which components nearby are on one the same trace. Like those green boss boards, there's two different shades of green, one for the traces and one for the space between the traces.

[egasimus]

Yeah, if two components are already connected by a trace, a solder bridge will have no ill effect. But, if you find yourself bridging adjacent joints too often, you should probably work on your soldering chops, and maybe get a sharper tip for your iron. Do you clean it and re-tin your tip every few joints? That helps a lot, and so does ising plenty of rosin (or other flux, as long as it's not conductive - now that's a major PITA), especially if your solder isn't of the rosin-core variety.

[Mark Hammer]

Personally, I like to get the flux off the board using methyl hydrate and a toothbrush (I'm too cheap to buy a spray can of flux remover).  I find the shine of flux often makes it difficul;t to tell the difference between flux and an actual solder bridge.  Taking the flux off makes visual inspection more reliable.

[R.G.]

All good info.

The real answer is "don't ever have a bridged joint". Work on your soldering until you don't . With experience, you will develop a feel for the solder's condition by the appearance of the liquid solder as it flows. In general if the solder drags out to a string as you remove the soldering iron from the joint, the iron and/or joint was too cold.

Proper soldering temperature makes solder flow like water, actively wicking into any crevices and being too fluid to make strings between the iron and joint as the iron moves away. It's only if the solder is cool enough to be a little pasty that it can mechanically support itself into threads that can drag out into other joints.

Of course, if you put too much solder onto a joint, it can flow across a short gap even if fluid enough. A good PCB joint should have concave surfaces, not convex. If they're convex, there's too much solder on the joint.

I still make bad joints after over 40 years of soldering. But I recognize them and correct them, and mentally chew on myself for not paying attention while I solder.

[oskar]

Or can you have a bridged joint where the pedal works but without the benefit of the sound improvement that that particular component change  was supposed to give the pedal?   
In other words,  yeah, the pedal works  but you haven't improved it because the bridged joint cancelled out or negated the improvement that the component change was supposed to give the pedal?

I think you nailed it. A good error is the one that sends out a trace of smoke and leaves your build obviously disabled. The bad error, and the one that would keep me awake at night if I had a construction on the market, would be the one that wouldn't do what it's supposed to but not bad enough to be an obviously a bug. The customer would be just unhappy and not use the product/pedal.

[R.G.]

A good error is the one that sends out a trace of smoke and leaves your build obviously disabled. The bad error, and the one that would keep me awake at night if I had a construction on the market, would be the one that wouldn't do what it's supposed to but not bad enough to be an obviously a bug. The customer would be just unhappy and not use the product/pedal.

Worse yet - in the computer biz  - is an error that just flips a bit every few million times, just enough to corrupt things but not enough to be detected till it's way too late. Especially where "too late" means "after several million dollars' worth have been shipped". That's what keeps engineers from sleeping well at night.

[oskar]

Yep. If you wanna have something break down with class... go digital!   
Have any good examples?

[Henry89789]

Thanks for the replies. I guess I am going back and try to unbridge the joint I am concerned about. It looks like it is on the same trace but  I am going to follow the "don't ever have a bridged joint " rule.

[R.G.]

Also, go get yourself some solder removal braid. When you bridge, there is excess solder left. Use the braid to remove the exess.