homemade double-sided PCB

[cb951303]

hi guys/girls

Never done a double-sided PCB before so doest is differ from single-sided ones? (for press and peel method ) In fact my only concern is how can I connect two sides (through a pad)?


thanks

[acenovelty]

Insert a wire thru the pad and solder on both sides.

[cb951303]

but I must also solder a component to the same pad..so?
do I solder the components' legs from both sides? that would be awkward

[acenovelty]

What is awkward about it? The board trace does not know where the connection came from. It will not resent your use of that hole.

[AuroraB]

Soldering components on both sides is as old as electronics itself....what's the problem??
-Except for radial electrolytics ( and a few other cases)....where you must provide the feedthrough either on another component or a dedicated pad with a piece of wire.

[clem_o]

I assume you're doing the layout yourself? In that case, make sure any feedthrough connections do not occur on a component leg. You can force a feedthrough pad in some other 'convenient' place to connect the two sides' traces as needed, then solder a wire there.

Cheers

[JensRasmussen]

I the past I have made layouts for double sided PCBs using resistor + transistor + diode pins to get the signal from one side to the other.

Caps are difficilt as they often hide the solderpads.

If you make the layout yourself just use the easiest way for you, or select parts that are easy to solder on both sides.

I have seen somewhere that you can get a small metal tube to insert in the PCB hole, this will make a "plated" hole that allows for pad hiding parts to be soldered. It may need bigger pads than normal, but if you do the layout yourself you should have no problem with it.

\Jens

[AuroraB]

Originally posted by clem_o
In that case, make sure any feedthrough connections do not occur on a component leg.
Cheers

For what reason?? This has been done for ages, and is still done in prototyping where you don't have plated holes...

I sometimes use the small rivets Jens is referring to, they are good, but finicky and time consuming ( and expensive tooling) - I only use them if I have to, like on high density boards an on RF groundplanes.
Component legs are easy and no extra cost.

You can also use some very thin wire - like 32 g wire wrap- if there is room for both, but it sometimes require some tricky soldering....

[clem_o]

Originally posted by AuroraB


For what reason?? This has been done for ages, and is still done in prototyping where you don't have plated holes...

For the reason that the originator of the thread felt it was 'awkward' to do so.

The other reason - it avoids heating the component at a point very near the die, which can cause failure if temp is too high / interval too long for soldering. Of course, its all very dependent on how skilled the person is; I am sure that many people feel fairly confident to go ahead and solder at that point, but persons without that much experience may feel more comfortable avoiding such a situation...

Cheers!

[AuroraB]

I've been hand soldering for almost 40 years now, and I truly fail to see how it can be awkward to solder both sides of a resistor, transistor etc. The problems of course arise with things like radial ellytics and other parts that cover the top pad- in which case other means have to be used- like feed-troughs outside these component areas.

The heat is a minor problem - assuming one has aquired basic soldering skills and good tools - a normal solder joint should take no more than 2-3 secs to complete. It is also common practice in prototyping these days to hand solder SMD's, SO's, QSOP and a lot even worse....
It does require a steady hand and lots of patience..don't rush it...
If you don't feel you master the "art of soldering" - please collect some info and practice before you waste your money on expensive parts..

Anyone here old enough to remember the first MOSFETS from the early 70ies??? You'd be lucky if one of 3 survived soldering at all.......until you learned the tricks.....
End of discussion from my end