tinning a pcb

[Wagener]

I finally received my 4 pcb's which the university manufactured directly from the pcb layout dr. Leach has on his website.

I noticed that they already tinned the pcb with a thin layer of solder or lead (silver stuff). I would like to tin it even more because I want the tracks to conduct maximum current when running it on lower loads.

How would I go about to neatly tin the tracks? A solder iron and solder just doesn't do a neat job.

I has thinking using a heat gun and solder?

Any ideas?

Also, Is the tracks on the leach amp pcb layout of dr. leach big enough to run 4-ohm loads? I noticed that they are quite narrow. I realise the the higher voltage makes for less current but I am still a bit concerned.

 

[dhaen]

Building up tracks in this way is not necessarily a good thing. They will suffer more from stress (thermal and mechanical), and thus be more liable to break.

 

[Bensen]

Hi Wagener,

When I'm drawing my PCB's (Yes I still do this manuel with a stift), I follow a certain rule I found somewhere on the web.

Rule:

Track width: | Copper thickness
| 35µ 70µ
_____________|____________________
1mm 5.5A 8.0A

3mm 8.0A 11.0A

5mm 10.0A 14.0A


(25.4mm = 1")


Greetz

Ben

 

[Bensen]

This looks better if I do "Preview Reply".

width Copper thickness
35um 70um
1mm 5,5A 8,0A
2mm 8,0A 11,0A
3mm 10,0A 14,0A

 

[sam9]

I doubt the benefits of tinning (or even silver plating) pcb tracks is inproved conductance; the copper itself should do that adequately. If not then, a little bit more metal, even silver won't help much. Partivularly for power amps, thermal disapation may be the most important consideration and increasing width is the key parameter. Doubling thickness (i.e., 2oz vs 1oz) increases the current rating by onlt 1.4 because the suface area has not been increased. To double capacity, you need to go from 1oz to 4oz. Here is a reference I use. http://www.vutrax.co.uk/vbook.htm

The real benefit of tinning or even silver plating is ease of soldering which in turn means better solder joints. At least in my experience, plated pcb tracks and pads are much, much easier to solder than bare copper and good solder joints increase the chances that the project will be a success..

 

[peranders]

I finally received my 4 pcb's which the university manufactured directly from the pcb layout dr. Leach has on his website.

I noticed that they already tinned the pcb with a thin layer of solder or lead (silver stuff). I would like to tin it even more because I want the tracks to conduct maximum current when running it on lower loads.

How would I go about to neatly tin the tracks? A solder iron and solder just doesn't do a neat job.

I has thinking using a heat gun and solder?

Any ideas?

Also, Is the tracks on the leach amp pcb layout of dr. leach big enough to run 4-ohm loads? I noticed that they are quite narrow. I realise the the higher voltage makes for less current but I am still a bit concerned.

1 The pcb's are tinned becuase they are of a bit cheaper sort than normal industry standard which have solder mask.

2 Tin or 60/40 alloy has 10 times more resistivity (spelling?) than copper meaning that you have to have 10 times 35 um in order reduce the resistance to the half.

3 How much current must the pcb be able to take?

4 How much current CAN the pcb take before the traces fuses?

My advice: Don't do anything.

 

[ingvar ahlberg]

The hot air reflow or chemical tinning of the pcb´s is for preventing oxidation of cu and improving solderability. Untinned bare cu pcb´s are totally useless in every respect.
Power amp pcb´s should be made on 70u cu, most are not. Best way to increase tracks is to cut and bend tinned cu wire to meassure and solder it in place on the track after mounting components.

 

[TonyTecson]

hi,

if you want the traces to conduct more current, you can solder a tinned wire awg #18 running along the traces, solder alone will not increase current....

i use this trick on pc psu's, particulary on the ground tracks....could very well work for you too!!!

good luck...