Tuesday, November 3, 2009

Tin Plating with Solder

Tin Plating with Solder on Home Brew PCB Projects.

On a previous post, a viewer ask via a comment; how did I do a "Solder Wipe"? as shown on one of the example HB PCB Projects.

At the time, I used a Soldering Iron with a little bit of solder and moving back-and-forth over the traces coating each with solder and then while the board is still hot, "Wipe" the solder with a cloth. This produced satisfactory results - but, you have to be quick!

Because I like the looks of bare copper for my projects, "Solder Wipe" is not used very often.

Now, many of my projects are showing their age as the copper tarnishes. I need to start using something more protective on all of my projects.

While removing parts and cleaning-up several old junk board (see below), that are going to be re-used for a SMD solder technique demonstration, I noticed that Solder Wick produced a nice clean dry finish, if it was rubbed over the traces with the heat of the soldering iron.

It looked great! I tried it on the rest of the board - with fantastic results.

Without and With Solder Plating

I recommend using a short section of used "Solder Wick" to tin plate (solder plate) new HB PCB projects before parts are loaded.

Used-Wick stays together and provides the small amount of needed solder, New-Wick tends to fall apart (see top left) before it collects enough solder to stay together. Do this task quickly, as you do not want to heat the board more than necessary - it will get HOT.

Be Careful, it is HOT

A little bit of liquid "Rosin Flux" helps the plating process (I use MG 835-100ml).

After plating, and Alcohol cleaning,  a quick buff with Scotch Bright removes the shiny surface and avoids the reflections that are so distractive while loading parts.

Note; more Alcohol cleaning is necessary after using Scotch Bright as the LEAD from the solder mars the PCB between the traces.

CAUTION: Remember,
this is "LEAD" that you are touching!

With previous HB PCB (without plating) I always liked to rub a little liquid "Rosin Flux" over the entire board before loading - it gets sticky (rosin is tree sap) and must be dried first, but it provided excellent soldering conditions for SMD parts - I still may continue this practice, even with Solder Plated PCBs. Note: I think rosin will also help seal the edge of the fibreglass PCB.

Now, . . . . if I could only find a way to do a decent Home Brew PCB Solder Resist Mask to seal the board?


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