Sunday, September 2, 2012

RE: [HamBrewers] Homebrewing PCBs

 

Active ingredient in Rosn is Zinc Chloride.

 

In about 100 ml of Conc. HCl, add a piece of Zinc metal. There will be a strong reaction in which Hydrogen is released. Fun factor : Bring a lighted match near the mouth of the bottle in which reaction is taking place – Hydrogen will burn with a popping sound.

 

If the reaction stops and you still see the zinc piece at the bottom, HCl is used up. Either remove the zinc piece or add some more HCl. Idea is to have Zinc chloride as well as HCl in the resulting mixture. Store this away.


This mixture is extremely good for removing oxides from copper surface or for that matter from any metal surface. Just brush this liquid on Coax braid and see how shiny the copper turns! – instantly solder ready. Note: Don't use this liquid to clean PCBs on which some components are already soldered because this mixture contains water.

 

Cheers,

Raj VU3RGK

 

From: HamBrewers@yahoogroups.com [mailto:HamBrewers@yahoogroups.com] On Behalf Of Aravind Balasubramanian (VU2ABS)
Sent: Wednesday, August 29, 2012 8:54 AM
To: HamBrewers@yahoogroups.com
Cc: gareth evans
Subject: Re: [HamBrewers] Homebrewing PCBs

 

 

Its a available in the indian country medicine shop and is known as Rohanam - Its actually a tree extract (resin which oozes out of a tree bark when it is injured) and is a good soldering flux without any toxic acid. Got a big rock sized one which lasted me for a couple of decades (go one  wayback in 1989 which just got exhausted in 2009. I promptly got another rocked sized one which should last me for quite some time.

Its also the stuff which is used by violinist to keep their bow's in shape.

I have also used it for coating home made pcbs. Made a powder of it and dissolved in thinner and coated the freshly made PCB using a rag cloth stuffed with coating, after giving it a quick scrub with steel wool to make it shiny.

73 de Aravind vu2abs - qrz.com/db/vu2abs

On 8/28/2012 2:30 PM, gareth evans wrote:

 

A question from the UK, where health and safety laws can
make it difficult to get hold of some materials, what exactly
do you mean by, "Rosin"?

73 de Gareth G4SDW (nee G8DXY) GQRP #3339


--- On Tue, 28/8/12, Sandeep Lohia <sandeeplohia12@gmail.com> wrote:

PPD Solder Paste can be used to TIN Pads.


Bare copper gets oxidizes soon after eitching, changing it's colour and
making it hard for soldering components after some ageing.

What I do is I dilute rosin in sprit, and give a fine coating of this
solution first, then I simply recycle used desoldering wick to TIN
PADS of small homebreawe PCB. Tinning entire homebrewed PCB is not
that important, as on commercial PCB Tinning is again coated with some
solder-resist masking. Just the Pads are left.

After Eitching homebrew PCB with ferric chloride, I immidetly coat it
with dilute rosin, then I put used de-soldering wick on Pads and apply
some heat & pressure with soldering iron, this causes to flow TIN/Lead
alloy out of wick making a fine coating on Pads.

*For very fine and small SSOP or BGA Pads, PPD paste can be used, but
it needs some baking, with hot air or stove.
PPD paste is readily available with mobile repair vendors.

Am not very expert with, & just sharying some practical work with
small recycling. :)
73's VU3SXT.

On 28/08/2012, Sarath <sarath.er@gmail.com> wrote:
> I have been making a few PCBs recently, I do not own a solder pot, and
> having trouble tinning these PCBs.
>
> I read about some products that could be used be used to tin the PCBs called
> liquid tin and some tinning powders. I would like to know if such products
> are available here in Bangalore, Or if you all use any other methods, or
> tricks to tin the PCBs.
>
> Regards,
> -Sarath
>
>

 

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