Hi,
this is my first post, so I hope you don't mind if I just stick my nose
right into this thread. It's just I've found it very interesting.
Actually, Bill is totally right. Liquid tin can be perfectly homebrewed,
but it's quite dangerous for anybody lacking good skills in chemistry.
If I understood well, the MSDS sheet for MG Chemicals Liquid Tin is this
one:
http://www.mgchemicals.com/msds/english/421-liquid.pdfand it lists the following hazardous chemicals:
CAS# Chemical Name Percentage by weight ACGIH TWA Osha Pel Osha Stel
16872-11-0 Fluoroboric Acid 9-11% 2.5mg/m3 2.5mg/m3 N/E
13814-97-6 Stannous Fluoroborate 9-11% 2mg/m3 2mg/m3 N/E
62-56-6 Thiourea 4-6% 2.5mg/m3 N/E N/E
To start with, fluoroboric acid is dangerous enough by itself, but safe
enough if handled carefully. However, it's probably not very easy to get
hold of the technical grade stuff. Preparing it is pretty
straightforward, but one of the reagents needed is hydrofluoric acid.
Hydrofluoric acid is ∗very∗ toxic and not something to be messing around
with. With access to a good fume hood and appropriate labware (or just
take the risk of working with hydrofluoric acid in an open,
well-ventilated place), then fluoroboric acid can be prepared rather easily.
A way of doing electroless tinning has been already posted in this
group, I copy the formula down here for the sake of simplicity:
.5g Stannous Chloride
2.0g Thiourea
3.0g Sulfamic Acid
100.0 mL Distilled water
These chemicals are much easier to get from your local supplier and can
be handled safely without any special precautions.
I hope this helps!
Pablo
Am 26.11.2010 15:47, schrieb William Laakkonen:
> Yes, it is dangerous and it could be home brewed- YMMV
>
> MG Chemicals MSDS shows it is stannus sulfate, sulfuric acid, and as I
> recall, it is mixed with water for the balance.
>
> CAS# Chemical Name Percentage by weight ACGIH TWA Osha Pel Osha Stel
> 7488-55-3 Stannous Sulfate 1-3 % N/E N/E N/E
> 7664-93-9 Sulfuric acid 9-10 % 0.2 mg/m3 N/E N/E
>
> I would recommend getting it from a known source pre-mixed for the intended
> purpose.
>
> 73
> Bill Laakkonen
> N4BKT
>
> On Fri, Nov 26, 2010 at 4:43 AM, liquias<liquias@...> wrote:
>
>>
>> Hi,
>> has anyone ever heard of this "Liquid Tin" by m.g. chemicals ?
>> this material is supposed to plate the PCB after the etch process, and
>> passivate the copper.
>> I never seen this stuff sold anywhere, and I can't get it since I live in
>> Israel.
>>
>> first, a link to see it with your own eyes:
>> http://www.youtube.com/watch?v=3aEwTRMEkOM
>> look at around 3:30 minutes...
>>
>> second, does anyone know how to home-brew this material ? Is it dangerous
>> to use ?
>>
>> third, does any of you use any other process to passivate the copper after
>> etching ?
>>
>> Thanks in advance,
>> Liquias.
>>
>>
>>
>
> [Non-text portions of this message have been removed]
>
>
>
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