[sdiy] Korg Poly61 a peculiar design!!

m.bareille at free.fr m.bareille at free.fr
Fri Apr 8 02:54:34 CEST 2011


Selon "David G. Dixon" <dixon at interchange.ubc.ca>:

> > I know how  to fix damages on carbon layers , i have a
> > special varnish that i apply in very thin layer , then  i
> > 'cook ' it many hours  under a heat source ( a tiny halogen
> > lamp placed a 1 or 2 cm of the area to dry ). I have a
> > similar warnish with liquid silver to fix copper pcb traces.
>
> Oooh!  Does this work well?  It sure would be nice to be able to "redraw"
> part of a PCB with a few damaged or erroneous traces.  Could you also use a
> heat gun, or would that do too much damage to the parts?  If it were a
> one-sided board, perhaps, eh?
>
>

Yes it work fine , but it is not very easy to use or manipulate
The product is very liquid and spread quickly all around. It is not easy at all
to draw a nice track with it !  It is not easy to remove/cleanup  and it always
leave some silver traces because particles are very thin inside. In fact is is a
little bit messy to apply by hand...

But the biggest drawback for a common use is the prohibitive price !! It is a
very very expensive product beacuse of the heavy amount of silver inside...
I do not think it is very reasonnable to use this to repairs damaged pcbs at
least if you have the space to solder a little wire on the board ..

 But for a small repair who must be flat, who do not need to carry a lot of
current and if you do not really worry about track resistivity and esthetics ,
it  can be ok ...  It cannot be soldered . It is far to be as stropng ascopper
track or a solder join...

I have never used it to draw a very long tracks or to fix a many errors on a
prototype pcb . I clearly prefear wires both cases anyway. It is the kind of
product i use when i do not have any other choices...

In fact it is a kind of condutive glue more than a varnish , unlike the carbon
version who is made to repair carbon contacts mainly .

An heat gun can be used , if you have the patience to hold it in place during
many hours ( 2 to 10 depending conditions , materials , temp of the heat
source, the amount of 'glue' )

The good temperature amount is between 100/150°C. Too much you may burn the pcb
or parts , and dry the glue too fast ( no good )  , not enough it will take days
to dry and be less strong too ...

A good application i did with it was to glue smd leds and others parts on
conductive glass 'pcbs' . In this case i have cooked the whole  thing
into an electric oven for many hours.

Thanks,

Marc B.




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