Re: gEDA-user: Isopropyl alcohol vs. ethanol

[Karel Kulhavy <clock@xxxxxxxxxxxxx>]

On Mon, Apr 24, 2006 at 10:18:32AM -0400, Marvin Dickens wrote:
> Karel Kulhavy wrote:
> >On Sun, Apr 23, 2006 at 10:51:43PM -0400, Marvin Dickens wrote:
> >  
> >>Karel Kulhavy wrote:
> >>    
> >>>Is it true that PCB's should be washed by isopropyl alcohol and not
> >>>ethanol because ethanol has small molecules that creep into the part
> >>>cases and wreak havoc there?
> >>>
> >>> 
> >>>      
> >>I've never heard of washing PCB's in ethyl alcohol or isopropyl alcohol. 
> >>In fact, - Yuk.
> >>
> >>Both isopropyl alcohol and ethyl alcohol are both  reasonably flammable 
> >>at 70% purity or above.
> >>Further, isopropyl alcohol has a low vapor pressure. In the long term, 
> >>without a well thought out
> >>ventilation system, flash fires would occur (Not if- but when....).
> >>
> >>We wash our boards in a mild solution of distilled water, clear ammonia 
> >>and a mild surfactant.
> >>This is followed with a wash with distilled water. The boards are then 
> >>dried for several
> >>hours in a drying oven.
> >>    
> >
> >But does ammonia dissolve rosin?
> >  
> No. ammonia does not dissolve rosin.
> 
> But, that's OK: We don't use traditional rosin based solders (Rosin as 
> in derived from pine trees and other conifers).
> In fact, I don't know why anyone would use rosin based solders (Unless 
> it is all that is available...). If you are using
> solder that contains rosin, the product you are trying to remove is 
> abietic acid that appears as a residue after soldering. 
> Abietic acid  is soluable in many alchohols.(As well as many other 
> solvents...). Wtth that said, we use water soluable solder.
> It's easier to work with and is more people/environmental friendly. Just 

So pines are not environmentally friendly because they secrete abietic
acid? Something doesn't sum up here.

CL<
> so you know - Abietic acid is nasty.
> 
> Regarding water soluable solders, take a look at:
> 
> http://www.tselectronic.com/solder/solder.html?tse_Session=87ad1697d9d7666613a61c09428f3791
> 
> Water soluable solder paste is also readily available. In fact, water 
> soluable solder products are available in
> any form factor you can think of.
> 
> 
> 
> Best
> 
> Marvin