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
