Homebrew PCBs

Newbies should also note that in this group we are
often a bit hit-and-miss, sometimes going on slapdash,
in our reagent concentrations...

At 10:04 am ((PDT)) Wed Apr 11, 2007, Dave Miller wrote:
>http://thinktink.com/stack/volumes/voliii/consumbl/devmix.htm
>
>The Soda Ash mentioned is the same as Washing Soda (sodium carbonate
>monohydrate) that can be picked up in your local grocery store in the
>laundry section [snip]

Not the first time that kind of thing has been posted here.
Better read this too ;-)

http://www.pburch.net/dyeing/FAQ/sodaash.shtml
"FAQ: What is soda ash, and what's it used for in dyeing?"

 > Hydration
 >
 > Some forms of soda ash (e.g. that labeled as 'washing soda')
 > contain more water molecules than others, which makes them
 > weigh more and be larger for a given number of sodium carbonate
 > molecules - this means that you need to measure out a larger
 > quantity of the hydrated form in order to get the same results.
 > If you buy sodium carbonate without the extra water molecules,
 > then store it for several years in humid conditions, it will absorb
 > the water and appear to lose strength, when in fact it has merely
 > 'bulked up' and needs to be used in larger volumes.
 >
 > The type of sodium carbonate used in washing soda is a decahydrate,
 > so you need to use almost three times as much washing soda as
 > you would anhydrous soda ash - assuming that you are able to find
 > washing soda that is suitable for use in dyeing, which may be
 > difficult in the US.

Molecular Weight Calculator should make it easier:
http://www.lmnoeng.com/molecule.htm
(enter the number of atoms of each element)

Molecular Weight (g/mole):
180.1528   10H2O
105.98844  Na2CO3
286.14124  Na2CO3.10H2O

286.14124 / 105.98844 = 2.6997

So you need 2.7 times as much of those nice glassy
washing soda crystals than of the anhydrous soda ash.


Regards, LenW