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Washing Soda?

Paul, are those the weights after dehydration? If so, what were the weights before dehydration?
 
So what you have is the weight of one teaspoon sodium carbonate of unknown hydration? That's going to vary with the size and shape of the grains, and can't really be used to determine anything, I'm afraid. Could be useful if you just want a quick way to measure out an approximate weight of chemical, but not for determining how much you need of one to replace another one...
 

No.

All this little experiment was, was a followup to PG's comments on the hydration levels of the washing soda vs. anhydrous. In no way an attempt to make a tablespoon equivalent, although there's no reason why not.

All the products look exactly the same. So, if a recipe calls for 40 grams of SC anhydrous, just use 44 grams of washing soda. You'll be close enough for any use that I'm familiar with.

Of course, you could heat the soda and get anhydrous, too.
 
46.8g monohydrate, I make it - not 44.

Or 107.9g dekahydrate, if that's what you have.

weighing before and after dehydration seems to be the best way to find out what you have, especially as a commercial product may be a mixture of anhydrous and monohydrate, or mono- and dekahydrate.
 
Not sure where you are taking this..


Monohydrate, Decahydrate, Poopahydrate......????

The question was, not was molecular form washing soda is, but the weight relationship between anhydrous sodium carbonate and the retail Super Washing Soda. It appears to be 10%, for whatever the reason or molecular structure.

The weights were as measured on an Ohaus Centigram, not a bad scale. I tried to be very careful in my procedure for accuracy.

That's all.
 
Dehydrated weight

I took 50 grams of Super Washing Soda, put it in an electric frying pan set on 250 degrees F for about an hour.

It weighed 44.7 grams then. I dumped it into my anhydrous sodium carbonate container.

So, it still seems that if you sub washing soda for anhydrous, adding 10% will put you right in the ball park. That may or may not be true if they soda has been "living" is a dry climate for awhile.
 
Akki14 said:
Honestly, when working with caffenol, you're all overworrying, you just follow the directions for using washing soda...
Click to expand...

What, me worry? :rolleyes:

With the quantities of sodium carbonate used for developer activator, it hardly matters. The reduction response curve to increasing pH is very non-linear. So, if you use 50 grams SC anhydrous and then another time use washing soda, I doubt if you could measure a density difference. But, per my experiments, you could up the soda to 55 grams and you will be right there.
 
Arm and Hammer "So Clean" Super Washing Soda contains detergents?

To make my Beutler developer, I decided to save about a dollar and buy grocery-store washing soda [see subject line] instead of anhydrous sodium carbonate. My first roll of Plus-X was ruined by many irregular white spots and streaks.

There is some soft, whitish sludge in my dissolved [!] Arm and Hammer "So Clean" Super Washing Soda. Filtering one litre with a coffee filter plugged two paper filters.

The whitish sludge captured on the filter paper is very soft and slimy, feeling soap-like. Also, the filtered mixture remains cloudy; not what I'd expect of a true solution.

Any advice? The developer seems sufficiently active. I have moderately hard tap water here, which is what I used.

[Thinking of ordering proper sodium carbonate.]

Thanks, Larry in Kingston, Ont.
 
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