Support our Sponsors, they keep FADU free: AG Photographic The Imaging Warehouse Process Supplies RH Designs Second-hand Darkroom Supplies |
> Home made Kodalk |
*** Click here for the FADU 2015/2014 Yearbooks *** |
|
Thread Tools | Search this Thread | Display Modes |
#1
|
|||
|
|||
Home made Kodalk
I am getting to the end of my Kodalk (Sodium metaborate.)
I have a formula to make my own shown below. 7g Borax mixed into 300ml water 1.5g Sodium Hydroxide Top up to 400ml with water 40ml = 1g Sodium metaborate. All seems OK until you consider I am making 500ml of TF-2 Alkaline Fix that requires 5g of Sodium metaborate. At 40ml = 1g that is 200ml to be added to the first amount of luid of 300ml fluid. To much liquid. So how concentrated can I mix the Sodium Mtaborate stock solution? Cheers.
__________________
It will all be over by Christmas. |
#2
|
|||
|
|||
The limiting factor would appear at first to be the solubility of borax. A search will offer various amounts, and warmer temperatures will allow more to dissolve. Sodium hydroxide is very soluble (And Dangerous Especially When in Dissolving in Warm Water).
I have a vague memory of an article at APUG (Photrio I think it's now called) where it didn't all need to be dissolved at first. I'll have a look. I haven't tried to make metaborate this way. My only reservation would be that the hydroxide is so powerful that an error in weighing might leave the mixture too alkaline. This could happen if, for example, your borax had absorbed atmospheric water and was consequentially effectively a bit less in real quantity. Checking the pH would be helpful. My wife says I'm often negative. I guess that's right. |
#3
|
|||
|
|||
Quote:
Worth asking him as I got a very quick answer on my "missing video" Mike |
#4
|
||||
|
||||
Pictorial Planet aka John Finch has a video on YouTube on how to make sod. Metaborate
__________________
"Tea is surely the king of all drinks. It helps against the cold, it helps against the heat,against discomfort and sickness, against weariness and weakness". Heinrich Harrer. |
#5
|
|||
|
|||
Nat, I have just had a look at John's Finch's "Making TF-2 Fixer" video where he mentions the difficulty of obtaining sodium metaborate and he simply suggests that you add the borax and sodium hydroxide powders straight into the rest of the ingredients when making TF-2
He doesn't seem to suggest the need to do this in any particular order so on the surface it would appear that at the stage when metaborate powder is added you simply substitute the borax and sodium hydroxide, presumably in the same order in which you make up "liquidised" sodium metaborate So it might be my naivety but might the process be simpler than you think On the other hand I may be missing something in what you see as a problem Mike |
#6
|
||||
|
||||
__________________
"Tea is surely the king of all drinks. It helps against the cold, it helps against the heat,against discomfort and sickness, against weariness and weakness". Heinrich Harrer. |
#7
|
|||
|
|||
Borax comes in different forms Anhydrous, Dihydrate, and Pentahydrate. We use the Anhydrous form usually here in the UK.
Be aware that Borax in hardware stores now is often marked in smaller print "Substitute" and is Dodium Sesquicarbonatehas no photographic use. It's easier to think: 10g Sodium Metaborate = 7g Borax (anhyd) + 1.5g Sodium Hydroxide. Ian |
#8
|
|||
|
|||
Now that I think about it, my reservations about getting the combination exactly right, because of the strength of sodium hydroxide, for fixer it would be inconsequential, as the pH could vary a bit without the slightest problem.
For a developer I think it would be more important to get it right. This is the article I was thinking of. Unnecessarily complicated in the present context. https://www.photrio.com/forum/thread.../#post-2458262 Last edited by Stocky; 26th July 2022 at 09:33 PM. Reason: addition |
#9
|
|||
|
|||
Quote:
If he can does he do it in the order in which he would add the sodium metaborate powder were that to be available ? Thanks Mike |
Support our Sponsors, they keep FADU free: AG Photographic The Imaging Warehouse Process Supplies RH Designs Second-hand Darkroom Supplies |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Home made neg insert | PaulDiz | Darkroom | 5 | 16th April 2020 09:41 AM |
Home made camera's | CornishChris | Photography in general | 2 | 13th November 2019 08:56 AM |
Home made filters. | CambsIan | Photography in general | 5 | 9th August 2018 08:04 AM |
Home made camera | pudgoodwin | Cameras - Large Format | 9 | 9th November 2015 09:10 PM |
Home made cameras | RayHeath | Cameras - Large Format | 6 | 31st December 2010 08:42 AM |