Scale for chemicals

[ChrisP]

I would like to mix my own developer (some ID-68 I believe , whatever the microphen equivilent is) and I need a scale to do so accurately. Where is the best place to purchase one (or would everyone just suggest I try to find a drug dealer and jump him).

Note this would mean I need to be able to measure 0.13 grams phenidone

 

[Calzone]

Chris,

I wish I could help you because I'd just use a micro gram scale that I have at work.

Fisher Scientific is a lab supplier that could help you secure a scale.

Cal

 

[sevo]

ebay has a wide assortment of drug dealers' scales - for whatever reason called "jewellers" scales. For my darkroom needs, a cocaine (a.k.a. diamond) scale with 0.01g resolution and 10g maximum and a pot (a.k.a. kitchen) scale that ranges to 2kg @ 0.1g resolution proved to be good enough.

 

[Fotohuis]

On the internet you can buy electronic balance in 100mg accuracy for less then Eur. 40,00. 0-500g e.g. EKS. Very suitable for measuring in photo chemicals.

best regards,

Robert

 

[Roger Hicks]

Or visit a few schools and see if they still have any old mechanical balances lying around. Unlikely but worth a try.

Cheers,

R.

 

[MDenton]

Available from about $6 on Amazon.

http://www.amazon.com/s/ref=nb_sb_n...+pocket+scale&rh=i:aps,k:digital+pocket+scale

 

[Freakscene]

The 'jewellers' scales or a scale that handloaders use for measuring propellant (gunpowder) are your best bet.

Marty

 

[f/14]

To mix my own BW developers I use a fairly cheap electronic scale normally used by ornithologists and biologist to weigh small birds and insects in the field.
The model http://www.jadeverscale.com/cgi-bin...me=JKD&Key_1=&Key_2=C14&FORUM=C14&FORUMTYPE=E has a claimed resolution of 0.05 grams. Still it is plastic on the outside and sells for some tens of dollars. About the size of two sigarette packs.

 

[neelin]

I got one from dealextreme.com 300g 0.01g delivered to Canada, all in for less than $15. Been really happy with it. Checked it against known mass of coins, and it's right on. Like others, I'd recommend mixing Phenidone with hot TEA, and use a syringe to take some. Much more accurate than measuring those quant. and keeps really good in triethanolamine. If you're mixing Phenidone dev's, make sure to try Chris Patton's E76, it's really sweet.

E76 http://www.flickr.com/photos/neelin/4357234544/
Scale http://www.flickr.com/photos/neelin/4398933648/

 

[splitimageview]

I have a vintage Kodak scale (with original box!) if you want to go retro. 🙂

 

[ChrisP]

Thanks but please keep going

Thanks but please keep going

This is an updated version of the one I have and it works really well. Make sure you get a calibration weight to keep your measurements accurate. http://www.myweigh.com/440z.html

If you are using Phenidone it is much more convenient to make a percentage solution. I would suggest that you use the neutral Propylene Glycol instead of TEA. Even a small amount of TEA will disturb the pH of many formulas.

This sounds like good advice but I don't know what it means. What is TEA (I've never mixed anything before but its hard to find a fast developer where I live). But you're right I am using Phenidone

 

[maddoc]

TEA = Tetra-Ethyl-Amine ? that would be a complex-forming compound ...

 

[sevo]

That would be either Triethanol- or Triethylamine. Both can be used as a developer solvent, but either has the same problem - while in many ways excellent solvents for developing agents, the TEA's are active, alkaline and cannot simply be added to an existing formula. There are plenty of perfectly good developer recipes that contain one or the other TEA, but it is not a trivial DIY additive. Unless you are into chemistry and have plenty of time and film for test runs, you'd better not add it to recipes that don't already ask for it...

 

[Bob W]

I think you mean triethanolamine or triethylamine. Tetraethylamine would be an ion.


Bob W

 

[maddoc]

TEA = Tetra-Ethyl-Amine ? that would be a complex-forming compound ...

My fault, TEA = Tetra-Ethyl-Ammonium and not Amine ... 🙂

 

[Freakscene]

TEA is triethanolamine, a triol tertiary amine. Its formal acronym in industry is TEOA to differentiate it from triethylamine (a totally different compound), but TEA has stuck among those who mix their own developers.

Triethanolamine is useful as a developer component because it is a liquid at room temperature, water soluble and a strong base, so a small amount will make an alkaline developer that can be stored as a liquid concentrate. Air does not dissolve well in it and it typically does not contain ions or other contaminants that can interfere with components of developers. It makes for long-term stability of stock solutions of developers that contain ascorbates particularly, but also phenidone and other compounds that are used in some developers where stock solution stability is problematic if water with ions in it is used.

One problem with triethanolamine as a developer component is that metol only dissolves in it if the metol is in the base form, not as the commonly available hemisulfate salt that is the most stable dry form of that compound.

For general purpose mixing of developers I agree that propylene glycol is a better solvent, because it will not change the pH of the solution you add it to.

Marty