Acid / Basic housekeeping - bad pun
The liquid concentrated acids I keep in my stocks are all stored in plastic nalgene type jugs with good fitting lids that my supplier - Claire at JD Photochem - ships to me.
I have a bit of sulfuric (pH lowering of developers, fixers), 31% hydrochloric (aka muratic) (some intensifiers, also good for concrete patches, and a safe place to store it is here) , and acetic (makes RA-4/C41 one shot stop bath) on hand. They live on a high shelf one their own; less likey to get disturbed there, and out of the reach of my kids (now 4 and 7). They are purposefully not stored near basic chemicals.
The kids know that they are not allowed in the darkroom unless dad is with them, and they are invited in.
The powerful acids get measured off sitting in the darkroom sink, where lots of water is easily at hand to rinse off any spills, and quickly rinse out any measuring equipment. Usually a little of a concentrated acid is all that is needed, so I save the little graduated cups that are found over the lids of cough syrup. I pour the required acid into one of these, then it is easier to add it bit by bit to adjust pH, or add the measured amount to the liquid solution. You all know the value of gloves, goggles, and a paddle to disperse the acid I hope. I find that stirring just before the acid goes in prevents micro boiling as it reacts with any base present to form the required buffer. Remember, always acid to water, and if not, as in a spill, always lots of water to rinse.
The other more minor special use acids - boric, citric, edta, oxalic, etc are dry powders and I store them in thier own labelled tightly capped plastic jars on a shelf mixed in with other dry chems. I for a long time salvaged washed vitamin pill bottles (and cough syrup bottles for liquid stock solution storage), to deal with chems that arrive in other than a good storage container. These small bottles and jars also allow me to keep a 'working stock' in the handy sink side cabinet, while the larger overstocks of the chemical live in old cheeze whiz etc jars in the bottom drawer of my enlarger desk (it is a big drawer). There is nothing magic about the sink side dry chemistry cabinet - just there is no need to vaccuum a ton of litte bottlles and jars when I am on a dust hunt.
The most powerful base is soduim hydroxide. Most darkroom rats can get by without it, unless you are into lith developers, etc. Because another mad habit of mine is home made soap ( domestic and craft sale scale productiuon) I buy it in a large (25kg) bag, and store it in two 5 gallon pails with well gasketted lids. It is vastly less expensive per kg than buying the little bottle of Red Devil drain cleaner lye, but that is the same stuff.
The transfer of the sodium hydroxide micropellets from the well sealed multilayer bag to the two pails is tricky. I cut a sheet of plastic to cover the laundry room floor (left over from a home reno), and have the laundry room sink full of water before beginning. If the pellets get away from me ( some do) they land on the plastic. After the transfer, I get a wet rag, and wipe down my shoes. I then fold up the plastic from the outside towards the middle and toss it.
I store my hydroxide as a 40% stock solution. It can be bought this way also. I have tried 50%, which is also sold commercailly, and large crystals formed after the solution had cooled- it was a PITA to re-dissolve them.
I have a 1 gallon stainless vat that sits on a magnetic stirrer (retro fitted with a coffee perk heating element clamped under the stir table to heat a beaker when heat is needed). I get the pre-weighed ice (about 50% of the totoal mass of H2O that will be needed and some measured amouint of liquid water spinning to prevent the ice from all clumping up. I then use an empty margarine tub to scoop and weigh the approx NaOH weight needed. I weigh it, subtract the weight of the margarine tub, then add the contents gradually to the swirling mix of ice and water. With gloved hand, rinse the tub in th solution, as some pellets will still be adhering to it. I then add any needed water (1mL equals 1gram when it is just water) to bring the solution to 40% NaOH by weight.
Do use anything that cannot take heat. Pyrex measuring cups are fine. Stainess steel is fine. Aluminum is not; it is consumed and the pot and aqueous solution are both ruined. Plastic may melt. The reaction generates lots of heat. If it boils, leave the room; do not breath the vapours.
You need to calculate the molecular weight of NaOH and H2O to make this 40% by weight solution work (think CRC handbook or periodic table of the elements- rememeber high school chemistry?). I pre work an ideal example, then work out the amount I am actually dealing with as I go. I tape saran wrap over a calculator, to keep the rinsed gloves from dripping water into the calculator keys. Dont take your gloves off until everything is washed up.
Once the hydroxide solution has somewhat cooled, pour it off into a glass storage bottle dedicated to the purpose, and put on a snug fitting lid. Tighen the lid once the solution is at room temperature. The solution will slightly etch the bottle, and also soduim carbonate will form around the inside at the top (as the hydroxide rips the O from CO2 in the air each time the bottle is openned to make OH and O into H2O).
After the hydroxide to stock solution is in the bottle, still with all lab coats, rubber gloves, and goggles on, take dying j-clothes from the kitchen and use them to wash everything and adjacent surfaces with lots of water. The pellets once they abosrb water feel kind of slippery like they are soap. If you feel anyting tingly and soapy on your skin, load on heaps of water, and you will already have a minor burn. Leave it there, and the hydroxide rips the fats from your skin to make soap, and leave a hole hwere the fats in your skin used to be. After wash up, put the lab coat or what ever was your top layer of clothing into the washing machine.
The less powerful bases are much more commonly used. Most of my B&W print developers are made alkaline with good old fashioned Arm and Hammer washing soda - sodium carbonate. 20 Mule Team borax also is used, as well as paint prep targetted Tri Soduim Phosphate as well as more strictly photo purposed soduim metaborate (aka Kodalk) potassium carbonate, and TEA. These are generally stored on their own shelf in the dry chemistry cabinet.
(except in winter, when the TEA (RA-4 developer) sits on top of a heating duct - it freezes at 20C).
Just because an acid or base is less powerful than sulfuric or hydroxide they may still be an irritant. Wear gloves, if only surgical types. if you are going to handle them. I use stainless steel measuring spoons for most of my work with them to keep my hands from touching the chemicals. I weight them in throw away dixie cups that I place on the pan of an old triple beam banace that is tared to cancel out the cups weight.
