Tools of the trade

[Ghazanfar Ghori]

KOH is a strong, corrosive base and should be handled with extreme care. If you do decide to go forward with dissolving your own, do so with a lot of care.

[Aaron]

KOH is a strong, corrosive base and should be handled with extreme care. If you do decide to go forward with dissolving your own, do so with a lot of care.

Yeah, I would. Goggles, gloves the whole getup. I'm still not sure my wife will go for it anyhow. It sure does make economical sense though.

[Aaron]

Would someone check my chemistry to make sure I'm not way off?

To make 100 ml of 0.1 M KOH solution.

Atomic weight of KOH...
H = 1.0079
K = 39.0983
O = 15.9994

Total = 56.11 grams

So to make a 1 M solution is 56.11 grams / Liter

Since we need a 0.1 M solution in 100 ml divide by 100 to get 0.5611 grams of KOH dissolved in 100 ml of distilled water.

[Ghazanfar Ghori]

So to make a 1 M solution is 56.11 grams / Liter

Since we need a 0.1 M solution in 100 ml divide by 100 to get 0.5611 grams of KOH dissolved in 100 ml of distilled water.

Looks right to me.

[Aaron]

I wrote Carol for advice as far as mixing my own BAP solutions goes. I told her to feel free to call me crazy and let it be at that.

I think right now the plan would be to make 0.1 M solutions in liter batches and ask a few bucks from GWAPA members who want to mix their own. I suspect the shelf life of the KOH is much longer than the BAP even in powder form so I thought letting members buy their own BAP powder and asking for more KOH solution when they need it made the most sense.

From what I've read it's not too terribly dangerous if you follow the right precautions. Gloves, goggles and long sleeves are a must. Keep an acid such as vinegar on hand to neutralize spills. Slowly add the KOH to COLD water. Keeping the solution in an ice bath while adding the KOH slowly is an even better idea.

[marydotson]

I'm just catching up on this, but there's one thing I don't quite get--why would you need special lids for canning jars? The regular lids are intended to be sterilizeable.

The standard way to sterilize canning jar lids is by boiling them. Granted, there is the possibility of contamination when you lid them (you'd have to do it after removing the jars from the microwave), but that could probably be managed by covering the jars with little pieces of saran wrap before heating them and boiling the lids while the jars heat. Once the jars are ready, just screw the lids on, sealing them loosely over the saran wrap seal. That slip of plastic wrap can be removed (or left in there) when you work in your clean box.

[SCMurphy]

The lids sold for TC use of canning jars are translucent and allow light in.

[marydotson]

Doh!