Wednesday, 16 January 2013

08:20 – We’re hoping that today will be the first “normal” day in a long time. No doctor appointments, no unexpected trips over to Barbara’s parents’ place. We’ll see. Barbara and Frances both need a break from the constant turmoil.

As of this morning, we have two BK01 biology kits, three CK01A chemistry kits, and zero FK01 forensic science kits in stock, and we got an order overnight for a biology kit. Fortunately, I spent yesterday building kit subassemblies. At this point, we have everything needed to build 14 more BK01 biology kits, 8 more CK01A chemistry kits, and half a dozen FK01 forensic science kits, which should be enough to carry us into next month.

I’m also issuing purchase orders, and they’re typically considerably larger than the ones I issued in the past. For example, we buy pocket magnifiers and alligator clip leads from one of our wholesalers. The last time I did a PO to them, I ordered 100 pocket magnifiers and 200 each of the black and red alligator clip leads. I issued a new PO to them yesterday, ordering 300 pocket magnifiers and 500 each of the alligator clip leads.

I have no clue how many kits we’re going to sell this year. In the first half of this month, we sold more kits than we sold in the first three months of 2012 combined. Annualizing that yields a very scary number. I guess all we can do is keep building kits as fast as we can, and hope we can keep up with demand.

Speaking of which, Brian Jepson, our O’Reilly/MAKE editor called yesterday just to touch base. During the conversation, I said, “I hope you’re not going to tell me you want another book out of us.” He said, “Whenever you’re ready.” I told him that Barbara really wanted to focus on kits, but I’d mention it to her. When I did that this morning, she said it was up to me. She knows I like doing books. But she also said that her strong preference was to spend our time doing kits rather than a new book. As she said, we’re already covered up just doing kit stuff, so doing a new book would end up costing us a lot of money, not to mention disappointing would-be kit customers when we can’t meet demand. So it looks like we’re not going to do another book any time soon.

12:41 – Well, another order for an FK01 forensic science kit just came in, so our stock status on those just went from zero to minus one. I mailed the woman who ordered the FK01 kit to say we couldn’t ship it until the day after tomorrow and that we’d be happy to refund her payment if she wished. Fortunately, she’d bought one of our other kits some time ago and was very happy with it, so she was willing to wait.

I have everything I need to build another 15 FK01 kits, except I have only five FK01 small parts bags and I’m completely out of Kastle-Meyer reagent and Dragendorff reagent bottles. I made up enough Dragendorff reagent for 30 sets, but I have to make up the Kastle-Meyer reagent this afternoon or tomorrow. That involves refluxing a concentrated solution of potassium hydroxide and phenolphthalein over zinc metal to reduce the phenolphthalein to phenolphthalin, which takes a while. I’ll make up enough of that for 15 or so kits, because the solution is fairly unstable. We use amber glass bottles, add some zinc powder, and store the bottles refrigerated to prevent the solution from oxidizing, but even so it’s unwise to make up more than we expect to ship in a couple months.

Speaking of which, I need to do something about how I ship kits. In the past, we might have kits sitting waiting for pickup only two or three days a week. Nowadays, it’s a rare day that we don’t have kits waiting for pickup. The mailman generally arrives mid- to late-afternoon but when a substitute is doing the route he or she sometimes arrives before 9:00 a.m. I don’t want to leave kits sitting on the front porch, and I can’t hear the doorbell when I’m working in my lab. Colin barks every few minutes at a passing dog or even a person walking down the street. I can hear him barking from my lab, but I’d soon be exhausted if I ran back upstairs every time he barked.

I could drive out to the post office and drop off kits, but that’s several miles round-trip. Also, oddly, if I drop off a Regional Rate box at the counter, they charge an extra $0.75 postage. Talk about adding insult to injury. Driving to the post office is time and money, even before they add the extra $0.75 per box. So I think what I’m going to do is start moving boxes that are ready to ship to my Trooper and go off driving around the neighborhood looking for a mail truck. Then I can just hand the boxes to the letter carrier. That’ll take a lot less time than driving to the post office, and the letter carrier doesn’t charge the extra $0.75/box.

14:17 – Just call me Baldrick, because I have come up with a truly Cunning Plan. Last Sunday, Barbara and I did a Costco run and dinner with Mary and Paul. I mentioned the stability problem with Kastle-Meyer reagent to Paul, and he suggested nitrogen-packing the bottles. The problem with that is that there’s no convenient source of pure nitrogen other than bottles, which are relatively expensive and dangerous to have around. (In college, I once saw the results of a full-size compressed gas bottle that had fallen over and broken off the valve. Instant rocket. The bottle crashed through two concrete-block walls and severely damaged a third.)

So I focused my Gigantic Brain™ on the problem, and came up with Cunning Plan A. Oxygen concentrators like the one Barbara’s dad has extract nearly all of the oxygen from ordinary air, leaving only nitrogen with tiny percentages of carbon dioxide, water vapor, and noble gases. Used concentrators are readily available and inexpensive. There’s a big market for them from people who need oxygen for stuff like micro-welding of jewelry and so on. I though that perhaps I could simply reverse the functioning of a used oxygen concentrator to collect the nitrogen and discard the oxygen. I was actually about to start searching google for used oxygen concentrators.

Then I was struck by Cunning Plan B, a great improvement over CP A. Barbara buys six-packs of Dust-Off canned “air” at Costco. The contents of the can are actually 100.0% 1,1-difluoroethane, which is a refrigerant and is essentially inert. It’s also denser than air. So, I’m going to fill the Kastle-Meyer reagent bottles normally, add a few grains of zinc dust to stabilize them against any oxygen that happens to remain, and then flush the bottles with canned air before capping them. Since I’ll also store them refrigerated at near 0C, their shelf life unopened should be at least a year and probably much more. There just won’t be anything in that bottle to sustain oxidation. I’ll put a few dated bottles aside and open and test one every six months or so to get a better idea of actual shelf life.