Month: August 2014

Sunday, 31 August 2014

10:41 – Barbara is ironing and cleaning house while I do kit stuff. Right now, I’m dehydrating some magnesium sulfate heptahydrate to anhydrous form. The hydrated form, AKA Epsom salts, is cheap, a couple bucks a kilo in USP/FCC form, which is as pure as reagent grade. Buying the anhydrate from a chemical supplier runs $80 to $100 per kilo, which is outrageous.

So I just spread about a kilo of Epsom salts in a large casserole dish and stuck it in the oven at 500F (260C) for an hour. That removes most of the water of hydration and forms a thin glassy layer of magnesium sulfate. I break that into chunks and toss it into a blender that I reserve for such work. I then blend it on high to break up the chunks into mostly powder, run it through a flour sifter, repeat as necessary until all the chunks are broken up, and then put the powder back in the oven for another hour at 500F to finish drying it out. I do this while I’m doing other stuff, so the whole process requires maybe ten minutes of my time. Add the cost of my time to maybe two or three bucks in materials cost and electricity, and I end up with half a kilo of magnesium sulfate anhydrate for less than $20, even billing myself at $100/hour.

The price of many chemicals has gotten ridiculously high. For example, we use copper(II) acetate to make up Barfoed’s reagent, which is essentially a 0.5 molar solution of copper(II) acetate with 10 mL of glacial acetic acid added per liter. I was about to order some copper(II) acetate, but found my regular supplier wanted $120/kilo. Geez.

So, the next time I need to make up Barfoed’s reagent I’ll do it from scratch on the fly. I generally make up four liters at a time, so I’ll start with two clean 2-liter Coke bottles. I’ll transfer two moles of copper(II) sulfate to one bottle. That copper(II) sulfate is from Home Depot, which sells a 2-pound (907 g) bottle of the stuff for about $10 under the name of Root Kill. The assay on the bottle says it’s 99% copper(II) sulfate, which I’ve verified gravimetrically. The remaining <1% by mass is mostly insoluble copper oxide. The molar mass of copper(II) sulfate is 249.68 g/mole. Dividing that by 0.99 gives 250.22 g/mole, so I'll transfer 500.44 g of the Root Kill to the two liter bottle and dissolve it in hot water. (It dissolves quickly in hot water; in room temperature water it can take literally a week to dissolve.) I'll then filter the resulting two liters of pretty blue solution into the second bottle, rinse out the first bottle, and divide the solution with one liter in each of the two bottles. So far, I'll have used up maybe five minutes of actual working time and about $5 worth of the Root Kill.

I’ll then add either sodium carbonate or sodium bicarbonate, both of which are cheap, to precipitate the copper ions as insoluble copper(II) carbonate. Once the precipitate settles, I’ll decant off the supernatant liquid, which contains mainly sodium sulfate with a small amount of the excess sodium carbonate or bicarbonate in solution. If I decant 90% of the supernatant liquid and refill the bottle with tap water, I’ve diluted the original level of soluble contaminants to 10% of what they were. Repeating that process a few times, ending with a distilled water wash, reduces the soluble contaminants to 1%, 0.1%, 0.01%, and finally 0.001%, which is better than good enough.

I don’t even need to filter out the copper(II) carbonate and dry it. I can simply wet it with a liter or so of distilled water and add glacial acetic acid stoichimetrically to convert the copper(II) carbonate to copper(II) acetate in situ, add an extra 20 mL of the glacial acetic acid, and then bottle the resulting Barfoed’s reagent.

And don’t get me started on ammonium metavanadate. The last time I bought it, maybe three or four years ago, I paid something like $15 for a 25 gram bottle. I thought $0.60/gram was pretty high then, but that’s now tripled to nearly $2/gram, and that doesn’t even include the required poison-pack container and hazardous shipping surcharge. Geez. I can synthesize the stuff from scratch here for something like $0.05/gram, and it’s no more difficult than the copper(II) acetate synthesis.

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Saturday, 30 August 2014

08:27 – We ended up getting 20 kit orders yesterday–including one custom order for 30 sets of six chemicals that aren’t stock items–and shipping 14 kits. We’ll ship three of the outstanding six orders today, plus whatever orders come in today that we have in stock, but the others will have to wait until Tuesday.

We’re down to two each of the CK01A and CK01B chemistry kits and the FK01A forensic kits, one of the FK01C forensic kits, and zero of the FK01B forensic kits. Fortunately, we still have 30 or so BK01 biology kits in stock. At least we have the next three days available to build up stocks before Tuesday.

We probably won’t quite match August 2013 revenues this month, but even so we’re running well over last year’s YTD revenues through August. As of now, we’re only a few thousand dollars short of matching total 2013 revenues, with a full third of the year remaining.

11:15 – This is the time of year when our usually-reliable inventory system descends into OMGWO! (OH MY GOD WE’RE OUT!).

The most recent incident took place a few minutes ago when I went down to get a bunch of 24-well reaction plates. I thought we had 10 or 15 10-packs left in stock, but the shelf was bare. OMGWO! Fortunately, after my pulse fell back into the double figures, I noticed the large box at my feet that I’d almost tripped over. Turns out it contains 15 10-packs of the reaction plates. I’d put the box there when the shelf space for the reaction plates was full so that I’d remember I had more. So much for remembering.

So I just issued an $1,800 PO to one of our vendors for stuff we’re running short of. They’ll get it Tuesday and probably ship Wednesday or Thursday, which means I should have the stuff by early the following week.

Oh, I forgot to mention. When we were at Costco last Sunday, one of the attorneys from Barbara’s firm saw us in the parking lot. She asked Barbara if those were our kids with us. Barbara told her that they were our friends, Mary and Paul. I told Barbara she missed an opportunity. I would have said something like, “That was our son Paul and our daughter-in-law Mary. Or was it our daughter Mary and our son-in-law Paul?”

Paul and Mary are half a generation younger than we are, so I suppose it’s remotely possible that I could be their parents, assuming I’d started fathering children when I was in my mid-teens. But the one Barbara and I still laugh about happened soon after Barbara and I were married. I was 31 years old. We were out to dinner with our friend Vicky Epley, who was 27 years old. Barbara ordered a glass of wine, as did Vicky. The waiter turned to me and asked if it was okay to serve Vicky. Mistaken at age 31 for the father of a 27-year-old woman. Geez.

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Friday, 29 August 2014

09:19 – As usual this time of year, we’re run ragged trying to ship science kits and build more. We got orders for 17 kits overnight and so far this morning, which wouldn’t be a problem except that we’re running out of stock on some of the kits. So I’ll get the kits shipped that we do have in stock, and then go build more of what we’ve run out of.

It’s funny. I remember the day we sold our very first kit. At that point kit #100 seemed very far away. Then we sold kit #100, and kit #1,000 seemed very far away. Then we sold kit #1,000, and kit #10,000 seemed impossibly far away. But it’s probably not as far in the future as it seemed at the time, particularly once we get our classroom kits available. When that happens, instead of a good month being 100 kit sales, it’ll be 1,000 kit sales. And at that point, we’ll need a lot more space and some employees. I’m still of two minds about that.

15:06 – Wow. Talk about advice so bad it’s scary: Why Your Passwords Should be at Least 24 Characters Long

And this comes from a supposed computer security expert. I have no problem with suggesting a 24-byte password. The issue is the kind of 24-byte password the author recommends. Here’s an example: HarleyDavidsonStarbucks!!!

That’s exactly three dictionary words and three bangs. Better than a six-byte password, but it needs to be a lot better than it is. Crackers use dictionaries, too, and a supercomputer is just as capable of concatenating dictionary words as it is of working byte by byte. As a matter of fact, there are special dictionaries for crackers.

I would suggest a 24-byte password, but using purely random characters generated by a hardware random-number generator (AKA, dice or coins). So you end up with a password that is 24-bytes of random gibberish. Everyone seems concerned that such passwords are impossible to remember. So what? Write them down and let Firefox store them. Sure, doing that creates a gaping security hole, but again so what? If someone has physical access to your premises and your computer, you’re screwed anyway. What you should be worrying about is someone gaining electronic access to the hashed versions of your passwords, either on your own machines or on, say, Target’s corporate servers. If the plaintext of your passwords is 24 random characters, they can crack away to their heart’s content and not gain access to the plaintext for many decades. Unless, of course, someone figures out (or has already figured out) how to quickly factor the products of large prime numbers. If that happens/has happened, all bets are off.

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Thursday, 28 August 2014

07:57 – So, I was down in the lab yesterday making up a new batch of Kastle-Meyer reagent, which is used in forensic science as a presumptive test for blood. It’s made by dissolving phenolphthalein powder in a concentrated solution of potassium hydroxide and then refluxing it over powdered zinc until the intense pink color of phenolphthalein in basic solution fades to colorless as the phenolphthalein is reduced to phenolphthalin.

Even cold, concentrated solutions of strong bases like potassium hydroxide etch/dissolve glass, and if they’re boiling they do so very quickly. Within a couple of minutes, the glass starts to turn cloudy with chalky white streaks. Once a flask is used to make up KM reagent, it’s too ugly to even consider using for anything else. So, the first time I made up a big batch of KM reagent a couple of years ago, I devoted a 2 L Erlenmeyer flask to the job, and that’s all I’ve used it for ever since. For the first batch, I put a kilo or so of zinc powder in the flask, made up the KM reagent, and then washed the flask out with several changes of water, leaving the unreacted zinc powder in the bottom of the flask. I store the flask full of water and stoppered, because damp zinc powder is pyrophoric (catches fire spontaneously when exposed to air). The next time I need to make up a batch, I drain the water, rinse the zinc several times, and use it again for that batch. I’ve done that several times over the last couple of years, and it’s always worked as expected.

Normally, I just add a liter of water to the flask along with the appropriate amounts of potassium hydroxide and phenolphthalein powder, put it on the hot plate, bring it to a boil, and then let it reflux for a few minutes. As it simmers, the bright pink color starts to fade and after five or ten minutes the solution turns colorless. But yesterday it didn’t work. After sitting there refluxing for half an hour or more, the solution was as pink as ever. Hmmm. Obviously, the zinc wasn’t reducing the phenolphthalein to phenolphthalin. It looked like there was still plenty of zinc in the flask, but instead of powder it looked more like a zinc coral reef. So I transferred another couple hundred grams of zinc powder to the flask. Sure enough, within five minutes the solution had turned colorless. The moral here is that just because it looks like there’s plenty of zinc remaining doesn’t mean there is.

10:45 – I get a surprising amount of private email from preppers, many of which ask me science-related questions. Sometimes they link to threads on various prepper forums. For example, one topic that I’m frequently asked about is storing antibiotics. The usual questions have to do with how long various antibiotics can be stored and the suitability of veterinary antibiotics for human use. I’m always surprised by how bad the information is on many of these threads, including quite a few comments by physicians, who should know better.

With regard to shelf life, the real answer is that most antibiotics if stored in the freezer will still be usable 20 or more years from now. Their potency may decline a bit, but long-term tests have shown that most antibiotics lose 10% or less (often, much less) of their potency after being stored frozen for 10 years. Just as important, any degradation that does occur does not create toxic byproducts. The one exception is the tetracyclines, which should not be stored long term. Tetracyclines do in fact produce hepatotoxic and nephrotoxic degradation products. Administering old tetracycline or its derivatives can kill the patient from liver or kidney failure.

With regard to human use of veterinary antibiotics, that’s generally not a problem. It’s not like pharmaceutical companies produce amoxicillin for humans in one plant and amoxicillin for veterinary use in another. It all comes from the same vats, and veterinary medications are packaged as carefully as human medications. One problem arises because people are not dogs or cows or chickens. The mechanisms are very similar in any of these animals, including humans, but our internal organs and processes may differ, sometimes significantly.

For example, on one forum thread someone asked if erythromycin packaged for oral veterinary use was suitable for oral human use. A physician responded that it was fine. It’s not. Veterinary erythromycin for oral use is often in the form of the phosphate salt. That’s fine if you’re treating chickens or turkeys. In humans (or other mammals), not so good. The problem is that the phosphate salt is quickly broken down by human gastric juices and the erythromycin is destroyed before it can be absorbed. Erythromycin for oral use in mammals is compounded with a different anion that renders the salt much less subject to being broken down by the hydrochloric acid in mammalian stomachs.

I keep a pretty good stock of veterinary antibiotics. For example, I order penicillin G potassium and sulfadimethoxine literally by the kilo for use in biology kits. Neither is intended for human use, but both are usable. The penicillin G potassium is not ideal for oral human use because it’s also degraded by stomach acids, but it can be used orally by increasing the dose and administering it when stomach acid is minimal, such as an hour or so before meals. One can also administer sodium bicarbonate (baking soda) a few minutes before the antibiotic to reduce stomach acidity even further. The sulfadimethoxine has never been approved for human use in the US, but it’s widely used in other countries, particularly Russia, and has been for decades. It’s as effective as the other sulfas on organisms susceptible to sulfas, and it has the added advantage of a very long biological half-time. That means it needs to be administered only once per day rather than the every four hours typical for short-acting sulfas.

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Wednesday, 27 August 2014

09:25 – One of the things that makes this time of year hectic for us is the unpredictability of orders. For example, as of yesterday morning, we had what I estimated as at least two or three weeks’ worth of forensic kits in stock. When I finished shipping kits yesterday, we were down to two forensic kits in stock. There’s no way to predict with any reasonable accuracy because our volume just isn’t large enough. We could get an order five minutes from now for 30 biology kits, which we could cover. Worse, we could get an order for 30 chemistry kits, which at the moment we couldn’t cover. So this time of year we just do the best we can to ship timely. I’m on my way downstairs right now to make up another batch of Kastle-Meyer reagent for forensic kits, along with several other chemicals we’re out of.

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Tuesday, 26 August 2014

08:36 – I called the local Costco yesterday morning to tell them they’d overcharged us by 41 4-packs of Coke. She corrected the charge and is mailing us a receipt. She did seem annoyed at the checker at the door, who should have noticed that we had only four 4-packs instead of 45 of them.

Last night, I tried on the Kirkland Signature jeans I picked up Sunday. The waist was nominally 38 inches. I didn’t actually measure it, but the waist fit me properly. The only issue is that this line of jeans is “relaxed fit”, which means it allows extra room in the seat of the pants that I don’t really need. I’d prefer standard fit, but they’re not really baggy on me.

The Costco/Kirkland jeans are made in Mexico. I’d prefer US-made but Mexico is okay. At $14, they’re less than a third the price of the US-made jeans I bought at All American Clothing or jeans from LL Bean or Lands’ End, which are made in places like Turkey and Syria and Pakistan. Barbara’s only comment was that if I’m going to keep buying new jeans she thinks I should start purging our closet of some of the old ones.

I’m filling bottles today for a new batch of chemistry kits, and I think I’m going to try something new. For hazardous chemicals, USPS shipping regulations require that “Each inner receptacle must be securely sealed with wire, tape, or other positive means.” Until now, Barbara has been taping the caps on hazardous chemical bottles, which is time-consuming. For example, 10 of the 40-odd chemicals in a chemistry kit are defined as hazardous for shipping purposes, so that’s 10 bottles per kit she needs to tape the caps of.

As a possible alternative, I just ordered a box of 500 shrink bags from Amazon. I already have a heat sealer and a heat gun. There are six 15 mL bottles and four 30 mL per kit that need their caps secured, so I’m going to try making up two blocks in heat-shrink bags: one block of six 15 mL bottles and a second of four 30 mL bottles. The heat shrink bag meets the requirement to secure the caps, and also eliminates one bagging step because the heat shrink bag itself counts as the inner bag. We’ll still need to use an outer bag with absorbent to contain the two heat-shrink bag blocks, but overall that should cut down on the total steps and total time needed. Also, having the bottles neatly blocked will cut down on cubic, which is always a good thing.

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Monday, 25 August 2014

09:27 – We did a Costco run and dinner with Mary and Paul yesterday. As we arrived at the restaurant, we were talking about how much we’d paid. Paul and Mary’s receipt had been for about their usual amount. Our usual amount is $250 to $350, but this time it was over $500. When I looked at the register tape, the reason jumped out at me. We’d actually bought four 2-liter 4-packs of Coke Classic at $4.99 each. The cashier had rung it up as 45 4-packs at $4.99. That’s 180 bottles of Coke, 360 liters, 360+ kilos, or about 800 pounds worth. Even if we could have fit that much into the Trooper, with the four of us and the rest of the stuff we bought, we’d have been so far over the Trooper’s rated payload capacity that the poor thing would probably have collapsed on its axles.

So I called Costco’s customer service number when they opened at 09:00 our time. The lady I spoke with said she couldn’t fix the problem on the phone, but if we took the register tape in the next time we went to Costco they could fix it there. She apologized for the error, but said they’d fix it no questions asked. I told her this was definitely a case where they’d have no doubt we were telling the truth, because we’d actually bought four 4-packs of Coke and been charged for 45 instead of four. She just started to laugh and said that was the most obvious cashier error she’d ever heard about.

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Sunday, 24 August 2014

09:04 – Barbara and I are doing the usual Sunday stuff. After Barbara finishes cleaning house and ironing, we’ll get back to building more science kits.

I’ve been saving the dehumidifier water in new 5-gallon (19 liter) buckets. Chemically, it’s as pure as distilled/deionized water from the supermarket, so it’s fine for making up solutions for kits and we don’t have to buy it. It’s not potable, of course, because it contains bacteria, mold spores, etc. that the filter doesn’t catch. I’m running out of new 5-gallon buckets, so I’m going to start transferring it to labeled 2-liter soda bottles that I’ll store for use later in the year when we’re no longer running the dehumidifier.

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Saturday, 23 August 2014

10:04 – The guys who poured our new sidewalk sprinkled what I thought was grass seed along the edges of the walk. I’m not sure what it was, but what’s growing doesn’t look like any lawn grass I’ve ever seen. More like baby marijuana plants. So Barbara is out there now with a spade and her edger digging up the baby plants and putting down actual grass seed.

We’re in pretty good shape on science kit inventory, but mainly because sales have slowed down considerably. Until Wednesday, we were shipping anything from four to nine kits per day. Thursday, we shipped only two, yesterday one, and so far today one. But that’s the way it goes this time of year. We could end up selling 50 or 100 kits in the next week. Things go in spurts.

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Friday, 22 August 2014

08:28 – I’m still building and shipping science kits. I have a new batch of 30 biology kits binned and ready to finish boxing up, which’ll take an hour or so. Then I’ll get started on another batch of 60 chemistry kits.

Meanwhile, when I have a spare moment, I’m still working on the new Earth Science and AP Chemistry kits. The more I work with the 2013 revision of the AP Chemistry lab curriculum, the less I like it. The pre-2013 curriculum included 22 labs, which I thought was too few. The 2013 revision cuts that to 16 labs, but duplication among those labs reduces it to only 12 or 13. They’ve also narrowed the scope, skipping many major topics that should be covered in a second-year high-school chemistry lab course. And they’ve gone to all “guided-inquiry” labs, which basically means the teacher tells the students what the goal is and leaves it up to them to figure out what to do and how to do it. I don’t think that’s appropriate even in a public school setting with a qualified AP Chemistry teacher, let alone in a homeschool environment. Students should think about what they’re doing and why, certainly, but tossing them in at the deep end results in a lot of flailing around and wasted time. Finally, the official AP Chemistry labs assume a formal high-school chemistry lab is available, with analytical balances, spectrophotometers, pH meters, fume hoods, suction filtration setups, etc. etc. Few homeschool families will have access to that kind of setup. In fact a lot of public high schools don’t.

So we’re going to go our own way. We won’t call the new kit “AP Chemistry”. We’ll call it “Advanced Chemistry” and cover what we think needs to be covered. We’ll certainly cover the key topics in the AP Chemistry lab curriculum, but much else besides.

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