You may have thought I didn't have another post about freezers in me, but you were wrong.
The -20 stopped working after we defrosted it. No obvious cause. We get the Sears repair guy out (yes, the freezer was a Kenmore....we're not keeping anything explosive in it). For $70, he tells us instantly that it's probably leaked the coolant (or something like this) and it will cost more to repair than to buy anew. (Sometimes? I really dislike America.)
He also says, "This freezer is designed to be opened and closed about four times a week. How often do you open and close it?"
"Uh, about 10 times a day."
"Yes, that's your problem."
This freezer was about 4 years old when it bought the farm. The question facing us was: do we buy another cheapo Sears freezer (~$600) and assume we'll just have to replace it every four years? Or do we buy the VWR equivalent ($1600) in the hopes that it is designed for lab usage and will last longer, and keep our stuff colder? (One of the reasons we defrosted the original freezer is that we noticed some things in it were disconcertingly unfrozen.)
The second question was, frost-free or manual defrost? I've always heard that frost-free is bad for science stuff, but we don't keep any enzymes or antibodies in this freezer, just drug aliquots etc that can probably stand a few degrees' fluctuation. Interestingly, a Sears freezer costs nearly the same whether it's manual defrost or frost-free. A VWR frost-free freezer costs about 30% more than its manual defrost counterpart. What the heck is going on inside these things, anyhow?
I don't particularly care what the lab does, but I do want to know what the general best answer in this situation is, so that when I have my own lab to run I know if it's worth the money to buy a VWR freezer.
In the end, our lab manager talked with a sales rep. Naturally, on Tuesday we are expecting a delivery of a new, bigger, frost-free, $3100 freezer.
I am none the wiser about how I will run the Jekyll lab.
15 years ago
7 comments:
Sometimes you don't even think about the little things that you need to have when an appliance is being modified for science. In the building I am at, the powers that be decided to save money by installing regular (non-science grade) walk-in fridges for the cold rooms. The problem is that these walk in fridges do not have humidifiers and we now have a constant mold problem.
My (new prof) boss got a cheapo -20 for non-enzyme stuff AND a super-fancy vacuum-pulled frost-free -30 for enzymes and antibodies.
We use the -20 less frequently (though more than 4 times a week, surely), and we don't have to defrost the -30. No idea how expensive those are, though.
SM--yikes! And EW! Who knew?
SGG--Yeah, I think it's smart to go cheap for freezers that don't hold enzymes, but I wish we had some sort of industrial freezer (what do chefs use?) for the frequency of opening.
My advice is to avoid frost-free in the lab. It's not worth it. Defrost once or twice a year and you should be fine, so long as you don't let people stand there with the door open. That's where the frost comes from.
I worked in a lab that had one of these frost-free -10 freezer things and for a long time I couldn't figure out why my experiments were working so inconsistently. In the end I eliminated all the variables except the crappy-ass not-cold-enough freezer making my reagents go bad. But I might not have if I hadn't already worked in so many different labs. I shudder to think how many grad students think they suck at science because of problems like that.
scientistmother, I think you mean de-humidifier if mold is a problem? But I think mold is always a problem in cold rooms, maybe just because over time the fans break and universities never fix them. I don't like cold rooms, actually. Most of the things we used to do in cold rooms (e.g. purify proteins) can now fit into a deli case style refridgerator. Much less wasted space and energy.
Hey, instead of VWR check out SciCool from Phenix. I am not a salesperson, (I just play one on TV :P) but I recently equipped my new lab with refrigeration equipment and the Phenix ones had a sweet price with a bunch of promos.
Ms PhD--Grr, my lab mates made me pretty angry about this. What you said is more or less what I said to them ("It's not a big deal to defrost the thing once or twice a year") and their response was, "Well, I don't want to do it, so if you want to do it, fine, but it would be better if no one ever had to do it."
Seriously? A once-a-year defrost is the gargantuan waste of time that is holding them back in life? Gaah. Anyhow, since this freezer only holds aliquots of some solutions, and nothing that should be particularly temp-sensitive, I just gave up fighting for the manual defrost. But thanks for the tip that I should watch for instability of solutions etc--will keep an eye out.
arlenna--oh, too late! but now I will keep it in mind for future JekyllLab.
4" paintbrush from DickBlick (artist supplies): $19.46
3 piece set of paintbrushes from HomeDepot: $20.46
Functional difference for covering large areas of canvas with paint: minimal (not saying high quality art supplies don't give me a thrill, just that for the big brushes the Home Depot version does the job nicely).
Sometimes, things cost a lot more because of the group they are marketed to. Sometimes there are important (e.g. mold-related!) differences of a most dire nature. One of the things that has always irked me about purchases for scientific supplies is that I can personally rarely tell which is which.
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