Jan-Erik Bergh
PRE-MAL www.nrm.se/premal
At 18:36 2008-10-16, you wrote:
Greetings -
Data loggers are precise and record many data points, but some folks can't afford them.
The least expensive thermometer set up I know of that is useful in monitoring the freezing of library materials is an indoor outdoor thermometer that I got at "Radio Shack" (electronics chain store).
$20, stock number 6301032, "indoor/outdoor" thermometer, temperature range -58F to +158F. Uses one AAA battery. The temperature probe is about 1" long and 1/4" in diameter and is on the end of a thin cord that is 10 ft. long. This model stores high and low temp readings and also monitors relative humidity.
The four older Radio Shack/Micronta units I have used for several years don't have the data recording and rH features, so I can't comment on how these new features work.
I use one of my thermometers with an old phone book (3 inches thick). I carved a channel into the middle of the phone book for the probe and the cord, and put the phone book in a plastic bag.
The cord is not too thick to keep the door of our freezer from closing properly. However, a freezer repair person drilled a hole through the freezer door that is large enough to place the probe inside the freezer, and sealed the hole with silicone caulk, so now the probe is permanently installed in the freezer.
This set up gives a "ball park" idea of the core temperature of the materials I am freezing. I check the thermometer after 4 hours to see if the core temperature has reached -20 Centigrade ( = -4 F). The old rule of thumb for killing bugs is that the bugs should be at ambient - comfortable for them- temperature right before they are placed in the freezer. The core temperature of materials in the freezer should reach -20 Centigrade within 4 hours so that the bugs don't acclimate to the cold and survive the freezing. Freeze for 72 hours and thaw over 24 hours.
It is also useful to know the core temperature before materials are removed from the freezer. If they are completely thawed, no condensation should form on the materials when they are removed from the freezer.
One comment about freezing textiles: there may be buttons made of bone or plastic, or other parts that could be damaged by freezing.
Mary Baughman
Book Conservator
Harry Ransom Humanities Research Center
The University of Texas at Austin
P.O.Drawer 7219
Austin, Texas 78713-7219
Telephone (512) 471-8635 or 471-9117
Fax (512) 471-7930
What kind of thermometer are you all using and where can they be purchased? How often do you monitor the temperature?
Thank you
Kate Wellspring
_____________________________________
Kate Wellspring
Collections Manager
Amherst College Museum of Natural History
Amherst, MA 01002
(413) 542-2165
www.amherst.edu/museumofnaturalhistory
On 10/15/08 11:40 AM, "Kaplan, Emily" <[EMAIL PROTECTED]> wrote:
- Hi Molly,
- You might also check resources on museumpests.net
- fact sheet on webbing clothes moth
- http://museumpests.net/whitesheets/default.php
- Fact sheet on low temperature treatment
- http://museumpests.net/tools/treatments/FINAL-Low_Temp_fact_sheet.pdf
- This fact sheet also includes references (Tom Strang's article in Collection Forum "A Review of Published Temperatures for the Control of Pest Insects in Museums." Collection Forum 8, no. 2 (1992): 41-67
- gives lethal low temperatures for various pests and his CCI note is very helpful as well
- http://www.cci-icc.gc.ca/publications/ccinotes/pdf-documents/n3-3_e.pdf
- What kind of a freezer are you using?
- You might look at this document about modifying chest freezers to get lower temperatures http://museumpests.net/resources/modifying_a_chest_freezer_for_pest_control.pdf
- Best,
- Emily
- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Margaret Geiss-Mooney
- Sent: Tuesday, October 14, 2008 7:46 PM
- To:
pestlist@museumpests.net
- Cc: 'Molly Gleeson'
- Subject: RE: [pestlist] question about freezing
- Good afternoon, PestListers - My understanding of the freezing process is that freezing if done correctly also kills the eggs, very important when you are dealing with infested textiles.
- Check out the following NPS ConserveOGram on freezing:
- http://www.nps.gov/history/museum/publications/conserveogram/03-06.pdf
- It appears that you do need to get that freezer temperature done to -20C for 48 hours. Rapid cooling to -20C is also necessary to assure a complete kill. The ConserveOGram covers the whole procedure very well.
- Depending on your budget and your staffing, perhaps anoxic treatment should be considered?
- Regards,
- Meg
- ._ _ _ _ _ _ _ _ _ _ _ _ ______
- Margaret (Meg) Geiss-Mooney
- Textile/Costume Conservator in Private Practice
- in beautiful Northern California
- Professional Associate, AIC
- [EMAIL PROTECTED]
- are in a freezer that is set at 0 F (-17 C). We are in the process of packing the other half in preparation to move them into the freezer as well. I would like them to be frozen in a freezer set to at least -20 C, however, the freezer company quoted exhorbitant fees for lowering the temperature of the freezer, even for only a few days. I'm concerned that -17 C isn't cold enough to ensure that the moths are killed, even if we keep them in the freezer for several weeks. Is this true?
- I'm also thinking that we should do a second freeze, to ensure that all life stages are killed, but if the temperature is not low enough, then maybe this is pointless. I plan to do a test by putting a bag of live moths/larvae into the freezer along with the objects, to monitor what's happening, but does anyone have any experience with this, or have any suggestions about adjusting the temperature and also about the recommended length of time to freeze at -17C to ensure mortality of the moths?
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