Re: [pestlist] Defrosting
This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- I believe that many institutions keep the things they've frozen in the bags. Given the use of collections, there may be no good reason to go through the time and trouble of handling things, and the plastic bags will keep bugs out as well as dust and gaseous pollutants, at least for a while. I know that we chronic worriers (conservators, registrars, and collection managers) are always looking for potential damage, but there are a lot of things that aren't as bad as we might think. RH issues often seem troublesome, but when a hygroscopic item takes up most of the space in a plastic bag, the controlling moisture is the moisture content of the item, not the RH of the air. Likewise, I think, with the possibility of thermal shock; it's a highly unlikely problem. It would help us if we could get reassurance about potential problems that , so far, turn out OK. Here's what I think we should do: make a concerted effort to report any damage we have observed on this list, along with reports of large-scale treatments - heat, cold, and anoxia - what kinds of objects were involved, and what the outcome was. Maybe someone can figure out a way to incorporate such a thing on Museumpests.net. I would guess that this dist list includes a large proportion of the people who do this work and who make the effort to examine the things after they have been treated. The information shared in this group is huge, and we should figure out as many ways as possible of making it usable. We need to know as much about good outcomes as bad ones. Barbara Appelbaum On Aug 23, 2012, at 8:49 PM, Neil Carey wrote: This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Since implementing IPM a month ago, we've been successfully freezing our ethnographic collection of mostly wooden African pieces, many with textile, feather, or metal attachments, at -30c. Thanks to the group for all their valuable input. However, I don't recall any discussion about controlling the defrost cycle. Are there any special considerations? Off hand, I can think of the possibility of mold growth if an object is kept double wrapped in polyethylene after defrosting, despite being wrapped in tissue paper. Am I overly paranoid? Just how long should a controlled defrost take? Must the object be removed immediately? If not, how long can it go heat sealed in bags? It's not like anoxic treatment where a piece can just be kept inside its polypropylene bag forever. Any input? Neil Carey -- To send an email to the list, send your msg to pestlist@museumpests.Net To unsubscribe from this list send an email to pestlist@museumpests.net and in the subject put: unsubscribe - no quotes please. You are receiving the Pestlist emails in standard mode. To change to the DIGEST mode send an email to imail...@museumpests.net with this command in the body: set mode digest pestlist Any problems email l...@collectionpests.com or l...@zaks.com Appelbaum Himmelstein 444 Central Park West New York, NY 10025 212-666-4630 (voice) 212-316-1039 (fax) aa...@mindspring.com website: aandhconservation.org -- To send an email to the list, send your msg to pestlist@museumpests.Net To unsubscribe from this list send an email to pestlist@museumpests.net and in the subject put: unsubscribe - no quotes please. You are receiving the Pestlist emails in standard mode. To change to the DIGEST mode send an email to imail...@museumpests.net with this command in the body: set mode digest pestlist Any problems email l...@collectionpests.com or l...@zaks.com
Re: [pestlist] Defrosting
This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Thanks, Barb… The Freezer is unpacked, and for the time being the objects are still in polyethylene pending treatment of the space. I am hoping that the freezing and defrosting caused no damage, but I will certainly report any. My concern is not regarding the actual wooden sculpture but the inlaid and attached metals and any encrusted sacrificial materials. BTW, the two data loggers showed temps of about -35c warming to lower than -20c during defrost cycles. I brought the unit back to room temp over 24 hours at 10 degree increments, and saw no evidence of in-bag condensation. I did however note some ponding of water along the lowest side of the freezer despite leveling it during installation. This points up another reason to carefully heat seal the polyethylene bags, or to use some other comparable method. The shame is that all 300+ pieces are wrapped in tissue paper, and double bagged, but are not bubble wrapped for transport and storage. Neil Carey On Aug 27, 2012, at 11:55 AM, Appelbaum Himmelstein wrote: This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- I believe that many institutions keep the things they've frozen in the bags. Given the use of collections, there may be no good reason to go through the time and trouble of handling things, and the plastic bags will keep bugs out as well as dust and gaseous pollutants, at least for a while. I know that we chronic worriers (conservators, registrars, and collection managers) are always looking for potential damage, but there are a lot of things that aren't as bad as we might think. RH issues often seem troublesome, but when a hygroscopic item takes up most of the space in a plastic bag, the controlling moisture is the moisture content of the item, not the RH of the air. Likewise, I think, with the possibility of thermal shock; it's a highly unlikely problem. It would help us if we could get reassurance about potential problems that , so far, turn out OK. Here's what I think we should do: make a concerted effort to report any damage we have observed on this list, along with reports of large-scale treatments - heat, cold, and anoxia - what kinds of objects were involved, and what the outcome was. Maybe someone can figure out a way to incorporate such a thing on Museumpests.net. I would guess that this dist list includes a large proportion of the people who do this work and who make the effort to examine the things after they have been treated. The information shared in this group is huge, and we should figure out as many ways as possible of making it usable. We need to know as much about good outcomes as bad ones. Barbara Appelbaum On Aug 23, 2012, at 8:49 PM, Neil Carey wrote: This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Since implementing IPM a month ago, we've been successfully freezing our ethnographic collection of mostly wooden African pieces, many with textile, feather, or metal attachments, at -30c. Thanks to the group for all their valuable input. However, I don't recall any discussion about controlling the defrost cycle. Are there any special considerations? Off hand, I can think of the possibility of mold growth if an object is kept double wrapped in polyethylene after defrosting, despite being wrapped in tissue paper. Am I overly paranoid? Just how long should a controlled defrost take? Must the object be removed immediately? If not, how long can it go heat sealed in bags? It's not like anoxic treatment where a piece can just be kept inside its polypropylene bag forever. Any input? Neil Carey -- To send an email to the list, send your msg to pestlist@museumpests.Net To unsubscribe from this list send an email to pestlist@museumpests.net and in the subject put: unsubscribe - no quotes please. You are receiving the Pestlist emails in standard mode. To change to the DIGEST mode send an email to imail...@museumpests.net with this command in the body: set mode digest pestlist Any problems email l...@collectionpests.com or l...@zaks.com Appelbaum Himmelstein 444 Central Park West New York, NY 10025 212-666-4630 (voice) 212-316-1039 (fax) aa...@mindspring.com website: aandhconservation.org
RE: [pestlist] Defrosting
This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Hi Neil. When you remove your package from the freezer, it is best to allow it come up to ambient temperature as slowly as possible. This reduces the thermal shock to the object. Ideally the object should be placed in a refrigerator until it is thawed then move it to the room. I realize that this does not always happen - it depends on your facilities. But the goal should be to bring the objects up to room temperature as slowly as is feasible. You are creating a micro-environment to protect the item. If you have placed your objects in a double layer well sealed plastic you will not have a problem with condensation or see any evidence of localized relative humidity on the piece when you remove it from the freezer. Allow them to come up to the ambient temperature slowly and when they are completely acclimated you can remove them from the plastic. You will not have a mold problem. It is a good idea to examine the object and maintain quarantine until you are sure that the object is pest free. One way to do this is to keep it in a bag for a while (length of time will depend on the life cycle of the pest species). Anoxic is another topic. With this method you are actively removing the oxygen from the bag or space around the object. There are advantages to this method, and there are some things that are best stored and displayed in an anoxic environment. But that is more complicated. For use of anoxia in pest control , take a look at the various strategies on Museum Pest Net http://www.museumpests.net/treatment.asp There is also a fact sheet on bagging for isolation. Good luck! Gretchen -Original Message- From: ad...@museumpests.net [mailto:ad...@museumpests.net] On Behalf Of Neil Carey Sent: Thursday, August 23, 2012 8:50 PM To: pestlist@museumpests.net Subject: [pestlist] Defrosting This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Since implementing IPM a month ago, we've been successfully freezing our ethnographic collection of mostly wooden African pieces, many with textile, feather, or metal attachments, at -30c. Thanks to the group for all their valuable input. However, I don't recall any discussion about controlling the defrost cycle. Are there any special considerations? Off hand, I can think of the possibility of mold growth if an object is kept double wrapped in polyethylene after defrosting, despite being wrapped in tissue paper. Am I overly paranoid? Just how long should a controlled defrost take? Must the object be removed immediately? If not, how long can it go heat sealed in bags? It's not like anoxic treatment where a piece can just be kept inside its polypropylene bag forever. Any input? Neil Carey -- To send an email to the list, send your msg to pestlist@museumpests.Net To unsubscribe from this list send an email to pestlist@museumpests.net and in the subject put: unsubscribe - no quotes please. You are receiving the Pestlist emails in standard mode. To change to the DIGEST mode send an email to imail...@museumpests.net with this command in the body: set mode digest pestlist Any problems email l...@collectionpests.com or l...@zaks.com The information contained in this message and/or attachments is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any system and destroy any copies. Any views expressed in this message are those of the individual sender. -- To send an email to the list, send your msg to pestlist@museumpests.Net To unsubscribe from this list send an email to pestlist@museumpests.net and in the subject put: unsubscribe - no quotes please. You are receiving the Pestlist emails in standard mode. To change to the DIGEST mode send an email to imail...@museumpests.net with this command in the body: set mode digest pestlist Any problems email l...@collectionpests.com or l...@zaks.com
RE: [pestlist] Defrosting
This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Hi all, We routinely treat collections with low temperature at minus 30 degrees C and have had no problems with unloading the freezer and allowing the collections items to come to room temperature - 24 hours minimum to be on the safe side (we do not use a refrigeration step.) Just make sure you keep them wrapped until they come to room temp so any condensation occurs on the wrapping not the object. Best, Emily Emily Kaplan Conservator Smithsonian National Museum of the American Indian Cultural Resources Center 4220 Silver Hill Rd Suitland MD 20746 301.238.1418 fax 301.238.3201 kapl...@si.edu -Original Message- From: ad...@museumpests.net [mailto:ad...@museumpests.net] On Behalf Of Neil Carey Sent: Friday, August 24, 2012 11:19 AM To: pestlist@museumpests.net Subject: Re: [pestlist] Defrosting This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Hi again, So then there is a need to bring objects back to room temp slowly. The rented freezer is getting picked up on Monday, so I'll need to unpack it on Sunday. There is a thermostat on it. I've had it cranked down all the way which has yielded -30c. I can gradually warm it up over time while keeping an eye on the temp. So, my question is, over how long a period is Allow them to come up to the ambient temperature slowly? 5 hours? 24 hours? Neil On Aug 24, 2012, at 10:40 AM, Anderson, Gretchen wrote: This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Hi Neil. When you remove your package from the freezer, it is best to allow it come up to ambient temperature as slowly as possible. This reduces the thermal shock to the object. Ideally the object should be placed in a refrigerator until it is thawed then move it to the room. I realize that this does not always happen - it depends on your facilities. But the goal should be to bring the objects up to room temperature as slowly as is feasible. You are creating a micro-environment to protect the item. If you have placed your objects in a double layer well sealed plastic you will not have a problem with condensation or see any evidence of localized relative humidity on the piece when you remove it from the freezer. Allow them to come up to the ambient temperature slowly and when they are completely acclimated you can remove them from the plastic. You will not have a mold problem. It is a good idea to examine the object and maintain quarantine until you are sure that the object is pest free. One way to do this is to keep it in a bag for a while (length of time will depend on the life cycle of the pest species). Anoxic is another topic. With this method you are actively removing the oxygen from the bag or space around the object. There are advantages to this method, and there are some things that are best stored and displayed in an anoxic environment. But that is more complicated. For use of anoxia in pest control , take a look at the various strategies on Museum Pest Net http://www.museumpests.net/treatment.asp There is also a fact sheet on bagging for isolation. Good luck! Gretchen -Original Message- From: ad...@museumpests.net [mailto:ad...@museumpests.net] On Behalf Of Neil Carey Sent: Thursday, August 23, 2012 8:50 PM To: pestlist@museumpests.net Subject: [pestlist] Defrosting This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Since implementing IPM a month ago, we've been successfully freezing our ethnographic collection of mostly wooden African pieces, many with textile, feather, or metal attachments, at -30c. Thanks to the group for all their valuable input. However, I don't recall any discussion about controlling the defrost cycle. Are there any special considerations? Off hand, I can think of the possibility of mold growth if an object is kept double wrapped in polyethylene after defrosting, despite being wrapped in tissue paper. Am I overly paranoid? Just how long should a controlled defrost take? Must the object be removed immediately? If not, how long can it go heat sealed in bags? It's not like anoxic treatment where a piece can just be kept inside its polypropylene bag forever. Any input? Neil
RE: [pestlist] Defrosting
This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Agreed - that is what I have done for the most part. Both at Science Museum of Minnesota and at the Carnegie Museum of Natural History. While it is usually recommended to stage the thaw through a refrigerator it is often not practical! I think the most important step is to keep the objects wrapped until they are up to room temperature. I have never seen any damage while doing this. -Original Message- From: ad...@museumpests.net [mailto:ad...@museumpests.net] On Behalf Of Kaplan, Emily Sent: Friday, August 24, 2012 12:01 PM To: pestlist@museumpests.net Subject: RE: [pestlist] Defrosting This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Hi all, We routinely treat collections with low temperature at minus 30 degrees C and have had no problems with unloading the freezer and allowing the collections items to come to room temperature - 24 hours minimum to be on the safe side (we do not use a refrigeration step.) Just make sure you keep them wrapped until they come to room temp so any condensation occurs on the wrapping not the object. Best, Emily Emily Kaplan Conservator Smithsonian National Museum of the American Indian Cultural Resources Center 4220 Silver Hill Rd Suitland MD 20746 301.238.1418 fax 301.238.3201 kapl...@si.edu -Original Message- From: ad...@museumpests.net [mailto:ad...@museumpests.net] On Behalf Of Neil Carey Sent: Friday, August 24, 2012 11:19 AM To: pestlist@museumpests.net Subject: Re: [pestlist] Defrosting This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Hi again, So then there is a need to bring objects back to room temp slowly. The rented freezer is getting picked up on Monday, so I'll need to unpack it on Sunday. There is a thermostat on it. I've had it cranked down all the way which has yielded -30c. I can gradually warm it up over time while keeping an eye on the temp. So, my question is, over how long a period is Allow them to come up to the ambient temperature slowly? 5 hours? 24 hours? Neil On Aug 24, 2012, at 10:40 AM, Anderson, Gretchen wrote: This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email. --- Hi Neil. When you remove your package from the freezer, it is best to allow it come up to ambient temperature as slowly as possible. This reduces the thermal shock to the object. Ideally the object should be placed in a refrigerator until it is thawed then move it to the room. I realize that this does not always happen - it depends on your facilities. But the goal should be to bring the objects up to room temperature as slowly as is feasible. You are creating a micro-environment to protect the item. If you have placed your objects in a double layer well sealed plastic you will not have a problem with condensation or see any evidence of localized relative humidity on the piece when you remove it from the freezer. Allow them to come up to the ambient temperature slowly and when they are completely acclimated you can remove them from the plastic. You will not have a mold problem. It is a good idea to examine the object and maintain quarantine until you are sure that the object is pest free. One way to do this is to keep it in a bag for a while (length of time will depend on the life cycle of the pest species). Anoxic is another topic. With this method you are actively removing the oxygen from the bag or space around the object. There are advantages to this method, and there are some things that are best stored and displayed in an anoxic environment. But that is more complicated. For use of anoxia in pest control , take a look at the various strategies on Museum Pest Net http://www.museumpests.net/treatment.asp There is also a fact sheet on bagging for isolation. Good luck! Gretchen -Original Message- From: ad...@museumpests.net [mailto:ad...@museumpests.net] On Behalf Of Neil Carey Sent: Thursday, August 23, 2012 8:50 PM To: pestlist@museumpests.net Subject: [pestlist] Defrosting This is a message from the Museumpests List. To post to this list send it as an email to pestlist@museumpests.net To unsubscribe please look at the footer of this email
