Connecting to Collections Care

Dear Todd,

I am writing as the co-chair of the MuseumPests Working Group. Thank you for your good question and the opportunity to explain why wrapping items for freezing is important. As you wrote, protecting pieces that are unusually shaped is important to prevent damage during the handling needed to treat the piece. Conducting a low-temp treatment while crated, boxed or wrapped is helpful and the kind of Coroplast box or slat crate you are proposing are good solutions for protecting a piece as it is move around. The reason for wrapping in plastic is different. Double wrapping in plastic sheeting is not needed. However, a single layer of polyethylene plastic, stretch wrap or other barrier is important. When the pieces come out of the freezer they will pass through the dew point as they acclimate back to room temperature. This will cause condensation on the surface (similar to what happens to a cool soda can that you take out of the fridge on a hot summer day). The condensation will form on the exterior surface. So the plastic wrapping is designed to ensure that moisture and wetness do not reach the artwork nor will it damage the inner packing.  If you box/crate and then wrap in plastic you will have two layers of protection from moisture and wetness. So you don't need two layers of plastic.  

There is more information on the museumpests.net website and you are welcome to reach out offline with further questions.

Best,

Rachael

Rachael-

Thankyou so much for this response! -I really appreciate it.  I just want to ask a few follow questions for clarification.

Basically, our freezing system for the vast majority of objects is:

1)  Place object in blueboard box

2)  Place that blueboard box in a poly bag and seal it.

3)  Place that bagged blueboard box in a second poly bag and seal it. 

4)  Object is ready to be frozen.

-If I am understanding you correctly, are you saying that if the object is placed in a box, the second poly bag would be unnecessary?

-Theoretically, would an object in a blueboard box that is placed in a well sealed travel frame ("crate") need any poly wrapping at all since it's now a "box inside a box" (2 layers?)

-I'm not a scientist, so this last question feels hard to explain, but I'll try to describe what I'm wondering about.  It has to do with the frozen object being taken out of the freezer and "passing through the due point" and "condensation forming on the exterior surface".  In theory, doesn't the object itself have an "exterior surface" even while it's inside a box?  Wouldn't the same rules apply to what's inside the box since it contains the same air as what's outside?  Wouldn't there be condensation on any exterior surfaces of whatever is in the bag?

Thankyou so much for any thoughts you might have regarding the follow up questions.

Thanks!

-Todd

Dear Todd,

I am writing as the co-chair of the MuseumPests Working Group. Thank you for your good question and the opportunity to explain why wrapping items for freezing is important. As you wrote, protecting pieces that are unusually shaped is important to prevent damage during the handling needed to treat the piece. Conducting a low-temp treatment while crated, boxed or wrapped is helpful and the kind of Coroplast box or slat crate you are proposing are good solutions for protecting a piece as it is move around. The reason for wrapping in plastic is different. Double wrapping in plastic sheeting is not needed. However, a single layer of polyethylene plastic, stretch wrap or other barrier is important. When the pieces come out of the freezer they will pass through the dew point as they acclimate back to room temperature. This will cause condensation on the surface (similar to what happens to a cool soda can that you take out of the fridge on a hot summer day). The condensation will form on the exterior surface. So the plastic wrapping is designed to ensure that moisture and wetness do not reach the artwork nor will it damage the inner packing.  If you box/crate and then wrap in plastic you will have two layers of protection from moisture and wetness. So you don't need two layers of plastic.  

There is more information on the museumpests.net website and you are welcome to reach out offline with further questions.

Best,

Rachael