how to prevent frost on freezers? - (Nov/21/2008 )

I really didn't know where to post this so I'll try here:

Does anyone know of a method to prevent frost buildup in freezers?

I have seen products as the following being advertised: http://www.shophometrends.com/product.asp?pn=026052

Do you guys think it total BS?

Best way is not to open the freezer Now actually the best you can do is keep it open for the minimum time possible.keeping it open, while looking for things is what adds to frost buildup. However, everyone using the freezer should follow this rule.
I guess the spray is some kind of alcohol. wouldn't use that on a daily basis. You might find your samples, which were labeled with a marker, all looking the same.

Just what the dude above said. Keep the door open for as short a time as possible.

Why does frost build up? It's because every time you open the door, the cold air (which is heavier than warm air) quickly rushes out and is replaced by warmer air. This is a problem for two reasons:

1-The temperature of the freezer increases. Your samples will warm up, and if the freezer is constantly opened and closed over the course of a day, the freezer won't have the chance to cool the warm air before it loses it all again the next time the door opens. Your -20 can easily become a -5 freezer or even a refrigerator instead of a freezer.

2. Warm air has more moisture than cold air. As warm air cools, the water vapour it carries precipitates out of it onto surfaces in the freezer and forms ice crystals. The more times you open and close the freezer, and the longer you keep the freezer open for at a time, the worse problems you will have with frost.

People used to complain about the amount of frost in one of our lab freezers and blame the freezer, while completely ignoring the fact that they open it all the time, and will stand in front of it with the door open while they look through their boxes. The alarm would be going off and everything, and they'd just shut the alarm off and continue to stand there with the door open. Not only is this bad for frost buildup, it's also bad for everything in the freezer.

We've since rearranged the freezer so everyone knows where everything is inside of it, and the rule is after you remove your box from the freezer, you have to close the door again, and you only open it again once you are ready to put the box back. Having the freezer open for 7 seconds twice is much better than having it open for 45 seconds continuously.

I would recommend that you give your freezer a good defrost, and when you put everything back, make sure it is all well-labelled and organised, then follow the 'keep the door open for as short a time as is humanly possible rule.' It's better for your samples, and better for your freezer.

Ginger

Use old developed sheets of xray film as shelf liners. Two large sheets per shelf will prevent frost buildup on the top of the shelves. Occasional scraping of the front edge is necessary.

You will still need to defrost the freezer (due to buildup on the exposed coils on the bottom of shelves), but this method drastically reduces the frequency.