Question Components kept in storage boxes

[omegaglory1]

Hi all, I’ve been keeping some of my components in plastic storage containers while renovation is being carried out in my house. I took them out for inspection after a month and noticed they feel cold to the touch and have a mild residue on them, almost like condensation?

Prior to storing, I had wiped my HDD with clorox wipes (just the housing unit, not the pcb). I cleaned the old paste off my cpu with arctic cleaner. They were left overnight to dry before I closed the containers, adding a handful of silica packets to keep things dry.

Could the residue just be the cleaning products I used? Winter has arrived here in the UK and I’m wondering if that’s why the parts feel cold and just a little damp? This has only happened to parts with metal in them.

 

[Deleted member 362816]

How humid is the room they were kept in?

 

[Paperdoc]

If your storage boxes have fairly tight lids - not completely sealed - then slowly whatever the humidity of the room air is, it will try to seep into the box. So, if you put things in during a warmer lower-humidity day and now the temperature is significantly lower, with NO air exchange the air trapped inside the box will have higher humidity - possibly enough to cause slight condensation. Moreover, as the days cool the room humidity may now be much higher, especially on rainy days. On those days, that humidity will seep into the box and contribute to possible condensation on cold days. The way to avoid that is to NOT have the box tightly closed. It needs a few air holes to allow easier and faster air flow in and out. That way the air in the box will almost always be at the SAME humidity as the room, and the same temperature, and you will NOT get condensation inside the box unless you also have condensation all over the room.

We are all accustomed to seeing little bags of silica gel used as moisture grabbers. But the sad truth is that silica gel can bring the humidity in a well-sealed contained very low, BUT is has a VERY LOW Capacity to absorb water vapour before it is saturated and can absorb no more. Analytical Chemistry labs use it in small cooling chambers with small volumes of air to keep dry, and they use a version with a built-in moisture sensitive dye that indicates when the silica gel is saturated. When that happens, the users change it out and bake it in an oven to dry it out for re-use. Those little sacks of gel beads do not show you when they are saturated. Chemists also have other materials for use as drying agents (desiccants) with much higher capacities and not quite so dry a result, but most are somewhat hazardous or messy to use, so silica gel beads are common for small-volume containers. They are safe and convenient, but with low moisture capacity.

 

[omegaglory1]

If your storage boxes have fairly tight lids - not completely sealed - then slowly whatever the humidity of the room air is, it will try to seep into the box. So, if you put things in during a warmer lower-humidity day and now the temperature is significantly lower, with NO air exchange the air trapped inside the box will have higher humidity - possibly enough to cause slight condensation. Moreover, as the days cool the room humidity may now be much higher, especially on rainy days. On those days, that humidity will seep into the box and contribute to possible condensation on cold days. The way to avoid that is to NOT have the box tightly closed. It needs a few air holes to allow easier and faster air flow in and out. That way the air in the box will almost always be at the SAME humidity as the room, and the same temperature, and you will NOT get condensation inside the box unless you also have condensation all over the room.

We are all accustomed to seeing little bags of silica gel used as moisture grabbers. But the sad truth is that silica gel can bring the humidity in a well-sealed contained very low, BUT is has a VERY LOW Capacity to absorb water vapour before it is saturated and can absorb no more. Analytical Chemistry labs use it in small cooling chambers with small volumes of air to keep dry, and they use a version with a built-in moisture sensitive dye that indicates when the silica gel is saturated. When that happens, the users change it out and bake it in an oven to dry it out for re-use. Those little sacks of gel beads do not show you when they are saturated. Chemists also have other materials for use as drying agents (desiccants) with much higher capacities and not quite so dry a result, but most are somewhat hazardous or messy to use, so silica gel beads are common for small-volume containers. They are safe and convenient, but with low moisture capacity.

They’re the Really Useful brand of box, the lids have clamps but aren’t very tight. I think there’s about 2mm of a gap.

I left them open last night and the residue/condensation seems to have disappeared. There’s still a very mild oily film on the HDD, which might be attributed to the Clorox wipes. Benzylkonium chloride and surfactants are the key ingredients in those wipes and do leave a soapy like residue after the water has dried/evaporated. The cpu still has a very mild feeling of a film of oil which could be the Arctic cleaner. I had a graphics card stored in a container as well, the heat sink feels somewhat oily despite only having been wiped with ipa.

My biggest concern is mould developing on my components. However, the musty smell seems to have disappeared after wing allowed to air out and cleaning the container with ipa. I can’t see obvious signs and I’m hoping that mould would have a hard time growing on these materials.

I was doubtful that one or two silica packets would have any real benefit, so from the beginning I made sure to put a generous amount (about a dozen). What puzzles me is that I have containers filled with other items, including fabric, in the same environment and they haven’t shown any dampness or condensation 🤔

 

[Paperdoc]

Comparison to fabrics gets trickier. The computer components you have stored are made of materials that have no affinity for water molecules, and no porous surfaces. So even tiny amounts of condensed water vapour will be solely on the surface in the form of microscopic droplets where they can be "seen" by their effect on light. But the same amount of liquid water on a fabric will NOT be on the surface. Instead, because of the porous construction, it all will be penetrated down among the fibres and not where you can see it. Moreover, many such fabrics are made from fibres with a real affinity for water molecules at the molecular level, so any water on them will NOT be as microscopic droplets that affect light reflection. Instead they will be as individual molecules bonded lightly to particular water-friendly sites on the surfaces of the fibres. In that form their interaction with light has very little impact on the light and does not scatter it to affect what your eyes see.

 

[omegaglory1]

Quick update:

It occurred to me that the smell from the boxes and contents could be the ingredients in the cleaning wipes breaking down. Benzylkonium chloride breaks down into Ammonia, the odour is definitely a stale smell and somewhat closer to sweat and urine! I’m not completely discounting mould/mildew but the smell is different.